Re: [PATCH v5] Bluetooth: btwilink driver

[Jesper Juhl]

On Tue, 16 Nov 2010, Pavan Savoy wrote:

> On Wed, Nov 10, 2010 at 6:37 PM,  <pavan_savoy@xxxxxx> wrote:
> > From: Pavan Savoy <pavan_savoy@xxxxxx>
> >
> Marcel,
> 
> Any comments? on this version 5 patch?
> 
> > Thanks for the comments...
> > This patch contains,
> > v5 comments :-
> > declaration and assiging of variables and private data fixed up.
> > proper casting.
> > removed redundant un-necessary checks in send_frame.
> > HCI_RUNNING fixes in terms of test_and_set/clear bit instead of set and
> > clear.
> > removed redundant checks for hdev, skb being NULL.
> > removed module_param of reset, also WiLink don't need HCI_RESET anyways.
> > removed ti_st_register_dev function and functionality moved to _probe.
> > module_init/exit function names fixed up.
> >
> > stat byte counter increments and tx_complete is similar to hci_ldisc.
> > Also I have not implemented the flush routine, since the functionality
> > which needs to be done in flush routine is done in the underlying driver
> > which is the shared transport driver and moreover the btwilink driver by
> > itself doesn't maintains queue or data relevant to transport, so nothing
> > to do.
> >
> > And Yes, I have verified this driver with multiple up/down reset on
> > hci0.
> > Also I generally test a2dp/ftp to verify large data transfers.
> >
> > Please review and comment.
> >
> > Thanks,
> > Pavan
> >
> > v4 comments :-
> > module init now returns what platform_driver_register returns.
> > type casting of void* private data has been removed
> >
> > v3 comments :-
> > Lizardo,
> > I have taken care of most of the comments you had.
> > Have re-wrote some of the code commenting you've mentioned.
> > Thanks for the comments,
> >
> > The other few like -EPERM for platform driver registration is to keep
> > it similar to other drivers, type casting is maintained just to feel safe
> > and have style similar to other drivers.
> > BT_WILINK in Kconfig is similar to BT_MRVL.
> > I hope those aren't too critical.
> >
> > -- 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 |  379 ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 390 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..1b1c4bc
> > --- /dev/null
> > +++ b/drivers/bluetooth/btwilink.c
> > @@ -0,0 +1,379 @@
> > +/*
> > + *  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);
> > +
> > +       /* 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 synchronize 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->reg_status = -EINPROGRESS;
> > +
> > +               /* ST is busy with either protocol registration or firmware
> > +                * download. Wait until the registration callback is called
> > +                */
> > +               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) {
> > +                       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) {
> > +                       BT_ERR("ST registration completed with invalid "
> > +                                       "status %d", hst->reg_status);
> > +                       return -EAGAIN;
> > +               }
> > +               err = 0;
> > +       } else if (err == -EPERM) {
> > +               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");
> > +
> > +               /* 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;
> > +       }
> > +
> > +       /* Registration with ST layer is successful,
> > +        * hardware is ready to accept commands from HCI core.
> > +        */
> > +       if (test_and_set_bit(HCI_RUNNING, &hdev->flags)) {
> > +               clear_bit(HCI_RUNNING, &hdev->flags);
> > +               err = st_unregister(ST_BT);
> > +               if (err)
> > +                       BT_ERR("st_unregister() failed with error %d", err);
> > +               hst->st_write = NULL;
> > +       }
> > +
> > +       return err;
> > +}
> > +
> > +/* Close device */
> > +static int ti_st_close(struct hci_dev *hdev)
> > +{
> > +       int err;
> > +       struct ti_st *hst = hdev->driver_data;
> > +
> > +       /* 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;
> > +
> > +       if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
> > +               return 0;
> > +
> > +       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);
> > +               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);
> > +
> > +       /* free ti_st memory */
> > +       kfree(hdev->driver_data);
> > +
> > +       return;
> > +}
> > +
> > +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)
> > +               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);
> > +
> > +       /* Free HCI device memory */
> > +       hci_free_dev(hdev);
> > +
> > +       /* Free driver data memory */
> > +       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)
> > +{
> > +       long ret;
> > +
> > +       BT_INFO(" Bluetooth Driver for TI WiLink - Version %s", VERSION);
> > +
> > +       ret = platform_driver_register(&btwilink_driver);
> > +       if (ret != 0) {
> > +               BT_ERR("btwilink platform driver registration failed");
> > +               return ret;
> > +       }
> > +       return 0;
> > +}

Personally I would prefer

static int __init btwilink_init(void)
{
       int ret;

       BT_INFO("Bluetooth Driver for TI WiLink - Version %s", VERSION);

       ret = platform_driver_register(&btwilink_driver);
       if (ret != 0)
               BT_ERR("btwilink platform driver registration failed"); 
       return ret;
}

The source is shorter. 'ret' is actually of the same type as returned by 
'platform_driver_register()' and the function itself. There's no space at 
the beginning of the BT_INFO() line (perhaps there's a reason for it, but 
I don't see it).


> > +
> > +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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> >
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-- 
Jesper Juhl <jj@xxxxxxxxxxxxx>            http://www.chaosbits.net/
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