Save battery thresholds to flash

src/board/system76/common/acpi.c

@@ -221,6 +221,7 @@ void acpi_write(uint8_t addr, uint8_t data) {
 
     case 0xBD:
         battery_set_end_threshold(data);
+        (void)battery_save_thresholds();
         break;
 
 #if HAVE_LED_AIRPLANE_N

src/board/system76/common/battery.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
 #include <board/battery.h>
+#include <board/flash.h>
 #include <board/gpio.h>
 #include <board/smbus.h>
 #include <common/debug.h>
@@ -13,6 +14,18 @@ uint16_t battery_charger_input_current = CHARGER_INPUT_CURRENT;
 #define BATTERY_START_DEFAULT 0
 #define BATTERY_END_DEFAULT 100
 
+// Flash address to save charging thresholds to
+static const uint32_t BAT_CFG_ADDR = CONFIG_EC_FLASH_SIZE - (2 * 1024);
+static const uint16_t BAT_CFG_MAGIC = 0x4254;
+
+struct battery_config {
+    uint16_t magic;
+    uint8_t start_threshold;
+    uint8_t end_threshold;
+};
+
+static struct battery_config __xdata bat_cfg = { { 0 } };
+
 // Represents a battery percentage level, below which charging will begin.
 // Valid values are [0, 100]
 // A value of 0 turns off the start threshold control.
@@ -112,3 +125,38 @@ void battery_reset(void) {
     battery_start_threshold = BATTERY_START_THRESHOLD;
     battery_end_threshold = BATTERY_END_THRESHOLD;
 }
+
+// Read the charge thresholds from flash. Falls back to defaults if not found.
+bool battery_load_thresholds(void) {
+    bool loaded = true;
+
+    flash_read(BAT_CFG_ADDR, (uint8_t *)&bat_cfg, sizeof(bat_cfg));
+
+    if (bat_cfg.magic != BAT_CFG_MAGIC) {
+        bat_cfg.magic = BAT_CFG_MAGIC;
+        bat_cfg.start_threshold = BATTERY_START_THRESHOLD;
+        bat_cfg.end_threshold = BATTERY_END_THRESHOLD;
+        loaded = false;
+    }
+
+    (void)battery_set_start_threshold(bat_cfg.start_threshold);
+    (void)battery_set_end_threshold(bat_cfg.end_threshold);
+
+    return loaded;
+}
+
+// Write the charge thresholds to flash.
+bool battery_save_thresholds(void) {
+    if ((bat_cfg.start_threshold == battery_start_threshold) &&
+        (bat_cfg.end_threshold == battery_end_threshold)) {
+        return true;
+    }
+
+    bat_cfg.start_threshold = battery_start_threshold;
+    bat_cfg.end_threshold = battery_end_threshold;
+
+    flash_erase(BAT_CFG_ADDR);
+    flash_write(BAT_CFG_ADDR, (uint8_t *)&bat_cfg, sizeof(bat_cfg));
+
+    return flash_read_u16(BAT_CFG_ADDR) == BAT_CFG_MAGIC;
+}

src/board/system76/common/flash/main.c

@@ -48,8 +48,8 @@ void flash_write_enable(void);
  */
 void flash_entry(uint32_t addr, uint8_t *data, uint32_t length,
                  uint8_t command) __reentrant __critical {
-    // Only allow access from 64KB to 128KB.
-    if ((addr < 0x10000) || (length > 0x10000) || ((addr + length) > 0x20000))
+    // Only allow access from 64 KiB to the end of flash.
+    if ((addr < 0x10000) || (length > 0x10000) || ((addr + length) > CONFIG_EC_FLASH_SIZE))
         return;
 
     if (command == FLASH_COMMAND_READ) {

src/board/system76/common/include/board/battery.h

@@ -43,6 +43,9 @@ bool battery_set_start_threshold(uint8_t value);
 uint8_t battery_get_end_threshold(void);
 bool battery_set_end_threshold(uint8_t value);
 
+bool battery_load_thresholds(void);
+bool battery_save_thresholds(void);
+
 int16_t battery_charger_configure(void);
 void battery_event(void);
 void battery_reset(void);

src/board/system76/common/keymap.c

@@ -8,7 +8,7 @@ bool keymap_fnlock = false;
 uint16_t __xdata DYNAMIC_KEYMAP[KM_LAY][KM_OUT][KM_IN];
 
 // Config is in the last sector of flash
-const uint32_t CONFIG_ADDR = 0x1FC00;
+const uint32_t CONFIG_ADDR = CONFIG_EC_FLASH_SIZE - 1024;
 // Signature is the size of the keymap
 const uint16_t CONFIG_SIGNATURE = sizeof(DYNAMIC_KEYMAP);
 

src/board/system76/common/main.c

@@ -90,6 +90,7 @@ void init(void) {
     // Must happen last
     power_init();
     board_init();
+    (void)battery_load_thresholds();
 }
 
 void main(void) {

src/ec/ite/ec.mk

@@ -45,3 +45,5 @@ CONFIG_EC_FLASH_SIZE = 262144
 else
 $(error flash size not specified)
 endif
+
+CFLAGS += -DCONFIG_EC_FLASH_SIZE=$(CONFIG_EC_FLASH_SIZE)