drm/amd/pm: correct the fan speed RPM setting

The relationship "PWM = RPM / smu->fan_max_rpm" between fan speed
PWM and RPM is not true for SMU11 ASICs. So, we need a new way to
perform the fan speed RPM setting.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h

@@ -1047,6 +1047,11 @@ struct pptable_funcs {
 	 */
 	int (*set_fan_speed_percent)(struct smu_context *smu, uint32_t speed);
 
+	/**
+	 * @set_fan_speed_rpm: Set a static fan speed in rpm.
+	 */
+	int (*set_fan_speed_rpm)(struct smu_context *smu, uint32_t speed);
+
 	/**
 	 * @set_xgmi_pstate: Set inter-chip global memory interconnect pstate.
 	 * &pstate: Pstate to set. D0 if Nonzero, D3 otherwise.

drivers/gpu/drm/amd/pm/inc/smu_v11_0.h

@@ -224,6 +224,9 @@ smu_v11_0_set_fan_control_mode(struct smu_context *smu,
 int smu_v11_0_set_fan_speed_percent(struct smu_context *smu,
 				    uint32_t speed);
 
+int smu_v11_0_set_fan_speed_rpm(struct smu_context *smu,
+				uint32_t speed);
+
 int smu_v11_0_set_xgmi_pstate(struct smu_context *smu,
 				     uint32_t pstate);
 

drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

@@ -2190,11 +2190,12 @@ static int smu_set_fan_speed_rpm(void *handle, uint32_t speed)
 
 	mutex_lock(&smu->mutex);
 
-	if (smu->ppt_funcs->set_fan_speed_percent) {
-		percent = speed * 100 / smu->fan_max_rpm;
-		ret = smu->ppt_funcs->set_fan_speed_percent(smu, percent);
-		if (!ret && !(smu->user_dpm_profile.flags & SMU_DPM_USER_PROFILE_RESTORE))
+	if (smu->ppt_funcs->set_fan_speed_rpm) {
+		ret = smu->ppt_funcs->set_fan_speed_rpm(smu, speed);
+		if (!ret && !(smu->user_dpm_profile.flags & SMU_DPM_USER_PROFILE_RESTORE)) {
+			percent = speed * 100 / smu->fan_max_rpm;
 			smu->user_dpm_profile.fan_speed_percent = percent;
+		}
 	}
 
 	mutex_unlock(&smu->mutex);

drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c

@@ -2316,6 +2316,7 @@ static const struct pptable_funcs arcturus_ppt_funcs = {
 	.get_fan_control_mode = smu_v11_0_get_fan_control_mode,
 	.set_fan_control_mode = smu_v11_0_set_fan_control_mode,
 	.set_fan_speed_percent = smu_v11_0_set_fan_speed_percent,
+	.set_fan_speed_rpm = smu_v11_0_set_fan_speed_rpm,
 	.set_xgmi_pstate = smu_v11_0_set_xgmi_pstate,
 	.gfx_off_control = smu_v11_0_gfx_off_control,
 	.register_irq_handler = smu_v11_0_register_irq_handler,

drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c

@@ -3271,6 +3271,7 @@ static const struct pptable_funcs navi10_ppt_funcs = {
 	.get_fan_control_mode = smu_v11_0_get_fan_control_mode,
 	.set_fan_control_mode = smu_v11_0_set_fan_control_mode,
 	.set_fan_speed_percent = smu_v11_0_set_fan_speed_percent,
+	.set_fan_speed_rpm = smu_v11_0_set_fan_speed_rpm,
 	.set_xgmi_pstate = smu_v11_0_set_xgmi_pstate,
 	.gfx_off_control = smu_v11_0_gfx_off_control,
 	.register_irq_handler = smu_v11_0_register_irq_handler,

drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c

@@ -3903,6 +3903,7 @@ static const struct pptable_funcs sienna_cichlid_ppt_funcs = {
 	.get_fan_control_mode = smu_v11_0_get_fan_control_mode,
 	.set_fan_control_mode = smu_v11_0_set_fan_control_mode,
 	.set_fan_speed_percent = smu_v11_0_set_fan_speed_percent,
+	.set_fan_speed_rpm = smu_v11_0_set_fan_speed_rpm,
 	.set_xgmi_pstate = smu_v11_0_set_xgmi_pstate,
 	.gfx_off_control = smu_v11_0_gfx_off_control,
 	.register_irq_handler = smu_v11_0_register_irq_handler,

drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c

@@ -1228,6 +1228,41 @@ smu_v11_0_set_fan_speed_percent(struct smu_context *smu, uint32_t speed)
 	return smu_v11_0_set_fan_static_mode(smu, FDO_PWM_MODE_STATIC);
 }
 
+int smu_v11_0_set_fan_speed_rpm(struct smu_context *smu,
+				uint32_t speed)
+{
+	struct amdgpu_device *adev = smu->adev;
+	/*
+	 * crystal_clock_freq used for fan speed rpm calculation is
+	 * always 25Mhz. So, hardcode it as 2500(in 10K unit).
+	 */
+	uint32_t crystal_clock_freq = 2500;
+	uint32_t tach_period;
+	int ret;
+
+	ret = smu_v11_0_auto_fan_control(smu, 0);
+	if (ret)
+		return ret;
+
+	/*
+	 * To prevent from possible overheat, some ASICs may have requirement
+	 * for minimum fan speed:
+	 * - For some NV10 SKU, the fan speed cannot be set lower than
+	 *   700 RPM.
+	 * - For some Sienna Cichlid SKU, the fan speed cannot be set
+	 *   lower than 500 RPM.
+	 */
+	tach_period = 60 * crystal_clock_freq * 10000 / (8 * speed);
+	WREG32_SOC15(THM, 0, mmCG_TACH_CTRL,
+		     REG_SET_FIELD(RREG32_SOC15(THM, 0, mmCG_TACH_CTRL),
+				   CG_TACH_CTRL, TARGET_PERIOD,
+				   tach_period));
+
+	ret = smu_v11_0_set_fan_static_mode(smu, FDO_PWM_MODE_STATIC_RPM);
+
+	return ret;
+}
+
 int
 smu_v11_0_set_fan_control_mode(struct smu_context *smu,
 			       uint32_t mode)