Re: [PATCH v8 4/7] Bluetooth: hci_qca: Add wrapper functions for setting UART speed
From: Matthias Kaehlcke <mka@chromium.org>
Date: 2018-06-25 23:44:02
Also in:
linux-arm-msm, linux-bluetooth, lkml
This is a nice improvement, a few remaining questions inline. On Mon, Jun 25, 2018 at 07:10:10PM +0530, Balakrishna Godavarthi wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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?
+ 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?
quoted hunk ↗ jump to hunk
+ 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.