Flash loader for STM32L4

[fw/stlink] / flashloaders / stm32l4.s

diff --git a/flashloaders/stm32l4.s b/flashloaders/stm32l4.s
new file mode 100644 (file)
index 0000000..4b90863
--- /dev/null
+++ b/flashloaders/stm32l4.s
@@ -0,0 +1,39 @@
+.global start
+.syntax unified
+
+@ Adapted from stm32f4.s
+@ STM32L4's flash controller expects double-word writes, has the flash
+@ controller mapped in a different location with the registers we care about
+@ moved down from the base address, and has BSY moved to bit 16 of SR.
+@ r0 = source
+@ r1 = target
+@ r2 = wordcount
+@ r3 = flash_base
+@ r4 = temp
+@ r5 = temp
+
+start:
+    ldr     r3, flash_base
+next:
+    cbz     r2, done
+    ldr     r4, [r0]            /* copy doubleword from source to target */
+    ldr     r5, [r0, #4]
+    str     r4, [r1]
+    str     r5, [r1, #4]
+
+wait:
+    ldrh    r4, [r3, #0x12]     /* high half of status register */
+    tst     r4, #1              /* BSY = bit 16 */
+    bne     wait
+
+    add     r0, #8
+    add     r1, #8
+    sub     r2, #2
+    b       next
+done:
+    bkpt
+
+.align 2
+
+flash_base:
+    .word 0x40022000