In the existing code every soundwire register read and register write
are kinda blocked. Each of these are using a special command id that
generates interrupt after it successfully finishes. This is really
overhead, limiting and not really necessary unless we are doing
something special.
We can simply read/write the fifo that should also give exactly
what we need! This will also allow to read/write registers in
interrupt context, which was not possible with the special
command approach.
+ if (id != SWR_BROADCAST_CMD_ID) {
+ if (id < 14)
+ id += 1;
+ else
+ id = 0;
+ if (cmd_id == SWR_BROADCAST_CMD_ID) {
+ /*
+ * sleep for 10ms for MSM soundwire variant to allow broadcast
+ * command to complete.
+ */
+ ret = wait_for_completion_timeout(&swrm->broadcast, (2 * HZ/10));
+ if (!ret)
+ ret = SDW_CMD_IGNORED;
+ else
+ ret = SDW_CMD_OK;
+static int qcom_swrm_cmd_fifo_rd_cmd(struct qcom_swrm_ctrl *swrm,
+ u8 dev_addr, u16 reg_addr,
+ u32 len, u8 *rval)
+{
+ u32 val;
+ u32 retry_attempt = 0;
+ u32 cmd_data;
+ int ret = SDW_CMD_OK;
+
+ mutex_lock(&swrm->io_lock);
+ val = swrm_get_packed_reg_val(&swrm->rcmd_id, len, dev_addr, reg_addr);
+
+ /* wait for FIFO RD to complete to avoid overflow */
+ usleep_range(100, 105);
+ swrm->reg_write(swrm, SWRM_CMD_FIFO_RD_CMD, val);
+ /* wait for FIFO RD CMD complete to avoid overflow */
+ usleep_range(250, 255);
+
+retry_read:
+
+ swrm->reg_read(swrm, SWRM_CMD_FIFO_RD_FIFO_ADDR, &cmd_data);
+ rval[0] = cmd_data & 0xFF;
+
+ if ((((cmd_data) & 0xF00) >> 8) != swrm->rcmd_id) {
+ if (retry_attempt < MAX_FIFO_RD_FAIL_RETRY) {
+ /* wait 500 us before retry on fifo read failure */
+ usleep_range(500, 505);
+ if (retry_attempt == (MAX_FIFO_RD_FAIL_RETRY - 1)) {
+ swrm->reg_write(swrm, SWRM_CMD_FIFO_CMD, 0x1);
+ swrm->reg_write(swrm, SWRM_CMD_FIFO_RD_CMD, val);
+ }
+ retry_attempt++;
+ goto retry_read;
+ } else {
+ dev_err(swrm->dev,
+ "failed to read fifo: reg: 0x%x, \
+ rcmd_id: 0x%x, dev_num: 0x%x, cmd_data: 0x%x\n",
+ reg_addr, swrm->rcmd_id,
+ dev_addr, cmd_data);
+ ret = SDW_CMD_IGNORED;
+ }
}