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, 19 insertions, 0 deletions

diff --git a/include/spi_flash.h b/include/spi_flash.h
index 4312d3d691..0ae0062d12 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -54,6 +54,9 @@ struct spi_slave;
  * @write_cmd:		Write cmd - page and quad program.
  * @dummy_byte:		Dummy cycles for read operation.
  * @memory_map:		Address of read-only SPI flash access
+ * @flash_lock:		lock a region of the SPI Flash
+ * @flash_unlock:	unlock a region of the SPI Flash
+ * @flash_is_locked:	check if a region of the SPI Flash is completely locked
  * @read:		Flash read ops: Read len bytes at offset into buf
  *			Supported cmds: Fast Array Read
  * @write:		Flash write ops: Write len bytes from buf into offset
@@ -87,6 +90,10 @@ struct spi_flash {
 	u8 dummy_byte;
 
 	void *memory_map;
+
+	int (*flash_lock)(struct spi_flash *flash, u32 ofs, size_t len);
+	int (*flash_unlock)(struct spi_flash *flash, u32 ofs, size_t len);
+	int (*flash_is_locked)(struct spi_flash *flash, u32 ofs, size_t len);
 #ifndef CONFIG_DM_SPI_FLASH
 	/*
 	 * These are not strictly needed for driver model, but keep them here
@@ -227,6 +234,18 @@ static inline int spi_flash_erase(struct spi_flash *flash, u32 offset,
 }
 #endif
 
+static inline int spi_flash_protect(struct spi_flash *flash, u32 ofs, u32 len,
+					bool prot)
+{
+	if (!flash->flash_lock)
+		return -EOPNOTSUPP;
+
+	if (prot)
+		return flash->flash_lock(flash, ofs, len);
+	else
+		return flash->flash_unlock(flash, ofs, len);
+}
+
 void spi_boot(void) __noreturn;
 void spi_spl_load_image(uint32_t offs, unsigned int size, void *vdst);