drivers/gpu/drm/mgag200/mgag200_g200se.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/mgag200/mgag200_g200se.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/mgag200/mgag200_g200se.c
Extension
.c
Size
14296 bytes
Lines
526
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

switch (format->format) {
		case DRM_FORMAT_XRGB8888:
		case DRM_FORMAT_RGB888:
			bpp = 32;
			break;
		case DRM_FORMAT_RGB565:
		case DRM_FORMAT_XRGB1555:
			bpp = 16;
			break;
		case DRM_FORMAT_C8:
			bpp = 8;
			break;
		}

		mb = (mode->clock * bpp) / 1000;
		if (mb > 3100)
			hiprilvl = 0;
		else if (mb > 2600)
			hiprilvl = 1;
		else if (mb > 1900)
			hiprilvl = 2;
		else if (mb > 1160)
			hiprilvl = 3;
		else if (mb > 440)
			hiprilvl = 4;
		else
			hiprilvl = 5;

	} else if (g200se->unique_rev_id >= 0x01) {
		hiprilvl = 3;
	} else {
		hiprilvl = 4;
	}

	crtcext6 = hiprilvl; /* implicitly sets maxhipri to 0 */

	WREG_ECRT(0x06, crtcext6);
}

/*
 * PIXPLLC
 */

static int mgag200_g200se_00_pixpllc_atomic_check(struct drm_crtc *crtc,
						  struct drm_atomic_commit *new_state)
{
	static const unsigned int vcomax = 320000;
	static const unsigned int vcomin = 160000;
	static const unsigned int pllreffreq = 25000;

	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(new_state, crtc);
	struct mgag200_crtc_state *new_mgag200_crtc_state = to_mgag200_crtc_state(new_crtc_state);
	long clock = new_crtc_state->mode.clock;
	struct mgag200_pll_values *pixpllc = &new_mgag200_crtc_state->pixpllc;
	unsigned int delta, tmpdelta, permitteddelta;
	unsigned int testp, testm, testn;
	unsigned int p, m, n, s;
	unsigned int computed;

	m = n = p = s = 0;
	delta = 0xffffffff;
	permitteddelta = clock * 5 / 1000;

	for (testp = 8; testp > 0; testp /= 2) {
		if (clock * testp > vcomax)
			continue;
		if (clock * testp < vcomin)
			continue;

		for (testn = 17; testn < 256; testn++) {
			for (testm = 1; testm < 32; testm++) {
				computed = (pllreffreq * testn) / (testm * testp);
				if (computed > clock)
					tmpdelta = computed - clock;
				else
					tmpdelta = clock - computed;
				if (tmpdelta < delta) {
					delta = tmpdelta;
					m = testm;
					n = testn;
					p = testp;
				}
			}
		}
	}

	if (delta > permitteddelta) {
		pr_warn("PLL delta too large\n");
		return -EINVAL;
	}

Annotation

Implementation Notes