drm/amd: Refactor `amdgpu_aspm` to be evaluated per device

Evaluating `pcie_aspm_enabled` as part of driver probe has the implication
that if one PCIe bridge with an AMD GPU connected doesn't support ASPM
then none of them do.  This is an invalid assumption as the PCIe core will
configure ASPM for individual PCIe bridges.

Create a new helper function that can be called by individual dGPUs to
react to the `amdgpu_aspm` module parameter without having negative results
for other dGPUs on the PCIe bus.

Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -1296,6 +1296,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
 void amdgpu_device_pci_config_reset(struct amdgpu_device *adev);
 int amdgpu_device_pci_reset(struct amdgpu_device *adev);
 bool amdgpu_device_need_post(struct amdgpu_device *adev);
+bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev);
 
 void amdgpu_cs_report_moved_bytes(struct amdgpu_device *adev, u64 num_bytes,
 				  u64 num_vis_bytes);

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -1318,6 +1318,31 @@ bool amdgpu_device_need_post(struct amdgpu_device *adev)
 	return true;
 }
 
+/**
+ * amdgpu_device_should_use_aspm - check if the device should program ASPM
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * Confirm whether the module parameter and pcie bridge agree that ASPM should
+ * be set for this device.
+ *
+ * Returns true if it should be used or false if not.
+ */
+bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev)
+{
+	switch (amdgpu_aspm) {
+	case -1:
+		break;
+	case 0:
+		return false;
+	case 1:
+		return true;
+	default:
+		return false;
+	}
+	return pcie_aspm_enabled(adev->pdev);
+}
+
 /* if we get transitioned to only one device, take VGA back */
 /**
  * amdgpu_device_vga_set_decode - enable/disable vga decode

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -2008,9 +2008,6 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 			return -ENODEV;
 	}
 
-	if (amdgpu_aspm == -1 && !pcie_aspm_enabled(pdev))
-		amdgpu_aspm = 0;
-
 	if (amdgpu_virtual_display ||
 	    amdgpu_device_asic_has_dc_support(flags & AMD_ASIC_MASK))
 		supports_atomic = true;

drivers/gpu/drm/amd/amdgpu/cik.c

@@ -1719,7 +1719,7 @@ static void cik_program_aspm(struct amdgpu_device *adev)
 	bool disable_l0s = false, disable_l1 = false, disable_plloff_in_l1 = false;
 	bool disable_clkreq = false;
 
-	if (amdgpu_aspm == 0)
+	if (!amdgpu_device_should_use_aspm(adev))
 		return;
 
 	if (pci_is_root_bus(adev->pdev->bus))

drivers/gpu/drm/amd/amdgpu/nv.c

@@ -522,7 +522,7 @@ static void nv_pcie_gen3_enable(struct amdgpu_device *adev)
 
 static void nv_program_aspm(struct amdgpu_device *adev)
 {
-	if (!amdgpu_aspm)
+	if (!amdgpu_device_should_use_aspm(adev))
 		return;
 
 	if (!(adev->flags & AMD_IS_APU) &&

drivers/gpu/drm/amd/amdgpu/si.c

@@ -2453,7 +2453,7 @@ static void si_program_aspm(struct amdgpu_device *adev)
 	bool disable_l0s = false, disable_l1 = false, disable_plloff_in_l1 = false;
 	bool disable_clkreq = false;
 
-	if (amdgpu_aspm == 0)
+	if (!amdgpu_device_should_use_aspm(adev))
 		return;
 
 	if (adev->flags & AMD_IS_APU)

drivers/gpu/drm/amd/amdgpu/soc15.c

@@ -670,7 +670,7 @@ static void soc15_pcie_gen3_enable(struct amdgpu_device *adev)
 
 static void soc15_program_aspm(struct amdgpu_device *adev)
 {
-	if (!amdgpu_aspm)
+	if (!amdgpu_device_should_use_aspm(adev))
 		return;
 
 	if (!(adev->flags & AMD_IS_APU) &&

drivers/gpu/drm/amd/amdgpu/vi.c

@@ -1140,7 +1140,7 @@ static void vi_program_aspm(struct amdgpu_device *adev)
 	bool bL1SS = false;
 	bool bClkReqSupport = true;
 
-	if (!amdgpu_aspm)
+	if (!amdgpu_device_should_use_aspm(adev))
 		return;
 
 	if (adev->flags & AMD_IS_APU ||

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

@@ -348,7 +348,7 @@ sienna_cichlid_get_allowed_feature_mask(struct smu_context *smu,
 	if (smu->dc_controlled_by_gpio)
        *(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_ACDC_BIT);
 
-	if (amdgpu_aspm)
+	if (amdgpu_device_should_use_aspm(adev))
 		*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_DS_LCLK_BIT);
 
 	return 0;