[PATCH 1/3] mmc: fsl_esdhc_spl: pre-PBL: check for BOOT signature instead of MBR/DBR

["Pali Rohár" <pali@kernel.org>]

Pre-PBL BootROMs (MPC8536E, MPC8569E, P2020, P1011, P1012, P1013, P1020,
P1021, P1022) require custom BOOT signature on sector 0 and MBR/DBR
signature is not required at all.

So add check for BOOT signature and remove check for MBR/DBR.

This allows U-Boot SPL to load proper U-Boot on pre-PBL BootROMs platforms
also from SD cards which do not have MBR/DBR signature on sector 0.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 drivers/mmc/fsl_esdhc_spl.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/fsl_esdhc_spl.c b/drivers/mmc/fsl_esdhc_spl.c
index bee76572ac6c..109f558dcad3 100644
--- a/drivers/mmc/fsl_esdhc_spl.c
+++ b/drivers/mmc/fsl_esdhc_spl.c
@@ -14,6 +14,8 @@
  * on SDCard, so we must read the MBR to get the start address and code
  * length of the u-boot image, then calculate the address of the env.
  */
+#define ESDHC_BOOT_SIGNATURE_OFF 0x40
+#define ESDHC_BOOT_SIGNATURE	0x424f4f54
 #define ESDHC_BOOT_IMAGE_SIZE	0x48
 #define ESDHC_BOOT_IMAGE_ADDR	0x50
 #define MBRDBR_BOOT_SIG_55	0x1fe
@@ -61,6 +63,9 @@ void __noreturn mmc_boot(void)
 	uchar *tmp_buf;
 	u32 blklen;
 	uchar val;
+#ifndef CONFIG_SPL_FSL_PBL
+	u32 val32;
+#endif
 	uint i, byte_num;
 #endif
 	u32 offset, code_len;
@@ -94,16 +99,34 @@ void __noreturn mmc_boot(void)
 		hang();
 	}
 
+#ifdef CONFIG_SPL_FSL_PBL
 	val = *(tmp_buf + MBRDBR_BOOT_SIG_55);
 	if (0x55 != val) {
-		puts("spl: mmc signature is not valid!!\n");
+		puts("spl: mmc MBR/DBR signature is not valid!!\n");
 		hang();
 	}
 	val = *(tmp_buf + MBRDBR_BOOT_SIG_AA);
 	if (0xAA != val) {
-		puts("spl: mmc signature is not valid!!\n");
+		puts("spl: mmc MBR/DBR signature is not valid!!\n");
 		hang();
 	}
+#else
+	/*
+	 * Booting from On-Chip ROM (eSDHC or eSPI), Document Number: AN3659, Rev. 2, 06/2012.
+	 * Pre-PBL BootROMs (MPC8536E, MPC8569E, P2020, P1011, P1012, P1013, P1020, P1021, P1022)
+	 * require custom BOOT signature on sector 0 and MBR/DBR signature is not required at all.
+	 */
+	byte_num = 4;
+	val32 = 0;
+	for (i = 0; i < byte_num; i++) {
+		val = *(tmp_buf + ESDHC_BOOT_SIGNATURE_OFF + i);
+		val32 = (val32 << 8) + val;
+	}
+	if (val32 != ESDHC_BOOT_SIGNATURE) {
+		puts("spl: mmc BOOT signature is not valid!!\n");
+		hang();
+	}
+#endif
 
 	byte_num = 4;
 	offset = 0;
-- 
2.20.1