Re: [PATCH] Bluetooth: TI_ST bluetooth driver
From: Gustavo F. Padovan
Date: Thu Oct 14 2010 - 15:31:10 EST
Hi Pavan,
* pavan_savoy@xxxxxx <pavan_savoy@xxxxxx> [2010-10-11 12:33:23 -0400]:
> From: Pavan Savoy <pavan_savoy@xxxxxx>
>
> Gustavo, Marcel,
>
> I have taken care of most of the comments which you provided.
> Couple of them like usage of goto's, I didn't handle since
> I am not doing much error handling repeatedly there.
>
> I have also removed the 2 states like _REGISTERED, _RUNNING which
> were not required and the flags associated with it.
> I have taken care of other style comments.
>
> Please review and provide your comments,
>
> -- 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 | 455 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 466 insertions(+), 0 deletions(-)
> create mode 100644 drivers/bluetooth/btwilink.c
>
> diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> index 02deef4..e0d67dd 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 "BlueZ bluetooth driver for TI ST"
> + 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..5351b62 100644
> --- a/drivers/bluetooth/Makefile
> +++ b/drivers/bluetooth/Makefile
> @@ -28,3 +28,4 @@ hci_uart-$(CONFIG_BT_HCIUART_BCSP) += hci_bcsp.o
> hci_uart-$(CONFIG_BT_HCIUART_LL) += hci_ll.o
> hci_uart-$(CONFIG_BT_HCIUART_ATH3K) += hci_ath.o
> hci_uart-objs := $(hci_uart-y)
> +obj-$(CONFIG_BT_WILINK) := btwilink.o
sort this after:
obj-$(CONFIG_BT_MRVL_SDIO) += btmrvl_sdio.o
> diff --git a/drivers/bluetooth/btwilink.c b/drivers/bluetooth/btwilink.c
> new file mode 100644
> index 0000000..e0bde79
> --- /dev/null
> +++ b/drivers/bluetooth/btwilink.c
> @@ -0,0 +1,455 @@
> +/*
> + * 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"
> +
> +/* Defines number of seconds to wait for reg completion
> + * callback getting called from ST (in case,registration
> + * with ST returns PENDING status)
> + */
> +#define BT_REGISTER_TIMEOUT 6000 /* 6 sec */
> +
> +/**
> + * struct ti_st - BT driver operation structure
> + * @hdev: hci device pointer which binds to bt driver
> + * @flags: used locally,to maintain various BT driver status
> + * @streg_cbdata: to hold ST registration callback status
> + * @st_write: write function pointer of ST driver
> + * @wait_for_btdrv_reg_completion - completion sync between ti_st_open
> + * and ti_st_registration_completion_cb.
> + */
> +struct ti_st {
> + struct hci_dev *hdev;
> + char streg_cbdata;
> + long (*st_write) (struct sk_buff *);
> + struct completion wait_for_btdrv_reg_completion;
wait_for_btdrv_reg_completion is too big.
> +};
> +
> +static int reset;
> +
> +/* 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;
> + 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 = (struct ti_st *)priv_data;
> + /* ti_st_open() function needs value of 'data' to know
> + * the registration status(success/fail),So have a back
> + * up of it.
> + */
> + lhst->streg_cbdata = data;
> +
> + /* Got a feedback from ST for BT driver registration
> + * request.Wackup ti_st_open() function to continue
> + * it's open operation.
> + */
> + complete(&lhst->wait_for_btdrv_reg_completion);
> +}
> +
> +/* Called by Shared Transport layer when receive data is
> + * available */
> +static long st_receive(void *priv_data, struct sk_buff *skb)
> +{
> + int err;
> + struct ti_st *lhst = (struct ti_st *)priv_data;
> +
> + if (skb == NULL) {
> + BT_ERR("Invalid SKB received from ST");
I don't think this error message is worth.
> + return -EFAULT;
> + }
Make this (!skb) or the check below (lhst == NULL). Try to use only one
pattern in your code.
> +
> + if (!lhst) {
> + kfree_skb(skb);
> + BT_ERR("Invalid ti_st memory,freeing SKB");
I don't think this error message is worth.
> + return -EFAULT;
> + }
> +
> + skb->dev = (struct net_device *)lhst->hdev;
Blank line here.
> + /* Forward skb to HCI CORE layer */
> + err = hci_recv_frame(skb);
> + if (err) {
> + kfree_skb(skb);
> + BT_ERR("Unable to push skb to HCI CORE(%d),freeing SKB",
Turn this message into:
"Unable to push skb to HCI core(%d)"
> + err);
> + return err;
> + }
> +
> + lhst->hdev->stat.byte_rx += skb->len;
> + return 0;
> +}
> +
> +/* ------- Interfaces to HCI layer ------ */
> +
> +/* Called from HCI core to initialize the device */
> +static int ti_st_open(struct hci_dev *hdev)
> +{
> + static struct st_proto_s ti_st_proto;
Usually we declare this outside of the function like this:
static struct usb_driver ath3k_driver = {
.name = "ath3k",
.probe = ath3k_probe,
.disconnect = ath3k_disconnect,
.id_table = ath3k_table,
};
> + unsigned long timeleft;
> + struct ti_st *hst;
> + int err;
> + err = 0;
No need to set err to 0 here.
> +
> + BT_DBG("%s %p", hdev->name, hdev);
Skip a line here.
> + hst = hdev->driver_data;
> +
> + /* Populate BT driver info required by ST */
> + memset(&ti_st_proto, 0, sizeof(ti_st_proto));
> +
> + /* BT driver ID */
> + ti_st_proto.type = ST_BT;
> +
> + /* Receive function which called from ST */
> + ti_st_proto.recv = st_receive;
> +
> + /* Callback to be called when registration is pending */
> + ti_st_proto.reg_complete_cb = st_registration_completion_cb;
> +
> + /* send in the hst to be received at registration complete callback
> + * and during st's receive
> + */
> + ti_st_proto.priv_data = hst;
> +
> + /* Register with ST layer */
No need for this comment, your function name already set that.
> + err = st_register(&ti_st_proto);
> + if (err == -EINPROGRESS) {
> + /* Prepare wait-for-completion handler data structures.
> + * Needed to syncronize this and st_registration_completion_cb()
> + * functions.
> + */
> + init_completion(&hst->wait_for_btdrv_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->streg_cbdata = -EINPROGRESS;
> +
> + /* ST is busy with other protocol registration(may be busy with
> + * firmware download).So,Wait till the registration callback
> + * (passed as a argument to st_register() function) getting
> + * called from ST.
> + */
> + BT_DBG(" %s waiting for reg completion signal from ST",
> + __func__);
BT_DBG already have __func__.
> +
> + timeleft =
> + wait_for_completion_timeout
this could be:
timeleft = wait_for_completion_timeout
> + (&hst->wait_for_btdrv_reg_completion,
> + msecs_to_jiffies(BT_REGISTER_TIMEOUT));
> + if (!timeleft) {
> + 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 value? */
> + if (hst->streg_cbdata != 0) {
> + BT_ERR("ST reg completion CB called with invalid"
> + "status %d", hst->streg_cbdata);
> + return -EAGAIN;
> + }
> + err = 0;
> + } else if (err == -1) {
Use the error macro instead of -1
> + BT_ERR("st_register failed %d", err);
> + return -EAGAIN;
> + }
> +
> + /* Do we have proper ST write function? */
> + if (ti_st_proto.write != NULL) {
> + /* We need this pointer for sending any Bluetooth pkts */
> + hst->st_write = ti_st_proto.write;
Didn't get this. Who sets ti_st_proto.write()?
> + } else {
> + BT_ERR("failed to get ST write func pointer");
> +
> + /* Undo registration with ST */
> + err = st_unregister(ST_BT);
> + if (err < 0)
> + BT_ERR("st_unregister failed %d", err);
> +
> + hst->st_write = NULL;
> + return -EAGAIN;
> + }
> +
> + /* Registration with ST layer is completed successfully,
> + * now chip is ready to accept commands from HCI CORE.
> + * Mark HCI Device flag as RUNNING
> + */
I don't think this comment is worth, your code already says that.
But one can argue here that comments are always good. ;)
> + set_bit(HCI_RUNNING, &hdev->flags);
> + return err;
> +}
> +
> +/* Close device */
> +static int ti_st_close(struct hci_dev *hdev)
> +{
> + int err = 0;
> + struct ti_st *hst;
> +
> + hst = hdev->driver_data;
> +
> + /* Clear HCI device RUNNING flag */
> + if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
> + BT_ERR("HCI not RUNNING?");
That's is not a error, just return 0.
> +
> + /* continue to unregister from transport */
> + err = st_unregister(ST_BT);
> + if (err != 0) {
> + hst->st_write = NULL;
> + BT_ERR("st_unregister failed %d", err);
> + return -EBUSY;
> + }
> +
> + hst->st_write = NULL;
> + return err;
This should be better:
if (err)
BT_ERR("st_unregister failed %d", err);
hst->st_write = NULL;
return err;
> +}
> +
> +/* Called from HCI CORE , Sends frames to Shared Transport */
> +static int ti_st_send_frame(struct sk_buff *skb)
> +{
> + struct hci_dev *hdev;
> + struct ti_st *hst;
> + long len;
> +
> + if (skb == NULL) {
> + BT_ERR("Invalid skb received from HCI CORE");
> + return -ENOMEM;
> + }
> +
> + hdev = (struct hci_dev *)skb->dev;
> + if (!hdev) {
> + BT_ERR("SKB received for invalid HCI Device (hdev=NULL)");
> + return -ENODEV;
> + }
> +
> + if (!test_bit(HCI_RUNNING, &hdev->flags)) {
> + BT_ERR("Device is not running");
Remove the last 3 BT_ERR
> + return -EBUSY;
> + }
> +
> + hst = (struct ti_st *)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.
> + */
> + if (!hst->st_write) {
> + kfree_skb(skb);
> + BT_ERR(" Can't write to ST, st_write null?");
> + return -EAGAIN;
> + }
> +
> + len = hst->st_write(skb);
> + if (len < 0) {
> + kfree_skb(skb);
> + BT_ERR(" ST write failed (%ld)", len);
> + 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)
> +{
> + if (!hdev) {
> + BT_ERR("Destruct called with invalid HCI Device"
> + "(hdev=NULL)");
> + return;
> + }
> +
> + BT_DBG("%s", hdev->name);
> +
> + /* free ti_st memory */
> + if (hdev->driver_data != NULL)
> + kfree(hdev->driver_data);
> +
> + return;
No return; here
> +}
> +
> +/* Creates new HCI device */
> +static int ti_st_register_dev(struct ti_st *hst)
> +{
> + struct hci_dev *hdev;
> +
> + /* Initialize and register HCI device */
> + hdev = hci_alloc_dev();
> + if (!hdev) {
> + BT_ERR("Can't allocate HCI device");
> + return -ENOMEM;
> + }
> + BT_DBG(" HCI device allocated. 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;
> +
> + if (reset)
> + set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
> +
> + if (hci_register_dev(hdev) < 0) {
> + BT_ERR("Can't register HCI device");
> + hci_free_dev(hdev);
> + return -ENODEV;
> + }
> +
> + BT_DBG(" HCI device registered. hdev= %p", hdev);
> + return 0;
> +}
> +
> +
> +static int bt_ti_probe(struct platform_device *pdev)
> +{
> + int err;
> + static struct ti_st *hst;
> + err = 0;
> +
> + BT_DBG(" Bluetooth Driver Version %s", VERSION);
> +
> + /* Allocate local resource memory */
I don't think this comment is needed.
> + hst = kzalloc(sizeof(struct ti_st), GFP_KERNEL);
> + if (!hst) {
> + BT_ERR("Can't allocate control structure");
remove the BT_ERR
> + return -ENFILE;
-ENOMEM
> + }
> +
> + /* Expose "hciX" device to user space */
> + err = ti_st_register_dev(hst);
> + if (err) {
> + /* Release local resource memory */
I don't think this comment is needed.
> + kfree(hst);
> +
> + BT_ERR("Unable to expose hci0 device(%d)", err);
Are you sure that this is hci0?
> + return err;
> + }
> +
> + dev_set_drvdata(&pdev->dev, hst);
> + return err;
> +}
> +
> +static int bt_ti_remove(struct platform_device *pdev)
> +{
> + struct ti_st *hst;
> +
> + hst = dev_get_drvdata(&pdev->dev);
> + /* Deallocate local resource's memory */
> + if (hst) {
> + struct hci_dev *hdev = hst->hdev;
> + if (hdev == NULL) {
> + BT_ERR("Invalid hdev memory");
> + kfree(hst);
> + } else {
> + ti_st_close(hdev);
> + hci_unregister_dev(hdev);
> + /* Free HCI device memory */
> + hci_free_dev(hdev);
> + }
> + }
> + return 0;
> +}
> +
> +static struct platform_driver bt_ti_driver = {
> + .probe = bt_ti_probe,
> + .remove = bt_ti_remove,
> + .driver = {
> + .name = "ti_st_bluetooth",
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +/* ------- Module Init/Exit interfaces ------ */
> +static int __init bt_drv_init(void)
> +{
> +long ret = 0;
Skip a line and don't set ret to 0.
> + ret = platform_driver_register(&bt_ti_driver);
> + if (ret != 0) {
> + BT_ERR("bt_ti platform drv registration failed");
> + return -1;
Why -1?
> + }
> + return 0;
> +}
> +
> +static void __exit bt_drv_exit(void)
> +{
> + platform_driver_unregister(&bt_ti_driver);
> +}
> +
> +module_init(bt_drv_init);
> +module_exit(bt_drv_exit);
> +
> +/* ------ Module Info ------ */
> +
> +module_param(reset, bool, 0644);
> +MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
> +MODULE_AUTHOR("Raja Mani <raja_mani@xxxxxx>");
> +MODULE_DESCRIPTION("Bluetooth Driver for TI Shared Transport" VERSION);
> +MODULE_VERSION(VERSION);
> +MODULE_LICENSE("GPL");
> --
> 1.6.5
>
> --
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--
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi
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