[PATCH v6] Bluetooth: btwilink driver

[pavan_savoy]

From: Pavan Savoy <pavan_savoy@xxxxxx>

Marcel, Gustavo,

comments attended to from v5,

1. Inside ti_st_open, I previously only checked for EINPROGRESS & EPERM,
ow I handle for EINPROGRESS - which is not really an error and
return during all other error cases.

2. _write is still a function pointer and not an exported function, I
need to change the underlying driver's code for this.
However, previous lkml comments on the underlying driver's code
suggested it to be kept as a function pointer and not EXPORT.
Gustavo, Marcel - Please comment on this.
Is this absolutely required? If so why?

3. test_and_set_bit of HCI_RUNNING is done at beginning of
ti_st_open, and did not see issues during firmware download.
However ideally I would still like to set HCI_RUNNING once the firmware
download is done, because I don't want to allow a _send_frame during
firmware download - Marcel, Gustavo - Please comment.

4. test_and_clear of HCI_RUNNING now done @ beginning of close.

5. EAGAIN on failure of st_write is to suggest to try and write again.
I have never this happen - However only if UART goes bad this case may
occur.

6. ti_st_tx_complete is very similar to hci_ldisc's tx_complete - in
fact the code is pretty much borrowed from there.
Marcel, Gustavo - Please suggest where should it be done? If not here.

7. comments cleaned-up + hst memory leak fixed when hci_alloc_dev fails.

8. platform_driver registration inside module_init now is similar to
other drivers.

Thanks for the comments...
Sorry, for previously not being very clear on which comments were
handled and which were not.

-- patch description --

This is the bluetooth protocol driver for the TI WiLink7 chipsets.
Texas Instrument's WiLink chipsets combine wireless technologies
like BT, FM, GPS and WLAN onto a single chip.

This Bluetooth driver works on top of the TI_ST shared transport
line discipline driver which also allows other drivers like
FM V4L2 and GPS character driver to make use of the same UART interface.

Kconfig and Makefile modifications to enable the Bluetooth
driver for Texas Instrument's WiLink 7 chipset.

Signed-off-by: Pavan Savoy <pavan_savoy@xxxxxx>
---
 drivers/bluetooth/Kconfig    |   10 ++
 drivers/bluetooth/Makefile   |    1 +
 drivers/bluetooth/btwilink.c |  362 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 373 insertions(+), 0 deletions(-)
 create mode 100644 drivers/bluetooth/btwilink.c

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 02deef4..8e0de9a 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -219,4 +219,14 @@ config BT_ATH3K
 	  Say Y here to compile support for "Atheros firmware download driver"
 	  into the kernel or say M to compile it as module (ath3k).
 
+config BT_WILINK
+	tristate "Texas Instruments WiLink7 driver"
+	depends on TI_ST
+	help
+	  This enables the Bluetooth driver for Texas Instrument's BT/FM/GPS
+	  combo devices. This makes use of shared transport line discipline
+	  core driver to communicate with the BT core of the combo chip.
+
+	  Say Y here to compile support for Texas Instrument's WiLink7 driver
+	  into the kernel or say M to compile it as module.
 endmenu
diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
index 71bdf13..f4460f4 100644
--- a/drivers/bluetooth/Makefile
+++ b/drivers/bluetooth/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_BT_HCIBTSDIO)	+= btsdio.o
 obj-$(CONFIG_BT_ATH3K)		+= ath3k.o
 obj-$(CONFIG_BT_MRVL)		+= btmrvl.o
 obj-$(CONFIG_BT_MRVL_SDIO)	+= btmrvl_sdio.o
+obj-$(CONFIG_BT_WILINK)		+= btwilink.o
 
 btmrvl-y			:= btmrvl_main.o
 btmrvl-$(CONFIG_DEBUG_FS)	+= btmrvl_debugfs.o
diff --git a/drivers/bluetooth/btwilink.c b/drivers/bluetooth/btwilink.c
new file mode 100644
index 0000000..2b83a12
--- /dev/null
+++ b/drivers/bluetooth/btwilink.c
@@ -0,0 +1,362 @@
+/*
+ *  Texas Instrument's Bluetooth Driver For Shared Transport.
+ *
+ *  Bluetooth Driver acts as interface between HCI core and
+ *  TI Shared Transport Layer.
+ *
+ *  Copyright (C) 2009-2010 Texas Instruments
+ *  Author: Raja Mani <raja_mani@xxxxxx>
+ *	Pavan Savoy <pavan_savoy@xxxxxx>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  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.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include <linux/ti_wilink_st.h>
+
+/* Bluetooth Driver Version */
+#define VERSION               "1.0"
+
+/* Number of seconds to wait for registration completion
+ * when ST returns PENDING status.
+ */
+#define BT_REGISTER_TIMEOUT   6000	/* 6 sec */
+
+/**
+ * struct ti_st - driver operation structure
+ * @hdev: hci device pointer which binds to bt driver
+ * @reg_status: ST registration callback status
+ * @st_write: write function provided by the ST driver
+ *	to be used by the driver during send_frame.
+ * @wait_reg_completion - completion sync between ti_st_open
+ *	and ti_st_registration_completion_cb.
+ */
+struct ti_st {
+	struct hci_dev *hdev;
+	char reg_status;
+	long (*st_write) (struct sk_buff *);
+	struct completion wait_reg_completion;
+};
+
+/* Increments HCI counters based on pocket ID (cmd,acl,sco) */
+static inline void ti_st_tx_complete(struct ti_st *hst, int pkt_type)
+{
+	struct hci_dev *hdev = hst->hdev;
+
+	/* Update HCI stat counters */
+	switch (pkt_type) {
+	case HCI_COMMAND_PKT:
+		hdev->stat.cmd_tx++;
+		break;
+
+	case HCI_ACLDATA_PKT:
+		hdev->stat.acl_tx++;
+		break;
+
+	case HCI_SCODATA_PKT:
+		hdev->stat.sco_tx++;
+		break;
+	}
+}
+
+/* ------- Interfaces to Shared Transport ------ */
+
+/* Called by ST layer to indicate protocol registration completion
+ * status.ti_st_open() function will wait for signal from this
+ * API when st_register() function returns ST_PENDING.
+ */
+static void st_registration_completion_cb(void *priv_data, char data)
+{
+	struct ti_st *lhst = priv_data;
+
+	/* Save registration status for use in ti_st_open() */
+	lhst->reg_status = data;
+	/* complete the wait in ti_st_open() */
+	complete(&lhst->wait_reg_completion);
+}
+
+/* Called by Shared Transport layer when receive data is
+ * available */
+static long st_receive(void *priv_data, struct sk_buff *skb)
+{
+	struct ti_st *lhst = priv_data;
+	int err;
+
+	if (!skb)
+		return -EFAULT;
+
+	if (!lhst) {
+		kfree_skb(skb);
+		return -EFAULT;
+	}
+
+	skb->dev = (void *) lhst->hdev;
+
+	/* Forward skb to HCI core layer */
+	err = hci_recv_frame(skb);
+	if (err < 0) {
+		BT_ERR("Unable to push skb to HCI core(%d)", err);
+		return err;
+	}
+
+	lhst->hdev->stat.byte_rx += skb->len;
+
+	return 0;
+}
+
+/* ------- Interfaces to HCI layer ------ */
+/* protocol structure registered with shared transport */
+static struct st_proto_s ti_st_proto = {
+	.type = ST_BT,
+	.recv = st_receive,
+	.reg_complete_cb = st_registration_completion_cb,
+};
+
+/* Called from HCI core to initialize the device */
+static int ti_st_open(struct hci_dev *hdev)
+{
+	unsigned long timeleft;
+	struct ti_st *hst;
+	int err;
+
+	BT_DBG("%s %p", hdev->name, hdev);
+	if (test_and_set_bit(HCI_RUNNING, &hdev->flags)) {
+		BT_ERR("btwilink already opened");
+		return -EBUSY;
+	}
+
+	/* provide contexts for callbacks from ST */
+	hst = hdev->driver_data;
+	ti_st_proto.priv_data = hst;
+
+	err = st_register(&ti_st_proto);
+	if (err == -EINPROGRESS) {
+		/* ST is busy with either protocol registration or firmware
+		 * download.
+		 */
+		/* Prepare wait-for-completion handler data structures.
+		 */
+		init_completion(&hst->wait_reg_completion);
+
+		/* Reset ST registration callback status flag , this value
+		 * will be updated in ti_st_registration_completion_cb()
+		 * function whenever it called from ST driver.
+		 */
+		hst->reg_status = -EINPROGRESS;
+
+		BT_DBG(" waiting for registration completion signal from ST");
+		timeleft = wait_for_completion_timeout
+			(&hst->wait_reg_completion,
+			 msecs_to_jiffies(BT_REGISTER_TIMEOUT));
+		if (!timeleft) {
+			clear_bit(HCI_RUNNING, &hdev->flags);
+			BT_ERR("Timeout(%d sec),didn't get reg "
+					"completion signal from ST",
+					BT_REGISTER_TIMEOUT / 1000);
+			return -ETIMEDOUT;
+		}
+
+		/* Is ST registration callback called with ERROR status? */
+		if (hst->reg_status != 0) {
+			clear_bit(HCI_RUNNING, &hdev->flags);
+			BT_ERR("ST registration completed with invalid "
+					"status %d", hst->reg_status);
+			return -EAGAIN;
+		}
+		err = 0;
+	} else if (err != 0) {
+		clear_bit(HCI_RUNNING, &hdev->flags);
+		BT_ERR("st_register failed %d", err);
+		return err;
+	}
+
+	/* ti_st_proto.write is filled up by the underlying shared
+	 * transport driver upon registration
+	 */
+	hst->st_write = ti_st_proto.write;
+	if (!hst->st_write) {
+		BT_ERR("undefined ST write function");
+		clear_bit(HCI_RUNNING, &hdev->flags);
+
+		/* Undo registration with ST */
+		err = st_unregister(ST_BT);
+		if (err)
+			BT_ERR("st_unregister() failed with error %d", err);
+
+		hst->st_write = NULL;
+		return err;
+	}
+
+	return err;
+}
+
+/* Close device */
+static int ti_st_close(struct hci_dev *hdev)
+{
+	int err;
+	struct ti_st *hst = hdev->driver_data;
+
+	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
+		return 0;
+
+	/* continue to unregister from transport */
+	err = st_unregister(ST_BT);
+	if (err)
+		BT_ERR("st_unregister() failed with error %d", err);
+
+	hst->st_write = NULL;
+
+	return err;
+}
+
+static int ti_st_send_frame(struct sk_buff *skb)
+{
+	struct hci_dev *hdev;
+	struct ti_st *hst;
+	long len;
+
+	hdev = (struct hci_dev *)skb->dev;
+
+	if (!test_bit(HCI_RUNNING, &hdev->flags))
+		return -EBUSY;
+
+	hst = hdev->driver_data;
+
+	/* Prepend skb with frame type */
+	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
+
+	BT_DBG(" %s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type,
+			skb->len);
+
+	/* Insert skb to shared transport layer's transmit queue.
+	 * Freeing skb memory is taken care in shared transport layer,
+	 * so don't free skb memory here.
+	 */
+	len = hst->st_write(skb);
+	if (len < 0) {
+		kfree_skb(skb);
+		BT_ERR(" ST write failed (%ld)", len);
+		/* Try Again, would only fail if UART has gone bad */
+		return -EAGAIN;
+	}
+
+	/* ST accepted our skb. So, Go ahead and do rest */
+	hdev->stat.byte_tx += len;
+	ti_st_tx_complete(hst, bt_cb(skb)->pkt_type);
+
+	return 0;
+}
+
+static void ti_st_destruct(struct hci_dev *hdev)
+{
+	BT_DBG("%s", hdev->name);
+	kfree(hdev->driver_data);
+}
+
+static int bt_ti_probe(struct platform_device *pdev)
+{
+	static struct ti_st *hst;
+	struct hci_dev *hdev;
+	int err;
+
+	hst = kzalloc(sizeof(struct ti_st), GFP_KERNEL);
+	if (!hst)
+		return -ENOMEM;
+
+	/* Expose "hciX" device to user space */
+	hdev = hci_alloc_dev();
+	if (!hdev) {
+		kfree(hst);
+		return -ENOMEM;
+	}
+
+	BT_DBG("hdev %p", hdev);
+
+	hst->hdev = hdev;
+	hdev->bus = HCI_UART;
+	hdev->driver_data = hst;
+	hdev->open = ti_st_open;
+	hdev->close = ti_st_close;
+	hdev->flush = NULL;
+	hdev->send = ti_st_send_frame;
+	hdev->destruct = ti_st_destruct;
+	hdev->owner = THIS_MODULE;
+
+	err = hci_register_dev(hdev);
+	if (err < 0) {
+		BT_ERR("Can't register HCI device error %d", err);
+		hci_free_dev(hdev);
+		return err;
+	}
+
+	BT_DBG(" HCI device registered (hdev %p)", hdev);
+
+	dev_set_drvdata(&pdev->dev, hst);
+	return err;
+}
+
+static int bt_ti_remove(struct platform_device *pdev)
+{
+	struct hci_dev *hdev;
+	struct ti_st *hst = dev_get_drvdata(&pdev->dev);
+
+	if (!hst)
+		return -EFAULT;
+
+	hdev = hst->hdev;
+	ti_st_close(hdev);
+	hci_unregister_dev(hdev);
+
+	hci_free_dev(hdev);
+	kfree(hst);
+
+	dev_set_drvdata(&pdev->dev, NULL);
+	return 0;
+}
+
+static struct platform_driver btwilink_driver = {
+	.probe = bt_ti_probe,
+	.remove = bt_ti_remove,
+	.driver = {
+		.name = "btwilink",
+		.owner = THIS_MODULE,
+	},
+};
+
+/* ------- Module Init/Exit interfaces ------ */
+static int __init btwilink_init(void)
+{
+	BT_INFO(" Bluetooth Driver for TI WiLink - Version %s", VERSION);
+
+	return platform_driver_register(&btwilink_driver);
+}
+
+static void __exit btwilink_exit(void)
+{
+	platform_driver_unregister(&btwilink_driver);
+}
+
+module_init(btwilink_init);
+module_exit(btwilink_exit);
+
+/* ------ Module Info ------ */
+
+MODULE_AUTHOR("Raja Mani <raja_mani@xxxxxx>");
+MODULE_DESCRIPTION("Bluetooth Driver for TI Shared Transport" VERSION);
+MODULE_VERSION(VERSION);
+MODULE_LICENSE("GPL");
-- 
1.5.6.3

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