// SPDX-License-Identifier: MIT/* * Copyright © 2021 Intel Corporation */ #include <drm/drm_edid.h>#include <drm/drm_print.h> #include "drm_crtc_internal.h"#include "drm_displayid_internal.h" enum {	QUIRK_IGNORE_CHECKSUM,}; struct displayid_quirk {	const struct drm_edid_ident ident;	u8 quirks;}; static const struct displayid_quirk quirks[] = {	{		.ident = DRM_EDID_IDENT_INIT('C', 'S', 'O', 5142, "MNE007ZA1-5"),		.quirks = BIT(QUIRK_IGNORE_CHECKSUM),	},}; static u8 get_quirks(const struct drm_edid *drm_edid){	int i; 	for (i = 0; i < ARRAY_SIZE(quirks); i++) {		if (drm_edid_match(drm_edid, &quirks[i].ident))			return quirks[i].quirks;	} 	return 0;} static const struct displayid_header *displayid_get_header(const u8 *displayid, int length, int index){	const struct displayid_header *base; 	if (sizeof(*base) > length - index)		return ERR_PTR(-EINVAL); 	base = (const struct displayid_header *)&displayid[index]; 	return base;} static const struct displayid_header *validate_displayid(const u8 *displayid, int length, int idx, bool ignore_checksum){	int i, dispid_length;	u8 csum = 0;	const struct displayid_header *base; 	base = displayid_get_header(displayid, length, idx);	if (IS_ERR(base))		return base; 	/* +1 for DispID checksum */	dispid_length = sizeof(*base) + base->bytes + 1;	if (dispid_length > length - idx)		return ERR_PTR(-EINVAL); 	for (i = 0; i < dispid_length; i++)		csum += displayid[idx + i];	if (csum) {		DRM_NOTE("DisplayID checksum invalid, remainder is %d%s\n", csum,			 ignore_checksum ? " (ignoring)" : ""); 		if (!ignore_checksum)			return ERR_PTR(-EINVAL);	} 	return base;} static const u8 *find_next_displayid_extension(struct displayid_iter *iter){	const struct displayid_header *base;	const u8 *displayid;	bool ignore_checksum = iter->quirks & BIT(QUIRK_IGNORE_CHECKSUM); 	displayid = drm_edid_find_extension(iter->drm_edid, DISPLAYID_EXT, &iter->ext_index);	if (!displayid)		return NULL; 	/* EDID extensions block checksum isn't for us */	iter->length = EDID_LENGTH - 1;	iter->idx = 1; 	base = validate_displayid(displayid, iter->length, iter->idx, ignore_checksum);	if (IS_ERR(base))		return NULL; 	iter->length = iter->idx + sizeof(*base) + base->bytes; 	return displayid;} void displayid_iter_edid_begin(const struct drm_edid *drm_edid,			       struct displayid_iter *iter){	memset(iter, 0, sizeof(*iter)); 	iter->drm_edid = drm_edid;	iter->quirks = get_quirks(drm_edid);} static const struct displayid_block *displayid_iter_block(const struct displayid_iter *iter){	const struct displayid_block *block; 	if (!iter->section)		return NULL; 	block = (const struct displayid_block *)&iter->section[iter->idx]; 	if (iter->idx + sizeof(*block) <= iter->length &&	    iter->idx + sizeof(*block) + block->num_bytes <= iter->length)		return block; 	return NULL;} const struct displayid_block *__displayid_iter_next(struct displayid_iter *iter){	const struct displayid_block *block; 	if (!iter->drm_edid)		return NULL; 	if (iter->section) {		/* current block should always be valid */		block = displayid_iter_block(iter);		if (WARN_ON(!block)) {			iter->section = NULL;			iter->drm_edid = NULL;			return NULL;		} 		/* next block in section */		iter->idx += sizeof(*block) + block->num_bytes; 		block = displayid_iter_block(iter);		if (block)			return block;	} 	for (;;) {		/* The first section we encounter is the base section */		bool base_section = !iter->section; 		iter->section = find_next_displayid_extension(iter);		if (!iter->section) {			iter->drm_edid = NULL;			return NULL;		} 		/* Save the structure version and primary use case. */		if (base_section) {			const struct displayid_header *base; 			base = displayid_get_header(iter->section, iter->length,						    iter->idx);			if (!IS_ERR(base)) {				iter->version = base->rev;				iter->primary_use = base->prod_id;			}		} 		iter->idx += sizeof(struct displayid_header); 		block = displayid_iter_block(iter);		if (block)			return block;	}} void displayid_iter_end(struct displayid_iter *iter){	memset(iter, 0, sizeof(*iter));} /* DisplayID Structure Version/Revision from the Base Section. */u8 displayid_version(const struct displayid_iter *iter){	return iter->version;} /* * DisplayID Primary Use Case (2.0+) or Product Type Identifier (1.0-1.3) from * the Base Section. */u8 displayid_primary_use(const struct displayid_iter *iter){	return iter->primary_use;}