drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c
Extension
.c
Size
4808 bytes
Lines
161
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

if (volt) {
			*ver = nvbios_rd08(bios, volt + 0);
			switch (*ver) {
			case 0x12:
				*hdr = 5;
				*cnt = nvbios_rd08(bios, volt + 2);
				*len = nvbios_rd08(bios, volt + 1);
				return volt;
			case 0x20:
				*hdr = nvbios_rd08(bios, volt + 1);
				*cnt = nvbios_rd08(bios, volt + 2);
				*len = nvbios_rd08(bios, volt + 3);
				return volt;
			case 0x30:
			case 0x40:
			case 0x50:
				*hdr = nvbios_rd08(bios, volt + 1);
				*cnt = nvbios_rd08(bios, volt + 3);
				*len = nvbios_rd08(bios, volt + 2);
				return volt;
			}
		}
	}

	return 0;
}

u32
nvbios_volt_parse(struct nvkm_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len,
		  struct nvbios_volt *info)
{
	u32 volt = nvbios_volt_table(bios, ver, hdr, cnt, len);
	memset(info, 0x00, sizeof(*info));
	switch (!!volt * *ver) {
	case 0x12:
		info->type    = NVBIOS_VOLT_GPIO;
		info->vidmask = nvbios_rd08(bios, volt + 0x04);
		info->ranged  = false;
		break;
	case 0x20:
		info->type    = NVBIOS_VOLT_GPIO;
		info->vidmask = nvbios_rd08(bios, volt + 0x05);
		info->ranged  = false;
		break;
	case 0x30:
		info->type    = NVBIOS_VOLT_GPIO;
		info->vidmask = nvbios_rd08(bios, volt + 0x04);
		info->ranged  = false;
		break;
	case 0x40:
		info->type    = NVBIOS_VOLT_GPIO;
		info->base    = nvbios_rd32(bios, volt + 0x04);
		info->step    = nvbios_rd16(bios, volt + 0x08);
		info->vidmask = nvbios_rd08(bios, volt + 0x0b);
		info->ranged  = true; /* XXX: find the flag byte */
		info->min     = min(info->base,
				    info->base + info->step * info->vidmask);
		info->max     = nvbios_rd32(bios, volt + 0x0e);
		if (!info->max)
			info->max = max(info->base, info->base + info->step * info->vidmask);
		break;
	case 0x50:
		info->min     = nvbios_rd32(bios, volt + 0x0a);
		info->max     = nvbios_rd32(bios, volt + 0x0e);
		info->base    = nvbios_rd32(bios, volt + 0x12) & 0x00ffffff;

		/* offset 4 seems to be a flag byte */
		if (nvbios_rd32(bios, volt + 0x4) & 1) {
			info->type      = NVBIOS_VOLT_PWM;
			info->pwm_freq  = nvbios_rd32(bios, volt + 0x5) / 1000;
			info->pwm_range = nvbios_rd32(bios, volt + 0x16);
		} else {
			info->type    = NVBIOS_VOLT_GPIO;
			info->vidmask = nvbios_rd08(bios, volt + 0x06);
			info->step    = nvbios_rd16(bios, volt + 0x16);
			info->ranged  =
				!!(nvbios_rd08(bios, volt + 0x4) & 0x2);
		}
		break;
	}
	return volt;
}

u32
nvbios_volt_entry(struct nvkm_bios *bios, int idx, u8 *ver, u8 *len)
{
	u8  hdr, cnt;
	u32 volt = nvbios_volt_table(bios, ver, &hdr, &cnt, len);
	if (volt && idx < cnt) {
		volt = volt + hdr + (idx * *len);

Annotation

Implementation Notes