1 files changed, 481 insertions, 0 deletions

diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
new file mode 100644
index 000000000000..cf3ee008dca2
--- /dev/null
+++ b/drivers/char/tile-srom.c
@@ -0,0 +1,481 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * SPI Flash ROM driver
+ *
+ * This source code is derived from code provided in "Linux Device
+ * Drivers, Third Edition", by Jonathan Corbet, Alessandro Rubini, and
+ * Greg Kroah-Hartman, published by O'Reilly Media, Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/kernel.h>       /* printk() */
+#include <linux/slab.h>         /* kmalloc() */
+#include <linux/fs.h>           /* everything... */
+#include <linux/errno.h>        /* error codes */
+#include <linux/types.h>        /* size_t */
+#include <linux/proc_fs.h>
+#include <linux/fcntl.h>        /* O_ACCMODE */
+#include <linux/aio.h>
+#include <linux/pagemap.h>
+#include <linux/hugetlb.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <hv/hypervisor.h>
+#include <linux/ioctl.h>
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <hv/drv_srom_intf.h>
+
+/*
+ * Size of our hypervisor I/O requests.  We break up large transfers
+ * so that we don't spend large uninterrupted spans of time in the
+ * hypervisor.  Erasing an SROM sector takes a significant fraction of
+ * a second, so if we allowed the user to, say, do one I/O to write the
+ * entire ROM, we'd get soft lockup timeouts, or worse.
+ */
+#define SROM_CHUNK_SIZE ((size_t)4096)
+
+/*
+ * When hypervisor is busy (e.g. erasing), poll the status periodically.
+ */
+
+/*
+ * Interval to poll the state in msec
+ */
+#define SROM_WAIT_TRY_INTERVAL 20
+
+/*
+ * Maximum times to poll the state
+ */
+#define SROM_MAX_WAIT_TRY_TIMES 1000
+
+struct srom_dev {
+        int hv_devhdl;                  /* Handle for hypervisor device */
+        u32 total_size;                 /* Size of this device */
+        u32 sector_size;                /* Size of a sector */
+        u32 page_size;                  /* Size of a page */
+        struct mutex lock;              /* Allow only one accessor at a time */
+};
+
+static int srom_major;                  /* Dynamic major by default */
+module_param(srom_major, int, 0);
+MODULE_AUTHOR("Tilera Corporation");
+MODULE_LICENSE("GPL");
+
+static int srom_devs;                   /* Number of SROM partitions */
+static struct cdev srom_cdev;
+static struct class *srom_class;
+static struct srom_dev *srom_devices;
+
+/*
+ * Handle calling the hypervisor and managing EAGAIN/EBUSY.
+ */
+
+static ssize_t _srom_read(int hv_devhdl, void *buf,
+                          loff_t off, size_t count)
+{
+        int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
+        for (;;) {
+                retval = hv_dev_pread(hv_devhdl, 0, (HV_VirtAddr)buf,
+                                      count, off);
+                if (retval >= 0)
+                        return retval;
+                if (retval == HV_EAGAIN)
+                        continue;
+                if (retval == HV_EBUSY && --retries > 0) {
+                        msleep(SROM_WAIT_TRY_INTERVAL);
+                        continue;
+                }
+                pr_err("_srom_read: error %d\n", retval);
+                return -EIO;
+        }
+}
+
+static ssize_t _srom_write(int hv_devhdl, const void *buf,
+                           loff_t off, size_t count)
+{
+        int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
+        for (;;) {
+                retval = hv_dev_pwrite(hv_devhdl, 0, (HV_VirtAddr)buf,
+                                       count, off);
+                if (retval >= 0)
+                        return retval;
+                if (retval == HV_EAGAIN)
+                        continue;
+                if (retval == HV_EBUSY && --retries > 0) {
+                        msleep(SROM_WAIT_TRY_INTERVAL);
+                        continue;
+                }
+                pr_err("_srom_write: error %d\n", retval);
+                return -EIO;
+        }
+}
+
+/**
+ * srom_open() - Device open routine.
+ * @inode: Inode for this device.
+ * @filp: File for this specific open of the device.
+ *
+ * Returns zero, or an error code.
+ */
+static int srom_open(struct inode *inode, struct file *filp)
+{
+        filp->private_data = &srom_devices[iminor(inode)];
+        return 0;
+}
+
+
+/**
+ * srom_release() - Device release routine.
+ * @inode: Inode for this device.
+ * @filp: File for this specific open of the device.
+ *
+ * Returns zero, or an error code.
+ */
+static int srom_release(struct inode *inode, struct file *filp)
+{
+        struct srom_dev *srom = filp->private_data;
+        char dummy;
+
+        /* Make sure we've flushed anything written to the ROM. */
+        mutex_lock(&srom->lock);
+        if (srom->hv_devhdl >= 0)
+                _srom_write(srom->hv_devhdl, &dummy, SROM_FLUSH_OFF, 1);
+        mutex_unlock(&srom->lock);
+
+        filp->private_data = NULL;
+
+        return 0;
+}
+
+
+/**
+ * srom_read() - Read data from the device.
+ * @filp: File for this specific open of the device.
+ * @buf: User's data buffer.
+ * @count: Number of bytes requested.
+ * @f_pos: File position.
+ *
+ * Returns number of bytes read, or an error code.
+ */
+static ssize_t srom_read(struct file *filp, char __user *buf,
+                         size_t count, loff_t *f_pos)
+{
+        int retval = 0;
+        void *kernbuf;
+        struct srom_dev *srom = filp->private_data;
+
+        kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
+        if (!kernbuf)
+                return -ENOMEM;
+
+        if (mutex_lock_interruptible(&srom->lock)) {
+                retval = -ERESTARTSYS;
+                kfree(kernbuf);
+                return retval;
+        }
+
+        while (count) {
+                int hv_retval;
+                int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
+
+                hv_retval = _srom_read(srom->hv_devhdl, kernbuf,
+                                       *f_pos, bytes_this_pass);
+                if (hv_retval > 0) {
+                        if (copy_to_user(buf, kernbuf, hv_retval) != 0) {
+                                retval = -EFAULT;
+                                break;
+                        }
+                } else if (hv_retval <= 0) {
+                        if (retval == 0)
+                                retval = hv_retval;
+                        break;
+                }
+
+                retval += hv_retval;
+                *f_pos += hv_retval;
+                buf += hv_retval;
+                count -= hv_retval;
+        }
+
+        mutex_unlock(&srom->lock);
+        kfree(kernbuf);
+
+        return retval;
+}
+
+/**
+ * srom_write() - Write data to the device.
+ * @filp: File for this specific open of the device.
+ * @buf: User's data buffer.
+ * @count: Number of bytes requested.
+ * @f_pos: File position.
+ *
+ * Returns number of bytes written, or an error code.
+ */
+static ssize_t srom_write(struct file *filp, const char __user *buf,
+                          size_t count, loff_t *f_pos)
+{
+        int retval = 0;
+        void *kernbuf;
+        struct srom_dev *srom = filp->private_data;
+
+        kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
+        if (!kernbuf)
+                return -ENOMEM;
+
+        if (mutex_lock_interruptible(&srom->lock)) {
+                retval = -ERESTARTSYS;
+                kfree(kernbuf);
+                return retval;
+        }
+
+        while (count) {
+                int hv_retval;
+                int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
+
+                if (copy_from_user(kernbuf, buf, bytes_this_pass) != 0) {
+                        retval = -EFAULT;
+                        break;
+                }
+
+                hv_retval = _srom_write(srom->hv_devhdl, kernbuf,
+                                        *f_pos, bytes_this_pass);
+                if (hv_retval <= 0) {
+                        if (retval == 0)
+                                retval = hv_retval;
+                        break;
+                }
+
+                retval += hv_retval;
+                *f_pos += hv_retval;
+                buf += hv_retval;
+                count -= hv_retval;
+        }
+
+        mutex_unlock(&srom->lock);
+        kfree(kernbuf);
+
+        return retval;
+}
+
+/* Provide our own implementation so we can use srom->total_size. */
+loff_t srom_llseek(struct file *filp, loff_t offset, int origin)
+{
+        struct srom_dev *srom = filp->private_data;
+
+        if (mutex_lock_interruptible(&srom->lock))
+                return -ERESTARTSYS;
+
+        switch (origin) {
+        case SEEK_END:
+                offset += srom->total_size;
+                break;
+        case SEEK_CUR:
+                offset += filp->f_pos;
+                break;
+        }
+
+        if (offset < 0 || offset > srom->total_size) {
+                offset = -EINVAL;
+        } else {
+                filp->f_pos = offset;
+                filp->f_version = 0;
+        }
+
+        mutex_unlock(&srom->lock);
+
+        return offset;
+}
+
+static ssize_t total_show(struct device *dev,
+                          struct device_attribute *attr, char *buf)
+{
+        struct srom_dev *srom = dev_get_drvdata(dev);
+        return sprintf(buf, "%u\n", srom->total_size);
+}
+
+static ssize_t sector_show(struct device *dev,
+                           struct device_attribute *attr, char *buf)
+{
+        struct srom_dev *srom = dev_get_drvdata(dev);
+        return sprintf(buf, "%u\n", srom->sector_size);
+}
+
+static ssize_t page_show(struct device *dev,
+                         struct device_attribute *attr, char *buf)
+{
+        struct srom_dev *srom = dev_get_drvdata(dev);
+        return sprintf(buf, "%u\n", srom->page_size);
+}
+
+static struct device_attribute srom_dev_attrs[] = {
+        __ATTR(total_size, S_IRUGO, total_show, NULL),
+        __ATTR(sector_size, S_IRUGO, sector_show, NULL),
+        __ATTR(page_size, S_IRUGO, page_show, NULL),
+        __ATTR_NULL
+};
+
+static char *srom_devnode(struct device *dev, mode_t *mode)
+{
+        *mode = S_IRUGO | S_IWUSR;
+        return kasprintf(GFP_KERNEL, "srom/%s", dev_name(dev));
+}
+
+/*
+ * The fops
+ */
+static const struct file_operations srom_fops = {
+        .owner =     THIS_MODULE,
+        .llseek =    srom_llseek,
+        .read =      srom_read,
+        .write =     srom_write,
+        .open =      srom_open,
+        .release =   srom_release,
+};
+
+/**
+ * srom_setup_minor() - Initialize per-minor information.
+ * @srom: Per-device SROM state.
+ * @index: Device to set up.
+ */
+static int srom_setup_minor(struct srom_dev *srom, int index)
+{
+        struct device *dev;
+        int devhdl = srom->hv_devhdl;
+
+        mutex_init(&srom->lock);
+
+        if (_srom_read(devhdl, &srom->total_size,
+                       SROM_TOTAL_SIZE_OFF, sizeof(srom->total_size)) < 0)
+                return -EIO;
+        if (_srom_read(devhdl, &srom->sector_size,
+                       SROM_SECTOR_SIZE_OFF, sizeof(srom->sector_size)) < 0)
+                return -EIO;
+        if (_srom_read(devhdl, &srom->page_size,
+                       SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
+                return -EIO;
+
+        dev = device_create(srom_class, &platform_bus,
+                            MKDEV(srom_major, index), srom, "%d", index);
+        return IS_ERR(dev) ? PTR_ERR(dev) : 0;
+}
+
+/** srom_init() - Initialize the driver's module. */
+static int srom_init(void)
+{
+        int result, i;
+        dev_t dev = MKDEV(srom_major, 0);
+
+        /*
+         * Start with a plausible number of partitions; the krealloc() call
+         * below will yield about log(srom_devs) additional allocations.
+         */
+        srom_devices = kzalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
+
+        /* Discover the number of srom partitions. */
+        for (i = 0; ; i++) {
+                int devhdl;
+                char buf[20];
+                struct srom_dev *new_srom_devices =
+                        krealloc(srom_devices, (i+1) * sizeof(struct srom_dev),
+                                 GFP_KERNEL | __GFP_ZERO);
+                if (!new_srom_devices) {
+                        result = -ENOMEM;
+                        goto fail_mem;
+                }
+                srom_devices = new_srom_devices;
+                sprintf(buf, "srom/0/%d", i);
+                devhdl = hv_dev_open((HV_VirtAddr)buf, 0);
+                if (devhdl < 0) {
+                        if (devhdl != HV_ENODEV)
+                                pr_notice("srom/%d: hv_dev_open failed: %d.\n",
+                                          i, devhdl);
+                        break;
+                }
+                srom_devices[i].hv_devhdl = devhdl;
+        }
+        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);