This patch adds character device support for the
ST-Ericsson CG2900 framework. The CG2900 is chip
supporting GPS, Bluetooth, and FM radio.
This patch adds support for creating character devices
so it is possible for stacks located in User space to
send data to and receive data from the connected
controller.
Signed-off-by: Par-Gunnar Hjalmdahl <[email protected]>
---
drivers/mfd/cg2900/Makefile | 2 +
drivers/mfd/cg2900/cg2900_char_devices.c | 701 ++++++++++++++++++++++++++++++
2 files changed, 703 insertions(+), 0 deletions(-)
create mode 100644 drivers/mfd/cg2900/cg2900_char_devices.c
diff --git a/drivers/mfd/cg2900/Makefile b/drivers/mfd/cg2900/Makefile
index a736101..0ac9bc6 100644
--- a/drivers/mfd/cg2900/Makefile
+++ b/drivers/mfd/cg2900/Makefile
@@ -5,3 +5,5 @@
obj-$(CONFIG_MFD_CG2900) += cg2900_core.o
export-objs := cg2900_core.o
+obj-$(CONFIG_MFD_CG2900) += cg2900_char_devices.o
+
diff --git a/drivers/mfd/cg2900/cg2900_char_devices.c b/drivers/mfd/cg2900/cg2900_char_devices.c
new file mode 100644
index 0000000..c878f5f
--- /dev/null
+++ b/drivers/mfd/cg2900/cg2900_char_devices.c
@@ -0,0 +1,701 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ * Authors:
+ * Par-Gunnar Hjalmdahl ([email protected]) for ST-Ericsson.
+ * Henrik Possung ([email protected]) for ST-Ericsson.
+ * Josef Kindberg ([email protected]) for ST-Ericsson.
+ * Dariusz Szymszak ([email protected]) for ST-Ericsson.
+ * Kjell Andersson ([email protected]) for ST-Ericsson.
+ * License terms: GNU General Public License (GPL), version 2
+ *
+ * Linux Bluetooth HCI H:4 Driver for ST-Ericsson connectivity controller.
+ */
+#define NAME "cg2900_char_dev"
+#define pr_fmt(fmt) NAME ": " fmt "\n"
+
+#include <linux/compiler.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/skbuff.h>
+#include <linux/mfd/cg2900.h>
+
+#include "cg2900_core.h"
+
+#define MAIN_DEV (dev->dev)
+
+/**
+ * struct char_dev_user - Stores device information.
+ * @dev: Current device.
+ * @miscdev: Registered device struct.
+ * @name: Name of device.
+ * @rx_queue: Data queue.
+ * @rx_wait_queue: Wait queue.
+ * @reset_wait_queue: Reset Wait queue.
+ * @read_mutex: Read mutex.
+ * @write_mutex: Write mutex.
+ * @list: List header for inserting into device list.
+ */
+struct char_dev_user {
+ struct device *dev;
+ struct miscdevice miscdev;
+ char *name;
+ struct sk_buff_head rx_queue;
+ wait_queue_head_t rx_wait_queue;
+ wait_queue_head_t reset_wait_queue;
+ struct mutex read_mutex;
+ struct mutex write_mutex;
+ struct list_head list;
+};
+
+/**
+ * struct char_info - Stores all current users.
+ * @open_mutex: Open mutex (used for both open and release).
+ * @man_mutex: Management mutex.
+ * @dev_users: List of char dev users.
+ */
+struct char_info {
+ struct mutex open_mutex;
+ struct mutex man_mutex;
+ struct list_head dev_users;
+};
+
+static struct char_info *char_info;
+
+/**
+ * char_dev_read_cb() - Handle data received from controller.
+ * @dev: Device receiving data.
+ * @skb: Buffer with data coming from controller.
+ *
+ * The char_dev_read_cb() function handles data received from the CG2900 driver.
+ */
+static void char_dev_read_cb(struct cg2900_user_data *dev, struct sk_buff *skb)
+{
+ struct char_dev_user *char_dev = dev_get_drvdata(dev->dev);
+
+ dev_dbg(dev->dev, "char_dev_read_cb len %d\n", skb->len);
+
+ skb_queue_tail(&char_dev->rx_queue, skb);
+
+ wake_up_interruptible(&char_dev->rx_wait_queue);
+}
+
+/**
+ * char_dev_reset_cb() - Handle reset from controller.
+ * @dev: Device resetting.
+ *
+ * The char_dev_reset_cb() function handles reset from the CG2900 driver.
+ */
+static void char_dev_reset_cb(struct cg2900_user_data *dev)
+{
+ struct char_dev_user *char_dev = dev_get_drvdata(dev->dev);
+
+ dev_dbg(dev->dev, "char_dev_reset_cb\n");
+
+ wake_up_interruptible(&char_dev->rx_wait_queue);
+ wake_up_interruptible(&char_dev->reset_wait_queue);
+}
+
+/**
+ * char_dev_open() - Open char device.
+ * @inode: Device driver information.
+ * @filp: Pointer to the file struct.
+ *
+ * The char_dev_open() function opens the char device.
+ *
+ * Returns:
+ * 0 if there is no error.
+ * -EINVAL if device cannot be found in device list.
+ * Error codes from cg2900->open.
+ */
+static int char_dev_open(struct inode *inode, struct file *filp)
+{
+ int err;
+ int minor;
+ struct char_dev_user *dev = NULL;
+ struct char_dev_user *tmp;
+ struct list_head *cursor;
+ struct cg2900_user_data *user;
+
+ mutex_lock(&char_info->open_mutex);
+
+ minor = iminor(inode);
+
+ /* Find the device for this file */
+ mutex_lock(&char_info->man_mutex);
+ list_for_each(cursor, &char_info->dev_users) {
+ tmp = list_entry(cursor, struct char_dev_user, list);
+ if (tmp->miscdev.minor == minor) {
+ dev = tmp;
+ break;
+ }
+ }
+ mutex_unlock(&char_info->man_mutex);
+ if (!dev) {
+ pr_err("Could not identify device in inode");
+ err = -EINVAL;
+ goto error_handling;
+ }
+
+ filp->private_data = dev;
+ user = dev_get_platdata(dev->dev);
+
+ /* First initiate wait queues for this device. */
+ init_waitqueue_head(&dev->rx_wait_queue);
+ init_waitqueue_head(&dev->reset_wait_queue);
+
+ /* Register to CG2900 Driver */
+ err = user->open(user);
+ if (err) {
+ dev_err(MAIN_DEV,
+ "Couldn't register to CG2900 for H:4 channel %s\n",
+ dev->name);
+ goto error_handling;
+ }
+ dev_info(MAIN_DEV, "char_dev %s opened\n", dev->name);
+
+error_handling:
+ mutex_unlock(&char_info->open_mutex);
+ return err;
+}
+
+/**
+ * char_dev_release() - Release char device.
+ * @inode: Device driver information.
+ * @filp: Pointer to the file struct.
+ *
+ * The char_dev_release() function release the char device.
+ *
+ * Returns:
+ * 0 if there is no error.
+ * -EBADF if NULL pointer was supplied in private data.
+ */
+static int char_dev_release(struct inode *inode, struct file *filp)
+{
+ int err = 0;
+ struct char_dev_user *dev = filp->private_data;
+ struct cg2900_user_data *user;
+
+ pr_debug("char_dev_release");
+
+ if (!dev) {
+ pr_err("Calling with NULL pointer");
+ return -EBADF;
+ }
+
+ mutex_lock(&char_info->open_mutex);
+ mutex_lock(&dev->read_mutex);
+ mutex_lock(&dev->write_mutex);
+
+ user = dev_get_platdata(dev->dev);
+ if (user->opened)
+ user->close(user);
+
+ dev_info(MAIN_DEV, "char_dev %s closed\n", dev->name);
+
+ filp->private_data = NULL;
+ wake_up_interruptible(&dev->rx_wait_queue);
+ wake_up_interruptible(&dev->reset_wait_queue);
+
+ mutex_unlock(&dev->write_mutex);
+ mutex_unlock(&dev->read_mutex);
+ mutex_unlock(&char_info->open_mutex);
+
+ return err;
+}
+
+/**
+ * char_dev_read() - Queue and copy buffer to user.
+ * @filp: Pointer to the file struct.
+ * @buf: Received buffer.
+ * @count: Size of buffer.
+ * @f_pos: Position in buffer.
+ *
+ * The char_dev_read() function queues and copy the received buffer to
+ * the user space char device. If no data is available this function will block.
+ *
+ * Returns:
+ * Bytes successfully read (could be 0).
+ * -EBADF if NULL pointer was supplied in private data.
+ * -EFAULT if copy_to_user fails.
+ * Error codes from wait_event_interruptible.
+ */
+static ssize_t char_dev_read(struct file *filp, char __user *buf, size_t count,
+ loff_t *f_pos)
+{
+ struct char_dev_user *dev = filp->private_data;
+ struct cg2900_user_data *user;
+ struct sk_buff *skb;
+ int bytes_to_copy;
+ int err = 0;
+
+ pr_debug("char_dev_read");
+
+ if (!dev) {
+ pr_err("Calling with NULL pointer");
+ return -EBADF;
+ }
+ mutex_lock(&dev->read_mutex);
+
+ user = dev_get_platdata(dev->dev);
+
+ if (user->opened && skb_queue_empty(&dev->rx_queue)) {
+ err = wait_event_interruptible(dev->rx_wait_queue,
+ (!(skb_queue_empty(&dev->rx_queue))) ||
+ !user->opened);
+ if (err) {
+ dev_err(MAIN_DEV, "Failed to wait for event\n");
+ goto error_handling;
+ }
+ }
+
+ if (!user->opened) {
+ dev_err(MAIN_DEV, "Channel has been closed\n");
+ err = -EBADF;
+ goto error_handling;
+ }
+
+ skb = skb_dequeue(&dev->rx_queue);
+ if (!skb) {
+ dev_dbg(MAIN_DEV,
+ "skb queue is empty - return with zero bytes\n");
+ bytes_to_copy = 0;
+ goto finished;
+ }
+
+ bytes_to_copy = min(count, skb->len);
+
+ err = copy_to_user(buf, skb->data, bytes_to_copy);
+ if (err) {
+ dev_err(MAIN_DEV, "Error %d from copy_to_user\n", err);
+ skb_queue_head(&dev->rx_queue, skb);
+ err = -EFAULT;
+ goto error_handling;
+ }
+
+ skb_pull(skb, bytes_to_copy);
+
+ if (skb->len > 0)
+ skb_queue_head(&dev->rx_queue, skb);
+ else
+ kfree_skb(skb);
+
+ goto finished;
+
+error_handling:
+ mutex_unlock(&dev->read_mutex);
+ return (ssize_t)err;
+finished:
+ mutex_unlock(&dev->read_mutex);
+ return bytes_to_copy;
+}
+
+/**
+ * char_dev_write() - Copy buffer from user and write to CG2900 driver.
+ * @filp: Pointer to the file struct.
+ * @buf: Write buffer.
+ * @count: Size of the buffer write.
+ * @f_pos: Position of buffer.
+ *
+ * Returns:
+ * Bytes successfully written (could be 0).
+ * -EBADF if NULL pointer was supplied in private data.
+ * -EFAULT if copy_from_user fails.
+ */
+static ssize_t char_dev_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *f_pos)
+{
+ struct sk_buff *skb;
+ struct char_dev_user *dev = filp->private_data;
+ struct cg2900_user_data *user;
+ int err = 0;
+
+ pr_debug("char_dev_write");
+
+ if (!dev) {
+ pr_err("Calling with NULL pointer");
+ return -EBADF;
+ }
+
+ user = dev_get_platdata(dev->dev);
+ if (!user->opened) {
+ dev_err(MAIN_DEV, "char_dev_write: Channel not opened\n");
+ return -EACCES;
+ }
+
+ mutex_lock(&dev->write_mutex);
+
+ skb = user->alloc_skb(count, GFP_ATOMIC);
+ if (!skb) {
+ dev_err(MAIN_DEV, "Couldn't allocate sk_buff with length %d\n",
+ count);
+ goto error_handling;
+ }
+
+ err = copy_from_user(skb_put(skb, count), buf, count);
+ if (err) {
+ dev_err(MAIN_DEV, "Error %d from copy_from_user\n", err);
+ kfree_skb(skb);
+ err = -EFAULT;
+ goto error_handling;
+ }
+
+ err = user->write(user, skb);
+ if (err) {
+ dev_err(MAIN_DEV, "cg2900_write failed (%d)\n", err);
+ kfree_skb(skb);
+ goto error_handling;
+ }
+
+ mutex_unlock(&dev->write_mutex);
+ return count;
+
+error_handling:
+ mutex_unlock(&dev->write_mutex);
+ return err;
+}
+
+/**
+ * char_dev_unlocked_ioctl() - Handle IOCTL call to the interface.
+ * @filp: Pointer to the file struct.
+ * @cmd: IOCTL command.
+ * @arg: IOCTL argument.
+ *
+ * Returns:
+ * 0 if there is no error.
+ * -EINVAL if supplied cmd is not supported.
+ * For cmd CG2900_CHAR_DEV_IOCTL_CHECK4RESET 0x01 is returned if device is
+ * reset and 0x02 is returned if device is closed.
+ */
+static long char_dev_unlocked_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct char_dev_user *dev = filp->private_data;
+ struct cg2900_user_data *user;
+ struct cg2900_rev_data rev_data;
+ int err = 0;
+ int ret_val;
+ void __user *user_arg = (void __user *)arg;
+
+ dev_dbg(dev->dev, "char_dev_unlocked_ioctl for %s\n"
+ "\tDIR: %d\n"
+ "\tTYPE: %d\n"
+ "\tNR: %d\n"
+ "\tSIZE: %d",
+ dev->name, _IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd),
+ _IOC_SIZE(cmd));
+
+ user = dev_get_platdata(dev->dev);
+
+ switch (cmd) {
+ case CG2900_CHAR_DEV_IOCTL_RESET:
+ if (!user->opened)
+ return -EACCES;
+ dev_dbg(MAIN_DEV, "ioctl reset command for device %s\n",
+ dev->name);
+ err = user->reset(user);
+ break;
+
+ case CG2900_CHAR_DEV_IOCTL_CHECK4RESET:
+ if (user->opened)
+ ret_val = CG2900_CHAR_DEV_IOCTL_EVENT_IDLE;
+ else
+ ret_val = CG2900_CHAR_DEV_IOCTL_EVENT_RESET;
+
+ dev_dbg(MAIN_DEV, "ioctl check for reset command for device %s",
+ dev->name);
+
+ err = copy_to_user(user_arg, &ret_val, sizeof(ret_val));
+ if (err) {
+ dev_err(MAIN_DEV,
+ "Error %d from copy_to_user for reset\n", err);
+ return -EFAULT;
+ }
+ break;
+
+ case CG2900_CHAR_DEV_IOCTL_GET_REVISION:
+ if (!user->get_local_revision(user, &rev_data)) {
+ dev_err(MAIN_DEV, "No revision data available\n");
+ return -EIO;
+ }
+ dev_dbg(MAIN_DEV, "ioctl check for local revision info\n"
+ "\trevision 0x%04X\n"
+ "\tsub_version 0x%04X\n",
+ rev_data.revision, rev_data.sub_version);
+ err = copy_to_user(user_arg, &rev_data, sizeof(rev_data));
+ if (err) {
+ dev_err(MAIN_DEV,
+ "Error %d from copy_to_user for "
+ "revision\n", err);
+ return -EFAULT;
+ }
+ break;
+
+ default:
+ dev_err(MAIN_DEV, "Unknown ioctl command %08X\n", cmd);
+ err = -EINVAL;
+ break;
+ };
+
+ return err;
+}
+
+/**
+ * char_dev_poll() - Handle POLL call to the interface.
+ * @filp: Pointer to the file struct.
+ * @wait: Poll table supplied to caller.
+ *
+ * Returns:
+ * Mask of current set POLL values
+ */
+static unsigned int char_dev_poll(struct file *filp, poll_table *wait)
+{
+ struct char_dev_user *dev = filp->private_data;
+ struct cg2900_user_data *user;
+ unsigned int mask = 0;
+
+ if (!dev) {
+ pr_debug("Device not open");
+ return POLLERR | POLLRDHUP;
+ }
+
+ user = dev_get_platdata(dev->dev);
+
+ poll_wait(filp, &dev->reset_wait_queue, wait);
+ poll_wait(filp, &dev->rx_wait_queue, wait);
+
+ if (!user->opened)
+ mask |= POLLERR | POLLRDHUP | POLLPRI;
+ else
+ mask |= POLLOUT; /* We can TX unless there is an error */
+
+ if (!(skb_queue_empty(&dev->rx_queue)))
+ mask |= POLLIN | POLLRDNORM;
+
+ return mask;
+}
+
+/*
+ * struct char_dev_fops - Char devices file operations.
+ * @read: Function that reads from the char device.
+ * @write: Function that writes to the char device.
+ * @unlocked_ioctl: Function that performs IO operations with
+ * the char device.
+ * @poll: Function that checks if there are possible operations
+ * with the char device.
+ * @open: Function that opens the char device.
+ * @release: Function that release the char device.
+ */
+static const struct file_operations char_dev_fops = {
+ .read = char_dev_read,
+ .write = char_dev_write,
+ .unlocked_ioctl = char_dev_unlocked_ioctl,
+ .poll = char_dev_poll,
+ .open = char_dev_open,
+ .release = char_dev_release
+};
+
+/**
+ * remove_dev() - Remove char device structure for device.
+ * @dev_usr: Char device user.
+ *
+ * The remove_dev() function releases the char_dev structure for this device.
+ */
+static void remove_dev(struct char_dev_user *dev_usr)
+{
+ if (!dev_usr)
+ return;
+
+ dev_dbg(dev_usr->dev,
+ "Removing char device %s with major %d and minor %d\n",
+ dev_usr->name,
+ MAJOR(dev_usr->miscdev.this_device->devt),
+ MINOR(dev_usr->miscdev.this_device->devt));
+
+ skb_queue_purge(&dev_usr->rx_queue);
+
+ mutex_destroy(&dev_usr->read_mutex);
+ mutex_destroy(&dev_usr->write_mutex);
+
+ /* Remove device node in file system. */
+ misc_deregister(&dev_usr->miscdev);
+ kfree(dev_usr);
+}
+
+/**
+ * cg2900_char_probe() - Initialize char device module.
+ * @pdev: Platform device.
+ *
+ * Returns:
+ * 0 if success.
+ * -ENOMEM if allocation fails.
+ * -EACCES if device already have been initiated.
+ */
+static int __devinit cg2900_char_probe(struct platform_device *pdev)
+{
+ int err = 0;
+ struct char_dev_user *dev_usr;
+ struct cg2900_user_data *user;
+
+ dev_dbg(&pdev->dev, "cg2900_char_probe\n");
+
+ user = dev_get_platdata(&pdev->dev);
+ user->dev = &pdev->dev;
+ user->read_cb = char_dev_read_cb;
+ user->reset_cb = char_dev_reset_cb;
+
+ dev_usr = kzalloc(sizeof(*dev_usr), GFP_KERNEL);
+ if (!dev_usr) {
+ dev_err(&pdev->dev, "Couldn't allocate dev_usr\n");
+ return -ENOMEM;
+ }
+
+ dev_set_drvdata(&pdev->dev, dev_usr);
+ dev_usr->dev = &pdev->dev;
+
+ /* Store device name */
+ dev_usr->name = user->channel_data.char_dev_name;
+
+ /* Prepare miscdevice struct before registering the device */
+ dev_usr->miscdev.minor = MISC_DYNAMIC_MINOR;
+ dev_usr->miscdev.name = dev_usr->name;
+ dev_usr->miscdev.nodename = dev_usr->name;
+ dev_usr->miscdev.fops = &char_dev_fops;
+ dev_usr->miscdev.parent = &pdev->dev;
+ dev_usr->miscdev.mode = S_IRUGO | S_IWUGO;
+
+ err = misc_register(&dev_usr->miscdev);
+ if (err) {
+ dev_err(&pdev->dev, "Error %d registering misc dev\n", err);
+ goto err_free_usr;
+ }
+
+ dev_dbg(&pdev->dev, "Added char device %s with major %d and minor %d\n",
+ dev_usr->name, MAJOR(dev_usr->miscdev.this_device->devt),
+ MINOR(dev_usr->miscdev.this_device->devt));
+
+ mutex_init(&dev_usr->read_mutex);
+ mutex_init(&dev_usr->write_mutex);
+
+ skb_queue_head_init(&dev_usr->rx_queue);
+
+ mutex_lock(&char_info->man_mutex);
+ list_add_tail(&dev_usr->list, &char_info->dev_users);
+ mutex_unlock(&char_info->man_mutex);
+
+ return 0;
+
+err_free_usr:
+ kfree(dev_usr);
+ dev_set_drvdata(&pdev->dev, NULL);
+ return err;
+}
+
+/**
+ * cg2900_char_remove() - Release the char device module.
+ * @pdev: Platform device.
+ *
+ * Returns:
+ * 0 if success (always success).
+ */
+static int __devexit cg2900_char_remove(struct platform_device *pdev)
+{
+ struct list_head *cursor, *next;
+ struct char_dev_user *tmp;
+ struct char_dev_user *user;
+
+ dev_dbg(&pdev->dev, "cg2900_char_remove\n");
+
+ user = dev_get_drvdata(&pdev->dev);
+
+ mutex_lock(&char_info->man_mutex);
+ list_for_each_safe(cursor, next, &char_info->dev_users) {
+ tmp = list_entry(cursor, struct char_dev_user, list);
+ if (tmp == user) {
+ list_del(cursor);
+ remove_dev(tmp);
+ dev_set_drvdata(&pdev->dev, NULL);
+ break;
+ }
+ }
+ mutex_unlock(&char_info->man_mutex);
+ return 0;
+}
+
+static struct platform_driver cg2900_char_driver = {
+ .driver = {
+ .name = "cg2900-chardev",
+ .owner = THIS_MODULE,
+ },
+ .probe = cg2900_char_probe,
+ .remove = __devexit_p(cg2900_char_remove),
+};
+
+/**
+ * cg2900_char_init() - Initialize module.
+ *
+ * Registers platform driver.
+ */
+static int __init cg2900_char_init(void)
+{
+ pr_debug("cg2900_char_init");
+
+ /* Initialize private data. */
+ char_info = kzalloc(sizeof(*char_info), GFP_ATOMIC);
+ if (!char_info) {
+ pr_err("Could not alloc char_info struct");
+ return -ENOMEM;
+ }
+
+ mutex_init(&char_info->open_mutex);
+ mutex_init(&char_info->man_mutex);
+ INIT_LIST_HEAD(&char_info->dev_users);
+
+ return platform_driver_register(&cg2900_char_driver);
+}
+
+/**
+ * cg2900_char_exit() - Remove module.
+ *
+ * Unregisters platform driver.
+ */
+static void __exit cg2900_char_exit(void)
+{
+ struct list_head *cursor, *next;
+ struct char_dev_user *tmp;
+
+ pr_debug("cg2900_char_exit");
+
+ platform_driver_unregister(&cg2900_char_driver);
+
+ if (!char_info)
+ return;
+
+ list_for_each_safe(cursor, next, &char_info->dev_users) {
+ tmp = list_entry(cursor, struct char_dev_user, list);
+ list_del(cursor);
+ remove_dev(tmp);
+ }
+
+ mutex_destroy(&char_info->open_mutex);
+ mutex_destroy(&char_info->man_mutex);
+
+ kfree(char_info);
+ char_info = NULL;
+}
+
+module_init(cg2900_char_init);
+module_exit(cg2900_char_exit);
+
+MODULE_AUTHOR("Henrik Possung ST-Ericsson");
+MODULE_AUTHOR("Par-Gunnar Hjalmdahl ST-Ericsson");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ST-Ericsson CG2900 Char Devices Driver");
--
1.7.3.2