gpu: nvgpu: Add timeout to L2 flush

Add a timeout mechanism to the L2 flushing code for gm20b.
Previously the code could spin forever in a loop if some
issue were to occur with the L2 causing the flush to fail.

Change-Id: I742c7671bac92aeb8e9674c43d30c45b2de4a836
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/423842
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/ltc_gm20b.c b/drivers/gpu/nvgpu/gm20b/ltc_gm20b.c
index 1f9bf44c..7a2bb5fd 100644
--- a/drivers/gpu/nvgpu/gm20b/ltc_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/ltc_gm20b.c
@@ -14,6 +14,7 @@
  */
 
 #include <linux/types.h>
+#include <linux/jiffies.h>
 
 #include "hw_ltc_gm20b.h"
 #include "hw_top_gm20b.h"
@@ -256,6 +257,19 @@ u32 gm20b_ltc_cbc_fix_config(struct gk20a *g, int base)
 void gm20b_flush_ltc(struct gk20a *g)
 {
         u32 op_pending;
+        unsigned long now, timeout;
+
+#define __timeout_init()                                \
+        do {                                            \
+                now = jiffies;  timeout = now + HZ;     \
+        } while (0)
+#define __timeout_check()                                               \
+        do {                                                            \
+                if (tegra_platform_is_silicon() && time_after(now, timeout)) { \
+                        gk20a_err(dev_from_gk20a(g), "L2 flush timeout!"); \
+                        break;                                          \
+                }                                                       \
+        } while (0)
 
         /* Clean... */
         gk20a_writel(g, ltc_ltcs_ltss_tstg_cmgmt1_r(),
@@ -267,13 +281,17 @@ void gm20b_flush_ltc(struct gk20a *g)
                 ltc_ltcs_ltss_tstg_cmgmt1_clean_evict_first_class_true_f());
 
         /* Wait on each LTC individually. */
+        __timeout_init();
         do {
                 op_pending = gk20a_readl(g, ltc_ltc0_ltss_tstg_cmgmt1_r());
+                __timeout_check();
         } while (op_pending &
                  ltc_ltc0_ltss_tstg_cmgmt1_clean_pending_f());
 
+        __timeout_init();
         do {
                 op_pending = gk20a_readl(g, ltc_ltc1_ltss_tstg_cmgmt1_r());
+                __timeout_check();
         } while (op_pending &
                  ltc_ltc1_ltss_tstg_cmgmt1_clean_pending_f());
 
@@ -286,13 +304,17 @@ void gm20b_flush_ltc(struct gk20a *g)
              ltc_ltcs_ltss_tstg_cmgmt0_invalidate_evict_first_class_true_f());
 
         /* Wait on each LTC individually. */
+        __timeout_init();
         do {
                 op_pending = gk20a_readl(g, ltc_ltc0_ltss_tstg_cmgmt0_r());
+                __timeout_check();
         } while (op_pending &
                  ltc_ltc0_ltss_tstg_cmgmt0_invalidate_pending_f());
 
+        __timeout_init();
         do {
                 op_pending = gk20a_readl(g, ltc_ltc1_ltss_tstg_cmgmt0_r());
+                __timeout_check();
         } while (op_pending &
                  ltc_ltc1_ltss_tstg_cmgmt0_invalidate_pending_f());
 }