[PATCH 2/2] drm/amd/powerplay: add sensor lock support for smu

[Feng, Kenneth]

Here's the case: the user mode driver and the tester access the sysfs simultaneously.
That causes the message/parameter mismatch.
Reviewed-by: Kenneth Feng <kenneth.feng at amd.com>


-----Original Message-----
From: Wang, Kevin(Yang) 
Sent: Thursday, September 26, 2019 4:56 PM
To: amd-gfx at lists.freedesktop.org
Cc: Huang, Ray <Ray.Huang at amd.com>; Feng, Kenneth <Kenneth.Feng at amd.com>; Wang, Kevin(Yang) <Kevin1.Wang at amd.com>
Subject: [PATCH 2/2] drm/amd/powerplay: add sensor lock support for smu

when multithreading access sysfs of amdgpu_pm_info at the sametime.
the swsmu driver cause smu firmware hang.

eg:
single thread access:
Message A + Param A ==> right
Message B + Param B ==> right
Message C + Param C ==> right
multithreading access:
Message A + Param B ==> error
Message B + Param A ==> error
Message C + Param C ==> right

the patch will add sensor lock(mutex) to avoid this error.

Signed-off-by: Kevin Wang <kevin1.wang at amd.com>
---
 drivers/gpu/drm/amd/powerplay/amdgpu_smu.c     | 2 ++
 drivers/gpu/drm/amd/powerplay/arcturus_ppt.c   | 2 ++
 drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h | 1 +
 drivers/gpu/drm/amd/powerplay/navi10_ppt.c     | 2 ++
 drivers/gpu/drm/amd/powerplay/vega20_ppt.c     | 2 ++
 5 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
index 23293e15636b..df510cb86da5 100644
--- a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
@@ -840,6 +840,8 @@ static int smu_sw_init(void *handle)
 	smu->smu_baco.state = SMU_BACO_STATE_EXIT;
 	smu->smu_baco.platform_support = false;
 
+	mutex_init(&smu->sensor_lock);
+
 	smu->watermarks_bitmap = 0;
 	smu->power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;
 	smu->default_power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;
diff --git a/drivers/gpu/drm/amd/powerplay/arcturus_ppt.c b/drivers/gpu/drm/amd/powerplay/arcturus_ppt.c
index a047a7ec3698..b9b7b73354a0 100644
--- a/drivers/gpu/drm/amd/powerplay/arcturus_ppt.c
+++ b/drivers/gpu/drm/amd/powerplay/arcturus_ppt.c
@@ -1025,6 +1025,7 @@ static int arcturus_read_sensor(struct smu_context *smu,
 	if (!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm; @@ -1051,6 +1052,7 @@ static int arcturus_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h b/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
index 5c898444ff97..bc4b73e0718e 100644
--- a/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
+++ b/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
@@ -350,6 +350,7 @@ struct smu_context
 	const struct smu_funcs		*funcs;
 	const struct pptable_funcs	*ppt_funcs;
 	struct mutex			mutex;
+	struct mutex			sensor_lock;
 	uint64_t pool_size;
 
 	struct smu_table_context	smu_table;
diff --git a/drivers/gpu/drm/amd/powerplay/navi10_ppt.c b/drivers/gpu/drm/amd/powerplay/navi10_ppt.c
index db2e181ba45a..c0b640d8d9e1 100644
--- a/drivers/gpu/drm/amd/powerplay/navi10_ppt.c
+++ b/drivers/gpu/drm/amd/powerplay/navi10_ppt.c
@@ -1387,6 +1387,7 @@ static int navi10_read_sensor(struct smu_context *smu,
 	if(!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm; @@ -1410,6 +1411,7 @@ static int navi10_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
index 9082da1578d1..f655ebd9ba22 100644
--- a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
+++ b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
@@ -3017,6 +3017,7 @@ static int vega20_read_sensor(struct smu_context *smu,
 	if(!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm; @@ -3042,6 +3043,7 @@ static int vega20_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }
--
2.17.1