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Date: Fri, 6 Jul 2018 12:40:59 -0700
From: Matthias Kaehlcke <mka@...omium.org>
To: Balakrishna Godavarthi <bgodavar@...eaurora.org>
Cc: marcel@...tmann.org, johan.hedberg@...il.com,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-bluetooth@...r.kernel.org, thierry.escande@...aro.org,
rtatiya@...eaurora.org, hemantg@...eaurora.org,
linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v9 4/7] Bluetooth: hci_qca: Add wrapper functions for
setting UART speed
On Thu, Jul 05, 2018 at 10:25:12PM +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 v9:
> * added corner case to fail driver if speeds are missing.
>
> Changes in v8:
> * common function to set INIT and operating speeds.
>
> Changes in v7:
> * initial patch
> * created wrapper functions for init and operating speeds.
> ---
> drivers/bluetooth/hci_qca.c | 94 ++++++++++++++++++++++++++++---------
> 1 file changed, 71 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index c02e1d465cca..9106547324fa 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 +928,62 @@ 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_check_speeds(struct hci_uart *hu)
> +{
> + /* One or the other speeds should be non zero. */
> + if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
> + !qca_get_speed(hu, QCA_OPER_SPEED))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +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);
mega-nit: for consistency with the 'else' branch you could return if
'speed == 0'. Not important though, feel free to ignore.
> + } else {
> + speed = qca_get_speed(hu, QCA_OPER_SPEED);
> + if (!speed)
> + 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)
> + return ret;
> +
> + host_set_baudrate(hu, speed);
> + }
> +
> + return 0;
> +}
> +
> static int qca_setup(struct hci_uart *hu)
> {
> struct hci_dev *hdev = hu->hdev;
> @@ -933,37 +994,24 @@ static int qca_setup(struct hci_uart *hu)
>
> bt_dev_info(hdev, "ROME setup");
>
> + ret = qca_check_speeds(hu);
> + if (ret)
> + return ret;
> +
> /* Patch downloading has to be done without IBS mode */
> 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;
> -
> + speed = qca_get_speed(hu, QCA_OPER_SPEED);
> if (speed) {
> - qca_baudrate = qca_get_baudrate_value(speed);
> -
> - bt_dev_info(hdev, "Set UART speed to %d", speed);
> - ret = qca_set_baudrate(hdev, qca_baudrate);
> - if (ret) {
> - bt_dev_err(hdev, "Failed to change the baud rate (%d)",
> - ret);
> + ret = qca_set_speed(hu, QCA_OPER_SPEED);
> + if (ret)
> return ret;
> - }
> - host_set_baudrate(hu, speed);
> +
> + qca_baudrate = qca_get_baudrate_value(speed);
> }
One doubt, the outcome of this change is:
qca_set_speed(hu, QCA_INIT_SPEED);
/* Setup user speed if needed */
speed = qca_get_speed(hu, QCA_OPER_SPEED);
if (speed) {
ret = qca_set_speed(hu, QCA_OPER_SPEED);
if (ret)
return ret;
qca_baudrate = qca_get_baudrate_value(speed);
}
So we set the init speed and then directly switch to operating speed
if it is defined.
Couldn't we do this instead:
/* Setup user speed if needed */
speed = qca_get_speed(hu, QCA_OPER_SPEED);
if (speed) {
ret = qca_set_speed(hu, QCA_OPER_SPEED);
if (ret)
return ret;
qca_baudrate = qca_get_baudrate_value(speed);
} else {
qca_set_speed(hu, QCA_INIT_SPEED);
}
?
Or is setting the init speed needed before the operating speed can be
set? Sorry if we discussed this earlier in this series, I know I had a
few doubts about the speed management but don't recall this one
specifically.
Other than that:
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
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