drm/amdgpu/gmc: add new helper to get the FB size used by pre-OS console

This adds a new gmc callback to get the size reserved by the pre-OS
console and provides a helper function for use by gmc IP drivers.
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -27,6 +27,7 @@
 #include <linux/io-64-nonatomic-lo-hi.h>
 
 #include "amdgpu.h"
+#include "amdgpu_gmc.h"
 #include "amdgpu_ras.h"
 #include "amdgpu_xgmi.h"
 
@@ -431,3 +432,45 @@ void amdgpu_gmc_set_vm_fault_masks(struct amdgpu_device *adev, int hub_type,
 		WREG32(reg, tmp);
 	}
 }
+
+void amdgpu_gmc_get_vbios_allocations(struct amdgpu_device *adev)
+{
+	unsigned size;
+
+	/*
+	 * TODO:
+	 * Currently there is a bug where some memory client outside
+	 * of the driver writes to first 8M of VRAM on S3 resume,
+	 * this overrides GART which by default gets placed in first 8M and
+	 * causes VM_FAULTS once GTT is accessed.
+	 * Keep the stolen memory reservation until the while this is not solved.
+	 */
+	switch (adev->asic_type) {
+	case CHIP_VEGA10:
+	case CHIP_RAVEN:
+	case CHIP_ARCTURUS:
+	case CHIP_RENOIR:
+		adev->gmc.keep_stolen_vga_memory = true;
+		break;
+	default:
+		adev->gmc.keep_stolen_vga_memory = false;
+		break;
+	}
+
+	if (!amdgpu_device_ip_get_ip_block(adev, AMD_IP_BLOCK_TYPE_DCE))
+		size = 0;
+	else
+		size = amdgpu_gmc_get_vbios_fb_size(adev);
+
+	/* set to 0 if the pre-OS buffer uses up most of vram */
+	if ((adev->gmc.real_vram_size - size) < (8 * 1024 * 1024))
+		size = 0;
+
+	if (size > AMDGPU_VBIOS_VGA_ALLOCATION) {
+		adev->gmc.stolen_vga_size = AMDGPU_VBIOS_VGA_ALLOCATION;
+		adev->gmc.stolen_extended_size = size - adev->gmc.stolen_vga_size;
+	} else {
+		adev->gmc.stolen_vga_size = size;
+		adev->gmc.stolen_extended_size = 0;
+	}
+}

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

@@ -131,6 +131,8 @@ struct amdgpu_gmc_funcs {
 	void (*get_vm_pte)(struct amdgpu_device *adev,
 			   struct amdgpu_bo_va_mapping *mapping,
 			   uint64_t *flags);
+	/* get the amount of memory used by the vbios for pre-OS console */
+	unsigned int (*get_vbios_fb_size)(struct amdgpu_device *adev);
 };
 
 struct amdgpu_xgmi {
@@ -253,6 +255,7 @@ struct amdgpu_gmc {
 #define amdgpu_gmc_map_mtype(adev, flags) (adev)->gmc.gmc_funcs->map_mtype((adev),(flags))
 #define amdgpu_gmc_get_vm_pde(adev, level, dst, flags) (adev)->gmc.gmc_funcs->get_vm_pde((adev), (level), (dst), (flags))
 #define amdgpu_gmc_get_vm_pte(adev, mapping, flags) (adev)->gmc.gmc_funcs->get_vm_pte((adev), (mapping), (flags))
+#define amdgpu_gmc_get_vbios_fb_size(adev) (adev)->gmc.gmc_funcs->get_vbios_fb_size((adev))
 
 /**
  * amdgpu_gmc_vram_full_visible - Check if full VRAM is visible through the BAR
@@ -307,4 +310,6 @@ extern void
 amdgpu_gmc_set_vm_fault_masks(struct amdgpu_device *adev, int hub_type,
 			      bool enable);
 
+void amdgpu_gmc_get_vbios_allocations(struct amdgpu_device *adev);
+
 #endif