tegra: add SPI SLINK driver

Add driver for tegra SPI "SLINK" style driver.  This controller is
similar to the tegra20 SPI "SFLASH" controller.  The difference is
that the SLINK controller is a genernal purpose SPI controller and the
SFLASH controller is special purpose and can only talk to FLASH
devices.  In addition there are potentially many instances of an SLINK
controller on tegra and only a single instance of SFLASH.  Tegra20 is
currently ths only version of tegra that instantiates an SFLASH
controller.

This driver supports basic PIO mode of operation and is configurable
(CONFIG_OF_CONTROL) to be driven off devicetree bindings.  Up to 4
devices per controller may be attached, although typically only a
single chip select line is exposed from tegra per controller so in
reality this is usually limited to 1.

To enable this driver, use CONFIG_TEGRA_SLINK

Signed-off-by: Allen Martin <amartin@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/include/asm/arch-tegra/tegra_slink.h

@@ -0,0 +1,84 @@
+/*
+ * NVIDIA Tegra SPI-SLINK controller
+ *
+ * Copyright 2010-2013 NVIDIA Corporation
+ *
+ * This software may be used and distributed according to the
+ * terms of the GNU Public License, Version 2, incorporated
+ * herein by reference.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * Version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _TEGRA_SLINK_H_
+#define _TEGRA_SLINK_H_
+
+#include <asm/types.h>
+
+struct slink_tegra {
+	u32 command;	/* SLINK_COMMAND_0 register  */
+	u32 command2;	/* SLINK_COMMAND2_0 reg */
+	u32 status;	/* SLINK_STATUS_0 register */
+	u32 reserved;	/* Reserved offset 0C */
+	u32 mas_data;	/* SLINK_MAS_DATA_0 reg */
+	u32 slav_data;	/* SLINK_SLAVE_DATA_0 reg */
+	u32 dma_ctl;	/* SLINK_DMA_CTL_0 register */
+	u32 status2;	/* SLINK_STATUS2_0 reg */
+	u32 rsvd[56];	/* 0x20 to 0xFF reserved */
+	u32 tx_fifo;	/* SLINK_TX_FIFO_0 reg off 100h */
+	u32 rsvd2[31];	/* 0x104 to 0x17F reserved */
+	u32 rx_fifo;	/* SLINK_RX_FIFO_0 reg off 180h */
+};
+
+/* COMMAND */
+#define SLINK_CMD_ENB			(1 << 31)
+#define SLINK_CMD_GO			(1 << 30)
+#define SLINK_CMD_M_S			(1 << 28)
+#define SLINK_CMD_CK_SDA		(1 << 21)
+#define SLINK_CMD_CS_POL		(1 << 13)
+#define SLINK_CMD_CS_VAL		(1 << 12)
+#define SLINK_CMD_CS_SOFT		(1 << 11)
+#define SLINK_CMD_BIT_LENGTH		(1 << 4)
+#define SLINK_CMD_BIT_LENGTH_MASK	0x0000001F
+/* COMMAND2 */
+#define SLINK_CMD2_TXEN			(1 << 30)
+#define SLINK_CMD2_RXEN			(1 << 31)
+#define SLINK_CMD2_SS_EN		(1 << 18)
+#define SLINK_CMD2_SS_EN_SHIFT		18
+#define SLINK_CMD2_SS_EN_MASK		0x000C0000
+#define SLINK_CMD2_CS_ACTIVE_BETWEEN	(1 << 17)
+/* STATUS */
+#define SLINK_STAT_BSY			(1 << 31)
+#define SLINK_STAT_RDY			(1 << 30)
+#define SLINK_STAT_ERR			(1 << 29)
+#define SLINK_STAT_RXF_FLUSH		(1 << 27)
+#define SLINK_STAT_TXF_FLUSH		(1 << 26)
+#define SLINK_STAT_RXF_OVF		(1 << 25)
+#define SLINK_STAT_TXF_UNR		(1 << 24)
+#define SLINK_STAT_RXF_EMPTY		(1 << 23)
+#define SLINK_STAT_RXF_FULL		(1 << 22)
+#define SLINK_STAT_TXF_EMPTY		(1 << 21)
+#define SLINK_STAT_TXF_FULL		(1 << 20)
+#define SLINK_STAT_TXF_OVF		(1 << 19)
+#define SLINK_STAT_RXF_UNR		(1 << 18)
+#define SLINK_STAT_CUR_BLKCNT		(1 << 15)
+/* STATUS2 */
+#define SLINK_STAT2_RXF_FULL_CNT	(1 << 16)
+#define SLINK_STAT2_TXF_FULL_CNT	(1 << 0)
+
+#define SPI_TIMEOUT		1000
+#define TEGRA_SPI_MAX_FREQ	52000000
+
+#endif	/* _TEGRA_SLINK_H_ */

board/nvidia/common/board.c

@@ -131,10 +131,11 @@ int board_init(void)
 #ifdef CONFIG_SPI_UART_SWITCH
 	gpio_config_uart();
 #endif
-#ifdef CONFIG_TEGRA_SPI
+#if defined(CONFIG_TEGRA_SPI) || defined(CONFIG_TEGRA_SLINK)
 	pin_mux_spi();
 	spi_init();
 #endif
+
 #ifdef CONFIG_PWM_TEGRA
 	if (pwm_init(gd->fdt_blob))
 		debug("%s: Failed to init pwm\n", __func__);

drivers/spi/Makefile

@@ -46,6 +46,7 @@ COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
 COBJS-$(CONFIG_SH_SPI) += sh_spi.o
 COBJS-$(CONFIG_FSL_ESPI) += fsl_espi.o
 COBJS-$(CONFIG_TEGRA_SPI) += tegra_spi.o
+COBJS-$(CONFIG_TEGRA_SLINK) += tegra_slink.o
 COBJS-$(CONFIG_XILINX_SPI) += xilinx_spi.o
 
 COBJS	:= $(COBJS-y)

drivers/spi/tegra_slink.c

@@ -0,0 +1,343 @@
+/*
+ * NVIDIA Tegra SPI-SLINK controller
+ *
+ * Copyright (c) 2010-2013 NVIDIA Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <asm/arch/clock.h>
+#include <asm/arch-tegra/clk_rst.h>
+#include <asm/arch-tegra/tegra_slink.h>
+#include <spi.h>
+#include <fdtdec.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct tegra_spi_ctrl {
+	struct slink_tegra *regs;
+	unsigned int freq;
+	unsigned int mode;
+	int periph_id;
+	int valid;
+};
+
+struct tegra_spi_slave {
+	struct spi_slave slave;
+	struct tegra_spi_ctrl *ctrl;
+};
+
+static struct tegra_spi_ctrl spi_ctrls[CONFIG_TEGRA_SLINK_CTRLS];
+
+static inline struct tegra_spi_slave *to_tegra_spi(struct spi_slave *slave)
+{
+	return container_of(slave, struct tegra_spi_slave, slave);
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	if (bus >= CONFIG_TEGRA_SLINK_CTRLS || cs > 3 || !spi_ctrls[bus].valid)
+		return 0;
+	else
+		return 1;
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+		unsigned int max_hz, unsigned int mode)
+{
+	struct tegra_spi_slave *spi;
+
+	debug("%s: bus: %u, cs: %u, max_hz: %u, mode: %u\n", __func__,
+		bus, cs, max_hz, mode);
+
+	if (!spi_cs_is_valid(bus, cs)) {
+		printf("SPI error: unsupported bus %d / chip select %d\n",
+		       bus, cs);
+		return NULL;
+	}
+
+	if (max_hz > TEGRA_SPI_MAX_FREQ) {
+		printf("SPI error: unsupported frequency %d Hz. Max frequency"
+			" is %d Hz\n", max_hz, TEGRA_SPI_MAX_FREQ);
+		return NULL;
+	}
+
+	spi = malloc(sizeof(struct tegra_spi_slave));
+	if (!spi) {
+		printf("SPI error: malloc of SPI structure failed\n");
+		return NULL;
+	}
+	spi->slave.bus = bus;
+	spi->slave.cs = cs;
+	spi->ctrl = &spi_ctrls[bus];
+	if (!spi->ctrl) {
+		printf("SPI error: could not find controller for bus %d\n",
+		       bus);
+		return NULL;
+	}
+
+	if (max_hz < spi->ctrl->freq) {
+		debug("%s: limiting frequency from %u to %u\n", __func__,
+		      spi->ctrl->freq, max_hz);
+		spi->ctrl->freq = max_hz;
+	}
+	spi->ctrl->mode = mode;
+
+	return &spi->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct tegra_spi_slave *spi = to_tegra_spi(slave);
+
+	free(spi);
+}
+
+void spi_init(void)
+{
+	struct tegra_spi_ctrl *ctrl;
+	int i;
+#ifdef CONFIG_OF_CONTROL
+	int node = 0;
+	int count;
+	int node_list[CONFIG_TEGRA_SLINK_CTRLS];
+
+	count = fdtdec_find_aliases_for_id(gd->fdt_blob, "spi",
+					   COMPAT_NVIDIA_TEGRA20_SLINK,
+					   node_list,
+					   CONFIG_TEGRA_SLINK_CTRLS);
+	for (i = 0; i < count; i++) {
+		ctrl = &spi_ctrls[i];
+		node = node_list[i];
+
+		ctrl->regs = (struct slink_tegra *)fdtdec_get_addr(gd->fdt_blob,
+								   node, "reg");
+		if ((fdt_addr_t)ctrl->regs == FDT_ADDR_T_NONE) {
+			debug("%s: no slink register found\n", __func__);
+			continue;
+		}
+		ctrl->freq = fdtdec_get_int(gd->fdt_blob, node,
+					    "spi-max-frequency", 0);
+		if (!ctrl->freq) {
+			debug("%s: no slink max frequency found\n", __func__);
+			continue;
+		}
+
+		ctrl->periph_id = clock_decode_periph_id(gd->fdt_blob, node);
+		if (ctrl->periph_id == PERIPH_ID_NONE) {
+			debug("%s: could not decode periph id\n", __func__);
+			continue;
+		}
+		ctrl->valid = 1;
+
+		debug("%s: found controller at %p, freq = %u, periph_id = %d\n",
+		      __func__, ctrl->regs, ctrl->freq, ctrl->periph_id);
+	}
+#else
+	for (i = 0; i < CONFIG_TEGRA_SLINK_CTRLS; i++) {
+		ctrl = &spi_ctrls[i];
+		u32 base_regs[] = {
+			NV_PA_SLINK1_BASE,
+			NV_PA_SLINK2_BASE,
+			NV_PA_SLINK3_BASE,
+			NV_PA_SLINK4_BASE,
+			NV_PA_SLINK5_BASE,
+			NV_PA_SLINK6_BASE,
+		};
+		int periph_ids[] = {
+			PERIPH_ID_SBC1,
+			PERIPH_ID_SBC2,
+			PERIPH_ID_SBC3,
+			PERIPH_ID_SBC4,
+			PERIPH_ID_SBC5,
+			PERIPH_ID_SBC6,
+		};
+		ctrl->regs = (struct slink_tegra *)base_regs[i];
+		ctrl->freq = TEGRA_SPI_MAX_FREQ;
+		ctrl->periph_id = periph_ids[i];
+		ctrl->valid = 1;
+
+		debug("%s: found controller at %p, freq = %u, periph_id = %d\n",
+		      __func__, ctrl->regs, ctrl->freq, ctrl->periph_id);
+	}
+#endif
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct tegra_spi_slave *spi = to_tegra_spi(slave);
+	struct slink_tegra *regs = spi->ctrl->regs;
+	u32 reg;
+
+	/* Change SPI clock to correct frequency, PLLP_OUT0 source */
+	clock_start_periph_pll(spi->ctrl->periph_id, CLOCK_ID_PERIPH,
+			       spi->ctrl->freq);
+
+	/* Clear stale status here */
+	reg = SLINK_STAT_RDY | SLINK_STAT_RXF_FLUSH | SLINK_STAT_TXF_FLUSH | \
+		SLINK_STAT_RXF_UNR | SLINK_STAT_TXF_OVF;
+	writel(reg, &regs->status);
+	debug("%s: STATUS = %08x\n", __func__, readl(&regs->status));
+
+	/* Set master mode and sw controlled CS */
+	reg = readl(&regs->command);
+	reg |= SLINK_CMD_M_S | SLINK_CMD_CS_SOFT;
+	writel(reg, &regs->command);
+	debug("%s: COMMAND = %08x\n", __func__, readl(&regs->command));
+
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct tegra_spi_slave *spi = to_tegra_spi(slave);
+	struct slink_tegra *regs = spi->ctrl->regs;
+
+	/* CS is negated on Tegra, so drive a 1 to get a 0 */
+	setbits_le32(&regs->command, SLINK_CMD_CS_VAL);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct tegra_spi_slave *spi = to_tegra_spi(slave);
+	struct slink_tegra *regs = spi->ctrl->regs;
+
+	/* CS is negated on Tegra, so drive a 0 to get a 1 */
+	clrbits_le32(&regs->command, SLINK_CMD_CS_VAL);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+		const void *data_out, void *data_in, unsigned long flags)
+{
+	struct tegra_spi_slave *spi = to_tegra_spi(slave);
+	struct slink_tegra *regs = spi->ctrl->regs;
+	u32 reg, tmpdout, tmpdin = 0;
+	const u8 *dout = data_out;
+	u8 *din = data_in;
+	int num_bytes;
+	int ret;
+
+	debug("%s: slave %u:%u dout %p din %p bitlen %u\n",
+	      __func__, slave->bus, slave->cs, dout, din, bitlen);
+	if (bitlen % 8)
+		return -1;
+	num_bytes = bitlen / 8;
+
+	ret = 0;
+
+	reg = readl(&regs->status);
+	writel(reg, &regs->status);	/* Clear all SPI events via R/W */
+	debug("%s entry: STATUS = %08x\n", __func__, reg);
+
+	reg = readl(&regs->status2);
+	writel(reg, &regs->status2);	/* Clear all STATUS2 events via R/W */
+	debug("%s entry: STATUS2 = %08x\n", __func__, reg);
+
+	debug("%s entry: COMMAND = %08x\n", __func__, readl(&regs->command));
+
+	clrsetbits_le32(&regs->command2, SLINK_CMD2_SS_EN_MASK,
+			SLINK_CMD2_TXEN | SLINK_CMD2_RXEN |
+			(slave->cs << SLINK_CMD2_SS_EN_SHIFT));
+	debug("%s entry: COMMAND2 = %08x\n", __func__, readl(&regs->command2));
+
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(slave);
+
+	/* handle data in 32-bit chunks */
+	while (num_bytes > 0) {
+		int bytes;
+		int is_read = 0;
+		int tm, i;
+
+		tmpdout = 0;
+		bytes = (num_bytes > 4) ?  4 : num_bytes;
+
+		if (dout != NULL) {
+			for (i = 0; i < bytes; ++i)
+				tmpdout = (tmpdout << 8) | dout[i];
+			dout += bytes;
+		}
+
+		num_bytes -= bytes;
+
+		clrsetbits_le32(&regs->command, SLINK_CMD_BIT_LENGTH_MASK,
+				bytes * 8 - 1);
+		writel(tmpdout, &regs->tx_fifo);
+		setbits_le32(&regs->command, SLINK_CMD_GO);
+
+		/*
+		 * Wait for SPI transmit FIFO to empty, or to time out.
+		 * The RX FIFO status will be read and cleared last
+		 */
+		for (tm = 0, is_read = 0; tm < SPI_TIMEOUT; ++tm) {
+			u32 status;
+
+			status = readl(&regs->status);
+
+			/* We can exit when we've had both RX and TX activity */
+			if (is_read && (status & SLINK_STAT_TXF_EMPTY))
+				break;
+
+			if ((status & (SLINK_STAT_BSY | SLINK_STAT_RDY)) !=
+					SLINK_STAT_RDY)
+				tm++;
+
+			else if (!(status & SLINK_STAT_RXF_EMPTY)) {
+				tmpdin = readl(&regs->rx_fifo);
+				is_read = 1;
+
+				/* swap bytes read in */
+				if (din != NULL) {
+					for (i = bytes - 1; i >= 0; --i) {
+						din[i] = tmpdin & 0xff;
+						tmpdin >>= 8;
+					}
+					din += bytes;
+				}
+			}
+		}
+
+		if (tm >= SPI_TIMEOUT)
+			ret = tm;
+
+		/* clear ACK RDY, etc. bits */
+		writel(readl(&regs->status), &regs->status);
+	}
+
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(slave);
+
+	debug("%s: transfer ended. Value=%08x, status = %08x\n",
+	      __func__, tmpdin, readl(&regs->status));
+
+	if (ret) {
+		printf("%s: timeout during SPI transfer, tm %d\n",
+		       __func__, ret);
+		return -1;
+	}
+
+	return 0;
+}

include/fdtdec.h

@@ -71,6 +71,7 @@ enum fdt_compat_id {
 	COMPAT_NVIDIA_TEGRA20_PWM,	/* Tegra 2 PWM controller */
 	COMPAT_NVIDIA_TEGRA20_DC,	/* Tegra 2 Display controller */
 	COMPAT_NVIDIA_TEGRA20_SFLASH,	/* Tegra 2 SPI flash controller */
+	COMPAT_NVIDIA_TEGRA20_SLINK,	/* Tegra 2 SPI SLINK controller */
 	COMPAT_SMSC_LAN9215,		/* SMSC 10/100 Ethernet LAN9215 */
 	COMPAT_SAMSUNG_EXYNOS5_SROMC,	/* Exynos5 SROMC */
 	COMPAT_SAMSUNG_S3C2440_I2C,	/* Exynos I2C Controller */

lib/fdtdec.c

@@ -46,6 +46,7 @@ static const char * const compat_names[COMPAT_COUNT] = {
 	COMPAT(NVIDIA_TEGRA20_PWM, "nvidia,tegra20-pwm"),
 	COMPAT(NVIDIA_TEGRA20_DC, "nvidia,tegra20-dc"),
 	COMPAT(NVIDIA_TEGRA20_SFLASH, "nvidia,tegra20-sflash"),
+	COMPAT(NVIDIA_TEGRA20_SLINK, "nvidia,tegra20-slink"),
 	COMPAT(SMSC_LAN9215, "smsc,lan9215"),
 	COMPAT(SAMSUNG_EXYNOS5_SROMC, "samsung,exynos-sromc"),
 	COMPAT(SAMSUNG_S3C2440_I2C, "samsung,s3c2440-i2c"),