[U-Boot] [PATCH v4 3/3] spi: Add SPI NOR protection mechanism

Fabio Estevam festevam at gmail.com
Wed Sep 30 20:03:51 CEST 2015


From: Fabio Estevam <fabio.estevam at freescale.com>

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.

Introduce the CONFIG_SPI_FLASH_STM_PROTECT option that can be
selectedby systems that want to protect regions of SPI NOR flash
using the same programming model as in the ST Micro SPI NOR flashes,
like for example the M25P32.

Tested on a mx6qsabresd:

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

Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v3:
- Split this patch in two parts (Jagan)

 common/cmd_sf.c               | 35 +++++++++++++++++++++++++++++++++++
 drivers/mtd/spi/Kconfig       | 15 +++++++++++++++
 drivers/mtd/spi/sf_internal.h | 10 ++++------
 drivers/mtd/spi/sf_ops.c      | 33 +++++++++++++++++++++++++++++++++
 drivers/mtd/spi/sf_probe.c    | 27 +++++++++++++++++++++++++++
 include/spi_flash.h           | 18 ++++++++++++++++++
 6 files changed, 132 insertions(+), 6 deletions(-)

diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index ac7f5df..bb39cb7 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], "on") == 0)
+		prot = true;
+	else if (strcmp(argv[1], "off") == 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 on/off sector len		- protect/unprotect 'len' bytes starting\n"
+	"					  at address 'sector'\n"
 	SF_TEST_HELP
 );
diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
index 3f7433c..2ee1089 100644
--- a/drivers/mtd/spi/Kconfig
+++ b/drivers/mtd/spi/Kconfig
@@ -101,6 +101,21 @@ config SPI_FLASH_USE_4K_SECTORS
 	  Please note that some tools/drivers/filesystems may not work with
 	  4096 B erase size (e.g. UBIFS requires 15 KiB as a minimum).
 
+config SPI_FLASH_STM_PROTECT
+	bool "Use STM flash protection mechanism"
+	depends on SPI_FLASH
+	help
+	  Enable the built-in protection mechanism provided by the
+	  BP2, BP1 and BP0 bits from the status register present
+	  on ST-Micro flashes such as M25P32. Please refer to the
+	  M25P32 datasheet to understand how to program these bits
+	  in order to protect a selected region of the SPI NOR flash.
+
+	  This same bit protection programming model applies to SPI
+	  NOR flashes from other manufacturers such as:
+	  - Micron M25P32
+	  - SST SST25V32B
+
 config SPI_FLASH_DATAFLASH
 	bool "AT45xxx DataFlash support"
 	depends on SPI_FLASH && DM_SPI_FLASH
diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 9c95d56..8fb1b18 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -162,12 +162,6 @@ int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,
 /* Flash erase(sectors) operation, support all possible erase commands */
 int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len);
 
-/* Read the status register */
-int spi_flash_cmd_read_status(struct spi_flash *flash, u8 *rs);
-
-/* Program the status register */
-int spi_flash_cmd_write_status(struct spi_flash *flash, u8 ws);
-
 /* Read the config register */
 int spi_flash_cmd_read_config(struct spi_flash *flash, u8 *rc);
 
@@ -222,6 +216,10 @@ int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
 int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 		size_t len, void *data);
 
+int spi_flash_cmd_lock_ops(struct spi_flash *flash, u32 offset, size_t len);
+int spi_flash_cmd_unlock_ops(struct spi_flash *flash, u32 offset, size_t len);
+int spi_flash_cmd_is_locked_ops(struct spi_flash *flash, u32 offset, size_t len);
+
 #ifdef CONFIG_SPI_FLASH_MTD
 int spi_flash_mtd_register(struct spi_flash *flash);
 void spi_flash_mtd_unregister(void);
diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c
index e12f8ee..281b06d 100644
--- a/drivers/mtd/spi/sf_ops.c
+++ b/drivers/mtd/spi/sf_ops.c
@@ -276,6 +276,11 @@ int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 		return -1;
 	}
 
+	if (flash->is_locked(flash, offset, len) > 0) {
+		printf("offset 0x%x is protected and cannot be erased\n", offset);
+		return -EINVAL;
+	}
+
 	cmd[0] = flash->erase_cmd;
 	while (len) {
 		erase_addr = offset;
@@ -318,6 +323,11 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 
 	page_size = flash->page_size;
 
+	if (flash->is_locked(flash, offset, len) > 0) {
+		printf("offset 0x%x is protected and cannot be written\n", offset);
+		return -EINVAL;
+	}
+
 	cmd[0] = flash->write_cmd;
 	for (actual = 0; actual < len; actual += chunk_len) {
 		write_addr = offset;
@@ -356,6 +366,21 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 	return ret;
 }
 
+int spi_flash_cmd_lock_ops(struct spi_flash *flash, u32 offset, size_t len)
+{
+	return stm_lock(flash, offset, len);
+}
+
+int spi_flash_cmd_unlock_ops(struct spi_flash *flash, u32 offset, size_t len)
+{
+	return stm_unlock(flash, offset, len);
+}
+
+int spi_flash_cmd_is_locked_ops(struct spi_flash *flash, u32 offset, size_t len)
+{
+	return stm_is_locked(flash, offset, len);
+}
+
 int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
 		size_t cmd_len, void *data, size_t data_len)
 {
@@ -761,3 +786,11 @@ int stm_unlock(struct spi_flash *nor, u32 ofs, u32 len)
 	return 0;
 }
 #endif  /* CONFIG_SPI_FLASH_STM_PROTECT */
+
+int spi_flash_protect(struct spi_flash *nor, loff_t ofs, u32 len, bool prot)
+{
+	if (prot)
+		return nor->lock(nor, ofs, len);
+	else
+		return nor->unlock(nor, ofs, len);
+}
diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index 954376d..6da9d6c 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -149,6 +149,9 @@ static int spi_flash_validate_params(struct spi_slave *spi, u8 *idcode,
 #endif
 	flash->erase = spi_flash_cmd_erase_ops;
 	flash->read = spi_flash_cmd_read_ops;
+	flash->lock = spi_flash_cmd_lock_ops;
+	flash->unlock = spi_flash_cmd_unlock_ops;
+	flash->is_locked = spi_flash_cmd_is_locked_ops;
 #endif
 
 	/* Compute the flash size */
@@ -469,6 +472,27 @@ int spi_flash_std_erase(struct udevice *dev, u32 offset, size_t len)
 	return spi_flash_cmd_erase_ops(flash, offset, len);
 }
 
+int spi_flash_std_lock(struct udevice *dev, u32 offset, size_t len)
+{
+	struct spi_flash *flash = dev_get_uclass_priv(dev);
+
+	return spi_flash_cmd_lock_ops(flash, offset, len);
+}
+
+int spi_flash_std_unlock(struct udevice *dev, u32 offset, size_t len)
+{
+	struct spi_flash *flash = dev_get_uclass_priv(dev);
+
+	return spi_flash_cmd_unlock_ops(flash, offset, len);
+}
+
+int spi_flash_std_is_locked(struct udevice *dev, u32 offset, size_t len)
+{
+	struct spi_flash *flash = dev_get_uclass_priv(dev);
+
+	return spi_flash_cmd_is_locked_ops(flash, offset, len);
+}
+
 int spi_flash_std_probe(struct udevice *dev)
 {
 	struct spi_slave *slave = dev_get_parentdata(dev);
@@ -485,6 +509,9 @@ static const struct dm_spi_flash_ops spi_flash_std_ops = {
 	.read = spi_flash_std_read,
 	.write = spi_flash_std_write,
 	.erase = spi_flash_std_erase,
+	.lock = spi_flash_std_lock,
+	.unlock = spi_flash_std_unlock,
+	.is_locked = spi_flash_std_is_locked,
 };
 
 static const struct udevice_id spi_flash_std_ids[] = {
diff --git a/include/spi_flash.h b/include/spi_flash.h
index 3b2d555..28ec357 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -105,6 +105,9 @@ struct spi_flash {
 	int (*write)(struct spi_flash *flash, u32 offset, size_t len,
 			const void *buf);
 	int (*erase)(struct spi_flash *flash, u32 offset, size_t len);
+	int (*lock)(struct spi_flash *flash, u32 offset, size_t len);
+	int (*unlock)(struct spi_flash *flash, u32 offset, size_t len);
+	int (*is_locked)(struct spi_flash *flash, u32 offset, size_t len);
 #endif
 };
 
@@ -113,8 +116,23 @@ struct dm_spi_flash_ops {
 	int (*write)(struct udevice *dev, u32 offset, size_t len,
 		     const void *buf);
 	int (*erase)(struct udevice *dev, u32 offset, size_t len);
+	int (*lock)(struct udevice *dev, u32 offset, size_t len);
+	int (*unlock)(struct udevice *dev, u32 offset, size_t len);
+	int (*is_locked)(struct udevice *dev, u32 offset, size_t len);
 };
 
+
+/* Read the status register */
+int spi_flash_cmd_read_status(struct spi_flash *flash, u8 *rs);
+
+/* Program the status register */
+int spi_flash_cmd_write_status(struct spi_flash *flash, u8 ws);
+
+int stm_is_locked(struct spi_flash *nor, loff_t ofs, u32 len);
+int stm_lock(struct spi_flash *nor, u32 ofs, u32 len);
+int stm_unlock(struct spi_flash *nor, u32 ofs, u32 len);
+int spi_flash_protect(struct spi_flash *nor, loff_t ofs, u32 len, bool prot);
+
 /* Access the serial operations for a device */
 #define sf_get_ops(dev) ((struct dm_spi_flash_ops *)(dev)->driver->ops)
 
-- 
1.9.1



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