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authorJonathan Corbet <corbet@lwn.net>2008-07-14 15:29:34 -0600
committerJonathan Corbet <corbet@lwn.net>2008-07-14 15:29:34 -0600
commit2fceef397f9880b212a74c418290ce69e7ac00eb (patch)
treed9cc09ab992825ef7fede4a688103503e3caf655 /drivers/spi/spidev.c
parentfeae1ef116ed381625d3731c5ae4f4ebcb3fa302 (diff)
parentbce7f793daec3e65ec5c5705d2457b81fe7b5725 (diff)
downloadlinux-linaro-stable-2fceef397f9880b212a74c418290ce69e7ac00eb.tar.gz
Merge commit 'v2.6.26' into bkl-removal
Diffstat (limited to 'drivers/spi/spidev.c')
-rw-r--r--drivers/spi/spidev.c176
1 files changed, 127 insertions, 49 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index ab2b769c83ca..ddbe1a5e970e 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -25,6 +25,7 @@
#include <linux/ioctl.h>
#include <linux/fs.h>
#include <linux/device.h>
+#include <linux/err.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/mutex.h>
@@ -68,10 +69,12 @@ static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG];
| SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP)
struct spidev_data {
- struct device dev;
+ dev_t devt;
+ spinlock_t spi_lock;
struct spi_device *spi;
struct list_head device_entry;
+ /* buffer is NULL unless this device is open (users > 0) */
struct mutex buf_lock;
unsigned users;
u8 *buffer;
@@ -86,12 +89,75 @@ MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
/*-------------------------------------------------------------------------*/
+/*
+ * We can't use the standard synchronous wrappers for file I/O; we
+ * need to protect against async removal of the underlying spi_device.
+ */
+static void spidev_complete(void *arg)
+{
+ complete(arg);
+}
+
+static ssize_t
+spidev_sync(struct spidev_data *spidev, struct spi_message *message)
+{
+ DECLARE_COMPLETION_ONSTACK(done);
+ int status;
+
+ message->complete = spidev_complete;
+ message->context = &done;
+
+ spin_lock_irq(&spidev->spi_lock);
+ if (spidev->spi == NULL)
+ status = -ESHUTDOWN;
+ else
+ status = spi_async(spidev->spi, message);
+ spin_unlock_irq(&spidev->spi_lock);
+
+ if (status == 0) {
+ wait_for_completion(&done);
+ status = message->status;
+ if (status == 0)
+ status = message->actual_length;
+ }
+ return status;
+}
+
+static inline ssize_t
+spidev_sync_write(struct spidev_data *spidev, size_t len)
+{
+ struct spi_transfer t = {
+ .tx_buf = spidev->buffer,
+ .len = len,
+ };
+ struct spi_message m;
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t, &m);
+ return spidev_sync(spidev, &m);
+}
+
+static inline ssize_t
+spidev_sync_read(struct spidev_data *spidev, size_t len)
+{
+ struct spi_transfer t = {
+ .rx_buf = spidev->buffer,
+ .len = len,
+ };
+ struct spi_message m;
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t, &m);
+ return spidev_sync(spidev, &m);
+}
+
+/*-------------------------------------------------------------------------*/
+
/* Read-only message with current device setup */
static ssize_t
spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
struct spidev_data *spidev;
- struct spi_device *spi;
ssize_t status = 0;
/* chipselect only toggles at start or end of operation */
@@ -99,18 +165,17 @@ spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
return -EMSGSIZE;
spidev = filp->private_data;
- spi = spidev->spi;
mutex_lock(&spidev->buf_lock);
- status = spi_read(spi, spidev->buffer, count);
- if (status == 0) {
+ status = spidev_sync_read(spidev, count);
+ if (status > 0) {
unsigned long missing;
- missing = copy_to_user(buf, spidev->buffer, count);
- if (count && missing == count)
+ missing = copy_to_user(buf, spidev->buffer, status);
+ if (missing == status)
status = -EFAULT;
else
- status = count - missing;
+ status = status - missing;
}
mutex_unlock(&spidev->buf_lock);
@@ -123,7 +188,6 @@ spidev_write(struct file *filp, const char __user *buf,
size_t count, loff_t *f_pos)
{
struct spidev_data *spidev;
- struct spi_device *spi;
ssize_t status = 0;
unsigned long missing;
@@ -132,14 +196,11 @@ spidev_write(struct file *filp, const char __user *buf,
return -EMSGSIZE;
spidev = filp->private_data;
- spi = spidev->spi;
mutex_lock(&spidev->buf_lock);
missing = copy_from_user(spidev->buffer, buf, count);
if (missing == 0) {
- status = spi_write(spi, spidev->buffer, count);
- if (status == 0)
- status = count;
+ status = spidev_sync_write(spidev, count);
} else
status = -EFAULT;
mutex_unlock(&spidev->buf_lock);
@@ -154,7 +215,6 @@ static int spidev_message(struct spidev_data *spidev,
struct spi_transfer *k_xfers;
struct spi_transfer *k_tmp;
struct spi_ioc_transfer *u_tmp;
- struct spi_device *spi = spidev->spi;
unsigned n, total;
u8 *buf;
int status = -EFAULT;
@@ -216,7 +276,7 @@ static int spidev_message(struct spidev_data *spidev,
spi_message_add_tail(k_tmp, &msg);
}
- status = spi_sync(spi, &msg);
+ status = spidev_sync(spidev, &msg);
if (status < 0)
goto done;
@@ -270,8 +330,16 @@ spidev_ioctl(struct inode *inode, struct file *filp,
if (err)
return -EFAULT;
+ /* guard against device removal before, or while,
+ * we issue this ioctl.
+ */
spidev = filp->private_data;
- spi = spidev->spi;
+ spin_lock_irq(&spidev->spi_lock);
+ spi = spi_dev_get(spidev->spi);
+ spin_unlock_irq(&spidev->spi_lock);
+
+ if (spi == NULL)
+ return -ESHUTDOWN;
switch (cmd) {
/* read requests */
@@ -357,8 +425,10 @@ spidev_ioctl(struct inode *inode, struct file *filp,
default:
/* segmented and/or full-duplex I/O request */
if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
- || _IOC_DIR(cmd) != _IOC_WRITE)
- return -ENOTTY;
+ || _IOC_DIR(cmd) != _IOC_WRITE) {
+ retval = -ENOTTY;
+ break;
+ }
tmp = _IOC_SIZE(cmd);
if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
@@ -386,6 +456,7 @@ spidev_ioctl(struct inode *inode, struct file *filp,
kfree(ioc);
break;
}
+ spi_dev_put(spi);
return retval;
}
@@ -398,7 +469,7 @@ static int spidev_open(struct inode *inode, struct file *filp)
mutex_lock(&device_list_lock);
list_for_each_entry(spidev, &device_list, device_entry) {
- if (spidev->dev.devt == inode->i_rdev) {
+ if (spidev->devt == inode->i_rdev) {
status = 0;
break;
}
@@ -432,10 +503,22 @@ static int spidev_release(struct inode *inode, struct file *filp)
mutex_lock(&device_list_lock);
spidev = filp->private_data;
filp->private_data = NULL;
+
+ /* last close? */
spidev->users--;
if (!spidev->users) {
+ int dofree;
+
kfree(spidev->buffer);
spidev->buffer = NULL;
+
+ /* ... after we unbound from the underlying device? */
+ spin_lock_irq(&spidev->spi_lock);
+ dofree = (spidev->spi == NULL);
+ spin_unlock_irq(&spidev->spi_lock);
+
+ if (dofree)
+ kfree(spidev);
}
mutex_unlock(&device_list_lock);
@@ -462,19 +545,7 @@ static struct file_operations spidev_fops = {
* It also simplifies memory management.
*/
-static void spidev_classdev_release(struct device *dev)
-{
- struct spidev_data *spidev;
-
- spidev = container_of(dev, struct spidev_data, dev);
- kfree(spidev);
-}
-
-static struct class spidev_class = {
- .name = "spidev",
- .owner = THIS_MODULE,
- .dev_release = spidev_classdev_release,
-};
+static struct class *spidev_class;
/*-------------------------------------------------------------------------*/
@@ -491,6 +562,7 @@ static int spidev_probe(struct spi_device *spi)
/* Initialize the driver data */
spidev->spi = spi;
+ spin_lock_init(&spidev->spi_lock);
mutex_init(&spidev->buf_lock);
INIT_LIST_HEAD(&spidev->device_entry);
@@ -501,20 +573,20 @@ static int spidev_probe(struct spi_device *spi)
mutex_lock(&device_list_lock);
minor = find_first_zero_bit(minors, N_SPI_MINORS);
if (minor < N_SPI_MINORS) {
- spidev->dev.parent = &spi->dev;
- spidev->dev.class = &spidev_class;
- spidev->dev.devt = MKDEV(SPIDEV_MAJOR, minor);
- snprintf(spidev->dev.bus_id, sizeof spidev->dev.bus_id,
+ struct device *dev;
+
+ spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
+ dev = device_create(spidev_class, &spi->dev, spidev->devt,
"spidev%d.%d",
spi->master->bus_num, spi->chip_select);
- status = device_register(&spidev->dev);
+ status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
} else {
dev_dbg(&spi->dev, "no minor number available!\n");
status = -ENODEV;
}
if (status == 0) {
set_bit(minor, minors);
- dev_set_drvdata(&spi->dev, spidev);
+ spi_set_drvdata(spi, spidev);
list_add(&spidev->device_entry, &device_list);
}
mutex_unlock(&device_list_lock);
@@ -527,15 +599,21 @@ static int spidev_probe(struct spi_device *spi)
static int spidev_remove(struct spi_device *spi)
{
- struct spidev_data *spidev = dev_get_drvdata(&spi->dev);
+ struct spidev_data *spidev = spi_get_drvdata(spi);
- mutex_lock(&device_list_lock);
+ /* make sure ops on existing fds can abort cleanly */
+ spin_lock_irq(&spidev->spi_lock);
+ spidev->spi = NULL;
+ spi_set_drvdata(spi, NULL);
+ spin_unlock_irq(&spidev->spi_lock);
+ /* prevent new opens */
+ mutex_lock(&device_list_lock);
list_del(&spidev->device_entry);
- dev_set_drvdata(&spi->dev, NULL);
- clear_bit(MINOR(spidev->dev.devt), minors);
- device_unregister(&spidev->dev);
-
+ device_destroy(spidev_class, spidev->devt);
+ clear_bit(MINOR(spidev->devt), minors);
+ if (spidev->users == 0)
+ kfree(spidev);
mutex_unlock(&device_list_lock);
return 0;
@@ -571,15 +649,15 @@ static int __init spidev_init(void)
if (status < 0)
return status;
- status = class_register(&spidev_class);
- if (status < 0) {
+ spidev_class = class_create(THIS_MODULE, "spidev");
+ if (IS_ERR(spidev_class)) {
unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
- return status;
+ return PTR_ERR(spidev_class);
}
status = spi_register_driver(&spidev_spi);
if (status < 0) {
- class_unregister(&spidev_class);
+ class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
}
return status;
@@ -589,7 +667,7 @@ module_init(spidev_init);
static void __exit spidev_exit(void)
{
spi_unregister_driver(&spidev_spi);
- class_unregister(&spidev_class);
+ class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
}
module_exit(spidev_exit);