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-/* $Id: xdma_channel_sg.c,v 1.6 2003/02/03 19:50:33 moleres Exp $ */
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-/******************************************************************************
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-*
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-* Author: Xilinx, Inc.
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-*
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-*
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-* This program is free software; you can redistribute it and/or modify it
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-* under the terms of the GNU General Public License as published by the
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-* Free Software Foundation; either version 2 of the License, or (at your
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-* option) any later version.
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-*
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-*
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-* XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS" AS A
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-* COURTESY TO YOU. BY PROVIDING THIS DESIGN, CODE, OR INFORMATION AS
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-* ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE, APPLICATION OR STANDARD,
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-* XILINX IS MAKING NO REPRESENTATION THAT THIS IMPLEMENTATION IS FREE
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-* FROM ANY CLAIMS OF INFRINGEMENT, AND YOU ARE RESPONSIBLE FOR OBTAINING
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-* ANY THIRD PARTY RIGHTS YOU MAY REQUIRE FOR YOUR IMPLEMENTATION.
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-* XILINX EXPRESSLY DISCLAIMS ANY WARRANTY WHATSOEVER WITH RESPECT TO
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-* THE ADEQUACY OF THE IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY
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-* WARRANTIES OR REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM
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-* CLAIMS OF INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND
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-* FITNESS FOR A PARTICULAR PURPOSE.
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-*
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-*
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-* Xilinx hardware products are not intended for use in life support
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-* appliances, devices, or systems. Use in such applications is
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-* expressly prohibited.
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-*
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-*
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-* (c) Copyright 2002-2004 Xilinx Inc.
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-* All rights reserved.
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-*
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-*
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-* You should have received a copy of the GNU General Public License along
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-* with this program; if not, write to the Free Software Foundation, Inc.,
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-* 675 Mass Ave, Cambridge, MA 02139, USA.
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-*
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-* FILENAME:
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-*
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-* xdma_channel_sg.c
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-*
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-* DESCRIPTION:
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-*
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-* This file contains the implementation of the XDmaChannel component which is
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-* related to scatter gather operations.
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-*
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-* Scatter Gather Operations
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-*
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-* The DMA channel may support scatter gather operations. A scatter gather
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-* operation automates the DMA channel such that multiple buffers can be
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-* sent or received with minimal software interaction with the hardware. Buffer
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-* descriptors, contained in the XBufDescriptor component, are used by the
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-* scatter gather operations of the DMA channel to describe the buffers to be
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-* processed.
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-*
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-* Scatter Gather List Operations
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-*
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-* A scatter gather list may be supported by each DMA channel. The scatter
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-* gather list allows buffer descriptors to be put into the list by a device
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-* driver which requires scatter gather. The hardware processes the buffer
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-* descriptors which are contained in the list and modifies the buffer
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-* descriptors to reflect the status of the DMA operations. The device driver
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-* is notified by interrupt that specific DMA events occur including scatter
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-* gather events. The device driver removes the completed buffer descriptors
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-* from the scatter gather list to evaluate the status of each DMA operation.
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-*
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-* The scatter gather list is created and buffer descriptors are inserted into
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-* the list. Buffer descriptors are never removed from the list after it's
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-* creation such that a put operation copies from a temporary buffer descriptor
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-* to a buffer descriptor in the list. Get operations don't copy from the list
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-* to a temporary, but return a pointer to the buffer descriptor in the list.
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-* A buffer descriptor in the list may be locked to prevent it from being
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-* overwritten by a put operation. This allows the device driver to get a
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-* descriptor from a scatter gather list and prevent it from being overwritten
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-* until the buffer associated with the buffer descriptor has been processed.
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-*
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-* The get and put functions only operate on the list and are asynchronous from
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-* the hardware which may be using the list of descriptors. This is important
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-* because there are no checks in the get and put functions to ensure that the
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-* hardware has processed the descriptors. This must be handled by the driver
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-* using the DMA scatter gather channel through the use of the other functions.
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-* When a scatter gather operation is started, the start function does ensure
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-* that the descriptor to start has not already been processed by the hardware
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-* and is not the first of a series of descriptors that have not been committed
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-* yet.
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-*
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-* Descriptors are put into the list but not marked as ready to use by the
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-* hardware until a commit operation is done. This allows multiple descriptors
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-* which may contain a single packet of information for a protocol to be
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-* guaranteed not to cause any underflow conditions during transmission. The
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-* hardware design only allows descriptors to cause it to stop after a descriptor
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-* has been processed rather than before it is processed. A series of
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-* descriptors are put into the list followed by a commit operation, or each
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-* descriptor may be commited. A commit operation is performed by changing a
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-* single descriptor, the first of the series of puts, to indicate that the
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-* hardware may now use all descriptors after it. The last descriptor in the
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-* list is always set to cause the hardware to stop after it is processed.
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-*
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-* Typical Scatter Gather Processing
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-*
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-* The following steps illustrate the typical processing to use the
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-* scatter gather features of a DMA channel.
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-*
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-* 1. Create a scatter gather list for the DMA channel which puts empty buffer
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-* descriptors into the list.
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-* 2. Create buffer descriptors which describe the buffers to be filled with
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-* receive data or the buffers which contain data to be sent.
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-* 3. Put buffer descriptors into the DMA channel scatter list such that scatter
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-* gather operations are requested.
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-* 4. Commit the buffer descriptors in the list such that they are ready to be
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-* used by the DMA channel hardware.
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-* 5. Start the scatter gather operations of the DMA channel.
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-* 6. Process any interrupts which occur as a result of the scatter gather
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-* operations or poll the DMA channel to determine the status. This may
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-* be accomplished by getting the packet count for the channel and then
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-* getting the appropriate number of descriptors from the list for that
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-* number of packets.
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-*
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-* Minimizing Interrupts
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-*
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-* The Scatter Gather operating mode is designed to reduce the amount of CPU
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-* throughput necessary to manage the hardware for devices. A key to the CPU
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-* throughput is the number and rate of interrupts that the CPU must service.
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-* Devices with higher data rates can cause larger numbers of interrupts and
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-* higher frequency interrupts. Ideally the number of interrupts can be reduced
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-* by only generating an interrupt when a specific amount of data has been
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-* received from the interface. This design suffers from a lack of interrupts
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-* when the amount of data received is less than the specified amount of data
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-* to generate an interrupt. In order to help minimize the number of interrupts
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-* which the CPU must service, an algorithm referred to as "interrupt coalescing"
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-* is utilized.
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-*
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-* Interrupt Coalescing
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-*
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-* The principle of interrupt coalescing is to wait before generating an
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-* interrupt until a certain number of packets have been received or sent. An
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-* interrupt is also generated if a smaller number of packets have been received
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-* followed by a certain period of time with no packet reception. This is a
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-* trade-off of latency for bandwidth and is accomplished using several
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-* mechanisms of the hardware including a counter for packets received or
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-* transmitted and a packet timer. These two hardware mechanisms work in
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-* combination to allow a reduction in the number of interrupts processed by the
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-* CPU for packet reception.
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-*
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-* Unserviced Packet Count
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-*
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-* The purpose of the packet counter is to count the number of packets received
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-* or transmitted and provide an interrupt when a specific number of packets
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-* have been processed by the hardware. An interrupt is generated whenever the
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-* counter is greater than or equal to the Packet Count Threshold. This counter
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-* contains an accurate count of the number of packets that the hardware has
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-* processed, either received or transmitted, and the software has not serviced.
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-*
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-* The packet counter allows the number of interrupts to be reduced by waiting
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-* to generate an interrupt until enough packets are received. For packet
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-* reception, packet counts of less than the number to generate an interrupt
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-* would not be serviced without the addition of a packet timer. This counter is
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-* continuously updated by the hardware, not latched to the value at the time
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-* the interrupt occurred.
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-*
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-* The packet counter can be used within the interrupt service routine for the
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-* device to reduce the number of interrupts. The interrupt service routine
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-* loops while performing processing for each packet which has been received or
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-* transmitted and decrements the counter by a specified value. At the same time,
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-* the hardware is possibly continuing to receive or transmit more packets such
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-* that the software may choose, based upon the value in the packet counter, to
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-* remain in the interrupt service routine rather than exiting and immediately
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-* returning. This feature should be used with caution as reducing the number of
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-* interrupts is beneficial, but unbounded interrupt processing is not desirable.
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-*
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-* Since the hardware may be incrementing the packet counter simultaneously
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-* with the software decrementing the counter, there is a need for atomic
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-* operations. The hardware ensures that the operation is atomic such that
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-* simultaneous accesses are properly handled.
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-*
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-* Packet Wait Bound
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-*
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-* The purpose of the packet wait bound is to augment the unserviced packet
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-* count. Whenever there is no pending interrupt for the channel and the
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-* unserviced packet count is non-zero, a timer starts counting timeout at the
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-* value contained the the packet wait bound register. If the timeout is
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-* reached, an interrupt is generated such that the software may service the
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-* data which was buffered.
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-*
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-* NOTES:
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-*
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-* Special Test Conditions:
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-*
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-* The scatter gather list processing must be thoroughly tested if changes are
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-* made. Testing should include putting and committing single descriptors and
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-* putting multiple descriptors followed by a single commit. There are some
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-* conditions in the code which handle the exception conditions.
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-*
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-* The Put Pointer points to the next location in the descriptor list to copy
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-* in a new descriptor. The Get Pointer points to the next location in the
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-* list to get a descriptor from. The Get Pointer only allows software to
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-* have a traverse the list after the hardware has finished processing some
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-* number of descriptors. The Commit Pointer points to the descriptor in the
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-* list which is to be committed. It is also used to determine that no
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-* descriptor is waiting to be commited (NULL). The Last Pointer points to
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-* the last descriptor that was put into the list. It typically points
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-* to the previous descriptor to the one pointed to by the Put Pointer.
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-* Comparisons are done between these pointers to determine when the following
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-* special conditions exist.
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-
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-* Single Put And Commit
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-*
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-* The buffer descriptor is ready to be used by the hardware so it is important
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-* for the descriptor to not appear to be waiting to be committed. The commit
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-* pointer is reset when a commit is done indicating there are no descriptors
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-* waiting to be committed. In all cases but this one, the descriptor is
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-* changed to cause the hardware to go to the next descriptor after processing
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-* this one. But in this case, this is the last descriptor in the list such
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-* that it must not be changed.
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-*
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-* 3 Or More Puts And Commit
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-*
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-* A series of 3 or more puts followed by a single commit is different in that
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-* only the 1st descriptor put into the list is changed when the commit is done.
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-* This requires each put starting on the 3rd to change the previous descriptor
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-* so that it allows the hardware to continue to the next descriptor in the list.
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-*
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-* The 1st Put Following A Commit
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-*
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-* The commit caused the commit pointer to be NULL indicating that there are no
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-* descriptors waiting to be committed. It is necessary for the next put to set
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-* the commit pointer so that a commit must follow the put for the hardware to
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-* use the descriptor.
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-*
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-* <pre>
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-* MODIFICATION HISTORY:
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-*
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-* Ver Who Date Changes
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-* ----- ---- -------- ------------------------------------------------------
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-* 1.00a rpm 02/03/03 Removed the XST_DMA_SG_COUNT_EXCEEDED return code
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-* from SetPktThreshold.
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-* </pre>
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-*
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-******************************************************************************/
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-
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-/***************************** Include Files *********************************/
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-
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-#include "xdma_channel.h"
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-#include "xbasic_types.h"
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-#include "xio.h"
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-#include "xbuf_descriptor.h"
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-#include "xstatus.h"
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-
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-/************************** Constant Definitions *****************************/
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-
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-#define XDC_SWCR_SG_ENABLE_MASK 0x80000000UL /* scatter gather enable */
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-
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-/**************************** Type Definitions *******************************/
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-
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-/***************** Macros (Inline Functions) Definitions *********************/
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-
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-/* the following macro copies selected fields of a buffer descriptor to another
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- * buffer descriptor, this was provided by the buffer descriptor component but
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- * was moved here since it is only used internally to this component and since
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- * it does not copy all fields
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- */
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-#define CopyBufferDescriptor(InstancePtr, DestinationPtr) \
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-{ \
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- *((u32 *)DestinationPtr + XBD_CONTROL_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_CONTROL_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_SOURCE_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_SOURCE_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_DESTINATION_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_DESTINATION_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_LENGTH_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_LENGTH_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_STATUS_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_STATUS_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_DEVICE_STATUS_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_DEVICE_STATUS_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_ID_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_ID_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_FLAGS_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_FLAGS_OFFSET); \
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- *((u32 *)DestinationPtr + XBD_RQSTED_LENGTH_OFFSET) = \
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- *((u32 *)InstancePtr + XBD_RQSTED_LENGTH_OFFSET); \
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-}
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-
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-/************************** Variable Definitions *****************************/
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-
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-/************************** Function Prototypes ******************************/
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-
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-/******************************************************************************
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-*
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-* FUNCTION:
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-*
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-* XDmaChannel_SgStart
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-*
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-* DESCRIPTION:
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-*
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-* This function starts a scatter gather operation for a scatter gather
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-* DMA channel. The first buffer descriptor in the buffer descriptor list
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-* will be started with the scatter gather operation. A scatter gather list
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-* should have previously been created for the DMA channel and buffer
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-* descriptors put into the scatter gather list such that there are scatter
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-* operations ready to be performed.
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-*
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-* ARGUMENTS:
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-*
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-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
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-* channel should be configured to use scatter gather in order for this function
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-* to be called.
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-*
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-* RETURN VALUE:
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-*
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-* A status containing XST_SUCCESS if scatter gather was started successfully
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-* for the DMA channel.
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-*
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-* A value of XST_DMA_SG_NO_LIST indicates the scatter gather list has not
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-* been created.
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-*
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-* A value of XST_DMA_SG_LIST_EMPTY indicates scatter gather was not started
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-* because the scatter gather list of the DMA channel does not contain any
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-* buffer descriptors that are ready to be processed by the hardware.
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-*
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-* A value of XST_DMA_SG_IS_STARTED indicates scatter gather was not started
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-* because the scatter gather was not stopped, but was already started.
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-*
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-* A value of XST_DMA_SG_BD_NOT_COMMITTED indicates the buffer descriptor of
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-* scatter gather list which was to be started is not committed to the list.
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-* This status is more likely if this function is being called from an ISR
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-* and non-ISR processing is putting descriptors into the list.
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-*
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-* A value of XST_DMA_SG_NO_DATA indicates that the buffer descriptor of the
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-* scatter gather list which was to be started had already been used by the
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-* hardware for a DMA transfer that has been completed.
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-*
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-* NOTES:
|
|
|
|
-*
|
|
|
|
-* It is the responsibility of the caller to get all the buffer descriptors
|
|
|
|
-* after performing a stop operation and before performing a start operation.
|
|
|
|
-* If buffer descriptors are not retrieved between stop and start operations,
|
|
|
|
-* buffer descriptors may be processed by the hardware more than once.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_SgStart(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- u32 Register;
|
|
|
|
- XBufDescriptor *LastDescriptorPtr;
|
|
|
|
-
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if a scatter gather list has not been created yet, return a status */
|
|
|
|
-
|
|
|
|
- if (InstancePtr->TotalDescriptorCount == 0) {
|
|
|
|
- return XST_DMA_SG_NO_LIST;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* if the scatter gather list exists but is empty then return a status */
|
|
|
|
-
|
|
|
|
- if (XDmaChannel_IsSgListEmpty(InstancePtr)) {
|
|
|
|
- return XST_DMA_SG_LIST_EMPTY;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* if scatter gather is busy for the DMA channel, return a status because
|
|
|
|
- * restarting it could lose data
|
|
|
|
- */
|
|
|
|
-
|
|
|
|
- Register = XIo_In32(InstancePtr->RegBaseAddress + XDC_DMAS_REG_OFFSET);
|
|
|
|
- if (Register & XDC_DMASR_SG_BUSY_MASK) {
|
|
|
|
- return XST_DMA_SG_IS_STARTED;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* get the address of the last buffer descriptor which the DMA hardware
|
|
|
|
- * finished processing
|
|
|
|
- */
|
|
|
|
- LastDescriptorPtr =
|
|
|
|
- (XBufDescriptor *) XIo_In32(InstancePtr->RegBaseAddress +
|
|
|
|
- XDC_BDA_REG_OFFSET);
|
|
|
|
-
|
|
|
|
- /* setup the first buffer descriptor that will be sent when the scatter
|
|
|
|
- * gather channel is enabled, this is only necessary one time since
|
|
|
|
- * the BDA register of the channel maintains the last buffer descriptor
|
|
|
|
- * processed
|
|
|
|
- */
|
|
|
|
- if (LastDescriptorPtr == NULL) {
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_BDA_REG_OFFSET,
|
|
|
|
- (u32) InstancePtr->GetPtr);
|
|
|
|
- } else {
|
|
|
|
- XBufDescriptor *NextDescriptorPtr;
|
|
|
|
-
|
|
|
|
- /* get the next descriptor to be started, if the status indicates it
|
|
|
|
- * hasn't already been used by the h/w, then it's OK to start it,
|
|
|
|
- * s/w sets the status of each descriptor to busy and then h/w clears
|
|
|
|
- * the busy when it is complete
|
|
|
|
- */
|
|
|
|
- NextDescriptorPtr =
|
|
|
|
- XBufDescriptor_GetNextPtr(LastDescriptorPtr);
|
|
|
|
-
|
|
|
|
- if ((XBufDescriptor_GetStatus(NextDescriptorPtr) &
|
|
|
|
- XDC_DMASR_BUSY_MASK) == 0) {
|
|
|
|
- return XST_DMA_SG_NO_DATA;
|
|
|
|
- }
|
|
|
|
- /* don't start the DMA SG channel if the descriptor to be processed
|
|
|
|
- * by h/w is to be committed by the s/w, this function can be called
|
|
|
|
- * such that it interrupts a thread that was putting into the list
|
|
|
|
- */
|
|
|
|
- if (NextDescriptorPtr == InstancePtr->CommitPtr) {
|
|
|
|
- return XST_DMA_SG_BD_NOT_COMMITTED;
|
|
|
|
- }
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* start the scatter gather operation by clearing the stop bit in the
|
|
|
|
- * control register and setting the enable bit in the s/w control register,
|
|
|
|
- * both of these are necessary to cause it to start, right now the order of
|
|
|
|
- * these statements is important, the software control register should be
|
|
|
|
- * set 1st. The other order can cause the CPU to have a loss of sync
|
|
|
|
- * because it cannot read/write the register while the DMA operation is
|
|
|
|
- * running
|
|
|
|
- */
|
|
|
|
-
|
|
|
|
- Register = XIo_In32(InstancePtr->RegBaseAddress + XDC_SWCR_REG_OFFSET);
|
|
|
|
-
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_SWCR_REG_OFFSET,
|
|
|
|
- Register | XDC_SWCR_SG_ENABLE_MASK);
|
|
|
|
-
|
|
|
|
- Register = XIo_In32(InstancePtr->RegBaseAddress + XDC_DMAC_REG_OFFSET);
|
|
|
|
-
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_DMAC_REG_OFFSET,
|
|
|
|
- Register & ~XDC_DMACR_SG_DISABLE_MASK);
|
|
|
|
-
|
|
|
|
- /* indicate the DMA channel scatter gather operation was started
|
|
|
|
- * successfully
|
|
|
|
- */
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_SgStop
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function stops a scatter gather operation for a scatter gather
|
|
|
|
-* DMA channel. This function starts the process of stopping a scatter
|
|
|
|
-* gather operation that is in progress and waits for the stop to be completed.
|
|
|
|
-* Since it waits for the operation to stopped before returning, this function
|
|
|
|
-* could take an amount of time relative to the size of the DMA scatter gather
|
|
|
|
-* operation which is in progress. The scatter gather list of the DMA channel
|
|
|
|
-* is not modified by this function such that starting the scatter gather
|
|
|
|
-* channel after stopping it will cause it to resume. This operation is
|
|
|
|
-* considered to be a graceful stop in that the scatter gather operation
|
|
|
|
-* completes the current buffer descriptor before stopping.
|
|
|
|
-*
|
|
|
|
-* If the interrupt is enabled, an interrupt will be generated when the
|
|
|
|
-* operation is stopped and the caller is responsible for handling the
|
|
|
|
-* interrupt.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* BufDescriptorPtr is also a return value which contains a pointer to the
|
|
|
|
-* buffer descriptor which the scatter gather operation completed when it
|
|
|
|
-* was stopped.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status containing XST_SUCCESS if scatter gather was stopped successfully
|
|
|
|
-* for the DMA channel.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_IS_STOPPED indicates scatter gather was not stoppped
|
|
|
|
-* because the scatter gather is not started, but was already stopped.
|
|
|
|
-*
|
|
|
|
-* BufDescriptorPtr contains a pointer to the buffer descriptor which was
|
|
|
|
-* completed when the operation was stopped.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* This function implements a loop which polls the hardware for an infinite
|
|
|
|
-* amount of time. If the hardware is not operating correctly, this function
|
|
|
|
-* may never return.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_SgStop(XDmaChannel * InstancePtr,
|
|
|
|
- XBufDescriptor ** BufDescriptorPtr)
|
|
|
|
-{
|
|
|
|
- u32 Register;
|
|
|
|
-
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(BufDescriptorPtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* get the contents of the software control register, if scatter gather is not
|
|
|
|
- * enabled (started), then return a status because the disable acknowledge
|
|
|
|
- * would not be generated
|
|
|
|
- */
|
|
|
|
- Register = XIo_In32(InstancePtr->RegBaseAddress + XDC_SWCR_REG_OFFSET);
|
|
|
|
-
|
|
|
|
- if ((Register & XDC_SWCR_SG_ENABLE_MASK) == 0) {
|
|
|
|
- return XST_DMA_SG_IS_STOPPED;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* Ensure the interrupt status for the scatter gather is cleared such
|
|
|
|
- * that this function will wait til the disable has occurred, writing
|
|
|
|
- * a 1 to only that bit in the register will clear only it
|
|
|
|
- */
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_IS_REG_OFFSET,
|
|
|
|
- XDC_IXR_SG_DISABLE_ACK_MASK);
|
|
|
|
-
|
|
|
|
- /* disable scatter gather by writing to the software control register
|
|
|
|
- * without modifying any other bits of the register
|
|
|
|
- */
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_SWCR_REG_OFFSET,
|
|
|
|
- Register & ~XDC_SWCR_SG_ENABLE_MASK);
|
|
|
|
-
|
|
|
|
- /* scatter gather does not disable immediately, but after the current
|
|
|
|
- * buffer descriptor is complete, so wait for the DMA channel to indicate
|
|
|
|
- * the disable is complete
|
|
|
|
- */
|
|
|
|
- do {
|
|
|
|
- Register =
|
|
|
|
- XIo_In32(InstancePtr->RegBaseAddress + XDC_IS_REG_OFFSET);
|
|
|
|
- } while ((Register & XDC_IXR_SG_DISABLE_ACK_MASK) == 0);
|
|
|
|
-
|
|
|
|
- /* Ensure the interrupt status for the scatter gather disable is cleared,
|
|
|
|
- * writing a 1 to only that bit in the register will clear only it
|
|
|
|
- */
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_IS_REG_OFFSET,
|
|
|
|
- XDC_IXR_SG_DISABLE_ACK_MASK);
|
|
|
|
-
|
|
|
|
- /* set the specified buffer descriptor pointer to point to the buffer
|
|
|
|
- * descriptor that the scatter gather DMA channel was processing
|
|
|
|
- */
|
|
|
|
- *BufDescriptorPtr =
|
|
|
|
- (XBufDescriptor *) XIo_In32(InstancePtr->RegBaseAddress +
|
|
|
|
- XDC_BDA_REG_OFFSET);
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_CreateSgList
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function creates a scatter gather list in the DMA channel. A scatter
|
|
|
|
-* gather list consists of a list of buffer descriptors that are available to
|
|
|
|
-* be used for scatter gather operations. Buffer descriptors are put into the
|
|
|
|
-* list to request a scatter gather operation to be performed.
|
|
|
|
-*
|
|
|
|
-* A number of buffer descriptors are created from the specified memory and put
|
|
|
|
-* into a buffer descriptor list as empty buffer descriptors. This function must
|
|
|
|
-* be called before non-empty buffer descriptors may be put into the DMA channel
|
|
|
|
-* to request scatter gather operations.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* MemoryPtr contains a pointer to the memory which is to be used for buffer
|
|
|
|
-* descriptors and must not be cached.
|
|
|
|
-*
|
|
|
|
-* ByteCount contains the number of bytes for the specified memory to be used
|
|
|
|
-* for buffer descriptors.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status contains XST_SUCCESS if the scatter gather list was successfully
|
|
|
|
-* created.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_LIST_EXISTS indicates that the scatter gather list
|
|
|
|
-* was not created because the list has already been created.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_CreateSgList(XDmaChannel * InstancePtr,
|
|
|
|
- u32 * MemoryPtr, u32 ByteCount)
|
|
|
|
-{
|
|
|
|
- XBufDescriptor *BufferDescriptorPtr = (XBufDescriptor *) MemoryPtr;
|
|
|
|
- XBufDescriptor *PreviousDescriptorPtr = NULL;
|
|
|
|
- XBufDescriptor *StartOfListPtr = BufferDescriptorPtr;
|
|
|
|
- u32 UsedByteCount;
|
|
|
|
-
|
|
|
|
- /* assert to verify valid input arguments, alignment for those
|
|
|
|
- * arguments that have alignment restrictions, and at least enough
|
|
|
|
- * memory for one buffer descriptor
|
|
|
|
- */
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(MemoryPtr != NULL);
|
|
|
|
- XASSERT_NONVOID(((u32) MemoryPtr & 3) == 0);
|
|
|
|
- XASSERT_NONVOID(ByteCount != 0);
|
|
|
|
- XASSERT_NONVOID(ByteCount >= sizeof (XBufDescriptor));
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if the scatter gather list has already been created, then return
|
|
|
|
- * with a status
|
|
|
|
- */
|
|
|
|
- if (InstancePtr->TotalDescriptorCount != 0) {
|
|
|
|
- return XST_DMA_SG_LIST_EXISTS;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* loop thru the specified memory block and create as many buffer
|
|
|
|
- * descriptors as possible putting each into the list which is
|
|
|
|
- * implemented as a ring buffer, make sure not to use any memory which
|
|
|
|
- * is not large enough for a complete buffer descriptor
|
|
|
|
- */
|
|
|
|
- UsedByteCount = 0;
|
|
|
|
- while ((UsedByteCount + sizeof (XBufDescriptor)) <= ByteCount) {
|
|
|
|
- /* setup a pointer to the next buffer descriptor in the memory and
|
|
|
|
- * update # of used bytes to know when all of memory is used
|
|
|
|
- */
|
|
|
|
- BufferDescriptorPtr = (XBufDescriptor *) ((u32) MemoryPtr +
|
|
|
|
- UsedByteCount);
|
|
|
|
-
|
|
|
|
- /* initialize the new buffer descriptor such that it doesn't contain
|
|
|
|
- * garbage which could be used by the DMA hardware
|
|
|
|
- */
|
|
|
|
- XBufDescriptor_Initialize(BufferDescriptorPtr);
|
|
|
|
-
|
|
|
|
- /* if this is not the first buffer descriptor to be created,
|
|
|
|
- * then link it to the last created buffer descriptor
|
|
|
|
- */
|
|
|
|
- if (PreviousDescriptorPtr != NULL) {
|
|
|
|
- XBufDescriptor_SetNextPtr(PreviousDescriptorPtr,
|
|
|
|
- BufferDescriptorPtr);
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* always keep a pointer to the last created buffer descriptor such
|
|
|
|
- * that they can be linked together in the ring buffer
|
|
|
|
- */
|
|
|
|
- PreviousDescriptorPtr = BufferDescriptorPtr;
|
|
|
|
-
|
|
|
|
- /* keep a count of the number of descriptors in the list to allow
|
|
|
|
- * error processing to be performed
|
|
|
|
- */
|
|
|
|
- InstancePtr->TotalDescriptorCount++;
|
|
|
|
-
|
|
|
|
- UsedByteCount += sizeof (XBufDescriptor);
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* connect the last buffer descriptor created and inserted in the list
|
|
|
|
- * to the first such that a ring buffer is created
|
|
|
|
- */
|
|
|
|
- XBufDescriptor_SetNextPtr(BufferDescriptorPtr, StartOfListPtr);
|
|
|
|
-
|
|
|
|
- /* initialize the ring buffer to indicate that there are no
|
|
|
|
- * buffer descriptors in the list which point to valid data buffers
|
|
|
|
- */
|
|
|
|
- InstancePtr->PutPtr = BufferDescriptorPtr;
|
|
|
|
- InstancePtr->GetPtr = BufferDescriptorPtr;
|
|
|
|
- InstancePtr->CommitPtr = NULL;
|
|
|
|
- InstancePtr->LastPtr = BufferDescriptorPtr;
|
|
|
|
- InstancePtr->ActiveDescriptorCount = 0;
|
|
|
|
-
|
|
|
|
- /* indicate the scatter gather list was successfully created */
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_IsSgListEmpty
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function determines if the scatter gather list of a DMA channel is
|
|
|
|
-* empty with regard to buffer descriptors which are pointing to buffers to be
|
|
|
|
-* used for scatter gather operations.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A value of TRUE if the scatter gather list is empty, otherwise a value of
|
|
|
|
-* FALSE.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-u32
|
|
|
|
-XDmaChannel_IsSgListEmpty(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- /* assert to verify valid input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if the number of descriptors which are being used in the list is zero
|
|
|
|
- * then the list is empty
|
|
|
|
- */
|
|
|
|
- return (InstancePtr->ActiveDescriptorCount == 0);
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_PutDescriptor
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function puts a buffer descriptor into the DMA channel scatter
|
|
|
|
-* gather list. A DMA channel maintains a list of buffer descriptors which are
|
|
|
|
-* to be processed. This function puts the specified buffer descriptor
|
|
|
|
-* at the next location in the list. Note that since the list is already intact,
|
|
|
|
-* the information in the parameter is copied into the list (rather than modify
|
|
|
|
-* list pointers on the fly).
|
|
|
|
-*
|
|
|
|
-* After buffer descriptors are put into the list, they must also be committed
|
|
|
|
-* by calling another function. This allows multiple buffer descriptors which
|
|
|
|
-* span a single packet to be put into the list while preventing the hardware
|
|
|
|
-* from starting the first buffer descriptor of the packet.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* BufferDescriptorPtr is a pointer to the buffer descriptor to be put into
|
|
|
|
-* the next available location of the scatter gather list.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status which indicates XST_SUCCESS if the buffer descriptor was
|
|
|
|
-* successfully put into the scatter gather list.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_NO_LIST indicates the scatter gather list has not
|
|
|
|
-* been created.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_LIST_FULL indicates the buffer descriptor was not
|
|
|
|
-* put into the list because the list was full.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_BD_LOCKED indicates the buffer descriptor was not
|
|
|
|
-* put into the list because the buffer descriptor in the list which is to
|
|
|
|
-* be overwritten was locked. A locked buffer descriptor indicates the higher
|
|
|
|
-* layered software is still using the buffer descriptor.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* It is necessary to create a scatter gather list for a DMA channel before
|
|
|
|
-* putting buffer descriptors into it.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_PutDescriptor(XDmaChannel * InstancePtr,
|
|
|
|
- XBufDescriptor * BufferDescriptorPtr)
|
|
|
|
-{
|
|
|
|
- u32 Control;
|
|
|
|
-
|
|
|
|
- /* assert to verify valid input arguments and alignment for those
|
|
|
|
- * arguments that have alignment restrictions
|
|
|
|
- */
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(BufferDescriptorPtr != NULL);
|
|
|
|
- XASSERT_NONVOID(((u32) BufferDescriptorPtr & 3) == 0);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if a scatter gather list has not been created yet, return a status */
|
|
|
|
-
|
|
|
|
- if (InstancePtr->TotalDescriptorCount == 0) {
|
|
|
|
- return XST_DMA_SG_NO_LIST;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* if the list is full because all descriptors are pointing to valid
|
|
|
|
- * buffers, then indicate an error, this code assumes no list or an
|
|
|
|
- * empty list is detected above
|
|
|
|
- */
|
|
|
|
- if (InstancePtr->ActiveDescriptorCount ==
|
|
|
|
- InstancePtr->TotalDescriptorCount) {
|
|
|
|
- return XST_DMA_SG_LIST_FULL;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* if the buffer descriptor in the list which is to be overwritten is
|
|
|
|
- * locked, then don't overwrite it and return a status
|
|
|
|
- */
|
|
|
|
- if (XBufDescriptor_IsLocked(InstancePtr->PutPtr)) {
|
|
|
|
- return XST_DMA_SG_BD_LOCKED;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* set the scatter gather stop bit in the control word of the descriptor
|
|
|
|
- * to cause the h/w to stop after it processes this descriptor since it
|
|
|
|
- * will be the last in the list
|
|
|
|
- */
|
|
|
|
- Control = XBufDescriptor_GetControl(BufferDescriptorPtr);
|
|
|
|
- XBufDescriptor_SetControl(BufferDescriptorPtr,
|
|
|
|
- Control | XDC_DMACR_SG_DISABLE_MASK);
|
|
|
|
-
|
|
|
|
- /* set both statuses in the descriptor so we tell if they are updated with
|
|
|
|
- * the status of the transfer, the hardware should change the busy in the
|
|
|
|
- * DMA status to be false when it completes
|
|
|
|
- */
|
|
|
|
- XBufDescriptor_SetStatus(BufferDescriptorPtr, XDC_DMASR_BUSY_MASK);
|
|
|
|
- XBufDescriptor_SetDeviceStatus(BufferDescriptorPtr, 0);
|
|
|
|
-
|
|
|
|
- /* copy the descriptor into the next position in the list so it's ready to
|
|
|
|
- * be used by the h/w, this assumes the descriptor in the list prior to this
|
|
|
|
- * one still has the stop bit in the control word set such that the h/w
|
|
|
|
- * use this one yet
|
|
|
|
- */
|
|
|
|
- CopyBufferDescriptor(BufferDescriptorPtr, InstancePtr->PutPtr);
|
|
|
|
-
|
|
|
|
- /* only the last in the list and the one to be committed have scatter gather
|
|
|
|
- * disabled in the control word, a commit requires only one descriptor
|
|
|
|
- * to be changed, when # of descriptors to commit > 2 all others except the
|
|
|
|
- * 1st and last have scatter gather enabled
|
|
|
|
- */
|
|
|
|
- if ((InstancePtr->CommitPtr != InstancePtr->LastPtr) &&
|
|
|
|
- (InstancePtr->CommitPtr != NULL)) {
|
|
|
|
- Control = XBufDescriptor_GetControl(InstancePtr->LastPtr);
|
|
|
|
- XBufDescriptor_SetControl(InstancePtr->LastPtr,
|
|
|
|
- Control & ~XDC_DMACR_SG_DISABLE_MASK);
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* update the list data based upon putting a descriptor into the list,
|
|
|
|
- * these operations must be last
|
|
|
|
- */
|
|
|
|
- InstancePtr->ActiveDescriptorCount++;
|
|
|
|
-
|
|
|
|
- /* only update the commit pointer if it is not already active, this allows
|
|
|
|
- * it to be deactivated after every commit such that a single descriptor
|
|
|
|
- * which is committed does not appear to be waiting to be committed
|
|
|
|
- */
|
|
|
|
- if (InstancePtr->CommitPtr == NULL) {
|
|
|
|
- InstancePtr->CommitPtr = InstancePtr->LastPtr;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* these updates MUST BE LAST after the commit pointer update in order for
|
|
|
|
- * the commit pointer to track the correct descriptor to be committed
|
|
|
|
- */
|
|
|
|
- InstancePtr->LastPtr = InstancePtr->PutPtr;
|
|
|
|
- InstancePtr->PutPtr = XBufDescriptor_GetNextPtr(InstancePtr->PutPtr);
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_CommitPuts
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function commits the buffer descriptors which have been put into the
|
|
|
|
-* scatter list for the DMA channel since the last commit operation was
|
|
|
|
-* performed. This enables the calling functions to put several buffer
|
|
|
|
-* descriptors into the list (e.g.,a packet's worth) before allowing the scatter
|
|
|
|
-* gather operations to start. This prevents the DMA channel hardware from
|
|
|
|
-* starting to use the buffer descriptors in the list before they are ready
|
|
|
|
-* to be used (multiple buffer descriptors for a single packet).
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status indicating XST_SUCCESS if the buffer descriptors of the list were
|
|
|
|
-* successfully committed.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_NOTHING_TO_COMMIT indicates that the buffer descriptors
|
|
|
|
-* were not committed because there was nothing to commit in the list. All the
|
|
|
|
-* buffer descriptors which are in the list are commited.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_CommitPuts(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if the buffer descriptor to be committed is already committed or
|
|
|
|
- * the list is empty (none have been put in), then indicate an error
|
|
|
|
- */
|
|
|
|
- if ((InstancePtr->CommitPtr == NULL) ||
|
|
|
|
- XDmaChannel_IsSgListEmpty(InstancePtr)) {
|
|
|
|
- return XST_DMA_SG_NOTHING_TO_COMMIT;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* last descriptor in the list must have scatter gather disabled so the end
|
|
|
|
- * of the list is hit by h/w, if descriptor to commit is not last in list,
|
|
|
|
- * commit descriptors by enabling scatter gather in the descriptor
|
|
|
|
- */
|
|
|
|
- if (InstancePtr->CommitPtr != InstancePtr->LastPtr) {
|
|
|
|
- u32 Control;
|
|
|
|
-
|
|
|
|
- Control = XBufDescriptor_GetControl(InstancePtr->CommitPtr);
|
|
|
|
- XBufDescriptor_SetControl(InstancePtr->CommitPtr, Control &
|
|
|
|
- ~XDC_DMACR_SG_DISABLE_MASK);
|
|
|
|
- }
|
|
|
|
- /* Update the commit pointer to indicate that there is nothing to be
|
|
|
|
- * committed, this state is used by start processing to know that the
|
|
|
|
- * buffer descriptor to start is not waiting to be committed
|
|
|
|
- */
|
|
|
|
- InstancePtr->CommitPtr = NULL;
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_GetDescriptor
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function gets a buffer descriptor from the scatter gather list of the
|
|
|
|
-* DMA channel. The buffer descriptor is retrieved from the scatter gather list
|
|
|
|
-* and the scatter gather list is updated to not include the retrieved buffer
|
|
|
|
-* descriptor. This is typically done after a scatter gather operation
|
|
|
|
-* completes indicating that a data buffer has been successfully sent or data
|
|
|
|
-* has been received into the data buffer. The purpose of this function is to
|
|
|
|
-* allow the device using the scatter gather operation to get the results of the
|
|
|
|
-* operation.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* BufDescriptorPtr is a pointer to a pointer to the buffer descriptor which
|
|
|
|
-* was retrieved from the list. The buffer descriptor is not really removed
|
|
|
|
-* from the list, but it is changed to a state such that the hardware will not
|
|
|
|
-* use it again until it is put into the scatter gather list of the DMA channel.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status indicating XST_SUCCESS if a buffer descriptor was retrieved from
|
|
|
|
-* the scatter gather list of the DMA channel.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_NO_LIST indicates the scatter gather list has not
|
|
|
|
-* been created.
|
|
|
|
-*
|
|
|
|
-* A value of XST_DMA_SG_LIST_EMPTY indicates no buffer descriptor was
|
|
|
|
-* retrieved from the list because there are no buffer descriptors to be
|
|
|
|
-* processed in the list.
|
|
|
|
-*
|
|
|
|
-* BufDescriptorPtr is updated to point to the buffer descriptor which was
|
|
|
|
-* retrieved from the list if the status indicates success.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_GetDescriptor(XDmaChannel * InstancePtr,
|
|
|
|
- XBufDescriptor ** BufDescriptorPtr)
|
|
|
|
-{
|
|
|
|
- u32 Control;
|
|
|
|
-
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(BufDescriptorPtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if a scatter gather list has not been created yet, return a status */
|
|
|
|
-
|
|
|
|
- if (InstancePtr->TotalDescriptorCount == 0) {
|
|
|
|
- return XST_DMA_SG_NO_LIST;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* if the buffer descriptor list is empty, then indicate an error */
|
|
|
|
-
|
|
|
|
- if (XDmaChannel_IsSgListEmpty(InstancePtr)) {
|
|
|
|
- return XST_DMA_SG_LIST_EMPTY;
|
|
|
|
- }
|
|
|
|
-
|
|
|
|
- /* retrieve the next buffer descriptor which is ready to be processed from
|
|
|
|
- * the buffer descriptor list for the DMA channel, set the control word
|
|
|
|
- * such that hardware will stop after the descriptor has been processed
|
|
|
|
- */
|
|
|
|
- Control = XBufDescriptor_GetControl(InstancePtr->GetPtr);
|
|
|
|
- XBufDescriptor_SetControl(InstancePtr->GetPtr,
|
|
|
|
- Control | XDC_DMACR_SG_DISABLE_MASK);
|
|
|
|
-
|
|
|
|
- /* set the input argument, which is also an output, to point to the
|
|
|
|
- * buffer descriptor which is to be retrieved from the list
|
|
|
|
- */
|
|
|
|
- *BufDescriptorPtr = InstancePtr->GetPtr;
|
|
|
|
-
|
|
|
|
- /* update the pointer of the DMA channel to reflect the buffer descriptor
|
|
|
|
- * was retrieved from the list by setting it to the next buffer descriptor
|
|
|
|
- * in the list and indicate one less descriptor in the list now
|
|
|
|
- */
|
|
|
|
- InstancePtr->GetPtr = XBufDescriptor_GetNextPtr(InstancePtr->GetPtr);
|
|
|
|
- InstancePtr->ActiveDescriptorCount--;
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/*********************** Interrupt Collescing Functions **********************/
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_GetPktCount
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function returns the value of the unserviced packet count register of
|
|
|
|
-* the DMA channel. This count represents the number of packets that have been
|
|
|
|
-* sent or received by the hardware, but not processed by software.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* The unserviced packet counter register contents for the DMA channel.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-u32
|
|
|
|
-XDmaChannel_GetPktCount(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* get the unserviced packet count from the register and return it */
|
|
|
|
-
|
|
|
|
- return XIo_In32(InstancePtr->RegBaseAddress + XDC_UPC_REG_OFFSET);
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_DecrementPktCount
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function decrements the value of the unserviced packet count register.
|
|
|
|
-* This informs the hardware that the software has processed a packet. The
|
|
|
|
-* unserviced packet count register may only be decremented by one in the
|
|
|
|
-* hardware.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-void
|
|
|
|
-XDmaChannel_DecrementPktCount(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- u32 Register;
|
|
|
|
-
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_VOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_VOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* if the unserviced packet count register can be decremented (rather
|
|
|
|
- * than rolling over) decrement it by writing a 1 to the register,
|
|
|
|
- * this is the only valid write to the register as it serves as an
|
|
|
|
- * acknowledge that a packet was handled by the software
|
|
|
|
- */
|
|
|
|
- Register = XIo_In32(InstancePtr->RegBaseAddress + XDC_UPC_REG_OFFSET);
|
|
|
|
- if (Register > 0) {
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_UPC_REG_OFFSET,
|
|
|
|
- 1UL);
|
|
|
|
- }
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_SetPktThreshold
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function sets the value of the packet count threshold register of the
|
|
|
|
-* DMA channel. It reflects the number of packets that must be sent or
|
|
|
|
-* received before generating an interrupt. This value helps implement
|
|
|
|
-* a concept called "interrupt coalescing", which is used to reduce the number
|
|
|
|
-* of interrupts from devices with high data rates.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* Threshold is the value that is written to the threshold register of the
|
|
|
|
-* DMA channel.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* A status containing XST_SUCCESS if the packet count threshold was
|
|
|
|
-* successfully set.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* The packet threshold could be set to larger than the number of descriptors
|
|
|
|
-* allocated to the DMA channel. In this case, the wait bound will take over
|
|
|
|
-* and always indicate data arrival. There was a check in this function that
|
|
|
|
-* returned an error if the treshold was larger than the number of descriptors,
|
|
|
|
-* but that was removed because users would then have to set the threshold
|
|
|
|
-* only after they set descriptor space, which is an order dependency that
|
|
|
|
-* caused confustion.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-XStatus
|
|
|
|
-XDmaChannel_SetPktThreshold(XDmaChannel * InstancePtr, u8 Threshold)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments, don't assert the threshold since
|
|
|
|
- * it's range is unknown
|
|
|
|
- */
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* set the packet count threshold in the register such that an interrupt
|
|
|
|
- * may be generated, if enabled, when the packet count threshold is
|
|
|
|
- * reached or exceeded
|
|
|
|
- */
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_PCT_REG_OFFSET,
|
|
|
|
- (u32) Threshold);
|
|
|
|
-
|
|
|
|
- /* indicate the packet count threshold was successfully set */
|
|
|
|
-
|
|
|
|
- return XST_SUCCESS;
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_GetPktThreshold
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function gets the value of the packet count threshold register of the
|
|
|
|
-* DMA channel. This value reflects the number of packets that must be sent or
|
|
|
|
-* received before generating an interrupt. This value helps implement a concept
|
|
|
|
-* called "interrupt coalescing", which is used to reduce the number of
|
|
|
|
-* interrupts from devices with high data rates.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* The packet threshold register contents for the DMA channel and is a value in
|
|
|
|
-* the range 0 - 1023. A value of 0 indicates the packet wait bound timer is
|
|
|
|
-* disabled.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-u8
|
|
|
|
-XDmaChannel_GetPktThreshold(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* get the packet count threshold from the register and return it,
|
|
|
|
- * since only 8 bits are used, cast it to return only those bits */
|
|
|
|
-
|
|
|
|
- return (u8) XIo_In32(InstancePtr->RegBaseAddress + XDC_PCT_REG_OFFSET);
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_SetPktWaitBound
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function sets the value of the packet wait bound register of the
|
|
|
|
-* DMA channel. This value reflects the timer value used to trigger an
|
|
|
|
-* interrupt when not enough packets have been received to reach the packet
|
|
|
|
-* count threshold.
|
|
|
|
-*
|
|
|
|
-* The timer is in millisecond units with +/- 33% accuracy.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* WaitBound is the value, in milliseconds, to be stored in the wait bound
|
|
|
|
-* register of the DMA channel and is a value in the range 0 - 1023. A value
|
|
|
|
-* of 0 disables the packet wait bound timer.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-void
|
|
|
|
-XDmaChannel_SetPktWaitBound(XDmaChannel * InstancePtr, u32 WaitBound)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_VOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_VOID(WaitBound < 1024);
|
|
|
|
- XASSERT_VOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* set the packet wait bound in the register such that interrupt may be
|
|
|
|
- * generated, if enabled, when packets have not been handled for a specific
|
|
|
|
- * amount of time
|
|
|
|
- */
|
|
|
|
- XIo_Out32(InstancePtr->RegBaseAddress + XDC_PWB_REG_OFFSET, WaitBound);
|
|
|
|
-}
|
|
|
|
-
|
|
|
|
-/******************************************************************************
|
|
|
|
-*
|
|
|
|
-* FUNCTION:
|
|
|
|
-*
|
|
|
|
-* XDmaChannel_GetPktWaitBound
|
|
|
|
-*
|
|
|
|
-* DESCRIPTION:
|
|
|
|
-*
|
|
|
|
-* This function gets the value of the packet wait bound register of the
|
|
|
|
-* DMA channel. This value contains the timer value used to trigger an
|
|
|
|
-* interrupt when not enough packets have been received to reach the packet
|
|
|
|
-* count threshold.
|
|
|
|
-*
|
|
|
|
-* The timer is in millisecond units with +/- 33% accuracy.
|
|
|
|
-*
|
|
|
|
-* ARGUMENTS:
|
|
|
|
-*
|
|
|
|
-* InstancePtr contains a pointer to the DMA channel to operate on. The DMA
|
|
|
|
-* channel should be configured to use scatter gather in order for this function
|
|
|
|
-* to be called.
|
|
|
|
-*
|
|
|
|
-* RETURN VALUE:
|
|
|
|
-*
|
|
|
|
-* The packet wait bound register contents for the DMA channel.
|
|
|
|
-*
|
|
|
|
-* NOTES:
|
|
|
|
-*
|
|
|
|
-* None.
|
|
|
|
-*
|
|
|
|
-******************************************************************************/
|
|
|
|
-u32
|
|
|
|
-XDmaChannel_GetPktWaitBound(XDmaChannel * InstancePtr)
|
|
|
|
-{
|
|
|
|
- /* assert to verify input arguments */
|
|
|
|
-
|
|
|
|
- XASSERT_NONVOID(InstancePtr != NULL);
|
|
|
|
- XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
|
|
|
|
-
|
|
|
|
- /* get the packet wait bound from the register and return it */
|
|
|
|
-
|
|
|
|
- return XIo_In32(InstancePtr->RegBaseAddress + XDC_PWB_REG_OFFSET);
|
|
|
|
-}
|
|
|