drivers/camera: Add config CHROMEOS_CAMERA

Add cros_camera_info struct for camera information, and
check_cros_camera_info() for checking the magic, CRC and version.

BUG=b:144820097
TEST=emerge-kukui coreboot
BRANCH=kukui

Change-Id: I1215fec76643b0cf7e09433e1190e8bd387e6953
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46042
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/camera/Kconfig

@@ -0,0 +1,7 @@
+config CHROMEOS_CAMERA
+	bool
+	default n
+	help
+	  Camera with identifiers following Chrome OS Camera Info. The info is
+	  usually available on MIPI camera EEPROM for identifying correct
+	  drivers and config.

src/drivers/camera/Makefile.inc

@@ -0,0 +1 @@
+ramstage-$(CONFIG_CHROMEOS_CAMERA) += cros_camera.c

src/drivers/camera/cros_camera.c

@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/console.h>
+#include <crc_byte.h>
+#include <string.h>
+
+#include "cros_camera.h"
+
+int check_cros_camera_info(const struct cros_camera_info *info)
+{
+	if (memcmp(info->magic, CROS_CAMERA_INFO_MAGIC, sizeof(info->magic))) {
+		printk(BIOS_ERR, "Invalid magic in camera info\n");
+		return -1;
+	}
+
+	const uint8_t *ptr = (void *)(&info->crc16 + 1);
+	uint16_t crc16 = 0;
+	while (ptr < (uint8_t *)info + sizeof(struct cros_camera_info))
+		crc16 = crc16_byte(crc16, *ptr++);
+
+	if (info->crc16 != crc16) {
+		printk(BIOS_ERR, "Incorrect CRC16: expected %#06x, got %#06x\n",
+		       crc16, info->crc16);
+		return -1;
+	}
+
+	if (info->version != CROS_CAMERA_INFO_VERSION) {
+		printk(BIOS_ERR, "Unknown camera info version: %u\n",
+		       info->version);
+		return -1;
+	}
+	if (info->size < CROS_CAMERA_INFO_SIZE_MIN) {
+		printk(BIOS_ERR, "Size of camera info is too small: %u\n",
+		       info->size);
+		return -1;
+	}
+
+	return 0;
+}

src/drivers/camera/cros_camera.h

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __VENDORCODE_GOOGLE_CHROMEOS_CAMERA_H
+#define __VENDORCODE_GOOGLE_CHROMEOS_CAMERA_H
+
+#include <stdint.h>
+
+#define CROS_CAMERA_INFO_MAGIC "CrOS"
+#define CROS_CAMERA_INFO_VERSION 1
+#define CROS_CAMERA_INFO_SIZE_MIN 0x0a
+
+struct cros_camera_info {
+	uint8_t magic[4];  /* CROS_CAMERA_INFO_MAGIC */
+	uint16_t crc16;
+	uint8_t version;
+	uint8_t size;
+	uint16_t data_format;
+	uint16_t module_pid;
+	uint8_t module_vid[2];
+	uint8_t sensor_vid[2];
+	uint16_t sensor_pid;
+};
+
+/* Returns 0 on success, non-zero on errors. */
+int check_cros_camera_info(const struct cros_camera_info *info);
+
+#endif