Re: [PATCH 1/2] drivers:bluetooth: TI_ST bluetooth driver

Gustavo F. Padovan
2010-10-07T21:45:21Z

Hi Pavan,

Change the commit subject to "Bluetooth: TI_ST bluetooth driver"

* pavan_savoy@ti.com <pavan_savoy@ti.com> [2010-10-07 14:47:16 -0400]:

> From: Pavan Savoy <pavan_savoy@ti.com>
>
> 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.
>
> Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
> ---
> drivers/bluetooth/bt_ti.c | 489 +++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 489 insertions(+), 0 deletions(-)
> create mode 100644 drivers/bluetooth/bt_ti.c

We don't have filename with bt_.. in drivers/bluetooth/. Maybe ti_st.c
should be a better name, or something like that.

>
> diff --git a/drivers/bluetooth/bt_ti.c b/drivers/bluetooth/bt_ti.c
> new file mode 100644
> index 0000000..dffbb56
> --- /dev/null
> +++ b/drivers/bluetooth/bt_ti.c
> @@ -0,0 +1,489 @@
> +/*
> + * 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@ti.com>
> + * Pavan Savoy <pavan_savoy@ti.com>
> + *
> + * 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 */
> +
> +/* BT driver's local status */
> +#define BT_DRV_RUNNING 0
> +#define BT_ST_REGISTERED 1
> +
> +/**
> + * struct hci_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 hci_st_open
> + * and hci_st_registration_completion_cb.
> + */
> +struct hci_st {
> + struct hci_dev *hdev;
> + unsigned long flags;
> + char streg_cbdata;
> + long (*st_write) (struct sk_buff *);
> + struct completion wait_for_btdrv_reg_completion;
> +};
> +
> +static int reset;
> +
> +/* Increments HCI counters based on pocket ID (cmd,acl,sco) */
> +static inline void hci_st_tx_complete(struct hci_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.cmd_tx++;

it should be sco_tx here.

> + break;
> + }
> +}
> +
> +/* ------- Interfaces to Shared Transport ------ */
> +
> +/* Called by ST layer to indicate protocol registration completion
> + * status.hci_st_open() function will wait for signal from this
> + * API when st_register() function returns ST_PENDING.
> + */
> +static void hci_st_registration_completion_cb(void *priv_data, char data)

That is not the hci layer, so rename this function (and the others) to
something that reflect where they are really doing.

> +{
> + struct hci_st *lhst = (struct hci_st *)priv_data;
> + /* hci_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 hci_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 hci_st_receive(void *priv_data, struct sk_buff *skb)
> +{
> + int err;
> + int len;

you can put err and len in the same line.

> + struct hci_st *lhst = (struct hci_st *)priv_data;
> +
> + err = 0;
> + len = 0;

and no need to set them to 0 here.

> +
> + if (skb == NULL) {
> + BT_ERR("Invalid SKB received from ST");
> + return -EFAULT;
> + }

We need a empty line here.

> + if (!lhst) {
> + kfree_skb(skb);
> + BT_ERR("Invalid hci_st memory,freeing SKB");
> + return -EFAULT;
> + }

And also here. Check the rest of the code for similar issues.

> + if (!test_bit(BT_DRV_RUNNING, &lhst->flags)) {
> + kfree_skb(skb);
> + BT_ERR("Device is not running,freeing SKB");
> + return -EINVAL;
> + }

If you are here, your device is running, right? Or am I missing
something?

> +
> + len = skb->len;
> + skb->dev = (struct net_device *)lhst->hdev;
> +
> + /* 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",
> + err);
> + return err;
> + }
> + lhst->hdev->stat.byte_rx += len;

actually you even don't need len, just use skb->len

> +
> + return 0;
> +}
> +
> +/* ------- Interfaces to HCI layer ------ */
> +
> +/* Called from HCI core to initialize the device */
> +static int hci_st_open(struct hci_dev *hdev)
> +{
> + static struct st_proto_s hci_st_proto;
> + unsigned long timeleft;
> + struct hci_st *hst;
> + int err;
> + err = 0;
> +
> + BT_DBG("%s %p", hdev->name, hdev);
> + hst = hdev->driver_data;
> +
> + /* Populate BT driver info required by ST */
> + memset(&hci_st_proto, 0, sizeof(hci_st_proto));
> +
> + /* BT driver ID */
> + hci_st_proto.type = ST_BT;
> +
> + /* Receive function which called from ST */
> + hci_st_proto.recv = hci_st_receive;
> +
> + /* Packet match function may used in future */
> + hci_st_proto.match_packet = NULL;

It is already NULL, you dua a memset.

> +
> + /* Callback to be called when registration is pending */
> + hci_st_proto.reg_complete_cb = hci_st_registration_completion_cb;
> +
> + /* This is write function pointer of ST. BT driver will make use of this
> + * for sending any packets to chip. ST will assign and give to us, so
> + * make it as NULL */
> + hci_st_proto.write = NULL;

Same here.

> +
> + /* send in the hst to be received at registration complete callback
> + * and during st's receive
> + */
> + hci_st_proto.priv_data = hst;
> +
> + /* Register with ST layer */
> + err = st_register(&hci_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);

I'm not liking that, but I'll leave for Marcel and others comment.

> +
> + /* Reset ST registration callback status flag , this value
> + * will be updated in hci_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__);
> +
> + 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 proper error macro instead "-1"

> + BT_ERR("st_register failed %d", err);
> + return -EAGAIN;
> + }
> +
> + /* Do we have proper ST write function? */
> + if (hci_st_proto.write != NULL) {
> + /* We need this pointer for sending any Bluetooth pkts */
> + hst->st_write = hci_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
> + */
> + set_bit(HCI_RUNNING, &hdev->flags);
> +
> + /* Registration with ST successful */
> + set_bit(BT_ST_REGISTERED, &hst->flags);
> +
> + return err;
> +}
> +
> +/* Close device */
> +static int hci_st_close(struct hci_dev *hdev)
> +{
> + int err;
> + struct hci_st *hst;

Skip a line after declarations.

> + err = 0;

you can set err to 0 in the declaration if you really need that.

> +
> + hst = hdev->driver_data;
> + /* Unregister from ST layer */
> + if (test_and_clear_bit(BT_ST_REGISTERED, &hst->flags)) {
> + err = st_unregister(ST_BT);
> + if (err != 0) {
> + BT_ERR("st_unregister failed %d", err);
> + return -EBUSY;
> + }
> + }
> +
> + hst->st_write = NULL;
> +
> + /* ST layer would have moved chip to inactive state.
> + * So,clear HCI device RUNNING flag.
> + */
> + if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
> + return 0;

Looks you are screwing up the flags here, if it fails on st_unregister()
and returns HCI_RUNNING should keep set?

> +
> + return err;

Rethink how you are doing error handling here, it should no be
complicated like that.

> +}
> +
> +/* Called from HCI CORE , Sends frames to Shared Transport */
> +static int hci_st_send_frame(struct sk_buff *skb)
> +{
> + struct hci_dev *hdev;
> + struct hci_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");
> + return -EBUSY;
> + }
> +
> + hst = (struct hci_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) {
> + /* Something went wrong in st write , free skb memory */

IMHO we don't need comments like that, clearly we now that something
went wrong.

> + 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;
> + hci_st_tx_complete(hst, bt_cb(skb)->pkt_type);
> +
> + return 0;

goto might be better to handle error here.

--
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi