Merge pull request #21043 from benpicco/cpu/sam0-flashpage/cachedis

cpu/sam0_common: flashpage: disable cache while writing

cpu/sam0_common/periph/flashpage.c

@@ -64,7 +64,7 @@ static inline void wait_nvm_is_ready(void)
 #endif
 }
 
-static unsigned _unlock(void)
+static void _unlock(void)
 {
     /* remove peripheral access lock for the NVMCTRL peripheral */
 #ifdef REG_PAC_WRCTRL
@@ -73,10 +73,14 @@ static unsigned _unlock(void)
     PAC1->WPCLR.reg = PAC1_WPROT_DEFAULT_VAL;
 #endif
 
-    return irq_disable();
+    /* NVM reads could be corrupted when mixing NVM reads with Page Buffer writes. */
+#ifdef NVMCTRL_CTRLA_CACHEDIS1
+    _NVMCTRL->CTRLA.reg |= NVMCTRL_CTRLA_CACHEDIS0
+                        |  NVMCTRL_CTRLA_CACHEDIS1;
+#endif
 }
 
-static void _lock(unsigned state)
+static void _lock(void)
 {
     wait_nvm_is_ready();
 
@@ -87,12 +91,15 @@ static void _lock(unsigned state)
     PAC1->WPSET.reg = PAC1_WPROT_DEFAULT_VAL;
 #endif
 
+#ifdef NVMCTRL_CTRLA_CACHEDIS1
+    _NVMCTRL->CTRLA.reg &= ~NVMCTRL_CTRLA_CACHEDIS0
+                        &  ~NVMCTRL_CTRLA_CACHEDIS1;
+#endif
+
     /* cached flash contents may have changed - invalidate cache */
 #ifdef CMCC
     CMCC->MAINT0.reg |= CMCC_MAINT0_INVALL;
 #endif
-
-    irq_restore(state);
 }
 
 static void _cmd_clear_page_buffer(void)
@@ -229,7 +236,7 @@ static void _write_page(void* dst, const void *data, size_t len, void (*cmd_writ
     /* word align destination address */
     uint32_t *dst32 = (void*)((uintptr_t)dst & ~0x3);
 
-    unsigned state = _unlock();
+    _unlock();
     _cmd_clear_page_buffer();
 
     /* write the first, unaligned bytes */
@@ -256,15 +263,15 @@ static void _write_page(void* dst, const void *data, size_t len, void (*cmd_writ
     }
 
     cmd_write();
-    _lock(state);
+    _lock();
 }
 
 static void _erase_page(void* page, void (*cmd_erase)(void))
 {
     uintptr_t page_addr = (uintptr_t)page;
 
     /* erase given page (the ADDR register uses 16-bit addresses) */
-    unsigned state = _unlock();
+    _unlock();
 
     /* ADDR drives the hardware (16-bit) address to the NVM when a command is executed using CMDEX.
      * 8-bit addresses must be shifted one bit to the right before writing to this register.
@@ -277,7 +284,7 @@ static void _erase_page(void* page, void (*cmd_erase)(void))
     _NVMCTRL->ADDR.reg = page_addr;
 
     cmd_erase();
-    _lock(state);
+    _lock();
 }
 
 static void _write_row(uint8_t *dst, const void *_data, size_t len, size_t chunk_size,