imx: add i.MX8 SoCs build info SIP(silicon provider) service support

This patch adds NXP i.MX8 SoCs' build info SIP support for easy debug.
With this function enabled, TF-A's commit hash can be showed in u-boot
debug console when booting up, when there is any issue which could be
related to TF-A, users can use the commit hash value to easily identify
which commit introduces the issue.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
diff --git a/plat/imx/common/imx_sip_handler.c b/plat/imx/common/imx_sip_handler.c
index 469e295..55639cd 100644
--- a/plat/imx/common/imx_sip_handler.c
+++ b/plat/imx/common/imx_sip_handler.c
@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <std_svc.h>
+#include <string.h>
 #include <platform_def.h>
 #include <common/debug.h>
 #include <common/runtime_svc.h>
@@ -137,3 +138,46 @@
 {
 	return sc_misc_set_temp(ipc_handle, x1, x2, x3, x4);
 }
+
+static uint64_t imx_get_commit_hash(u_register_t x2,
+		    u_register_t x3,
+		    u_register_t x4)
+{
+	/* Parse the version_string */
+	char *parse = (char *)version_string;
+	uint64_t hash = 0;
+
+	do {
+		parse = strchr(parse, '-');
+		if (parse) {
+			parse += 1;
+			if (*(parse) == 'g') {
+				/* Default is 7 hexadecimal digits */
+				memcpy((void *)&hash, (void *)(parse + 1), 7);
+				break;
+			}
+		}
+
+	} while (parse != NULL);
+
+	return hash;
+}
+
+uint64_t imx_buildinfo_handler(uint32_t smc_fid,
+		    u_register_t x1,
+		    u_register_t x2,
+		    u_register_t x3,
+		    u_register_t x4)
+{
+	uint64_t ret;
+
+	switch (x1) {
+	case IMX_SIP_BUILDINFO_GET_COMMITHASH:
+		ret = imx_get_commit_hash(x2, x3, x4);
+		break;
+	default:
+		return SMC_UNK;
+	}
+
+	return ret;
+}