gpu: nvgpu: add __must_check to gk20a_busy

The return value of gk20a_busy must be checked since it may not succeed
in some cases. Add the __must_check attribute that generates a compiler
warning for code that does not read the return value and fix all uses of
the function to take error cases into account.

Bug 200040921

Change-Id: Ibc2b119985fa230324c88026fe94fc5f1894fe4f
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/542552
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

7 files changed, 58 insertions, 17 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/as_gk20a.c b/drivers/gpu/nvgpu/gk20a/as_gk20a.c
index ed7602f0..5ca7c806 100644
--- a/drivers/gpu/nvgpu/gk20a/as_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/as_gk20a.c
@@ -82,8 +82,12 @@ int gk20a_as_release_share(struct gk20a_as_share *as_share)
         if (atomic_dec_return(&as_share->ref_cnt) > 0)
                 return 0;
 
-        gk20a_busy(g->dev);
+        err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+
         err = gk20a_vm_release_share(as_share);
+
         gk20a_idle(g->dev);
 
         release_as_share_id(as_share->as, as_share->id);
diff --git a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
index 746460c7..cd70d7c3 100644
--- a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
@@ -136,7 +136,7 @@ static int gk20a_ctrl_mark_compressible_write(
                 struct gk20a *g,
                 struct nvgpu_gpu_mark_compressible_write_args *args)
 {
-        int ret = 0;
+        int ret;
 
         ret = gk20a_busy(g->dev);
         if (ret)
diff --git a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
index 40751b88..6af54e68 100644
--- a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
@@ -571,7 +571,10 @@ static int dbg_set_powergate(struct dbg_session_gk20a *dbg_s,
                     (g->dbg_powergating_disabled_refcount++ == 0)) {
 
                         gk20a_dbg(gpu_dbg_gpu_dbg | gpu_dbg_fn, "module busy");
-                        gk20a_busy(g->dev);
+                        err = gk20a_busy(g->dev);
+                        if (err)
+                                return err;
+
                         err = gk20a_busy(dbg_s->pdev);
                         if (err)
                                 return -EPERM;
diff --git a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
index f41d883f..2cc3d38d 100644
--- a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
@@ -166,9 +166,14 @@ void gk20a_debug_show_dump(struct platform_device *pdev,
         struct gk20a *g = platform->g;
         struct fifo_gk20a *f = &g->fifo;
         u32 chid;
-        int i;
+        int i, err;
+
+        err = gk20a_busy(g->dev);
+        if (err) {
+                gk20a_debug_output(o, "failed to power on gpu: %d\n", err);
+                return;
+        }
 
-        gk20a_busy(g->dev);
         for (i = 0; i < fifo_pbdma_status__size_1_v(); i++) {
                 u32 status = gk20a_readl(g, fifo_pbdma_status_r(i));
                 u32 chan_status = fifo_pbdma_status_chan_status_v(status);
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index 6617f684..38322c87 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -703,7 +703,7 @@ void gk20a_create_sysfs(struct platform_device *dev);
 #define GK20A_SIM_IORESOURCE_MEM 2
 
 void gk20a_busy_noresume(struct platform_device *pdev);
-int gk20a_busy(struct platform_device *pdev);
+int __must_check gk20a_busy(struct platform_device *pdev);
 void gk20a_idle(struct platform_device *pdev);
 void gk20a_disable(struct gk20a *g, u32 units);
 void gk20a_enable(struct gk20a *g, u32 units);
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
index b23a1406..52a34086 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
@@ -45,11 +45,15 @@ static ssize_t elcg_enable_store(struct device *device,
         struct platform_device *ndev = to_platform_device(device);
         struct gk20a *g = get_gk20a(ndev);
         unsigned long val = 0;
+        int err;
 
         if (kstrtoul(buf, 10, &val) < 0)
                 return -EINVAL;
 
-        gk20a_busy(g->dev);
+        err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+
         if (val) {
                 g->elcg_enabled = true;
                 gr_gk20a_init_elcg_mode(g, ELCG_AUTO, ENGINE_GR_GK20A);
@@ -84,6 +88,7 @@ static ssize_t blcg_enable_store(struct device *device,
         struct platform_device *ndev = to_platform_device(device);
         struct gk20a *g = get_gk20a(ndev);
         unsigned long val = 0;
+        int err;
 
         if (kstrtoul(buf, 10, &val) < 0)
                 return -EINVAL;
@@ -93,7 +98,10 @@ static ssize_t blcg_enable_store(struct device *device,
         else
                 g->blcg_enabled = false;
 
-        gk20a_busy(g->dev);
+        err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+
         if (g->ops.clock_gating.blcg_bus_load_gating_prod)
                 g->ops.clock_gating.blcg_bus_load_gating_prod(g, g->blcg_enabled);
         if (g->ops.clock_gating.blcg_ctxsw_firmware_load_gating_prod)
@@ -133,6 +141,7 @@ static ssize_t slcg_enable_store(struct device *device,
         struct platform_device *ndev = to_platform_device(device);
         struct gk20a *g = get_gk20a(ndev);
         unsigned long val = 0;
+        int err;
 
         if (kstrtoul(buf, 10, &val) < 0)
                 return -EINVAL;
@@ -147,7 +156,10 @@ static ssize_t slcg_enable_store(struct device *device,
          * init. Therefore, it would be incongruous to add it here. Once
          * it is added to init, we should add it here too.
          */
-        gk20a_busy(g->dev);
+        err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+
         if (g->ops.clock_gating.slcg_bus_load_gating_prod)
                 g->ops.clock_gating.slcg_bus_load_gating_prod(g, g->slcg_enabled);
         if (g->ops.clock_gating.slcg_ce2_load_gating_prod)
@@ -305,11 +317,15 @@ static ssize_t gk20a_load_show(struct device *dev,
         struct gk20a *g = get_gk20a(pdev);
         u32 busy_time;
         ssize_t res;
+        int err;
 
         if (!g->power_on) {
                 busy_time = 0;
         } else {
-                gk20a_busy(g->dev);
+                err = gk20a_busy(g->dev);
+                if (err)
+                        return err;
+
                 gk20a_pmu_load_update(g);
                 gk20a_pmu_load_norm(g, &busy_time);
                 gk20a_idle(g->dev);
@@ -436,6 +452,9 @@ static ssize_t aelpg_enable_store(struct device *device,
                 return -EINVAL;
 
         err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+
         if (g->pmu.pmu_ready) {
                 if (val && !g->aelpg_enabled) {
                         g->aelpg_enabled = true;
diff --git a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
index f7af9035..c4872ab8 100644
--- a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
@@ -3721,13 +3721,12 @@ int gk20a_pmu_load_update(struct gk20a *g)
 void gk20a_pmu_get_load_counters(struct gk20a *g, u32 *busy_cycles,
                                  u32 *total_cycles)
 {
-        if (!g->power_on) {
+        if (!g->power_on || gk20a_busy(g->dev)) {
                 *busy_cycles = 0;
                 *total_cycles = 0;
                 return;
         }
 
-        gk20a_busy(g->dev);
         *busy_cycles = pwr_pmu_idle_count_value_v(
                 gk20a_readl(g, pwr_pmu_idle_count_r(1)));
         rmb();
@@ -3740,10 +3739,9 @@ void gk20a_pmu_reset_load_counters(struct gk20a *g)
 {
         u32 reg_val = pwr_pmu_idle_count_reset_f(1);
 
-        if (!g->power_on)
+        if (!g->power_on || gk20a_busy(g->dev))
                 return;
 
-        gk20a_busy(g->dev);
         gk20a_writel(g, pwr_pmu_idle_count_r(2), reg_val);
         wmb();
         gk20a_writel(g, pwr_pmu_idle_count_r(1), reg_val);
@@ -3929,10 +3927,14 @@ static int elpg_residency_show(struct seq_file *s, void *data)
         u32 ungating_time = 0;
         u32 gating_cnt;
         u64 total_ingating, total_ungating, residency, divisor, dividend;
+        int err;
 
         /* Don't unnecessarily power on the device */
         if (g->power_on) {
-                gk20a_busy(g->dev);
+                err = gk20a_busy(g->dev);
+                if (err)
+                        return err;
+
                 gk20a_pmu_get_elpg_residency_gating(g, &ingating_time,
                         &ungating_time, &gating_cnt);
                 gk20a_idle(g->dev);
@@ -3974,9 +3976,13 @@ static int elpg_transitions_show(struct seq_file *s, void *data)
         struct gk20a *g = s->private;
         u32 ingating_time, ungating_time, total_gating_cnt;
         u32 gating_cnt = 0;
+        int err;
 
         if (g->power_on) {
-                gk20a_busy(g->dev);
+                err = gk20a_busy(g->dev);
+                if (err)
+                        return err;
+
                 gk20a_pmu_get_elpg_residency_gating(g, &ingating_time,
                         &ungating_time, &gating_cnt);
                 gk20a_idle(g->dev);
@@ -4066,6 +4072,7 @@ static ssize_t perfmon_events_enable_write(struct file *file,
         unsigned long val = 0;
         char buf[40];
         int buf_size;
+        int err;
 
         memset(buf, 0, sizeof(buf));
         buf_size = min(count, (sizeof(buf)-1));
@@ -4078,7 +4085,10 @@ static ssize_t perfmon_events_enable_write(struct file *file,
 
         /* Don't turn on gk20a unnecessarily */
         if (g->power_on) {
-                gk20a_busy(g->dev);
+                err = gk20a_busy(g->dev);
+                if (err)
+                        return err;
+
                 if (val && !g->pmu.perfmon_sampling_enabled) {
                         g->pmu.perfmon_sampling_enabled = true;
                         pmu_perfmon_start_sampling(&(g->pmu));