[U-Boot] [PATCH 2/2] arm: stm32f4: fix a bug when a random sector gets erased

[Vadzim Dambrouski]

Old sector number is not being cleared from FLASH_CR register. For example
when first erased sector was 001 and then you want to erase sector 010,
sector 011 gets erased instead.
This patch clears old sector number from FLASH_CR register before a new
one is written.

Signed-off-by: Vadzim Dambrouski <pftbest at gmail.com>
---

 arch/arm/cpu/armv7m/stm32f4/flash.c       | 3 +++
 arch/arm/include/asm/arch-stm32f4/stm32.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/cpu/armv7m/stm32f4/flash.c b/arch/arm/cpu/armv7m/stm32f4/flash.c
index ae63790..dd058bd 100644
--- a/arch/arm/cpu/armv7m/stm32f4/flash.c
+++ b/arch/arm/cpu/armv7m/stm32f4/flash.c
@@ -97,6 +97,9 @@ int flash_erase(flash_info_t *info, int first, int last)
 		while (readl(&STM32_FLASH->sr) & STM32_FLASH_SR_BSY)
 			;
 
+		/* clear old sector number before writing a new one */
+		clrbits_le32(&STM32_FLASH->cr, STM32_FLASH_CR_SNB_MASK);
+
 		if (bank == 0) {
 			setbits_le32(&STM32_FLASH->cr,
 				     (i << STM32_FLASH_CR_SNB_OFFSET));
diff --git a/arch/arm/include/asm/arch-stm32f4/stm32.h b/arch/arm/include/asm/arch-stm32f4/stm32.h
index 3ed3801..7ca6dc3 100644
--- a/arch/arm/include/asm/arch-stm32f4/stm32.h
+++ b/arch/arm/include/asm/arch-stm32f4/stm32.h
@@ -104,6 +104,7 @@ struct stm32_flash_regs {
 #define STM32_FLASH_CR_STRT		(1 << 16)
 #define STM32_FLASH_CR_LOCK		(1 << 31)
 #define STM32_FLASH_CR_SNB_OFFSET	3
+#define STM32_FLASH_CR_SNB_MASK		(15 << STM32_FLASH_CR_SNB_OFFSET)
 
 enum clock {
 	CLOCK_CORE,
-- 
2.6.1