Hi Marcel,
thank you for looking into this latest version!
On Tue, Jan 2, 2018 at 12:04 PM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
> Hi Martin,
>
>> The three-wire (H5) protocol is the only protocol which uses
>> HCI_UART_INIT_PENDING.
>> Unfortunately the benefits of using this flag are currently unknown. It
>> was added in commit 9f2aee848fe6 ("Bluetooth: Add delayed init sequence
>> support for UART controllers"). In my experiments (with the
>> "rtk_hciattach" tool - a customized version of hciattach for Realtek
>> chipsets) I started the tool before and after this patch while the
>> Bluetooth chipset was disabled (by pulling it's enable GPIO LOW). In
>> both cases hci0 was not created - thus HCI_UART_INIT_PENDING is not
>> required in that case.
>>
>> Removing this code also has another benefit: hci_serdev.c does not
>> support the delayed initialization / registration. Thus the protocol
>> implementation (hci_h5) never receives any data with this check still
>> in place. For the H5 protocol this means that the initialization never
>> completes (because the sync response never arrives). Even if the
>> initialization would succeed later on the drivers would call
>> hci_uart_init_ready() which schedules the registration which is
>> currently not implemented by hci_serdev.c.
>>
>> Removing the HCI_UART_INIT_PENDING check makes the code easier to read
>> and also fixes the initalization of devices (implemented with the serdev
>> library) which use the H5 protocol.
>>
>> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
>
> I really like Johan to ack this one, but generally I am fine with removing unneeded code.
I would also like as many ACKs/Tested-by/Reviewed-by as possible since
this is all new code for me (so it's easy for me to make mistakes)!
> We might also want to look at hciattach to btattach code and make sure it gets removed there as well. I am not even sure anybody used hciattach with H:5 ever.
a quick glance shows that it's defined in bluez.git but never used
there (which is good in this case)
>> ---
>> drivers/bluetooth/hci_h5.c | 3 ---
>> drivers/bluetooth/hci_ldisc.c | 38 --------------------------------------
>> drivers/bluetooth/hci_serdev.c | 3 ---
>> drivers/bluetooth/hci_uart.h | 4 +---
>> 4 files changed, 1 insertion(+), 47 deletions(-)
>>
>> diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
>> index 6a8d0d06aba7..6cfc2f276250 100644
>> --- a/drivers/bluetooth/hci_h5.c
>> +++ b/drivers/bluetooth/hci_h5.c
>> @@ -210,8 +210,6 @@ static int h5_open(struct hci_uart *hu)
>>
>> h5->tx_win = H5_TX_WIN_MAX;
>>
>> - set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
>> -
>> /* Send initial sync request */
>> h5_link_control(hu, sync, sizeof(sync));
>> mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
>> @@ -316,7 +314,6 @@ static void h5_handle_internal_rx(struct hci_uart *hu)
>> h5->tx_win = (data[2] & 0x07);
>> BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
>> h5->state = H5_ACTIVE;
>> - hci_uart_init_ready(hu);
>> return;
>> } else if (memcmp(data, sleep_req, 2) == 0) {
>> BT_DBG("Peer went to sleep");
>> diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
>> index c823914b3a80..5dd3e1bebfe4 100644
>> --- a/drivers/bluetooth/hci_ldisc.c
>> +++ b/drivers/bluetooth/hci_ldisc.c
>> @@ -195,39 +195,6 @@ static void hci_uart_write_work(struct work_struct *work)
>> clear_bit(HCI_UART_SENDING, &hu->tx_state);
>> }
>>
>> -static void hci_uart_init_work(struct work_struct *work)
>> -{
>> - struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
>> - int err;
>> - struct hci_dev *hdev;
>> -
>> - if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
>> - return;
>> -
>> - err = hci_register_dev(hu->hdev);
>> - if (err < 0) {
>> - BT_ERR("Can't register HCI device");
>> - hdev = hu->hdev;
>> - hu->hdev = NULL;
>> - hci_free_dev(hdev);
>> - clear_bit(HCI_UART_PROTO_READY, &hu->flags);
>> - hu->proto->close(hu);
>> - return;
>> - }
>> -
>> - set_bit(HCI_UART_REGISTERED, &hu->flags);
>> -}
>> -
>> -int hci_uart_init_ready(struct hci_uart *hu)
>> -{
>> - if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
>> - return -EALREADY;
>> -
>> - schedule_work(&hu->init_ready);
>> -
>> - return 0;
>> -}
>> -
>> /* ------- Interface to HCI layer ------ */
>> /* Initialize device */
>> static int hci_uart_open(struct hci_dev *hdev)
>> @@ -490,7 +457,6 @@ static int hci_uart_tty_open(struct tty_struct *tty)
>> hu->alignment = 1;
>> hu->padding = 0;
>>
>> - INIT_WORK(&hu->init_ready, hci_uart_init_work);
>> INIT_WORK(&hu->write_work, hci_uart_write_work);
>>
>> percpu_init_rwsem(&hu->proto_lock);
>> @@ -653,9 +619,6 @@ static int hci_uart_register_dev(struct hci_uart *hu)
>> else
>> hdev->dev_type = HCI_PRIMARY;
>>
>> - if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
>> - return 0;
>> -
>> if (hci_register_dev(hdev) < 0) {
>> BT_ERR("Can't register HCI device");
>> hu->hdev = NULL;
>> @@ -699,7 +662,6 @@ static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
>> unsigned long valid_flags = BIT(HCI_UART_RAW_DEVICE) |
>> BIT(HCI_UART_RESET_ON_INIT) |
>> BIT(HCI_UART_CREATE_AMP) |
>> - BIT(HCI_UART_INIT_PENDING) |
>> BIT(HCI_UART_EXT_CONFIG) |
>> BIT(HCI_UART_VND_DETECT);
>>
>> diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
>> index e0e6461b9200..fe67eb6d4278 100644
>> --- a/drivers/bluetooth/hci_serdev.c
>> +++ b/drivers/bluetooth/hci_serdev.c
>> @@ -333,9 +333,6 @@ int hci_uart_register_device(struct hci_uart *hu,
>> else
>> hdev->dev_type = HCI_PRIMARY;
>>
>> - if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
>> - return 0;
>> -
>> if (hci_register_dev(hdev) < 0) {
>> BT_ERR("Can't register HCI device");
>> err = -ENODEV;
>> diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
>> index 66e8c68e4607..47e755ff4092 100644
>> --- a/drivers/bluetooth/hci_uart.h
>> +++ b/drivers/bluetooth/hci_uart.h
>> @@ -53,7 +53,7 @@
>> #define HCI_UART_RAW_DEVICE 0
>> #define HCI_UART_RESET_ON_INIT 1
>> #define HCI_UART_CREATE_AMP 2
>> -#define HCI_UART_INIT_PENDING 3
>> +/* 3 is unused - was HCI_UART_INIT_PENDING */
>
> #define HCI_UART_INIT_PENDING 3 /* unused */
>
> I prefer it this way since it is easier on the eyes.
OK, I'll do it that way in the next version
>> #define HCI_UART_EXT_CONFIG 4
>> #define HCI_UART_VND_DETECT 5
>>
>> @@ -83,7 +83,6 @@ struct hci_uart {
>> unsigned long flags;
>> unsigned long hdev_flags;
>>
>> - struct work_struct init_ready;
>> struct work_struct write_work;
>>
>> const struct hci_uart_proto *proto;
>> @@ -115,7 +114,6 @@ int hci_uart_register_device(struct hci_uart *hu, const struct hci_uart_proto *p
>> void hci_uart_unregister_device(struct hci_uart *hu);
>>
>> int hci_uart_tx_wakeup(struct hci_uart *hu);
>> -int hci_uart_init_ready(struct hci_uart *hu);
>> void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed);
>> void hci_uart_set_flow_control(struct hci_uart *hu, bool enable);
>> void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
Regards
Martin
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