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authorLinus Torvalds <torvalds@linux-foundation.org>2011-08-02 21:16:11 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2011-08-02 21:16:11 -1000
commit1850536b93888e6cc3ee42e63e20e61f35f8b3e2 (patch)
tree7b78bf5196ca79f52f0fd7c932ea8062c91ff154 /drivers/char
parented8f37370d83e695c0a4fa5d5fc7a83ecb947526 (diff)
parentd1afa65ca59d4e6a5f1a8c1ab9bfa73f2fa8b777 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile/mm/init.c: trivial: use BUG_ON arch/tile: remove useless set_fixmap_nocache() macro arch/tile: add hypervisor-based character driver for SPI flash ROM ioctl-number.txt: add the tile hardwall ioctl range tile: use generic-y format for one-line asm-generic headers clocksource: tile: convert to use clocksource_register_hz
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/Kconfig11
-rw-r--r--drivers/char/Makefile2
-rw-r--r--drivers/char/tile-srom.c481
3 files changed, 494 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 49502bc5360a..423fd56bf612 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -616,5 +616,16 @@ config MSM_SMD_PKT
Enables userspace clients to read and write to some packet SMD
ports via device interface for MSM chipset.
+config TILE_SROM
+ bool "Character-device access via hypervisor to the Tilera SPI ROM"
+ depends on TILE
+ default y
+ ---help---
+ This device provides character-level read-write access
+ to the SROM, typically via the "0", "1", and "2" devices
+ in /dev/srom/. The Tilera hypervisor makes the flash
+ device appear much like a simple EEPROM, and knows
+ how to partition a single ROM for multiple purposes.
+
endmenu
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 7a00672bd85d..32762ba769c2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -63,3 +63,5 @@ obj-$(CONFIG_RAMOOPS) += ramoops.o
obj-$(CONFIG_JS_RTC) += js-rtc.o
js-rtc-y = rtc.o
+
+obj-$(CONFIG_TILE_SROM) += tile-srom.o
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);

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