RE: [PATCH] Bluetooth: btwilink driver

[Savoy, Pavan]

> -----Original Message-----
> From: Gustavo F. Padovan [mailto:pao@xxxxxxxxxxxxxx] On Behalf Of Gustavo F.
> Padovan
> Sent: Monday, October 18, 2010 2:48 PM
> To: Savoy, Pavan
> Cc: marcel@xxxxxxxxxxxx; linux-bluetooth@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] Bluetooth: btwilink driver
>
> Hi Pavan,
>
> * pavan_savoy@xxxxxx <pavan_savoy@xxxxxx> [2010-10-15 16:58:19 -0400]:
>
> > From: Pavan Savoy <pavan_savoy@xxxxxx>
> >
> > Gustavo, Marcel,
> >
> > Renaming the patch, since the driver is renamed to btwilink.
> > Thanks for the comments,
> > Please review and provide your comments on this version of patch,
> >
> > -- 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 |  424
> ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 435 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..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..f67791f
> > --- /dev/null
> > +++ b/drivers/bluetooth/btwilink.c
> > @@ -0,0 +1,424 @@
> > +/*
> > + *  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_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_reg_completion;
> > +};
> > +
> > +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;
>
> Blank line here.
>
> > +   /* 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_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)
> > +           return -EFAULT;
> > +
> > +   if (!lhst) {
> > +           kfree_skb(skb);
> > +           return -EFAULT;
> > +   }
> > +
> > +   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)", err);
>
> s/CORE/core/
>
> > +           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,
> > +   .priv_data = NULL,
> > +};
> > +
> > +/* 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);
> > +
> > +   /* 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) {
> > +           /* Prepare wait-for-completion handler data structures.
> > +            * Needed to syncronize this and st_registration_completion_cb()
> > +            * functions.
> > +            */
> > +           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->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(" waiting for reg completion signal from ST");
> > +
> > +           timeleft = wait_for_completion_timeout
> > +                   (&hst->wait_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);
>
> How does this get printed. "...regcompletion..." ?
>
> > +                   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 == -EPERM) {
> > +           BT_ERR("st_register failed %d", err);
> > +           return -EAGAIN;
>
> Why? if -EPERM 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;
>
> I asked in the other e-mail:  Who sets ti_st_proto.write()? I didn't get
> this.

The write function is set by the TI-ST driver.
This was in order to avoid another EXPORT_SYMBOL(st_write) or so.
So, as soon as some protocol driver registers to shared transport driver, the
registration function inside the driver will set it's write function to this
function pointer.

Yes, I will fix up the rest and post another version,
Thanks.

> > +   } else {
> > +           BT_ERR("failed to get ST write func pointer");
> > +
> > +           /* Undo registration with ST */
> > +           err = st_unregister(ST_BT);
> > +           if (err)
> > +                   BT_ERR("st_unregister failed %d", err);
> > +
> > +           hst->st_write = NULL;
> > +           return -EAGAIN;
>
> return err; instead
>
> > +   }
> > +
> > +   /* 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);
> > +   return err;
> > +}
> > +
> > +/* Close device */
> > +static int ti_st_close(struct hci_dev *hdev)
> > +{
> > +   int err = 0;
>
> do not set err to 0 here.
>
> > +   struct ti_st *hst;
>
> you can set hst to hdev->.... here.
>
> > +
> > +   hst = hdev->driver_data;
> > +
> > +   /* Clear HCI device RUNNING flag */
> > +   if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
> > +           BT_ERR("HCI not RUNNING?");
>
>
> You didn't fix the things I told you. This is not a error. Just return 0
> here.
>
> > +
> > +   /* continue to unregister from transport */
> > +   err = st_unregister(ST_BT);
> > +   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)
> > +           return -ENOMEM;
> > +
> > +   hdev = (struct hci_dev *)skb->dev;
> > +   if (!hdev)
> > +           return -ENODEV;
> > +
> > +   if (!test_bit(HCI_RUNNING, &hdev->flags))
> > +           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;
> > +   }
>
> Explain to me why it is worth return -EAGAIN in both cases.
>
> > +
> > +   /* 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)");
> > +
> > +   BT_DBG("%s", hdev->name);
> > +
> > +   /* free ti_st memory */
> > +   kfree(hdev->driver_data);
> > +   return;
> > +}
> > +
> > +/* 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)
> > +           return -ENOMEM;
> > +
> > +   BT_DBG(" HCI device allocated. hdev= %p", hdev);
>
> just  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;
> > +
> > +   if (reset)
> > +           set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
> > +
> > +   if (hci_register_dev(hdev) < 0) {
>
>       err = hci_register_dev()
>       if (err < 0)
>        ...
>        ...
>        return err;
>
> > +           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);
> > +
> > +   hst = kzalloc(sizeof(struct ti_st), GFP_KERNEL);
> > +   if (!hst) {
> > +           BT_ERR("Can't allocate control structure");
>
> remove this BT_ERR.
>
> > +           return -ENOMEM;
> > +   }
> > +
> > +   /* Expose "hciX" device to user space */
> > +   err = ti_st_register_dev(hst);
> > +   if (err) {
> > +           kfree(hst);
> > +           BT_ERR("Unable to expose hciX device(%d)", err);
>
> Ok, if you don't know how to extract the hci id, remove the whole error
> message then.
>
> > +           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) {
> > +                   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 btwilink_driver = {
> > +   .probe = bt_ti_probe,
> > +   .remove = bt_ti_remove,
> > +   .driver = {
> > +           .name = "btwilink",
> > +           .owner = THIS_MODULE,
> > +   },
> > +};
> > +
> > +/* ------- Module Init/Exit interfaces ------ */
> > +static int __init bt_drv_init(void)
> > +{
> > +   long ret;
> > +
> > +   ret = platform_driver_register(&btwilink_driver);
> > +   if (ret != 0) {
> > +           BT_ERR("btwilink platform drv registration failed");
> > +           return -EPERM;
> > +   }
> > +   return 0;
>
>       if (ret)
>       BT_ERR("btwilink platform drv registration failed");
>
>       return ret;
>
> and s/drv/driver/
>
>
> Please fix all the issues, then we go to another round of review. ;)
>
>
> --
> Gustavo F. Padovan
> ProFUSION embedded systems - http://profusion.mobi
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