flash: detect stm32f4x device id errata

This allows us to detect a device arrata where the device id returned is
incorrect.

This issue only effects stm32f4x Rev A silicon.

Change-Id: Ic9f4985f9abf562f97322dcf484199f0a4eb01bb
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/354
Tested-by: jenkins

diff --git a/src/flash/nor/stm32f2x.c b/src/flash/nor/stm32f2x.c
index 6457f203847a80c62447db008dace514755d1351..4ae4304ec9cdfb0ddffa6ae997a7497dacf44027 100644 (file)
--- a/src/flash/nor/stm32f2x.c
+++ b/src/flash/nor/stm32f2x.c
@@ -580,6 +580,37 @@ static void setup_sector(struct flash_bank *bank, int start, int num, int size)
        }
 }
 
+static int stm32x_get_device_id(struct flash_bank *bank, uint32_t *device_id)
+{
+       /* this checks for a stm32f4x errata issue where a
+        * stm32f2x DBGMCU_IDCODE is incorrectly returned.
+        * If the issue is detected target is forced to stm32f4x Rev A.
+        * Only effects Rev A silicon */
+
+       struct target *target = bank->target;
+       uint32_t cpuid;
+
+       /* read stm32 device id register */
+       int retval = target_read_u32(target, 0xE0042000, device_id);
+       if (retval != ERROR_OK)
+               return retval;
+
+       if ((*device_id & DEV_ID_MASK) == 0x411) {
+               /* read CPUID reg to check core type */
+               retval = target_read_u32(target, 0xE000ED00, &cpuid);
+               if (retval != ERROR_OK)
+                       return retval;
+
+               /* check for cortex_m4 */
+               if (((cpuid >> 4) & 0xFFF) == 0xC24) {
+                       *device_id &= ~((0xFFFF << 16) | DEV_ID_MASK);
+                       *device_id |= (0x1000 << 16) | 0x413;
+                       LOG_INFO("stm32f4x errata detected - fixing incorrect MCU_IDCODE");
+               }
+       }
+       return retval;
+}
+
 static int stm32x_probe(struct flash_bank *bank)
 {
        struct target *target = bank->target;
@@ -592,7 +623,7 @@ static int stm32x_probe(struct flash_bank *bank)
        stm32x_info->probed = 0;
 
        /* read stm32 device id register */
-       int retval = target_read_u32(target, 0xE0042000, &device_id);
+       int retval = stm32x_get_device_id(bank, &device_id);
        if (retval != ERROR_OK)
                return retval;
        LOG_INFO("device id = 0x%08" PRIx32 "", device_id);
@@ -672,12 +703,11 @@ static int stm32x_auto_probe(struct flash_bank *bank)
 
 static int get_stm32x_info(struct flash_bank *bank, char *buf, int buf_size)
 {
-       struct target *target = bank->target;
        uint32_t device_id;
        int printed;
 
        /* read stm32 device id register */
-       int retval = target_read_u32(target, 0xE0042000, &device_id);
+       int retval = stm32x_get_device_id(bank, &device_id);
        if (retval != ERROR_OK)
                return retval;