stm32g0: flash: add erase/program stuff

probably can be refactored with other chips, did not really looked yet.

include/libopencm3/stm32/g0/flash.h

@@ -258,6 +258,24 @@
 
 BEGIN_DECLS
 
+void flash_clear_progerr_flag(void);
+void flash_clear_pgserr_flag(void);
+void flash_clear_size_flag(void);
+void flash_clear_pgaerr_flag(void);
+void flash_clear_wrperr_flag(void);
+void flash_clear_operr_flag(void);
+void flash_clear_eop_flag(void);
+
+void flash_clear_status_flags(void);
+
+void flash_wait_for_last_operation(void);
+
+void flash_program_double_word(uint32_t address, uint64_t data);
+void flash_program(uint32_t address, uint8_t *data, uint32_t len);
+
+void flash_erase_page(uint32_t page);
+void flash_erase_all_pages(void);
+
 /** Enable instruction cache */
 void flash_icache_enable(void);
 /** Disable instruction cache */

lib/stm32/g0/flash.c

@@ -30,6 +30,145 @@
 
 #include <libopencm3/stm32/flash.h>
 
+/** @brief Wait until Last Flash Operation has Ended */
+void flash_wait_for_last_operation(void)
+{
+	while ((FLASH_SR & FLASH_SR_BSY) == FLASH_SR_BSY);
+}
+
+/** @brief Program a 64bits word to FLASH
+ *
+ * Program a 64bit word to FLASH memory.
+ * Flash programing error must be checked and cleared if needed
+ * before starting programming.
+ *
+ * @param[in] address Address in FLASH
+ * @param[in] data Double word to write
+ */
+void flash_program_double_word(uint32_t address, uint64_t data)
+{
+	flash_wait_for_last_operation();
+
+	FLASH_CR |= FLASH_CR_PG;
+
+	MMIO32(address) = (uint32_t)data;
+	MMIO32(address+4) = (uint32_t)(data >> 32);
+
+	flash_wait_for_last_operation();
+
+	FLASH_CR &= ~FLASH_CR_PG;
+}
+
+/** @brief Program a Data Block to FLASH
+ *
+ * This programs an arbitrary length data block to FLASH memory.
+ * The program error flag should be checked separately for the event that memory
+ * was not properly erased.
+ *
+ * @param[in] address Starting address in Flash.
+ * @param[in] data Pointer to start of data block.
+ * @param[in] len Length of data block in bytes (multiple of 8).
+ **/
+void flash_program(uint32_t address, uint8_t *data, uint32_t len)
+{
+	for (uint32_t i = 0; i < len; i += 8) {
+		flash_program_double_word(address+i, *(uint64_t*)(data + i));
+	}
+}
+
+/** @brief Erase a page of FLASH
+ * @param[in] page
+ */
+void flash_erase_page(uint32_t page)
+{
+	flash_wait_for_last_operation();
+
+	uint32_t reg = FLASH_CR;
+	reg &= ~(FLASH_CR_PNB_MASK << FLASH_CR_PNB_SHIFT);
+	reg |= (page & FLASH_CR_PNB_MASK)  << FLASH_CR_PNB_SHIFT;
+	reg |= FLASH_CR_PER;
+	reg |= FLASH_CR_STRT;
+
+	FLASH_CR = reg;
+
+	flash_wait_for_last_operation();
+
+	FLASH_CR &= ~FLASH_CR_PER;
+}
+
+/** @brief Erase All FLASH
+ * This performs all operations necessary to erase all sectors in the FLASH
+ * memory.
+ */
+void flash_erase_all_pages(void)
+{
+	flash_wait_for_last_operation();
+
+	FLASH_CR |= FLASH_CR_MER;
+	FLASH_CR |= FLASH_CR_STRT;
+
+	flash_wait_for_last_operation();
+	FLASH_CR &= ~FLASH_CR_MER;
+}
+
+/** @brief Clear the Programming Sequence Error Flag */
+void flash_clear_pgserr_flag(void)
+{
+	FLASH_SR |= FLASH_SR_PGSERR;
+}
+
+/** @brief Clear the End of Operation Flag */
+void flash_clear_eop_flag(void)
+{
+	FLASH_SR |= FLASH_SR_EOP;
+}
+
+/** @brief Clear programming size error flag */
+void flash_clear_size_flag(void)
+{
+	FLASH_SR |= FLASH_SR_SIZERR;
+}
+
+/** @brief Clear the Programming Alignment Error Flag
+ */
+void flash_clear_pgaerr_flag(void)
+{
+	FLASH_SR |= FLASH_SR_PGAERR;
+}
+
+/** @brief Clear the Write Protected Error Flag
+ */
+void flash_clear_wrperr_flag(void)
+{
+	FLASH_SR |= FLASH_SR_WRPERR;
+}
+
+/** @brief Clear the Programming Error Status Flag
+ */
+void flash_clear_progerr_flag(void)
+{
+	FLASH_SR |= FLASH_SR_PROGERR;
+}
+
+/** @brief Clear the Operation Error Status Flag
+ */
+void flash_clear_operr_flag(void)
+{
+	FLASH_SR |= FLASH_SR_OPERR;
+}
+
+/** @brief Clear All Status Flags */
+void flash_clear_status_flags(void)
+{
+	flash_clear_pgserr_flag();
+	flash_clear_size_flag();
+	flash_clear_pgaerr_flag();
+	flash_clear_wrperr_flag();
+	flash_clear_progerr_flag();
+	flash_clear_eop_flag();
+	flash_clear_operr_flag();
+}
+
 void flash_icache_enable(void)
 {
 	FLASH_ACR |= FLASH_ACR_ICEN;