From: Keith Packard <keithp@keithp.com>
Date: Mon, 8 Jan 2024 00:47:47 +0000 (-0800)
Subject: altos/stm32f1: Add eeprom emulation using flash
X-Git-Tag: 1.9.18~2^2~65
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=e959061fa17e15dfdd75d35c6c67e68a0e5e98e2

altos/stm32f1: Add eeprom emulation using flash

Use the last 2kB of flash to emulate eeprom storage for TeleLCO. This should
also be useful for EasyMega.

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

diff --git a/src/stm32f1/altos.ld b/src/stm32f1/altos.ld
index 15be8fae..85493115 100644
--- a/src/stm32f1/altos.ld
+++ b/src/stm32f1/altos.ld
@@ -16,8 +16,9 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  */
 
-__flash = 0x08001000;
-__flash_size = 60K;
+__flash       = 0x08001000;
+__eeprom_base = 0x0800e800;
+__flash_size = 58K;
 __ram = 0x20000000;
 __ram_size = 20k;
 __stack_size = 512;
diff --git a/src/stm32f1/ao_eeprom.c b/src/stm32f1/ao_eeprom.c
new file mode 100644
index 00000000..ec6654d5
--- /dev/null
+++ b/src/stm32f1/ao_eeprom.c
@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2024 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, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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>
+
+extern uint8_t	__eeprom_base[2048];
+
+uint8_t
+ao_eeprom_read(ao_pos_t pos, void *v, uint16_t len)
+{
+	memcpy(v, &__eeprom_base[pos], len);
+	return 1;
+}
+
+uint8_t
+ao_eeprom_write(ao_pos_t pos, void *v, uint16_t len)
+{
+	bool hsi_on = (stm_rcc.cr & (1UL << STM_RCC_CR_HSIRDY)) != 0;
+
+	if (!hsi_on) {
+		stm_rcc.cr |= (1UL << STM_RCC_CR_HSION);
+		while (!(stm_rcc.cr & (1 << STM_RCC_CR_HSIRDY)))
+			ao_arch_nop();
+
+	}
+	ao_flash_bytes(&__eeprom_base[pos], v, len);
+
+	if (!hsi_on) {
+		stm_rcc.cr &= ~(1UL << STM_RCC_CR_HSION);
+	}
+
+	return 1;
+}
+
diff --git a/src/stm32f1/ao_flash.h b/src/stm32f1/ao_flash.h
index d191d80d..9937a51f 100644
--- a/src/stm32f1/ao_flash.h
+++ b/src/stm32f1/ao_flash.h
@@ -25,4 +25,7 @@ ao_flash_erase_page(uint32_t *page);
 void
 ao_flash_page(uint32_t *page, uint32_t *src);
 
+void
+ao_flash_bytes(void *page, void *src, size_t size);
+
 #endif /* _AO_FLASH_STM_H_ */
diff --git a/src/stm32f1/ao_flash_stm.c b/src/stm32f1/ao_flash_stm.c
index 48c702f7..103e83a5 100644
--- a/src/stm32f1/ao_flash_stm.c
+++ b/src/stm32f1/ao_flash_stm.c
@@ -104,13 +104,13 @@ ao_flash_erase_page(uint32_t *page)
 }
 
 static void __attribute__ ((section(".sdata2.flash"), noinline))
-_ao_flash_page(uint16_t *dst, uint16_t *src)
+_ao_flash_page(uint16_t *dst, uint16_t *src, unsigned int shorts)
 {
 	uint8_t		i;
 
 	stm_flash.cr |= (1 << STM_FLASH_CR_PG);
 
-	for (i = 0; i < 128; i++) {
+	for (i = 0; i < shorts; i++) {
 		*dst++ = *src++;
 		ao_flash_wait_bsy();
 	}
@@ -126,7 +126,24 @@ ao_flash_page(uint32_t *page, uint32_t *src)
 	ao_arch_block_interrupts();
 	ao_flash_unlock();
 
-	_ao_flash_page((uint16_t *) page, (uint16_t *) src);
+	_ao_flash_page((uint16_t *) page, (uint16_t *) src, 128);
+
+	ao_flash_lock();
+	ao_arch_release_interrupts();
+}
+
+/* Stores less than a full page while still smashing the full page */
+void
+ao_flash_bytes(void *page, void *src, size_t size)
+{
+	unsigned int shorts = (unsigned int) ((size + 1) >> 1);
+
+	ao_flash_erase_page(page);
+
+	ao_arch_block_interrupts();
+	ao_flash_unlock();
+
+	_ao_flash_page((uint16_t *) page, (uint16_t *) src, shorts);
 
 	ao_flash_lock();
 	ao_arch_release_interrupts();