gpu: nvgpu: Disable trace_printk use by default

trace_printk() does an extra stringify operation before calling
do_trace_printk(). The string ends up unused. This has an impact
to kernel even if we never end up using trace_printk().

Disable use of trace_printk() and introduce a Kconfig option for
re-enabling it.

Change-Id: I2e1014f5231f2089d7dc3cb2539e3eb5f4d58361
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1295298
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

5 files changed, 18 insertions, 12 deletions

diff --git a/drivers/gpu/nvgpu/Kconfig.nvgpu b/drivers/gpu/nvgpu/Kconfig.nvgpu
index 8baf6897..d15a9fd0 100644
--- a/drivers/gpu/nvgpu/Kconfig.nvgpu
+++ b/drivers/gpu/nvgpu/Kconfig.nvgpu
@@ -111,6 +111,14 @@ config GK20A_PCI
         help
           Enable support for GPUs on PCIe bus.
 
+config GK20A_TRACE_PRINTK
+        bool "Support trace_printk debugging"
+        depends on CONFIG_FTRACE_PRINTK
+        default n
+        help
+          Enable nvgpu debug facility to redirect debug spew to ftrace. This
+          affects kernel memory use, so should not be enabled by default.
+
 config GK20A_VIDMEM
         bool "Support separate video memory on nvgpu"
         depends on GK20A
diff --git a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
index 6341a962..7c7d7ae6 100644
--- a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
@@ -417,9 +417,10 @@ void gk20a_debug_init(struct device *dev, const char *debugfs_symlink)
         debugfs_create_bool("disable_syncpoints", S_IRUGO|S_IWUSR,
                 platform->debugfs, &platform->disable_syncpoints);
 
-#if defined(GK20A_DEBUG)
         debugfs_create_u32("dbg_mask", S_IRUGO|S_IWUSR,
                 platform->debugfs, &gk20a_dbg_mask);
+
+#ifdef CONFIG_GK20A_TRACE_PRINTK
         debugfs_create_u32("dbg_ftrace", S_IRUGO|S_IWUSR,
                 platform->debugfs, &gk20a_dbg_ftrace);
 #endif
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 6b026ee2..583e77b4 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -89,8 +89,8 @@
 
 #define GK20A_NUM_CDEVS 7
 
-#if defined(GK20A_DEBUG)
 u32 gk20a_dbg_mask = GK20A_DEFAULT_DBG_MASK;
+#ifdef CONFIG_GK20A_TRACE_PRINTK
 u32 gk20a_dbg_ftrace;
 #endif
 
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index 69528c1f..b27b36d3 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -1108,12 +1108,10 @@ struct gk20a_cyclestate_buffer_elem {
 
 #ifdef CONFIG_DEBUG_FS
     /* debug info, default is compiled-in but effectively disabled (0 mask) */
-    #define GK20A_DEBUG
     /*e.g: echo 1 > /d/gk20a.0/dbg_mask */
     #define GK20A_DEFAULT_DBG_MASK 0
 #else
     /* manually enable and turn it on the mask */
-    /*#define NVGPU_DEBUG*/
     #define GK20A_DEFAULT_DBG_MASK (dbg_info)
 #endif
 
@@ -1141,8 +1139,8 @@ enum gk20a_dbg_categories {
         gpu_dbg_mem     = BIT(31), /* memory accesses, very verbose */
 };
 
-#if defined(GK20A_DEBUG)
 extern u32 gk20a_dbg_mask;
+#ifdef CONFIG_GK20A_TRACE_PRINTK
 extern u32 gk20a_dbg_ftrace;
 #define gk20a_dbg(dbg_mask, format, arg...)                             \
 do {                                                                    \
@@ -1154,14 +1152,14 @@ do {									\
                                         __func__, ##arg);               \
         }                                                               \
 } while (0)
-
-#else /* GK20A_DEBUG */
+#else
 #define gk20a_dbg(dbg_mask, format, arg...)                             \
 do {                                                                    \
-        if (0)                                                          \
-                pr_info("gk20a %s: " format "\n", __func__, ##arg);\
+        if (unlikely((dbg_mask) & gk20a_dbg_mask)) {            \
+                pr_info("gk20a %s: " format "\n",               \
+                                __func__, ##arg);               \
+        }                                                               \
 } while (0)
-
 #endif
 
 #define gk20a_err(d, fmt, arg...)                                       \
diff --git a/drivers/gpu/nvgpu/gp10b/cde_gp10b.c b/drivers/gpu/nvgpu/gp10b/cde_gp10b.c
index 4a16abd1..56700211 100644
--- a/drivers/gpu/nvgpu/gp10b/cde_gp10b.c
+++ b/drivers/gpu/nvgpu/gp10b/cde_gp10b.c
@@ -129,14 +129,13 @@ static int gp10b_populate_scatter_buffer(struct gk20a *g,
         if ((page & 7) != 0)
                 scatter_buffer[page >> 3] = d;
 
-#if defined(GK20A_DEBUG)
         if (unlikely(gpu_dbg_cde & gk20a_dbg_mask)) {
                 gk20a_dbg(gpu_dbg_cde, "scatterBuffer content:");
                 for (i=0; i < page>>3; i++) {
                         gk20a_dbg(gpu_dbg_cde, " %x", scatter_buffer[i]);
                 }
         }
-#endif
+
         return 0;
 }