remoteproc: qcom_q6v5_mss: Monitor MSS_STATUS for boot completion

On secure devices there exists a race condition which could lock the MSS
CONFIG AHB bus thus preventing access to BOOT_STATUS register during SSR.
Switch to polling the MSS_STATUS register with an additional 10 us delay
to reliably track boot completion.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200716120514.21588-1-sibis@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
index dd37e46..1fd270a 100644 (file)
--- a/drivers/remoteproc/qcom_q6v5_mss.c
+++ b/drivers/remoteproc/qcom_q6v5_mss.c
@@ -112,8 +112,6 @@
 #define QDSP6SS_SLEEP                   0x3C
 #define QDSP6SS_BOOT_CORE_START         0x400
 #define QDSP6SS_BOOT_CMD                0x404
-#define QDSP6SS_BOOT_STATUS            0x408
-#define BOOT_STATUS_TIMEOUT_US         200
 #define BOOT_FSM_TIMEOUT                10000
 
 struct reg_info {
@@ -579,13 +577,15 @@ static int q6v5proc_reset(struct q6v5 *qproc)
                /* De-assert the Q6 stop core signal */
                writel(1, qproc->reg_base + QDSP6SS_BOOT_CORE_START);
 
+               /* Wait for 10 us for any staggering logic to settle */
+               usleep_range(10, 20);
+
                /* Trigger the boot FSM to start the Q6 out-of-reset sequence */
                writel(1, qproc->reg_base + QDSP6SS_BOOT_CMD);
 
-               /* Poll the QDSP6SS_BOOT_STATUS for FSM completion */
-               ret = readl_poll_timeout(qproc->reg_base + QDSP6SS_BOOT_STATUS,
-                                        val, (val & BIT(0)) != 0, 1,
-                                        BOOT_STATUS_TIMEOUT_US);
+               /* Poll the MSS_STATUS for FSM completion */
+               ret = readl_poll_timeout(qproc->rmb_base + RMB_MBA_MSS_STATUS,
+                                        val, (val & BIT(0)) != 0, 10, BOOT_FSM_TIMEOUT);
                if (ret) {
                        dev_err(qproc->dev, "Boot FSM failed to complete.\n");
                        /* Reset the modem so that boot FSM is in reset state */