drivers/gpu/drm/ast/ast_mm.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/ast/ast_mm.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/ast/ast_mm.c
Extension
.c
Size
2562 bytes
Lines
98
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/pci.h>

#include <drm/drm_managed.h>
#include <drm/drm_print.h>

#include "ast_drv.h"

static u32 ast_get_vram_size(struct ast_device *ast)
{
	u32 vram_size;
	u8 vgacr99, vgacraa;

	vgacraa = ast_get_index_reg(ast, AST_IO_VGACRI, 0xaa);
	switch (vgacraa & AST_IO_VGACRAA_VGAMEM_SIZE_MASK) {
	case 0:
		vram_size = SZ_8M;
		break;
	case 1:
		vram_size = SZ_16M;
		break;
	case 2:
		vram_size = SZ_32M;
		break;
	case 3:
		vram_size = SZ_64M;
		break;
	}

	vgacr99 = ast_get_index_reg(ast, AST_IO_VGACRI, 0x99);
	switch (vgacr99 & AST_IO_VGACR99_VGAMEM_RSRV_MASK) {
	case 1:
		vram_size -= SZ_1M;
		break;
	case 2:
		vram_size -= SZ_2M;
		break;
	case 3:
		vram_size -= SZ_4M;
		break;
	}

	return vram_size;
}

int ast_mm_init(struct ast_device *ast)
{
	struct drm_device *dev = &ast->base;
	struct pci_dev *pdev = to_pci_dev(dev->dev);
	resource_size_t base, size;
	u32 vram_size;

	base = pci_resource_start(pdev, 0);
	size = pci_resource_len(pdev, 0);

	/* Don't fail on errors, but performance might be reduced. */
	devm_arch_io_reserve_memtype_wc(dev->dev, base, size);
	devm_arch_phys_wc_add(dev->dev, base, size);

	vram_size = ast_get_vram_size(ast);

	ast->vram = devm_ioremap_wc(dev->dev, base, vram_size);
	if (!ast->vram)
		return -ENOMEM;

	ast->vram_base = base;
	ast->vram_size = vram_size;

	return 0;
}

Annotation

Implementation Notes