stm32: enable flash bank size override

It has been seen on some stm32 targets that the flash size register that
is probed by the driver may contain an invalid size.

This change enables the user to override the probed value.

Change-Id: I09359e59a96f9133d3d939670957d32a830a944e
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/1132
Tested-by: jenkins
Reviewed-by: Johan Almquist <johan.almquist@assaabloy.com>

doc/openocd.texi

@@ -5243,6 +5243,14 @@ the chip identification register, and autoconfigures itself.
 flash bank $_FLASHNAME stm32f1x 0 0 0 0 $_TARGETNAME
 @end example
 
+Note that some devices have been found that have a flash size register that contains
+an invalid value, to workaround this issue you can override the probed value used by
+the flash driver.
+
+@example
+flash bank $_FLASHNAME stm32f1x 0 0x20000 0 0 $_TARGETNAME
+@end example
+
 If you have a target with dual flash banks then define the second bank
 as per the following example.
 @example
@@ -5283,6 +5291,14 @@ include internal flash and use ARM Cortex-M3/M4 cores.
 The driver automatically recognizes a number of these chips using
 the chip identification register, and autoconfigures itself.
 
+Note that some devices have been found that have a flash size register that contains
+an invalid value, to workaround this issue you can override the probed value used by
+the flash driver.
+
+@example
+flash bank $_FLASHNAME stm32f2x 0 0x20000 0 0 $_TARGETNAME
+@end example
+
 Some stm32f2x-specific commands are defined:
 
 @deffn Command {stm32f2x lock} num
@@ -5296,6 +5312,21 @@ The @var{num} parameter is a value shown by @command{flash banks}.
 @end deffn
 @end deffn
 
+@deffn {Flash Driver} stm32lx
+All members of the STM32L microcontroller families from ST Microelectronics
+include internal flash and use ARM Cortex-M3 cores.
+The driver automatically recognizes a number of these chips using
+the chip identification register, and autoconfigures itself.
+
+Note that some devices have been found that have a flash size register that contains
+an invalid value, to workaround this issue you can override the probed value used by
+the flash driver.
+
+@example
+flash bank $_FLASHNAME stm32lx 0 0x20000 0 0 $_TARGETNAME
+@end example
+@end deffn
+
 @deffn {Flash Driver} str7x
 All members of the STR7 microcontroller family from ST Microelectronics
 include internal flash and use ARM7TDMI cores.

src/flash/nor/stm32f1x.c

@@ -956,6 +956,13 @@ static int stm32x_probe(struct flash_bank *bank)
 		}
 	}
 
+	/* if the user sets the size manually then ignore the probed value
+	 * this allows us to work around devices that have a invalid flash size register value */
+	if (bank->size) {
+		LOG_INFO("ignoring flash probed value, using configured bank size");
+		flash_size_in_kb = bank->size / 1024;
+	}
+
 	LOG_INFO("flash size = %dkbytes", flash_size_in_kb);
 
 	/* did we assign flash size? */

src/flash/nor/stm32f2x.c

@@ -791,6 +791,13 @@ static int stm32x_probe(struct flash_bank *bank)
 		flash_size_in_kb = max_flash_size_in_kb;
 	}
 
+	/* if the user sets the size manually then ignore the probed value
+	 * this allows us to work around devices that have a invalid flash size register value */
+	if (bank->size) {
+		LOG_INFO("ignoring flash probed value, using configured bank size");
+		flash_size_in_kb = bank->size / 1024;
+	}
+
 	LOG_INFO("flash size = %dkbytes", flash_size_in_kb);
 
 	/* did we assign flash size? */

src/flash/nor/stm32lx.c

@@ -552,6 +552,13 @@ static int stm32lx_probe(struct flash_bank *bank)
 		flash_size_in_kb = max_flash_size_in_kb;
 	}
 
+	/* if the user sets the size manually then ignore the probed value
+	 * this allows us to work around devices that have a invalid flash size register value */
+	if (bank->size) {
+		LOG_INFO("ignoring flash probed value, using configured bank size");
+		flash_size_in_kb = bank->size / 1024;
+	}
+
 	/* STM32L - we have 32 sectors, 16 pages per sector -> 512 pages
 	 * 16 pages for a protection area */