From: Hector Palacios <hector.palacios@digi.com>
Date: Fri, 18 Oct 2013 10:11:29 +0200
Subject: discover boot ROM version from FDT if available

New kernels don't get CPU information from U-Boot ATAGS and
so the /proc/cpuinfo file does not have the Hardware/Revision
lines filled in.
This patch gets the CPU model from the device tree information
at /proc/device-tree/compatible.
For backwards compatibility, if the CPU model cannot be retrieved
from this file, we try to get it from /proc/cpuinfo.

Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Reviewed-by: Robert Hodaszi <robert.hodaszi@digi.com>
---
 src/plat_boot_config.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 94 insertions(+), 1 deletion(-)

diff --git a/src/plat_boot_config.c b/src/plat_boot_config.c
index e3bf242..af7e03a 100644
--- a/src/plat_boot_config.c
+++ b/src/plat_boot_config.c
@@ -105,7 +105,91 @@ static platform_config mx6q_boot_config = {
 	.rom_mtd_commit_structures = v4_rom_mtd_commit_structures,
 };
 
-int discover_boot_rom_version(void)
+#define MAX_STRLEN	256
+int get_rom_version_from_fdt(void)
+{
+	FILE *fd;
+	char line_buffer[MAX_STRLEN];
+	char *p;
+	static char *compatible = "fsl,imx";
+	char *rev;
+	int system_rev;
+
+	fd = fopen("/proc/device-tree/compatible", "r");
+	if (!fd)
+		return -1;
+
+	p = &line_buffer[0];
+	if (fgets(p, MAX_STRLEN, fd)) {
+		/*
+		 * The compatible string can contain more than one string.
+		 * Each string value is separated from the next one by a
+		 * NULL char. We must check all values one by one until
+		 * we find two consecutive NULL chars.
+		 */
+		while (p[0] != 0) {
+			if (!strncmp(p, compatible, strlen(compatible))) {
+				rev = p + strlen(compatible);
+				/*
+				 * check if it's an imx6 CPU series, or
+				 * a parsable number.
+				 */
+				if (!strncmp(rev, "6q", 2))
+					system_rev = MX6Q;
+				else if (!strncmp(rev, "6d", 2))
+					system_rev = MX6DL;
+				else if (!strncmp(rev, "6s", 2))
+					system_rev = MX6;
+				else
+					system_rev = strtoul(rev, NULL, 16);
+
+				switch (system_rev) {
+				case  MX23:
+					plat_config_data = &mx23_boot_config;
+					break;
+
+				case  MX28:
+					plat_config_data = &mx28_boot_config;
+					break;
+
+				case  MX53:
+					/*
+					 * TODO: check CPU revision
+					 * Consider it is a TO2 for the
+					 * moment
+					 */
+					plat_config_data = &mx53to2_boot_config;
+					break;
+
+				case  MX50:
+					plat_config_data = &mx50_boot_config;
+					break;
+
+				case MX6:
+				case MX6Q:
+				case MX6DL:
+					plat_config_data = &mx6q_boot_config;
+					break;
+
+				default:
+					break;
+				}
+
+				if (plat_config_data) {
+					plat_config_data->m_u32Arm_type = system_rev;
+					return 0;
+				}
+			}
+			/* Move string pointer to next possible value */
+			p += strlen(p) + 1;
+		}
+	}
+
+	fclose(fd);
+	return -1;
+}
+
+int get_rom_version_from_cpuinfo(void)
 {
 	FILE         *cpuinfo;
 	char         line_buffer[100];
@@ -203,3 +287,12 @@ int discover_boot_rom_version(void)
 	}
 	return -1;
 }
+
+int discover_boot_rom_version(void)
+{
+	/* First, try to get ROM version from FDT */
+	if (get_rom_version_from_fdt())
+		return (get_rom_version_from_cpuinfo());
+
+	return 0;
+}