[PATCH] cmd_nandbcb: Support secondary boot address of imx8mn

[Michael Trimarchi <michael@amarulasolutions.com>]

Add support of secondary boot address for imx8mn. The secondary
boot address is hardcoded in the fuse. The value is calculated
from there according to the algo.

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
• For FlexSPI boot, the valid values are: 0, 1, 2, 3, 4, 5, 6, and 7.

Tested remove the first one image and have the board still booting on
second one. This implementation cover one architecture

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
---
 arch/arm/mach-imx/cmd_nandbcb.c | 41 +++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-imx/cmd_nandbcb.c b/arch/arm/mach-imx/cmd_nandbcb.c
index 09622c13c9..348f8b626a 100644
--- a/arch/arm/mach-imx/cmd_nandbcb.c
+++ b/arch/arm/mach-imx/cmd_nandbcb.c
@@ -132,6 +132,7 @@ static struct platform_config imx8q_plat_config = {
 
 /* boot search related variables and definitions */
 static int g_boot_search_count = 4;
+static int g_boot_secondary_offset;
 static int g_boot_search_stride;
 static int g_pages_per_stride;
 
@@ -275,9 +276,9 @@ static int nandbcb_set_boot_config(int argc, char * const argv[],
 	boot_stream2_address = ((maxsize - boot_stream1_address) / 2 +
 			       boot_stream1_address);
 
-	if (boot_cfg->secondary_boot_stream_off_in_MB)
+	if (g_boot_secondary_offset)
 		boot_stream2_address =
-			(loff_t)boot_cfg->secondary_boot_stream_off_in_MB * 1024 * 1024;
+			(loff_t)g_boot_secondary_offset * 1024 * 1024;
 
 	max_boot_stream_size = boot_stream2_address - boot_stream1_address;
 
@@ -1269,6 +1270,36 @@ static bool check_fingerprint(void *data, int fingerprint)
 	return (*(int *)(data + off) == fingerprint);
 }
 
+static int fuse_secondary_boot(u32 bank, u32 word, u32 mask, u32 off)
+{
+	int err;
+	u32 val;
+	int ret;
+
+	err = fuse_read(bank, word, &val);
+	if (err)
+		return 0;
+
+	val = (val & mask) >> off;
+
+	if (val > 10)
+		return 0;
+
+	switch (val) {
+	case 0:
+		ret = 4;
+		break;
+	case 1:
+		ret = 1;
+		break;
+	default:
+		ret = 2 << val;
+		break;
+	}
+
+	return ret;
+};
+
 static int fuse_to_search_count(u32 bank, u32 word, u32 mask, u32 off)
 {
 	int err;
@@ -1506,6 +1537,12 @@ static int do_nandbcb(struct cmd_tbl *cmdtp, int flag, int argc,
 		       g_boot_search_count);
 	}
 
+	if ((plat_config.misc_flags) & FIRMWARE_SECONDARY_FIXED_ADDR) {
+		if (is_imx8mn())
+			g_boot_secondary_offset = fuse_secondary_boot(2, 1, 0xff0000, 16);
+
+	}
+
 	cmd = argv[1];
 	--argc;
 	++argv;
-- 
2.25.1