Re: [PATCH v4] Add support for the Atheros AR300x Bluetooth Chip

["Gustavo F. Padovan" <gustavo@padovan.org>]

* suraj <suraj@atheros.com> [2010-04-21 15:52:17 +0530]:

> This implements the Atheros Bluetooth serial protocol to
> support the AR300x Bluetooth chipsets.
> The serial protocol implements enhanced power management
> features for the AR300x chipsets.
> 
> Reviewed-by: Luis R. Rodriguez <lrodriguez@atheros.com>
> Signed-off-by: Suraj <suraj@atheros.com>
> 
> ---
>  drivers/bluetooth/Kconfig     |   14 ++
>  drivers/bluetooth/Makefile    |    1 +
>  drivers/bluetooth/hci_ath.c   |  378 +++++++++++++++++++++++++++++++++++++++++
>  drivers/bluetooth/hci_ldisc.c |    6 +
>  drivers/bluetooth/hci_uart.h  |    8 +-
>  5 files changed, 406 insertions(+), 1 deletions(-)
>  create mode 100755 drivers/bluetooth/hci_ath.c
> 
> diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> index 058fbcc..5546142 100644
> --- a/drivers/bluetooth/Kconfig
> +++ b/drivers/bluetooth/Kconfig
> @@ -58,6 +58,20 @@ config BT_HCIUART_BCSP
>  
>  	  Say Y here to compile support for HCI BCSP protocol.
>  
> +config BT_HCIUART_ATH
> +	bool "Atheros AR300x serial Bluetooth support"
> +	depends on BT_HCIUART
> +	help
> +	  HCIATH (HCI Atheros) is a serial protocol for communication
> +	  between the host and Atheros AR300x Bluetooth devices. The
> +	  protocol implements enhaned power management features for the
> +	  the AR300x chipsets. it lets the controller chip go to sleep
> +	  mode if there is no Bluetooth activity for some time and wakes
> +	  up the chip in case of a Bluetooth activity. Enable this option
> +	  if you have an UART Atheros AR300x serial device.
> +
> +	  Say Y here to compile support for HCIATH protocol.
> +
>  config BT_HCIUART_LL
>  	bool "HCILL protocol support"
>  	depends on BT_HCIUART
> diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
> index 7e5aed5..1481faa 100644
> --- a/drivers/bluetooth/Makefile
> +++ b/drivers/bluetooth/Makefile
> @@ -26,4 +26,5 @@ hci_uart-y				:= hci_ldisc.o
>  hci_uart-$(CONFIG_BT_HCIUART_H4)	+= hci_h4.o
>  hci_uart-$(CONFIG_BT_HCIUART_BCSP)	+= hci_bcsp.o
>  hci_uart-$(CONFIG_BT_HCIUART_LL)	+= hci_ll.o
> +hci_uart-$(CONFIG_BT_HCIUART_ATH)	+= hci_ath.o
>  hci_uart-objs				:= $(hci_uart-y)
> diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
> new file mode 100755
> index 0000000..7e99559
> --- /dev/null
> +++ b/drivers/bluetooth/hci_ath.c
> @@ -0,0 +1,378 @@
> +/*
> + * Copyright (c) 2009-2010 Atheros Communications Inc.
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  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/module.h>
> +#include <linux/kernel.h>
> +
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/tty.h>
> +#include <linux/errno.h>
> +#include <linux/ioctl.h>
> +#include <linux/skbuff.h>
> +
> +#include <net/bluetooth/bluetooth.h>
> +#include <net/bluetooth/hci_core.h>
> +
> +#include "hci_uart.h"
> +
> +/* HCIATH receiver States */
> +#define HCIATH_W4_PACKET_TYPE			0
> +#define HCIATH_W4_EVENT_HDR			1
> +#define HCIATH_W4_ACL_HDR			2
> +#define HCIATH_W4_SCO_HDR			3
> +#define HCIATH_W4_DATA				4
> +
> +struct ath_struct {
> +	struct hci_uart *hu;
> +	unsigned int rx_state;
> +	unsigned int rx_count;
> +	unsigned int cur_sleep;
> +
> +	spinlock_t hciath_lock;
> +	struct sk_buff *rx_skb;
> +	struct sk_buff_head txq;
> +	wait_queue_head_t wqevt;
> +	struct work_struct ctxtsw;
> +};
> +
> +static int ath_wakeup_ar3001(struct tty_struct *tty)
> +{
> +	struct termios settings;
> +	int status = tty->driver->ops->tiocmget(tty, NULL);
> +
> +	if (status & TIOCM_CTS)
> +		return status;
> +
> +	n_tty_ioctl_helper(tty, NULL, TCGETS, (unsigned long)&settings);
> +
> +	/* Disable Automatic RTSCTS */
> +	settings.c_cflag &= ~CRTSCTS;
> +	n_tty_ioctl_helper(tty, NULL, TCSETS, (unsigned long)&settings);
> +
> +	status = tty->driver->ops->tiocmget(tty, NULL);
> +
> +	/* Clear RTS first */
> +	tty->driver->ops->tiocmset(tty, NULL, 0x00, TIOCM_RTS);
> +	mdelay(20);
> +
> +	status = tty->driver->ops->tiocmget(tty, NULL);
> +
> +	/* Set RTS, wake up board */
> +	tty->driver->ops->tiocmset(tty, NULL, TIOCM_RTS, 0x00);
> +	mdelay(20);
> +
> +	status = tty->driver->ops->tiocmget(tty, NULL);
> +
> +	n_tty_ioctl_helper(tty, NULL, TCGETS, (unsigned long)&settings);
> +
> +	settings.c_cflag |= CRTSCTS;
> +	n_tty_ioctl_helper(tty, NULL, TCSETS, (unsigned long)&settings);
> +
> +	return status;
> +}
> +
> +static void ath_hci_uart_work(struct work_struct *work)
> +{
> +	int status;
> +	struct ath_struct *ath;
> +	struct hci_uart *hu;
> +	struct tty_struct *tty;
> +
> +	ath = container_of(work, struct ath_struct, ctxtsw);
> +
> +	hu = ath->hu;
> +	tty = hu->tty;
> +
> +	/* verify and wake up controller */
> +	if (ath->cur_sleep) {
> +		status = ath_wakeup_ar3001(tty);
> +
> +		if (!(status & TIOCM_CTS))
> +			return;
> +	}
> +
> +	/* Ready to send Data */
> +	clear_bit(HCI_UART_SENDING, &hu->tx_state);
> +	hci_uart_tx_wakeup(hu);
> +}
> +
> +/* Initialize protocol */
> +static int ath_open(struct hci_uart *hu)
> +{
> +	struct ath_struct *ath;
> +
> +	BT_DBG("hu %p", hu);
> +
> +	ath = kzalloc(sizeof(*ath), GFP_ATOMIC);
> +	if (!ath)
> +		return -ENOMEM;
> +
> +	skb_queue_head_init(&ath->txq);
> +	spin_lock_init(&ath->hciath_lock);
> +
> +	hu->priv = ath;
> +	ath->hu = hu;
> +
> +	init_waitqueue_head(&ath->wqevt);
> +	INIT_WORK(&ath->ctxtsw, ath_hci_uart_work);
> +
> +	return 0;
> +}
> +
> +/* Flush protocol data */
> +static int ath_flush(struct hci_uart *hu)
> +{
> +	struct ath_struct *ath = hu->priv;
> +
> +	BT_DBG("hu %p", hu);
> +
> +	skb_queue_purge(&ath->txq);
> +
> +	return 0;
> +}
> +
> +/* Close protocol */
> +static int ath_close(struct hci_uart *hu)
> +{
> +	struct ath_struct *ath = hu->priv;
> +
> +	BT_DBG("hu %p", hu);
> +
> +	skb_queue_purge(&ath->txq);
> +
> +	kfree_skb(ath->rx_skb);
> +
> +	cancel_work_sync(&ath->ctxtsw);
> +
> +	hu->priv = NULL;
> +	kfree(ath);
> +
> +	return 0;
> +}
> +
> +/* Enqueue frame for transmittion */
> +static int ath_enqueue(struct hci_uart *hu, struct sk_buff *skb)
> +{
> +	struct ath_struct *ath = hu->priv;
> +
> +	if (bt_cb(skb)->pkt_type == HCI_SCODATA_PKT) {
> +
> +		/* Discard SCO packet. AR3001 does not support SCO over HCI */
> +		BT_DBG("SCO Packet over HCI received Dropping");
> +
> +		kfree(skb);
> +
> +		return 0;
> +	}
> +
> +	BT_DBG("hu %p skb %p", hu, skb);
> +
> +	/* Prepend skb with frame type */
> +	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
> +
> +	skb_queue_tail(&ath->txq, skb);
> +	set_bit(HCI_UART_SENDING, &hu->tx_state);
> +
> +	schedule_work(&ath->ctxtsw);
> +
> +	return 0;
> +}
> +
> +static struct sk_buff *ath_dequeue(struct hci_uart *hu)
> +{
> +	struct ath_struct *ath = hu->priv;
> +	struct sk_buff *skbuf;
> +
> +	skbuf = skb_dequeue(&ath->txq);
> +
> +	if (!skbuf)
> +		return NULL;
> +
> +	/*
> +	 * Check if the HCI command is  HCI sleep enable and
> +	 * update the sleep enable flag with command parameter.
> +	 *
> +	 * Value of sleep enable flag will be used later
> +	 * to verify if controller has to be woken up before
> +	 * sending any packet.
> +	 */
> +	if (skbuf->data[0] == 0x01 &&
> +	    skbuf->data[1] == 0x04 &&
> +	    skbuf->data[2] == 0xFC)
> +		ath->cur_sleep = skbuf->data[4];
> +
> +	return skbuf;
> +}
> +
> +static void ath_check_data_len(struct ath_struct *ath, int len)
> +{
> +	int room = skb_tailroom(ath->rx_skb);
> +
> +	BT_DBG("len %d room %d", len, room);
> +
> +	if (len > room) {
> +		BT_ERR("Data length is too large");
> +		kfree_skb(ath->rx_skb);
> +		ath->rx_state = HCIATH_W4_PACKET_TYPE;
> +		ath->rx_skb = NULL;
> +		ath->rx_count = 0;
> +	} else {
> +		ath->rx_state = HCIATH_W4_DATA;
> +		ath->rx_count = len;
> +	}
> +}
> +
> +/* Recv data */
> +static int ath_recv(struct hci_uart *hu, void *data, int count)
> +{
> +	struct ath_struct *ath = hu->priv;
> +	char *ptr = data;
> +	struct hci_event_hdr *eh;
> +	struct hci_acl_hdr *ah;
> +	struct hci_sco_hdr *sh;
> +	int len, type, dlen;
> +
> +	BT_DBG("hu %p count %d rx_state %d rx_count %d", hu, count,
> +	       ath->rx_state, ath->rx_count);
> +
> +	while (count) {
> +		if (ath->rx_count) {
> +
> +			len = min_t(unsigned int, ath->rx_count, count);
> +			memcpy(skb_put(ath->rx_skb, len), ptr, len);
> +			ath->rx_count -= len;
> +			count -= len;
> +			ptr += len;
> +
> +			if (ath->rx_count)
> +				continue;
> +			switch (ath->rx_state) {
> +			case HCIATH_W4_DATA:
> +				hci_recv_frame(ath->rx_skb);
> +				ath->rx_state = HCIATH_W4_PACKET_TYPE;
> +				ath->rx_skb = NULL;
> +				ath->rx_count = 0;
> +				continue;
> +
> +			case HCIATH_W4_EVENT_HDR:
> +				eh = (struct hci_event_hdr *)ath->rx_skb->data;

Use hci_event_hdr() here like hci_h4.c does.

> +
> +				BT_DBG("Event header: evt 0x%2.2x plen %d",
> +				       eh->evt, eh->plen);
> +
> +				ath_check_data_len(ath, eh->plen);
> +				continue;
> +
> +			case HCIATH_W4_ACL_HDR:
> +				ah = (struct hci_acl_hdr *)ath->rx_skb->data;

And hci_acl_hdr() here.

> +				dlen = __le16_to_cpu(ah->dlen);
> +
> +				BT_DBG("ACL header: dlen %d", dlen);
> +
> +				ath_check_data_len(ath, dlen);
> +				continue;
> +
> +			case HCIATH_W4_SCO_HDR:
> +				sh = (struct hci_sco_hdr *)ath->rx_skb->data;

hci_sco_hdr() here.

> +
> +				BT_DBG("SCO header: dlen %d", sh->dlen);
> +
> +				ath_check_data_len(ath, sh->dlen);
> +				continue;
> +
> +			}
> +		}
> +
> +		/* HCIATH_W4_PACKET_TYPE */
> +		switch (*ptr) {
> +		case HCI_EVENT_PKT:
> +			BT_DBG("Event packet");
> +			ath->rx_state = HCIATH_W4_EVENT_HDR;
> +			ath->rx_count = HCI_EVENT_HDR_SIZE;
> +			type = HCI_EVENT_PKT;
> +			break;
> +
> +		case HCI_ACLDATA_PKT:
> +			BT_DBG("ACL packet");
> +			ath->rx_state = HCIATH_W4_ACL_HDR;
> +			ath->rx_count = HCI_ACL_HDR_SIZE;
> +			type = HCI_ACLDATA_PKT;
> +			break;
> +
> +		case HCI_SCODATA_PKT:
> +			BT_DBG("SCO packet");
> +			ath->rx_state = HCIATH_W4_SCO_HDR;
> +			ath->rx_count = HCI_SCO_HDR_SIZE;
> +			type = HCI_SCODATA_PKT;
> +			break;
> +
> +		default:
> +			BT_ERR("Unknown HCI packet type %2.2x", (__u8) *ptr);
> +			hu->hdev->stat.err_rx++;
> +			ptr++;
> +			count--;
> +			continue;
> +
> +		};
> +		ptr++;
> +		count--;
> +
> +		/* Allocate packet */
> +		ath->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
> +		if (!ath->rx_skb) {
> +			BT_ERR("Can't allocate mem for new packet");
> +			ath->rx_state = HCIATH_W4_PACKET_TYPE;
> +			ath->rx_count = 0;
> +
> +			return -ENOMEM;
> +		}
> +		ath->rx_skb->dev = (void *)hu->hdev;
> +		bt_cb(ath->rx_skb)->pkt_type = type;
> +	}
> +
> +	return count;
> +}

Just out of curiosity. I never worked in the driver world, but is it ok
to duplicate lots of code when working with drivers? hci_h4.c and this
patch share lots of similar code. ath_recv() and h4_recv() are exactly
the same except for one line, the ath->rx_count = 0; at case HCIATH_W4_DATA.
Does this line makes real difference? recv() is not the only function
duplicating code here.

> +
> +static struct hci_uart_proto athp = {
> +	.id = HCI_UART_ATH,
> +	.open = ath_open,
> +	.close = ath_close,
> +	.recv = ath_recv,
> +	.enqueue = ath_enqueue,
> +	.dequeue = ath_dequeue,
> +	.flush = ath_flush,
> +};
> +
> +int ath_init(void)
> +{
> +	int err = hci_uart_register_proto(&athp);
> +
> +	if (!err)
> +		BT_INFO("HCIATH protocol initialized");
> +	else
> +		BT_ERR("HCIATH protocol registration failed");
> +
> +	return err;
> +}

BTW, we never check this return value on hci_ldisc.c, why?

> +
> +int ath_deinit(void)
> +{
> +	return hci_uart_unregister_proto(&athp);
> +}
> diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
> index 76a1abb..7dd76d1 100644
> --- a/drivers/bluetooth/hci_ldisc.c
> +++ b/drivers/bluetooth/hci_ldisc.c
> @@ -542,6 +542,9 @@ static int __init hci_uart_init(void)
>  #ifdef CONFIG_BT_HCIUART_LL
>  	ll_init();
>  #endif
> +#ifdef CONFIG_BT_HCIUART_ATH
> +	ath_init();
> +#endif
>  
>  	return 0;
>  }
> @@ -559,6 +562,9 @@ static void __exit hci_uart_exit(void)
>  #ifdef CONFIG_BT_HCIUART_LL
>  	ll_deinit();
>  #endif
> +#ifdef CONFIG_BT_HCIUART_ATH
> +	ath_deinit();
> +#endif
>  
>  	/* Release tty registration of line discipline */
>  	if ((err = tty_unregister_ldisc(N_HCI)))
> diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
> index 50113db..385537f 100644
> --- a/drivers/bluetooth/hci_uart.h
> +++ b/drivers/bluetooth/hci_uart.h
> @@ -33,13 +33,14 @@
>  #define HCIUARTGETDEVICE	_IOR('U', 202, int)
>  
>  /* UART protocols */
> -#define HCI_UART_MAX_PROTO	5
> +#define HCI_UART_MAX_PROTO	6
>  
>  #define HCI_UART_H4	0
>  #define HCI_UART_BCSP	1
>  #define HCI_UART_3WIRE	2
>  #define HCI_UART_H4DS	3
>  #define HCI_UART_LL	4
> +#define HCI_UART_ATH	5
>  
>  struct hci_uart;
>  
> @@ -91,3 +92,8 @@ int bcsp_deinit(void);
>  int ll_init(void);
>  int ll_deinit(void);
>  #endif
> +
> +#ifdef CONFIG_BT_HCIUART_ATH
> +int ath_init(void);
> +int ath_deinit(void);
> +#endif
> -- 
> 1.7.0
> 
> 
> 
> 
> 

-- 
Gustavo F. Padovan
http://padovan.org