sf: Add SPI NOR protection mechanism

Many SPI flashes have protection bits (BP2, BP1 and BP0) in the
status register that can protect selected regions of the SPI NOR.

Take these bits into account when performing erase operations,
making sure that the protected areas are skipped.

Tested on a mx6qsabresd:

=> sf probe
SF: Detected M25P32 with page size 256 Bytes, erase size 64 KiB, total 4 MiB
=> sf protect lock  0x3f0000 0x10000
=> sf erase 0x3f0000 0x10000
offset 0x3f0000 is protected and cannot be erased
SF: 65536 bytes @ 0x3f0000 Erased: ERROR
=> sf protect unlock  0x3f0000 0x10000
=> sf erase 0x3f0000 0x10000
SF: 65536 bytes @ 0x3f0000 Erased: OK

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
[re-worked to fit the lock common to dm and non-dm]
Signed-off-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index ac7f5df..42862d9 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -348,6 +348,37 @@ static int do_spi_flash_erase(int argc, char * const argv[])
 	return ret == 0 ? 0 : 1;
 }
 
+static int do_spi_protect(int argc, char * const argv[])
+{
+	int ret = 0;
+	loff_t start, len;
+	bool prot = false;
+
+	if (argc != 4)
+		return -1;
+
+	if (!str2off(argv[2], &start)) {
+		puts("start sector is not a valid number\n");
+		return 1;
+	}
+
+	if (!str2off(argv[3], &len)) {
+		puts("len is not a valid number\n");
+		return 1;
+	}
+
+	if (strcmp(argv[1], "lock") == 0)
+		prot = true;
+	else if (strcmp(argv[1], "unlock") == 0)
+		prot = false;
+	else
+		return -1;  /* Unknown parameter */
+
+	ret = spi_flash_protect(flash, start, len, prot);
+
+	return ret == 0 ? 0 : 1;
+}
+
 #ifdef CONFIG_CMD_SF_TEST
 enum {
 	STAGE_ERASE,
@@ -540,6 +571,8 @@ static int do_spi_flash(cmd_tbl_t *cmdtp, int flag, int argc,
 		ret = do_spi_flash_read_write(argc, argv);
 	else if (strcmp(cmd, "erase") == 0)
 		ret = do_spi_flash_erase(argc, argv);
+	else if (strcmp(cmd, "protect") == 0)
+		ret = do_spi_protect(argc, argv);
 #ifdef CONFIG_CMD_SF_TEST
 	else if (!strcmp(cmd, "test"))
 		ret = do_spi_flash_test(argc, argv);
@@ -579,5 +612,7 @@ U_BOOT_CMD(
 	"sf update addr offset|partition len	- erase and write `len' bytes from memory\n"
 	"					  at `addr' to flash at `offset'\n"
 	"					  or to start of mtd `partition'\n"
+	"sf protect lock/unlock sector len	- protect/unprotect 'len' bytes starting\n"
+	"					  at address 'sector'\n"
 	SF_TEST_HELP
 );