mfd/cg2900: Support HCI Raw Channel.

Add support for HCI Raw channel so that CG2900
can be accessed directly from user space.

ST-Ericsson Linux next: Not tested, ER351170
ST-Ericsson ID: 351170
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: If8a2455be32f0eb99f7c0bc7a5cf0e09270fa6af
Signed-off-by: Hemant Gupta <hemant.gupta@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/32206
Reviewed-by: Henrik POSSUNG <henrik.possung@stericsson.com>
Reviewed-by: Par-Gunnar HJALMDAHL <par-gunnar.p.hjalmdahl@stericsson.com>

3 files changed, 211 insertions, 6 deletions

diff --git a/Documentation/DocBook/cg2900.tmpl b/Documentation/DocBook/cg2900.tmpl
index 318bb8e7d2e..34667f1b1d9 100644
--- a/Documentation/DocBook/cg2900.tmpl
+++ b/Documentation/DocBook/cg2900.tmpl
@@ -1268,6 +1268,24 @@
        </listitem>
      </varlistentry>
 
+     <varlistentry>
+       <term>HCI Raw</term>
+       <listitem>
+         <variablelist>
+           <varlistentry>
+             <term>File</term>
+             <listitem><para><filename>/dev/cg2900_hci_raw</filename></para></listitem>
+           </varlistentry>
+           <varlistentry>
+             <term>Description</term>
+             <listitem>
+             <para>The cg2900_hci_raw is the device for raw access to HCI interface.</para>
+             </listitem>
+           </varlistentry>
+         </variablelist>
+       </listitem>
+     </varlistentry>
+
     </variablelist>
   </section>
 
@@ -1297,6 +1315,24 @@
          </para>
        </listitem>
      </varlistentry>
+     <varlistentry>
+       <term>HCI Raw channel requires exclusive access to chip.</term>
+       <listitem>
+         <para>
+           cg2900_hci_raw channel cannot be opened if there are any other channels already opened except hci_logger channel.
+           Also any other channels cannot be opened except hci_logger channel when cg2900_hci_raw is already opened.
+           This is to guarantee that different users won't interfere with each other and prevent flow control issues.
+           <!-- TODO: Briefly describe the limitation, unless all
+              information is already present in the title.
+              Use full english sentences.
+              Repeat the varlistentry for each limitation.
+              If none are known, replace this varlistentry
+              with the one below. -->
+           <!-- TODO: This guideline for this chapter may be extended
+              during the user-guide guidelines drop. -->
+         </para>
+       </listitem>
+     </varlistentry>
      </variablelist>
    </para>
  </chapter>
diff --git a/drivers/staging/cg2900/mfd/cg2900_char_devices.c b/drivers/staging/cg2900/mfd/cg2900_char_devices.c
index ae1659c4a5e..81d230227db 100644
--- a/drivers/staging/cg2900/mfd/cg2900_char_devices.c
+++ b/drivers/staging/cg2900/mfd/cg2900_char_devices.c
@@ -210,6 +210,9 @@ static int char_dev_release(struct inode *inode, struct file *filp)
 	wake_up_interruptible(&dev->rx_wait_queue);
 	wake_up_interruptible(&dev->reset_wait_queue);
 
+	/* Purge the queue since the device is closed now */
+	skb_queue_purge(&dev->rx_queue);
+
 	mutex_unlock(&dev->write_mutex);
 	mutex_unlock(&dev->read_mutex);
 	mutex_unlock(&char_info->open_mutex);
diff --git a/drivers/staging/cg2900/mfd/cg2900_chip.c b/drivers/staging/cg2900/mfd/cg2900_chip.c
index c438ef0bc9c..020f7c906ad 100644
--- a/drivers/staging/cg2900/mfd/cg2900_chip.c
+++ b/drivers/staging/cg2900/mfd/cg2900_chip.c
@@ -111,6 +111,11 @@
  */
 #define CHANNEL_CORE				0xFD
 
+/** CHANNEL_HCI_RAW - Bluetooth HCI H:4 channel
+ * for user space read/write on the ST-Ericsson connectivity controller.
+ */
+#define CHANNEL_HCI_RAW				0xFE
+
 /** CG2900_BT_CMD - Bluetooth HCI H4 channel for Bluetooth commands.
  */
 #define CG2900_BT_CMD				"cg2900_bt_cmd"
@@ -161,6 +166,12 @@
  */
 #define CG2900_CORE				"cg2900_core"
 
+/** CG2900_HCI_RAW - Channel for HCI RAW data exchange.
+ * Opening this channel will not allow any others HCI Channels
+ * to be opened except Logger Channel.
+ */
+#define CG2900_HCI_RAW				"cg2900_hci_raw"
+
 /**
  * enum main_state - Main-state for CG2900 driver.
  * @CG2900_INIT:	CG2900 initializing.
@@ -330,6 +341,7 @@ struct cg2900_skb_data {
  *				this will never be set for bt_audio and
  *				fm_audio.
  * @logger:			Logger user of this chip.
+ * @hci_raw:			HCI Raw user of this chip.
  * @selftest_work:		Delayed work for reading selftest results.
  * @nbr_of_polls:		Number of times we should poll for selftest
  *				results.
@@ -364,6 +376,7 @@ struct cg2900_chip_info {
 	struct cg2900_user_data		*user_in_charge;
 	struct cg2900_user_data		*last_user;
 	struct cg2900_user_data		*logger;
+	struct cg2900_user_data		*hci_raw;
 	struct cg2900_user_data		*bt_audio;
 	struct cg2900_user_data		*fm_audio;
 	struct cg2900_delayed_work_struct	selftest_work;
@@ -2089,6 +2102,16 @@ static void data_from_chip(struct cg2900_chip_dev *dev,
 		cg2900_send_to_hci_logger(info->logger, skb,
 						LOGGER_DIRECTION_RX);
 
+	/*
+	 * HCI Raw user can only have exclusive access to chip, there won't be
+	 * other users once it's opened.
+	 */
+	if (info->hci_raw && info->hci_raw->opened) {
+		info->hci_raw->read_cb(info->hci_raw, skb);
+		spin_unlock_bh(&info->rw_lock);
+		return;
+	}
+
 	h4_channel = skb->data[0];
 	skb_pull(skb, HCI_H4_SIZE);
 
@@ -2323,6 +2346,15 @@ static int cg2900_open(struct cg2900_user_data *user)
 	dev = cg2900_get_prv(user);
 	info = dev->c_data;
 
+	/* HCI Raw channel shall have exclusive access to chip. */
+	if (info->hci_raw && user->h4_channel != CHANNEL_HCI_RAW &&
+		user->h4_channel != CHANNEL_HCI_LOGGER) {
+		dev_err(user->dev, "cg2900_open: Cannot open %s "
+			"channel while HCI Raw channel is opened\n",
+			user->channel_data.char_dev_name);
+		return -EACCES;
+	}
+
 	mutex_lock(&main_info->man_mutex);
 
 	/*
@@ -2437,7 +2469,7 @@ err_free_mutex:
  * Returns:
  *   0 if success.
  *   -EINVAL if user is NULL.
- *   -EACCES if H4 channel is already opened.
+ *   -EEXIST if H4 channel is already opened.
  *   Error codes generated by cg2900_open.
  */
 static int cg2900_hci_log_open(struct cg2900_user_data *user)
@@ -2461,7 +2493,7 @@ static int cg2900_hci_log_open(struct cg2900_user_data *user)
 
 	if (info->logger) {
 		dev_err(user->dev, "HCI Logger already stored\n");
-		return -EACCES;
+		return -EEXIST;
 	}
 
 	info->logger = user;
@@ -2472,6 +2504,69 @@ static int cg2900_hci_log_open(struct cg2900_user_data *user)
 }
 
 /**
+ * cg2900_hci_raw_open() - Called when user wants to open HCI Raw channel.
+ * @user:	MFD device to open.
+ *
+ * Registers user as hci_raw and calls @cg2900_open to open the channel.
+ *
+ * Returns:
+ *   0 if success.
+ *   -EINVAL if user is NULL.
+ *   -EEXIST if H4 channel is already opened.
+ *   -EACCES if H4 channel iother than HCI RAW is already opened.
+ *   Error codes generated by cg2900_open.
+ */
+static int cg2900_hci_raw_open(struct cg2900_user_data *user)
+{
+	struct cg2900_chip_dev *dev;
+	struct cg2900_chip_info *info;
+	struct list_head *cursor;
+	struct cg2900_channel_item *tmp;
+	int err;
+
+	BUG_ON(!main_info);
+
+	if (!user) {
+		dev_err(MAIN_DEV,
+			"cg2900_hci_raw_open: Calling with NULL pointer\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(user->dev, "cg2900_hci_raw_open\n");
+
+	dev = cg2900_get_prv(user);
+	info = dev->c_data;
+
+	if (info->hci_raw) {
+		dev_err(user->dev, "HCI Raw Channel already stored\n");
+		return -EEXIST;
+	}
+
+	if (!list_empty(&info->open_channels)) {
+		/*
+		 * Go through each open channel to check if it is logger
+		 * channel or some other channel.
+		 */
+		list_for_each(cursor, &info->open_channels) {
+			tmp = list_entry(cursor,
+					struct cg2900_channel_item, list);
+			if (tmp->user->h4_channel != CHANNEL_HCI_LOGGER) {
+				dev_err(user->dev, "Other channels other than "
+					"Logger is already opened. Cannot open "
+					"HCI Raw Channel\n");
+				return -EACCES;
+			}
+		}
+	}
+
+	info->hci_raw = user;
+	err = cg2900_open(user);
+	if (err)
+		info->hci_raw = NULL;
+	return err;
+}
+
+/**
  * cg2900_bt_audio_open() - Called when user wants to open BT audio channel.
  * @user:	MFD device to open.
  *
@@ -2480,7 +2575,7 @@ static int cg2900_hci_log_open(struct cg2900_user_data *user)
  * Returns:
  *   0 if success.
  *   -EINVAL if user is NULL.
- *   -EACCES if H4 channel is already opened.
+ *   -EEXIST if H4 channel is already opened.
  *   Error codes generated by cg2900_open.
  */
 static int cg2900_bt_audio_open(struct cg2900_user_data *user)
@@ -2504,7 +2599,7 @@ static int cg2900_bt_audio_open(struct cg2900_user_data *user)
 
 	if (info->bt_audio) {
 		dev_err(user->dev, "BT Audio already stored\n");
-		return -EACCES;
+		return -EEXIST;
 	}
 
 	info->bt_audio = user;
@@ -2523,7 +2618,7 @@ static int cg2900_bt_audio_open(struct cg2900_user_data *user)
  * Returns:
  *   0 if success.
  *   -EINVAL if user is NULL.
- *   -EACCES if H4 channel is already opened.
+ *   -EEXIST if H4 channel is already opened.
  *   Error codes generated by cg2900_open.
  */
 static int cg2900_fm_audio_open(struct cg2900_user_data *user)
@@ -2547,7 +2642,7 @@ static int cg2900_fm_audio_open(struct cg2900_user_data *user)
 
 	if (info->fm_audio) {
 		dev_err(user->dev, "FM Audio already stored\n");
-		return -EACCES;
+		return -EEXIST;
 	}
 
 	info->fm_audio = user;
@@ -2675,6 +2770,40 @@ static void cg2900_hci_log_close(struct cg2900_user_data *user)
 }
 
 /**
+ * cg2900_hci_raw_close() - Called when user wants to close HCI Raw channel.
+ * @user:	MFD device to close.
+ *
+ * Clears hci_raw user and calls @cg2900_close to close the channel.
+ */
+static void cg2900_hci_raw_close(struct cg2900_user_data *user)
+{
+	struct cg2900_chip_dev *dev;
+	struct cg2900_chip_info *info;
+
+	BUG_ON(!main_info);
+
+	if (!user) {
+		dev_err(MAIN_DEV,
+			"cg2900_hci_raw_close: Calling with NULL pointer\n");
+		return;
+	}
+
+	dev_dbg(user->dev, "cg2900_hci_raw_close\n");
+
+	dev = cg2900_get_prv(user);
+	info = dev->c_data;
+
+	if (user != info->hci_raw) {
+		dev_err(user->dev, "cg2900_hci_raw_close: Trying to remove "
+			"another user\n");
+		return;
+	}
+
+	info->hci_raw = NULL;
+	cg2900_close(user);
+}
+
+/**
  * cg2900_bt_audio_close() - Called when user wants to close BT audio channel.
  * @user:	MFD device to close.
  *
@@ -2872,6 +3001,18 @@ static int cg2900_write(struct cg2900_user_data *user, struct sk_buff *skb)
 		return -EACCES;
 	}
 
+	if (user->h4_channel == CHANNEL_HCI_RAW) {
+		/*
+		 * Since the data transmitted on HCI Raw channel
+		 * can be byte by byte, flow control cannot be used.
+		 * This should be handled by user space application
+		 * of the HCI Raw channel, so just transmit the
+		 * received data to chip.
+		 */
+		cg2900_tx_to_chip(user, info->logger, skb);
+		return 0;
+	}
+
 	/*
 	 * Move the data pointer to the H:4 header position and
 	 * store the H4 header.
@@ -2983,6 +3124,11 @@ static struct cg2900_user_data audio_fm_data = {
 	.open = cg2900_fm_audio_open,
 	.close = cg2900_fm_audio_close,
 };
+static struct cg2900_user_data hci_raw_data = {
+	.h4_channel = CHANNEL_HCI_RAW,
+	.open = cg2900_hci_raw_open,
+	.close = cg2900_hci_raw_close,
+};
 
 static struct mfd_cell cg2900_devs[] = {
 	{
@@ -3040,6 +3186,11 @@ static struct mfd_cell cg2900_devs[] = {
 		.platform_data = &audio_fm_data,
 		.pdata_size = sizeof(audio_fm_data),
 	},
+	{
+		.name = "cg2900-hciraw",
+		.platform_data = &hci_raw_data,
+		.pdata_size = sizeof(hci_raw_data),
+	},
 };
 
 static struct cg2900_user_data char_btcmd_data = {
@@ -3115,6 +3266,15 @@ static struct cg2900_user_data char_audio_fm_data = {
 	.h4_channel = CHANNEL_FM_RADIO,
 	.is_audio = true,
 };
+static struct cg2900_user_data char_hci_raw_data = {
+	.channel_data = {
+		.char_dev_name = CG2900_HCI_RAW,
+	},
+	.h4_channel = CHANNEL_HCI_RAW,
+	.open = cg2900_hci_raw_open,
+	.close = cg2900_hci_raw_close,
+};
+
 
 static struct mfd_cell cg2900_char_devs[] = {
 	{
@@ -3183,6 +3343,12 @@ static struct mfd_cell cg2900_char_devs[] = {
 		.platform_data = &char_audio_fm_data,
 		.pdata_size = sizeof(char_audio_fm_data),
 	},
+	{
+		.name = "cg2900-chardev",
+		.id = 11,
+		.platform_data = &char_hci_raw_data,
+		.pdata_size = sizeof(char_hci_raw_data),
+	},
 };
 
 /**