Message-ID: <20101116225418.GA15101@vigoh>
Date:	Tue, 16 Nov 2010 20:54:18 -0200
From:	"Gustavo F. Padovan" <padovan@...fusion.mobi>
To:	pavan_savoy@...com
Cc:	marcel@...tmann.org, linux-bluetooth@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5] Bluetooth: btwilink driver

Hi Pavan,

* pavan_savoy@...com <pavan_savoy@...com> [2010-11-10 08:07:26 -0500]:

> From: Pavan Savoy <pavan_savoy@...com>
> 
> Marcel,
> 
> 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.

Before re-submit a patch you have to fix all issues reported by the
reviewer or reply to patch thread why do you think you right and don't
want to change that. That is not happening with your patches, you are
not fixing all the stuff before re-submiting and it is not the first
time.  If you do it right we can review it fast and your code goes
earlier to mainline.
You should also answer the questions first  like "Where is the
ti_st_proto.write coming from?" You just ignored the
review and submitted a new patch.

> 
> 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@...com>
> ---
>  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@...com>
> + *	Pavan Savoy <pavan_savoy@...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"
> +
> +/* 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;
> +	}


Again, you are checking for only EPERM and EINPROGRESS. You should check
for everything. I actually don't undertand why you have a special check
for EPERM.

> +
> +	/* ti_st_proto.write is filled up by the underlying shared
> +	 * transport driver upon registration
> +	 */
> +	hst->st_write = ti_st_proto.write;

I do not like that, the underlying should export the write function.

> +	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;
> +	}


What are you trying to do here? test_and_set_bit() result doesn't say
nothing about error and you shall put test_and_set_bit should be in the
beginning, to know if your device is already opened or not and then
clear_bit if some error ocurrs during the function.

> +
> +	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;

test_and_clear_bit should come first to check if your device is already
closed.

> +
> +	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;

Why 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);

>From Marcel in the other thread: 
"What is the reason for this deferred stats update. That code looks
pretty much hackish to me." 

> +
> +	return 0;
> +}
> +
> +static void ti_st_destruct(struct hci_dev *hdev)
> +{
> +	BT_DBG("%s", hdev->name);
> +
> +	/* free ti_st memory */

get ride of the comment, it's pointless

> +	kfree(hdev->driver_data);
> +
> +	return;

No return; here

> +}
> +
> +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;

You are leaking hst, if hci_alloc_dev() fails.

> +
> +	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 */

get ride of both commnets here. The name of the funcion is already
saying that.

> +	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;

Old issue again: 

>From Marcel: please just do like we do with all other drivers;

        BT_INFO(...)

        return platform_driver_register(&btwilink_driver);

-- 
Gustavo F. Padovan
http://profusion.mobi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists