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Message-ID: <89b1e4ce98a26d79935bf2ba9a4bc278@codeaurora.org>
Date: Tue, 26 Jun 2018 07:01:18 +0530
From: Balakrishna Godavarthi <bgodavar@...eaurora.org>
To: Matthias Kaehlcke <mka@...omium.org>
Cc: marcel@...tmann.org, johan.hedberg@...il.com,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-bluetooth@...r.kernel.org, rtatiya@...eaurora.org,
hemantg@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v8 4/7] Bluetooth: hci_qca: Add wrapper functions for
setting UART speed
Hi Matthias,
On 2018-06-26 05:13, Matthias Kaehlcke wrote:
> This is a nice improvement, a few remaining questions inline.
>
> On Mon, Jun 25, 2018 at 07:10:10PM +0530, Balakrishna Godavarthi wrote:
>> In function qca_setup, we set initial and operating speeds for
>> Qualcomm
>> Bluetooth SoC's. This block of code is common across different
>> Qualcomm Bluetooth SoC's. Instead of duplicating the code, created
>> a wrapper function to set the speeds. So that future coming SoC's
>> can use these wrapper functions to set speeds.
>>
>> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
>> ---
>> Changes in v8:
>> * common function to set INIT and operating speeds.
>> * moved hardware flow control to qca_set_speed().
>>
>> Changes in v7:
>> * initial patch
>> * created wrapper functions for init and operating speeds.
>> ---
>> drivers/bluetooth/hci_qca.c | 89
>> +++++++++++++++++++++++++++----------
>> 1 file changed, 65 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index fe62420ef838..38b7dbe6c897 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -119,6 +119,11 @@ struct qca_data {
>> u64 votes_off;
>> };
>>
>> +enum qca_speed_type {
>> + QCA_INIT_SPEED = 1,
>> + QCA_OPER_SPEED
>> +};
>> +
>> struct qca_serdev {
>> struct hci_uart serdev_hu;
>> struct gpio_desc *bt_en;
>> @@ -923,6 +928,60 @@ static inline void host_set_baudrate(struct
>> hci_uart *hu, unsigned int speed)
>> hci_uart_set_baudrate(hu, speed);
>> }
>>
>> +static unsigned int qca_get_speed(struct hci_uart *hu,
>> + enum qca_speed_type speed_type)
>> +{
>> + unsigned int speed = 0;
>> +
>> + if (speed_type == QCA_INIT_SPEED) {
>> + if (hu->init_speed)
>> + speed = hu->init_speed;
>> + else if (hu->proto->init_speed)
>> + speed = hu->proto->init_speed;
>> + } else {
>> + if (hu->oper_speed)
>> + speed = hu->oper_speed;
>> + else if (hu->proto->oper_speed)
>> + speed = hu->proto->oper_speed;
>> + }
>> +
>> + return speed;
>> +}
>> +
>> +static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type
>> speed_type)
>> +{
>> + unsigned int speed, qca_baudrate;
>> + int ret;
>> +
>> + if (speed_type == QCA_INIT_SPEED) {
>> + speed = qca_get_speed(hu, QCA_INIT_SPEED);
>> + if (speed)
>> + host_set_baudrate(hu, speed);
>> + else
>> + bt_dev_err(hu->hdev, "Init speed should be non zero");
>
> The check for 'speed == 0' is done in multiple places. From this
> code I deduce that it is expected that both INIT and OPER speed are
> set to non-zero values. What happens if either of them is zero? Is the
> driver still operational?
>
[Bala]: yes in hci_uart_setup()(hci_serdev.c) function before calling
qca_setup().
we actually set baudrate, but int above code missed to restrict
the further call to qca_setup()
if speed =0. so we are checking the same in the qca_setup()..
i.e. qca_get_speed().
>> + return 0;
>> + }
>> +
>> + speed = qca_get_speed(hu, QCA_OPER_SPEED);
>> + if (!speed) {
>> + bt_dev_err(hu->hdev, "operating speed should be non zero");
>> + return 0;
>> + }
>> +
>> + qca_baudrate = qca_get_baudrate_value(speed);
>> + bt_dev_info(hu->hdev, "Set UART speed to %d", speed);
>> + ret = qca_set_baudrate(hu->hdev, qca_baudrate);
>> + if (ret) {
>> + bt_dev_err(hu->hdev, "Failed to change the baudrate (%d)", ret);
>> + return ret;
>> + }
>> +
>> + host_set_baudrate(hu, speed);
>> +
>> + return ret;
>> +}
>
> In the discussion on "[v7,8/8] Bluetooth: hci_qca: Add support for
> Qualcomm Bluetooth chip wcn3990" you mentioned the possbility to move
> the hci_uart_set_flow_control() calls into _set_speed(). This seemed
> interesting but finally it isn't done in this series. Did you
> encounter that it is not feasible/desirable for some reason?
>
[Bala]: this patch is for rome where flow control is not used.
after we integrate wcn3990, flow control is hidden in the
qca_set_speed()
Pls check [v8 7/7] patch.
>> +
>> static int qca_setup(struct hci_uart *hu)
>> {
>> struct hci_dev *hdev = hu->hdev;
>> @@ -937,35 +996,17 @@ static int qca_setup(struct hci_uart *hu)
>> clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
>>
>> /* Setup initial baudrate */
>> - speed = 0;
>> - if (hu->init_speed)
>> - speed = hu->init_speed;
>> - else if (hu->proto->init_speed)
>> - speed = hu->proto->init_speed;
>> -
>> - if (speed)
>> - host_set_baudrate(hu, speed);
>> + qca_set_speed(hu, QCA_INIT_SPEED);
>>
>> /* Setup user speed if needed */
>> - speed = 0;
>> - if (hu->oper_speed)
>> - speed = hu->oper_speed;
>> - else if (hu->proto->oper_speed)
>> - speed = hu->proto->oper_speed;
>> + ret = qca_set_speed(hu, QCA_OPER_SPEED);
>> + if (ret)
>> + return ret;
>>
>> - if (speed) {
>> + speed = qca_get_speed(hu, QCA_OPER_SPEED);
>> + if (speed)
>> qca_baudrate = qca_get_baudrate_value(speed);
>
> Is the check here necessary? qca_get_baudrate_value() returns
> QCA_BAUDRATE_115200 for a zero speed.
this if for no zero operating speed,
--
Regards
Balakrishna.
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