From: sujeet baranwal <sbaranwal@nvidia.com>
Date: Fri, 29 Aug 2014 20:56:49 +0000 (-0700)
Subject: video: tegra: Wait PMU finishes booting
X-Git-Tag: tegra-l4t-r21-er-2015-02-02~40
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/sojka/nv-tegra/linux-3.10.git/commitdiff_plain/f69b7093accdacfa653b4bd45d78e04a2676dc2a

video: tegra: Wait PMU finishes booting

GPU PMU booting is in a separate thread(workqueue) and currently
there is a race condition that PMU booting doesn't finish when
"nvhost_gk20a_finalize_power_on" is returning.
If the GPU starts to runtime powergate(nvhost_gk20a_prepare_poweroff)
at that time, we left a unfinished PMU booting workqueue task there.
So next time when this task starts running, GPU will be put into
a bad state which causes lots of GPU errors.
This patch adds a wait at the end of "nvhost_gk20a_finalize_power_on"
, so that the race condition can be avoided.

Bug 200055546

Change-Id: I4f2d0798fcadb4effc555a66f3c3e3061b18d246
Signed-off-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: sujeet baranwal <sbaranwal@nvidia.com>
Reviewed-on: http://git-master/r/494065
(cherry picked from commit 3b9866a952ba0a1dea05d20bf32b6bcc9113f38b)
Reviewed-on: http://git-master/r/655952
Reviewed-by: Automatic_Commit_Validation_User
Tested-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: Winnie Hsu <whsu@nvidia.com>
---

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index fdfc9260da9..03d466ef3dc 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -914,6 +914,8 @@ static int gk20a_pm_finalize_poweron(struct device *dev)
 		goto done;
 	}
 
+	wait_event(g->pmu.boot_wq, g->pmu.pmu_state == PMU_STATE_STARTED);
+
 	gk20a_channel_resume(g);
 	set_user_nice(current, nice_value);
 
@@ -1469,6 +1471,7 @@ static int gk20a_probe(struct platform_device *dev)
 					&gk20a->timeouts_enabled);
 	gk20a_pmu_debugfs_init(dev);
 #endif
+	init_waitqueue_head(&gk20a->pmu.boot_wq);
 
 	gk20a_init_gr(gk20a);
 
diff --git a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
index 21e4d611611..62b9a022351 100644
--- a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
@@ -1967,6 +1967,8 @@ static void pmu_setup_hw_enable_elpg(struct gk20a *g)
 		gk20a_aelpg_init(g);
 		gk20a_aelpg_init_and_enable(g, PMU_AP_CTRL_ID_GRAPHICS);
 	}
+
+	wake_up(&g->pmu.boot_wq);
 }
 
 int gk20a_init_pmu_support(struct gk20a *g)
diff --git a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
index c13bf9a8ec1..a577890edd4 100644
--- a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
@@ -1032,6 +1032,7 @@ struct pmu_gk20a {
 	u32 elpg_stat;
 
 	int pmu_state;
+	wait_queue_head_t boot_wq;
 
 #define PMU_ELPG_ENABLE_ALLOW_DELAY_MSEC	1 /* msec */
 	struct work_struct pg_init;