ARM: imx: Use correct U-Boot offset in case of secondary boot from eMMC

In case of a secondary image boot from the user area of an eMMC device,
the correct offset must be calculated. The offset is fused in the fuse
IMG_CNTN_SET1_OFFSET of the i.MX8M Nano and Plus. The calculation of the
offset is described in the reference manual (IMX8MNRM Rev. 2, 07/2022
and IMX8MPRM Rev. 1, 06/2021):

The fuse IMG_CNTN_SET1_OFFSET (0x490[22:19]) is defined as follows:
* Secondary boot is disabled if fuse value is bigger than 10,
  n = fuse value bigger than 10.
* n == 0: Offset = 4MB
* n == 2: Offset = 1MB
* Others & n <= 10 : Offset = 1MB*2^n

Signed-off-by: Fedor Ross <fedor.ross@ifm.com>
Signed-off-by: Marek Vasut <marex@denx.de>

1 files changed, 39 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/imx8m/soc.c b/arch/arm/mach-imx/imx8m/soc.c
index 7bfba4febcf..ce67b439e87 100644
--- a/arch/arm/mach-imx/imx8m/soc.c
+++ b/arch/arm/mach-imx/imx8m/soc.c
@@ -28,8 +28,10 @@
 #include <errno.h>
 #include <fdt_support.h>
 #include <fsl_wdog.h>
+#include <fuse.h>
 #include <imx_sip.h>
 #include <linux/bitops.h>
+#include <linux/bitfield.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -727,6 +729,43 @@ int spl_mmc_emmc_boot_partition(struct mmc *mmc)
 }
 #endif
 
+#if defined(CONFIG_IMX8MN) || defined(CONFIG_IMX8MP)
+#define IMG_CNTN_SET1_OFFSET	GENMASK(22, 19)
+unsigned long arch_spl_mmc_get_uboot_raw_sector(struct mmc *mmc,
+						unsigned long raw_sect)
+{
+	u32 val, offset;
+
+	if (fuse_read(2, 1, &val)) {
+		debug("Error reading fuse!\n");
+		return raw_sect;
+	}
+
+	val = FIELD_GET(IMG_CNTN_SET1_OFFSET, val);
+	if (val > 10) {
+		debug("Secondary image boot disabled!\n");
+		return raw_sect;
+	}
+
+	if (val == 0)
+		offset = SZ_4M;
+	else if (val == 1)
+		offset = SZ_2M;
+	else if (val == 2)
+		offset = SZ_1M;
+	else	/* flash.bin offset = 1 MiB * 2^n */
+		offset = SZ_1M << val;
+
+	offset /= 512;
+	offset -= CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_DATA_PART_OFFSET;
+
+	if (imx8m_detect_secondary_image_boot())
+		raw_sect += offset;
+
+	return raw_sect;
+}
+#endif
+
 bool is_usb_boot(void)
 {
 	return get_boot_device() == USB_BOOT;