Tegra186: mce: max retries for ARI requests

This patch adds max retries for all ARI requests and asserts
if the ARI request is still busy.

Change-Id: I454ad9b557bb59e513e4c0c6f071275c87d0e07a
Signed-off-by: Steven Kao <skao@nvidia.com>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

diff --git a/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c b/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
index 7f711a7265dfdb0942aab91d2d024e3660ace7e1..87fadbe69131f6dac33702f658fcee5afae5dd9a 100644 (file)
--- a/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
+++ b/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -30,10 +30,13 @@
 
 #include <arch.h>
 #include <arch_helpers.h>
+#include <assert.h>
 #include <debug.h>
+#include <delay_timer.h>
 #include <denver.h>
 #include <mmio.h>
 #include <mce_private.h>
+#include <platform.h>
 #include <sys/errno.h>
 #include <t18x_ari.h>
 
@@ -49,10 +52,13 @@
 #define ARI_RESPONSE_DATA_HI           0x18
 
 /* Status values for the current request */
-#define ARI_REQ_PENDING                        1
-#define ARI_REQ_ONGOING                        3
-#define ARI_REQUEST_VALID_BIT          (1 << 8)
-#define ARI_EVT_MASK_STANDBYWFI_BIT    (1 << 7)
+#define ARI_REQ_PENDING                        1U
+#define ARI_REQ_ONGOING                        3U
+#define ARI_REQUEST_VALID_BIT          (1U << 8)
+#define ARI_EVT_MASK_STANDBYWFI_BIT    (1U << 7)
+
+/* default timeout (ms) to wait for ARI completion */
+#define ARI_MAX_RETRY_COUNT            2000
 
 /*******************************************************************************
  * ARI helper functions
@@ -96,7 +102,8 @@ static inline void ari_clobber_response(uint32_t ari_base)
 static int ari_request_wait(uint32_t ari_base, uint32_t evt_mask, uint32_t req,
                uint32_t lo, uint32_t hi)
 {
-       int status;
+       uint32_t retries = ARI_MAX_RETRY_COUNT;
+       uint32_t status;
 
        /* program the request, event_mask, hi and lo registers */
        ari_write_32(ari_base, lo, ARI_REQUEST_DATA_LO);
@@ -112,10 +119,36 @@ static int ari_request_wait(uint32_t ari_base, uint32_t evt_mask, uint32_t req,
        if (evt_mask)
                return 0;
 
-       /* NOTE: add timeout check if needed */
-       status = ari_read_32(ari_base, ARI_STATUS);
-       while (status & (ARI_REQ_ONGOING | ARI_REQ_PENDING))
+       /* For shutdown/reboot commands, we dont have to check for timeouts */
+       if ((req == (uint32_t)TEGRA_ARI_MISC_CCPLEX) &&
+           ((lo == (uint32_t)TEGRA_ARI_MISC_CCPLEX_SHUTDOWN_POWER_OFF) ||
+            (lo == (uint32_t)TEGRA_ARI_MISC_CCPLEX_SHUTDOWN_REBOOT))) {
+                       return 0;
+       }
+
+       /*
+        * Wait for the command response for not more than the timeout
+        */
+       while (retries != 0U) {
+
+               /* read the command status */
                status = ari_read_32(ari_base, ARI_STATUS);
+               if ((status & (ARI_REQ_ONGOING | ARI_REQ_PENDING)) == 0U)
+                       break;
+
+               /* delay 1 ms */
+               mdelay(1);
+
+               /* decrement the retry count */
+               retries--;
+       }
+
+       /* assert if the command timed out */
+       if (retries == 0U) {
+               ERROR("ARI request timed out: req %d on CPU %d\n",
+                       req, plat_my_core_pos());
+               assert(retries != 0U);
+       }
 
        return 0;
 }