On 31-03-21, 18:00, Srinivas Kandagatla wrote:
If we write registers very fast we can endup in a situation where some of the writes will be dropped without any notice.
So wait for the fifo space to be available before reading/writing the soundwire registers.
Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org
drivers/soundwire/qcom.c | 74 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index 6affa3cd4039..9b45717577f2 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -24,6 +24,8 @@ #define SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK BIT(1) #define SWRM_COMP_CFG_ENABLE_MSK BIT(0) #define SWRM_COMP_PARAMS 0x100 +#define SWRM_COMP_PARAMS_WR_FIFO_DEPTH GENMASK(14, 10) +#define SWRM_COMP_PARAMS_RD_FIFO_DEPTH GENMASK(19, 15) #define SWRM_COMP_PARAMS_DOUT_PORTS_MASK GENMASK(4, 0) #define SWRM_COMP_PARAMS_DIN_PORTS_MASK GENMASK(9, 5) #define SWRM_INTERRUPT_STATUS 0x200 @@ -51,6 +53,8 @@ #define SWRM_CMD_FIFO_CMD 0x308 #define SWRM_CMD_FIFO_FLUSH 0x1 #define SWRM_CMD_FIFO_STATUS 0x30C +#define SWRM_RD_CMD_FIFO_CNT_MASK GENMASK(20, 16) +#define SWRM_WR_CMD_FIFO_CNT_MASK GENMASK(12, 8) #define SWRM_CMD_FIFO_CFG_ADDR 0x314 #define SWRM_CONTINUE_EXEC_ON_CMD_IGNORE BIT(31) #define SWRM_RD_WR_CMD_RETRIES 0x7 @@ -104,6 +108,7 @@ #define SWR_BROADCAST_CMD_ID 0x0F #define SWR_MAX_CMD_ID 14 #define MAX_FIFO_RD_RETRY 3 +#define SWR_OVERFLOW_RETRY_COUNT 30
struct qcom_swrm_port_config { u8 si; @@ -147,6 +152,8 @@ struct qcom_swrm_ctrl { int (*reg_read)(struct qcom_swrm_ctrl *ctrl, int reg, u32 *val); int (*reg_write)(struct qcom_swrm_ctrl *ctrl, int reg, int val); u32 slave_status;
- u32 wr_fifo_depth;
- u32 rd_fifo_depth;
};
struct qcom_swrm_data { @@ -238,6 +245,63 @@ static u32 swrm_get_packed_reg_val(u8 *cmd_id, u8 cmd_data, return val; }
+static int swrm_wait_for_rd_fifo_avail(struct qcom_swrm_ctrl *swrm) +{
- u32 fifo_outstanding_cmd, value;
- u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT;
- /* Check for fifo underflow during read */
- swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
- fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value);
/* Check number of outstanding commands in fifo before read */- if (fifo_outstanding_cmd)
return 0;- do {
usleep_range(500, 510);swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value);if (fifo_outstanding_cmd > 0)break;- } while (fifo_retry_count--);
- if (fifo_outstanding_cmd == 0) {
dev_err_ratelimited(swrm->dev, "%s err read underflow\n", __func__);return -ENOMEM;
ENOMEM ? that should be EIO, we expected data but didnt get it in read fifo
- }
- return 0;
+}
+static int swrm_wait_for_wr_fifo_avail(struct qcom_swrm_ctrl *swrm) +{
- u32 fifo_outstanding_cmd, value;
- u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT;
- /* Check for fifo overflow during write */
- swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
- fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);
- /* Check number of outstanding commands in fifo before write */
- if (fifo_outstanding_cmd != swrm->wr_fifo_depth)
return 0;
maybe the comment should say, check for space in write fifo?
- do {
usleep_range(500, 510);swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);if (fifo_outstanding_cmd < swrm->wr_fifo_depth)break;- } while (fifo_retry_count--);
- if (fifo_outstanding_cmd == swrm->wr_fifo_depth) {
dev_err_ratelimited(swrm->dev, "%s err write overflow\n", __func__);return -ENOMEM;
EIO or better error code here too