altos: Add self-flash support for STM32F042 processor

Also moves the usual address for applications out of the way of the
flash loader.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/src/stmf0/ao_flash_stm.c b/src/stmf0/ao_flash_stm.c
new file mode 100644
index 00000000..5fe0e619
--- /dev/null
+++ b/src/stmf0/ao_flash_stm.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao.h>
+#include <ao_flash.h>
+
+static uint8_t
+ao_flash_is_locked(void)
+{
+	return (stm_flash.cr & (1 << STM_FLASH_CR_LOCK)) != 0;
+}
+
+static void
+ao_flash_unlock(void)
+{
+	if (!ao_flash_is_locked())
+		return;
+
+	/* Unlock FLASH_CR register */
+	stm_flash.keyr = STM_FLASH_KEYR_KEY1;
+	stm_flash.keyr = STM_FLASH_KEYR_KEY2;
+	if (ao_flash_is_locked())
+		ao_panic(AO_PANIC_FLASH);
+}
+
+static void
+ao_flash_lock(void)
+{
+	stm_flash.cr |= (1 << STM_FLASH_CR_LOCK);
+}
+
+static void
+ao_flash_wait_bsy(void)
+{
+	while (stm_flash.sr & (1 << STM_FLASH_SR_BSY))
+		;
+}
+
+static void __attribute__ ((section(".ramtext"),noinline))
+_ao_flash_erase_page(uint32_t *page)
+{
+	stm_flash.cr |= (1 << STM_FLASH_CR_PER);
+
+	stm_flash.ar = (uintptr_t) page;
+
+	stm_flash.cr |= (1 << STM_FLASH_CR_STRT);
+
+	ao_flash_wait_bsy();
+
+	stm_flash.cr &= ~(1 << STM_FLASH_CR_PER);
+}
+
+static uint32_t
+stm_flash_page_size(void)
+{
+	uint16_t	dev_id = stm_dev_id();
+
+	switch (dev_id) {
+	case 0x440:	/* stm32f05x */
+	case 0x444:	/* stm32f03x */
+	case 0x445:	/* stm32f04x */
+		return 1024;
+	case 0x442:	/* stm32f09x */
+	case 0x448:	/* stm32f07x */
+		return 2048;
+	}
+	ao_panic(AO_PANIC_FLASH);
+	return 0;
+}
+
+void
+ao_flash_erase_page(uint32_t *page)
+{
+	/* Erase the whole page at the start. This assumes we'll be flashing things
+	 * in memory order
+	 */
+
+	if ((uintptr_t) page & (stm_flash_page_size() - 1))
+		return;
+
+	ao_arch_block_interrupts();
+	ao_flash_unlock();
+
+	_ao_flash_erase_page(page);
+
+	ao_flash_lock();
+	ao_arch_release_interrupts();
+}
+
+static void __attribute__ ((section(".ramtext"), noinline))
+_ao_flash_page(uint16_t *dst, uint16_t *src)
+{
+	uint8_t		i;
+
+	stm_flash.cr |= (1 << STM_FLASH_CR_PG);
+
+	for (i = 0; i < 128; i++) {
+		*dst++ = *src++;
+		ao_flash_wait_bsy();
+	}
+
+	stm_flash.cr &= ~(1 << STM_FLASH_CR_PG);
+}
+
+void
+ao_flash_page(uint32_t *page, uint32_t *src)
+{
+	ao_flash_erase_page(page);
+
+	ao_arch_block_interrupts();
+	ao_flash_unlock();
+
+	_ao_flash_page((uint16_t *) page, (uint16_t *) src);
+
+	ao_flash_lock();
+	ao_arch_release_interrupts();
+}