drm/radeon/dpm: implement force performance levels for rs780 (v2)

Allows you to limit the selected power levels via sysfs.

Force the feedback divider to select a power level.

v2: fix checking in rs780_force_fbdiv,
    drop a duplicate divider structure in rs780_dpm_force_performance_level,
    Force the voltage level too.
Signed-off-by: Anthoine Bourgeois <anthoine.bourgeois@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_asic.c

@@ -1141,6 +1141,7 @@ static struct radeon_asic rs780_asic = {
 		.get_mclk = &rs780_dpm_get_mclk,
 		.print_power_state = &rs780_dpm_print_power_state,
 		.debugfs_print_current_performance_level = &rs780_dpm_debugfs_print_current_performance_level,
+		.force_performance_level = &rs780_dpm_force_performance_level,
 	},
 	.pflip = {
 		.pre_page_flip = &rs600_pre_page_flip,

drivers/gpu/drm/radeon/radeon_asic.h

@@ -428,6 +428,8 @@ void rs780_dpm_print_power_state(struct radeon_device *rdev,
 				 struct radeon_ps *ps);
 void rs780_dpm_debugfs_print_current_performance_level(struct radeon_device *rdev,
 						       struct seq_file *m);
+int rs780_dpm_force_performance_level(struct radeon_device *rdev,
+				      enum radeon_dpm_forced_level level);
 
 /*
  * rv770,rv730,rv710,rv740

drivers/gpu/drm/radeon/rs780_dpm.c

@@ -376,9 +376,8 @@ static void rs780_disable_vbios_powersaving(struct radeon_device *rdev)
 	WREG32_P(CG_INTGFX_MISC, 0, ~0xFFF00000);
 }
 
-static void rs780_force_voltage_to_high(struct radeon_device *rdev)
+static void rs780_force_voltage(struct radeon_device *rdev, u16 voltage)
 {
-	struct igp_power_info *pi = rs780_get_pi(rdev);
 	struct igp_ps *current_state = rs780_get_ps(rdev->pm.dpm.current_ps);
 
 	if ((current_state->max_voltage == RS780_VDDC_LEVEL_HIGH) &&
@@ -390,7 +389,7 @@ static void rs780_force_voltage_to_high(struct radeon_device *rdev)
 	udelay(1);
 
 	WREG32_P(FVTHROT_PWM_CTRL_REG0,
-		 STARTING_PWM_HIGHTIME(pi->max_voltage),
+		 STARTING_PWM_HIGHTIME(voltage),
 		 ~STARTING_PWM_HIGHTIME_MASK);
 
 	WREG32_P(FVTHROT_PWM_CTRL_REG0,
@@ -404,6 +403,26 @@ static void rs780_force_voltage_to_high(struct radeon_device *rdev)
 	WREG32_P(GFX_MACRO_BYPASS_CNTL, 0, ~SPLL_BYPASS_CNTL);
 }
 
+static void rs780_force_fbdiv(struct radeon_device *rdev, u32 fb_div)
+{
+	struct igp_ps *current_state = rs780_get_ps(rdev->pm.dpm.current_ps);
+
+	if (current_state->sclk_low == current_state->sclk_high)
+		return;
+
+	WREG32_P(GFX_MACRO_BYPASS_CNTL, SPLL_BYPASS_CNTL, ~SPLL_BYPASS_CNTL);
+
+	WREG32_P(FVTHROT_FBDIV_REG2, FORCED_FEEDBACK_DIV(fb_div),
+		 ~FORCED_FEEDBACK_DIV_MASK);
+	WREG32_P(FVTHROT_FBDIV_REG1, STARTING_FEEDBACK_DIV(fb_div),
+		 ~STARTING_FEEDBACK_DIV_MASK);
+	WREG32_P(FVTHROT_FBDIV_REG1, FORCE_FEEDBACK_DIV, ~FORCE_FEEDBACK_DIV);
+
+	udelay(100);
+
+	WREG32_P(GFX_MACRO_BYPASS_CNTL, 0, ~SPLL_BYPASS_CNTL);
+}
+
 static int rs780_set_engine_clock_scaling(struct radeon_device *rdev,
 					  struct radeon_ps *new_ps,
 					  struct radeon_ps *old_ps)
@@ -432,17 +451,7 @@ static int rs780_set_engine_clock_scaling(struct radeon_device *rdev,
 	if (ret)
 		return ret;
 
-	WREG32_P(GFX_MACRO_BYPASS_CNTL, SPLL_BYPASS_CNTL, ~SPLL_BYPASS_CNTL);
-
-	WREG32_P(FVTHROT_FBDIV_REG2, FORCED_FEEDBACK_DIV(max_dividers.fb_div),
-		 ~FORCED_FEEDBACK_DIV_MASK);
-	WREG32_P(FVTHROT_FBDIV_REG1, STARTING_FEEDBACK_DIV(max_dividers.fb_div),
-		 ~STARTING_FEEDBACK_DIV_MASK);
-	WREG32_P(FVTHROT_FBDIV_REG1, FORCE_FEEDBACK_DIV, ~FORCE_FEEDBACK_DIV);
-
-	udelay(100);
-
-	WREG32_P(GFX_MACRO_BYPASS_CNTL, 0, ~SPLL_BYPASS_CNTL);
+	rs780_force_fbdiv(rdev, max_dividers.fb_div);
 
 	if (max_dividers.fb_div > min_dividers.fb_div) {
 		WREG32_P(FVTHROT_FBDIV_REG0,
@@ -649,7 +658,7 @@ int rs780_dpm_set_power_state(struct radeon_device *rdev)
 	rs780_set_uvd_clock_before_set_eng_clock(rdev, new_ps, old_ps);
 
 	if (pi->voltage_control) {
-		rs780_force_voltage_to_high(rdev);
+		rs780_force_voltage(rdev, pi->max_voltage);
 		mdelay(5);
 	}
 
@@ -986,3 +995,53 @@ void rs780_dpm_debugfs_print_current_performance_level(struct radeon_device *rde
 		seq_printf(m, "power level 1    sclk: %u vddc_index: %d\n",
 			   ps->sclk_high, ps->max_voltage);
 }
+
+int rs780_dpm_force_performance_level(struct radeon_device *rdev,
+				      enum radeon_dpm_forced_level level)
+{
+	struct igp_power_info *pi = rs780_get_pi(rdev);
+	struct radeon_ps *rps = rdev->pm.dpm.current_ps;
+	struct igp_ps *ps = rs780_get_ps(rps);
+	struct atom_clock_dividers dividers;
+	int ret;
+
+	rs780_clk_scaling_enable(rdev, false);
+	rs780_voltage_scaling_enable(rdev, false);
+
+	if (level == RADEON_DPM_FORCED_LEVEL_HIGH) {
+		if (pi->voltage_control)
+			rs780_force_voltage(rdev, pi->max_voltage);
+
+		ret = radeon_atom_get_clock_dividers(rdev, COMPUTE_ENGINE_PLL_PARAM,
+						     ps->sclk_high, false, &dividers);
+		if (ret)
+			return ret;
+
+		rs780_force_fbdiv(rdev, dividers.fb_div);
+	} else if (level == RADEON_DPM_FORCED_LEVEL_LOW) {
+		ret = radeon_atom_get_clock_dividers(rdev, COMPUTE_ENGINE_PLL_PARAM,
+						     ps->sclk_low, false, &dividers);
+		if (ret)
+			return ret;
+
+		rs780_force_fbdiv(rdev, dividers.fb_div);
+
+		if (pi->voltage_control)
+			rs780_force_voltage(rdev, pi->min_voltage);
+	} else {
+		if (pi->voltage_control)
+			rs780_force_voltage(rdev, pi->max_voltage);
+
+		WREG32_P(FVTHROT_FBDIV_REG1, 0, ~FORCE_FEEDBACK_DIV);
+		rs780_clk_scaling_enable(rdev, true);
+
+		if (pi->voltage_control) {
+			rs780_voltage_scaling_enable(rdev, true);
+			rs780_enable_voltage_scaling(rdev, rps);
+		}
+	}
+
+	rdev->pm.dpm.forced_level = level;
+
+	return 0;
+}