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@@ -0,0 +1,481 @@
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+/*
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+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation, version 2.
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+ *
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+ * This program is distributed in the hope that it will be useful, but
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+ * WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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+ * NON INFRINGEMENT. See the GNU General Public License for
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+ * more details.
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+ *
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+ * SPI Flash ROM driver
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+ *
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+ * This source code is derived from code provided in "Linux Device
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+ * Drivers, Third Edition", by Jonathan Corbet, Alessandro Rubini, and
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+ * Greg Kroah-Hartman, published by O'Reilly Media, Inc.
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+ */
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+
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+#include <linux/module.h>
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+#include <linux/moduleparam.h>
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+#include <linux/init.h>
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+#include <linux/kernel.h> /* printk() */
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+#include <linux/slab.h> /* kmalloc() */
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+#include <linux/fs.h> /* everything... */
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+#include <linux/errno.h> /* error codes */
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+#include <linux/types.h> /* size_t */
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+#include <linux/proc_fs.h>
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+#include <linux/fcntl.h> /* O_ACCMODE */
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+#include <linux/aio.h>
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+#include <linux/pagemap.h>
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+#include <linux/hugetlb.h>
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+#include <linux/uaccess.h>
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+#include <linux/platform_device.h>
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+#include <hv/hypervisor.h>
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+#include <linux/ioctl.h>
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+#include <linux/cdev.h>
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+#include <linux/delay.h>
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+#include <hv/drv_srom_intf.h>
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+
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+/*
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+ * Size of our hypervisor I/O requests. We break up large transfers
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+ * so that we don't spend large uninterrupted spans of time in the
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+ * hypervisor. Erasing an SROM sector takes a significant fraction of
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+ * a second, so if we allowed the user to, say, do one I/O to write the
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+ * entire ROM, we'd get soft lockup timeouts, or worse.
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+ */
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+#define SROM_CHUNK_SIZE ((size_t)4096)
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+
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+/*
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+ * When hypervisor is busy (e.g. erasing), poll the status periodically.
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+ */
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+
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+/*
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+ * Interval to poll the state in msec
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+ */
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+#define SROM_WAIT_TRY_INTERVAL 20
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+
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+/*
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+ * Maximum times to poll the state
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+ */
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+#define SROM_MAX_WAIT_TRY_TIMES 1000
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+
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+struct srom_dev {
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+ int hv_devhdl; /* Handle for hypervisor device */
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+ u32 total_size; /* Size of this device */
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+ u32 sector_size; /* Size of a sector */
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+ u32 page_size; /* Size of a page */
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+ struct mutex lock; /* Allow only one accessor at a time */
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+};
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+
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+static int srom_major; /* Dynamic major by default */
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+module_param(srom_major, int, 0);
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+MODULE_AUTHOR("Tilera Corporation");
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+MODULE_LICENSE("GPL");
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+
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+static int srom_devs; /* Number of SROM partitions */
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+static struct cdev srom_cdev;
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+static struct class *srom_class;
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+static struct srom_dev *srom_devices;
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+
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+/*
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+ * Handle calling the hypervisor and managing EAGAIN/EBUSY.
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+ */
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+
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+static ssize_t _srom_read(int hv_devhdl, void *buf,
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+ loff_t off, size_t count)
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+{
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+ int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
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+ for (;;) {
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+ retval = hv_dev_pread(hv_devhdl, 0, (HV_VirtAddr)buf,
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+ count, off);
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+ if (retval >= 0)
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+ return retval;
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+ if (retval == HV_EAGAIN)
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+ continue;
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+ if (retval == HV_EBUSY && --retries > 0) {
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+ msleep(SROM_WAIT_TRY_INTERVAL);
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+ continue;
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+ }
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+ pr_err("_srom_read: error %d\n", retval);
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+ return -EIO;
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+ }
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+}
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+
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+static ssize_t _srom_write(int hv_devhdl, const void *buf,
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+ loff_t off, size_t count)
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+{
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+ int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
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+ for (;;) {
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+ retval = hv_dev_pwrite(hv_devhdl, 0, (HV_VirtAddr)buf,
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+ count, off);
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+ if (retval >= 0)
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+ return retval;
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+ if (retval == HV_EAGAIN)
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+ continue;
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+ if (retval == HV_EBUSY && --retries > 0) {
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+ msleep(SROM_WAIT_TRY_INTERVAL);
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+ continue;
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+ }
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+ pr_err("_srom_write: error %d\n", retval);
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+ return -EIO;
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+ }
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+}
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+
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+/**
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+ * srom_open() - Device open routine.
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+ * @inode: Inode for this device.
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+ * @filp: File for this specific open of the device.
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+ *
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+ * Returns zero, or an error code.
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+ */
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+static int srom_open(struct inode *inode, struct file *filp)
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+{
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+ filp->private_data = &srom_devices[iminor(inode)];
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+ return 0;
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+}
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+
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+
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+/**
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+ * srom_release() - Device release routine.
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+ * @inode: Inode for this device.
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+ * @filp: File for this specific open of the device.
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+ *
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+ * Returns zero, or an error code.
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+ */
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+static int srom_release(struct inode *inode, struct file *filp)
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+{
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+ struct srom_dev *srom = filp->private_data;
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+ char dummy;
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+
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+ /* Make sure we've flushed anything written to the ROM. */
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+ mutex_lock(&srom->lock);
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+ if (srom->hv_devhdl >= 0)
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+ _srom_write(srom->hv_devhdl, &dummy, SROM_FLUSH_OFF, 1);
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+ mutex_unlock(&srom->lock);
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+
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+ filp->private_data = NULL;
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+
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+ return 0;
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+}
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+
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+
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+/**
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+ * srom_read() - Read data from the device.
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+ * @filp: File for this specific open of the device.
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+ * @buf: User's data buffer.
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+ * @count: Number of bytes requested.
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+ * @f_pos: File position.
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+ *
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+ * Returns number of bytes read, or an error code.
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+ */
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+static ssize_t srom_read(struct file *filp, char __user *buf,
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+ size_t count, loff_t *f_pos)
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+{
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+ int retval = 0;
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+ void *kernbuf;
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+ struct srom_dev *srom = filp->private_data;
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+
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+ kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
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+ if (!kernbuf)
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+ return -ENOMEM;
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+
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+ if (mutex_lock_interruptible(&srom->lock)) {
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+ retval = -ERESTARTSYS;
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+ kfree(kernbuf);
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+ return retval;
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+ }
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+
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+ while (count) {
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+ int hv_retval;
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+ int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
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+
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+ hv_retval = _srom_read(srom->hv_devhdl, kernbuf,
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+ *f_pos, bytes_this_pass);
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+ if (hv_retval > 0) {
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+ if (copy_to_user(buf, kernbuf, hv_retval) != 0) {
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+ retval = -EFAULT;
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+ break;
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+ }
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+ } else if (hv_retval <= 0) {
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+ if (retval == 0)
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+ retval = hv_retval;
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+ break;
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+ }
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+
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+ retval += hv_retval;
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+ *f_pos += hv_retval;
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+ buf += hv_retval;
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+ count -= hv_retval;
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+ }
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+
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+ mutex_unlock(&srom->lock);
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+ kfree(kernbuf);
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+
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+ return retval;
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+}
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+
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+/**
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+ * srom_write() - Write data to the device.
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+ * @filp: File for this specific open of the device.
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+ * @buf: User's data buffer.
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+ * @count: Number of bytes requested.
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+ * @f_pos: File position.
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+ *
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+ * Returns number of bytes written, or an error code.
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+ */
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+static ssize_t srom_write(struct file *filp, const char __user *buf,
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+ size_t count, loff_t *f_pos)
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+{
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+ int retval = 0;
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+ void *kernbuf;
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+ struct srom_dev *srom = filp->private_data;
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+
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+ kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
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+ if (!kernbuf)
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+ return -ENOMEM;
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+
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+ if (mutex_lock_interruptible(&srom->lock)) {
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+ retval = -ERESTARTSYS;
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+ kfree(kernbuf);
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+ return retval;
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+ }
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+
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+ while (count) {
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+ int hv_retval;
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+ int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
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+
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+ if (copy_from_user(kernbuf, buf, bytes_this_pass) != 0) {
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+ retval = -EFAULT;
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+ break;
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+ }
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+
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+ hv_retval = _srom_write(srom->hv_devhdl, kernbuf,
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+ *f_pos, bytes_this_pass);
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+ if (hv_retval <= 0) {
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+ if (retval == 0)
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+ retval = hv_retval;
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+ break;
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+ }
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+
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+ retval += hv_retval;
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+ *f_pos += hv_retval;
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+ buf += hv_retval;
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+ count -= hv_retval;
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+ }
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+
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+ mutex_unlock(&srom->lock);
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+ kfree(kernbuf);
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+
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+ return retval;
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+}
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+
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+/* Provide our own implementation so we can use srom->total_size. */
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+loff_t srom_llseek(struct file *filp, loff_t offset, int origin)
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+{
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+ struct srom_dev *srom = filp->private_data;
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+
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+ if (mutex_lock_interruptible(&srom->lock))
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+ return -ERESTARTSYS;
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+
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+ switch (origin) {
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+ case SEEK_END:
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+ offset += srom->total_size;
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+ break;
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+ case SEEK_CUR:
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+ offset += filp->f_pos;
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+ break;
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+ }
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+
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+ if (offset < 0 || offset > srom->total_size) {
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+ offset = -EINVAL;
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+ } else {
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+ filp->f_pos = offset;
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+ filp->f_version = 0;
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+ }
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+
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+ mutex_unlock(&srom->lock);
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+
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+ return offset;
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+}
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+
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+static ssize_t total_show(struct device *dev,
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+ struct device_attribute *attr, char *buf)
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+{
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+ struct srom_dev *srom = dev_get_drvdata(dev);
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+ return sprintf(buf, "%u\n", srom->total_size);
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+}
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+
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+static ssize_t sector_show(struct device *dev,
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+ struct device_attribute *attr, char *buf)
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+{
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+ struct srom_dev *srom = dev_get_drvdata(dev);
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+ return sprintf(buf, "%u\n", srom->sector_size);
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+}
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+
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+static ssize_t page_show(struct device *dev,
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+ struct device_attribute *attr, char *buf)
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+{
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+ struct srom_dev *srom = dev_get_drvdata(dev);
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+ return sprintf(buf, "%u\n", srom->page_size);
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+}
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+
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+static struct device_attribute srom_dev_attrs[] = {
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+ __ATTR(total_size, S_IRUGO, total_show, NULL),
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+ __ATTR(sector_size, S_IRUGO, sector_show, NULL),
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+ __ATTR(page_size, S_IRUGO, page_show, NULL),
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+ __ATTR_NULL
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+};
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+
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+static char *srom_devnode(struct device *dev, mode_t *mode)
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+{
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+ *mode = S_IRUGO | S_IWUSR;
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+ return kasprintf(GFP_KERNEL, "srom/%s", dev_name(dev));
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+}
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+
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+/*
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+ * The fops
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+ */
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+static const struct file_operations srom_fops = {
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+ .owner = THIS_MODULE,
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+ .llseek = srom_llseek,
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+ .read = srom_read,
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+ .write = srom_write,
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+ .open = srom_open,
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+ .release = srom_release,
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+};
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+
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+/**
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+ * srom_setup_minor() - Initialize per-minor information.
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+ * @srom: Per-device SROM state.
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+ * @index: Device to set up.
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+ */
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+static int srom_setup_minor(struct srom_dev *srom, int index)
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+{
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+ struct device *dev;
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+ int devhdl = srom->hv_devhdl;
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+
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+ mutex_init(&srom->lock);
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+
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+ if (_srom_read(devhdl, &srom->total_size,
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+ SROM_TOTAL_SIZE_OFF, sizeof(srom->total_size)) < 0)
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+ return -EIO;
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+ if (_srom_read(devhdl, &srom->sector_size,
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+ SROM_SECTOR_SIZE_OFF, sizeof(srom->sector_size)) < 0)
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+ return -EIO;
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+ if (_srom_read(devhdl, &srom->page_size,
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+ SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
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+ return -EIO;
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+
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+ dev = device_create(srom_class, &platform_bus,
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+ MKDEV(srom_major, index), srom, "%d", index);
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+ return IS_ERR(dev) ? PTR_ERR(dev) : 0;
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+}
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+
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+/** srom_init() - Initialize the driver's module. */
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+static int srom_init(void)
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+{
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+ int result, i;
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+ dev_t dev = MKDEV(srom_major, 0);
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+
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+ /*
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+ * Start with a plausible number of partitions; the krealloc() call
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+ * below will yield about log(srom_devs) additional allocations.
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+ */
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+ srom_devices = kzalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
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+
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+ /* Discover the number of srom partitions. */
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+ for (i = 0; ; i++) {
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+ int devhdl;
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+ char buf[20];
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+ struct srom_dev *new_srom_devices =
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+ krealloc(srom_devices, (i+1) * sizeof(struct srom_dev),
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+ GFP_KERNEL | __GFP_ZERO);
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+ if (!new_srom_devices) {
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+ result = -ENOMEM;
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+ goto fail_mem;
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+ }
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+ srom_devices = new_srom_devices;
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+ sprintf(buf, "srom/0/%d", i);
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+ devhdl = hv_dev_open((HV_VirtAddr)buf, 0);
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+ if (devhdl < 0) {
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+ if (devhdl != HV_ENODEV)
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+ pr_notice("srom/%d: hv_dev_open failed: %d.\n",
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+ i, devhdl);
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+ break;
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+ }
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+ srom_devices[i].hv_devhdl = devhdl;
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|
+ }
|
|
|
+ srom_devs = i;
|
|
|
+
|
|
|
+ /* Bail out early if we have no partitions at all. */
|
|
|
+ if (srom_devs == 0) {
|
|
|
+ result = -ENODEV;
|
|
|
+ goto fail_mem;
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Register our major, and accept a dynamic number. */
|
|
|
+ if (srom_major)
|
|
|
+ result = register_chrdev_region(dev, srom_devs, "srom");
|
|
|
+ else {
|
|
|
+ result = alloc_chrdev_region(&dev, 0, srom_devs, "srom");
|
|
|
+ srom_major = MAJOR(dev);
|
|
|
+ }
|
|
|
+ if (result < 0)
|
|
|
+ goto fail_mem;
|
|
|
+
|
|
|
+ /* Register a character device. */
|
|
|
+ cdev_init(&srom_cdev, &srom_fops);
|
|
|
+ srom_cdev.owner = THIS_MODULE;
|
|
|
+ srom_cdev.ops = &srom_fops;
|
|
|
+ result = cdev_add(&srom_cdev, dev, srom_devs);
|
|
|
+ if (result < 0)
|
|
|
+ goto fail_chrdev;
|
|
|
+
|
|
|
+ /* Create a sysfs class. */
|
|
|
+ srom_class = class_create(THIS_MODULE, "srom");
|
|
|
+ if (IS_ERR(srom_class)) {
|
|
|
+ result = PTR_ERR(srom_class);
|
|
|
+ goto fail_cdev;
|
|
|
+ }
|
|
|
+ srom_class->dev_attrs = srom_dev_attrs;
|
|
|
+ srom_class->devnode = srom_devnode;
|
|
|
+
|
|
|
+ /* Do per-partition initialization */
|
|
|
+ for (i = 0; i < srom_devs; i++) {
|
|
|
+ result = srom_setup_minor(srom_devices + i, i);
|
|
|
+ if (result < 0)
|
|
|
+ goto fail_class;
|
|
|
+ }
|
|
|
+
|
|
|
+ return 0;
|
|
|
+
|
|
|
+fail_class:
|
|
|
+ for (i = 0; i < srom_devs; i++)
|
|
|
+ device_destroy(srom_class, MKDEV(srom_major, i));
|
|
|
+ class_destroy(srom_class);
|
|
|
+fail_cdev:
|
|
|
+ cdev_del(&srom_cdev);
|
|
|
+fail_chrdev:
|
|
|
+ unregister_chrdev_region(dev, srom_devs);
|
|
|
+fail_mem:
|
|
|
+ kfree(srom_devices);
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
+/** srom_cleanup() - Clean up the driver's module. */
|
|
|
+static void srom_cleanup(void)
|
|
|
+{
|
|
|
+ int i;
|
|
|
+ for (i = 0; i < srom_devs; i++)
|
|
|
+ device_destroy(srom_class, MKDEV(srom_major, i));
|
|
|
+ class_destroy(srom_class);
|
|
|
+ cdev_del(&srom_cdev);
|
|
|
+ unregister_chrdev_region(MKDEV(srom_major, 0), srom_devs);
|
|
|
+ kfree(srom_devices);
|
|
|
+}
|
|
|
+
|
|
|
+module_init(srom_init);
|
|
|
+module_exit(srom_cleanup);
|
Linus Torvalds