feat(core): Introduce backup_ram driver [no changelog]

core/embed/models/T3W1/memory.ld

@@ -49,6 +49,8 @@ SAES_RAM_START = 0x300cfe00;
 SAES_RAM_SIZE = 0x200;
 FB2_RAM_START = 0x300d0000;
 FB2_RAM_SIZE = 0xc0000;
+BACKUP_RAM_START = 0x50036400;
+BACKUP_RAM_SIZE = 0x800;
 AUX1_RAM_START = 0x30190000;
 AUX1_RAM_SIZE = 0xe0000;
 CODE_ALIGNMENT = 0x400;

core/embed/models/T3W1/model_T3W1.h

@@ -101,6 +101,9 @@
 #define AUX1_RAM_START 0x30190000
 #define AUX1_RAM_SIZE (896 * 1024)
 
+#define BACKUP_RAM_START 0x50036400
+#define BACKUP_RAM_SIZE 2048
+
 // misc
 #define CODE_ALIGNMENT 0x400
 #define COREAPP_ALIGNMENT 0x2000

core/embed/sys/backup_ram/backup_ram.c

@@ -0,0 +1,110 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+// #include <trezor_types.h>
+#include <trezor_bsp.h>
+#include <trezor_rtl.h>
+
+#include <sys/backup_ram.h>
+
+// Place backup RAM data structure in the linker backup SRAM section
+__attribute__((section(".backup_ram"))) backup_ram_data_t backup_ram;
+
+typedef struct {
+  bool initialized;
+  RAMCFG_HandleTypeDef hramcfg;
+} backup_ram_driver_t;
+
+static backup_ram_driver_t backup_ram_driver = {
+    .initialized = false,
+};
+
+backup_ram_status_t backup_ram_init(void) {
+  backup_ram_driver_t *drv = &backup_ram_driver;
+
+  if (drv->initialized) {
+    return BACKUP_RAM_OK;
+  }
+
+  // Enable backup SRAM clock
+  __HAL_RCC_RAMCFG_FORCE_RESET();
+  __HAL_RCC_RAMCFG_RELEASE_RESET();
+  __HAL_RCC_RAMCFG_CLK_ENABLE();
+  __HAL_RCC_BKPSRAM_CLK_ENABLE();
+
+  memset((void *)drv, 0, sizeof(backup_ram_driver_t));
+  drv->hramcfg.Instance = RAMCFG_BKPRAM;
+  HAL_StatusTypeDef status = HAL_RAMCFG_Init(&drv->hramcfg);
+
+  if (status != HAL_OK) {
+    __HAL_RCC_BKPSRAM_CLK_DISABLE();
+    return BACKUP_RAM_ERROR;
+  }
+
+  drv->initialized = true;
+
+  return BACKUP_RAM_OK;
+}
+
+backup_ram_status_t backup_ram_deinit(void) {
+  backup_ram_driver_t *drv = &backup_ram_driver;
+
+  HAL_RAMCFG_DeInit(&drv->hramcfg);
+
+  // Disable backup SRAM clock
+  __HAL_RCC_BKPSRAM_CLK_DISABLE();
+  __HAL_RCC_RAMCFG_CLK_DISABLE();
+  backup_ram_driver.initialized = false;
+
+  return BACKUP_RAM_OK;
+}
+
+backup_ram_status_t backup_ram_erase(void) {
+  backup_ram_driver_t *drv = &backup_ram_driver;
+
+  HAL_StatusTypeDef status = HAL_RAMCFG_Erase(&drv->hramcfg);
+  if (status != HAL_OK) {
+    return BACKUP_RAM_ERROR;
+  }
+
+  return BACKUP_RAM_OK;
+}
+
+backup_ram_status_t backup_ram_erase_unused(void) {
+  memset(backup_ram.bytes + sizeof(backup_ram.data), 0,
+         sizeof(backup_ram.bytes) - sizeof(backup_ram.data));
+
+  return BACKUP_RAM_OK;
+}
+
+backup_ram_status_t backup_ram_store_fuel_gauge_state(
+    const fuel_gauge_backup_storage_t *fg_state) {
+  memcpy((void *)&backup_ram.data.fg, fg_state,
+         sizeof(fuel_gauge_backup_storage_t));
+
+  return BACKUP_RAM_OK;
+}
+
+backup_ram_status_t backup_ram_read_fuel_gauge_state(
+    fuel_gauge_backup_storage_t *fg_state) {
+  memcpy(fg_state, (const void *)&backup_ram.data.fg,
+         sizeof(fuel_gauge_backup_storage_t));
+
+  return BACKUP_RAM_OK;
+}

core/embed/sys/backup_ram/inc/sys/backup_ram.h

@@ -0,0 +1,65 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <trezor_model.h>
+#include <trezor_types.h>
+
+typedef enum {
+  BACKUP_RAM_OK = 0,
+  BACKUP_RAM_ERROR,
+} backup_ram_status_t;
+
+// Fuel gauge backup storage definition
+typedef struct {
+  float soc;  // Captured state of charge <0, 1>
+  // Captures RTC time at which SOC was captured
+  uint32_t last_capture_timestamp;
+} fuel_gauge_backup_storage_t;
+
+typedef union {
+  uint8_t bytes[BACKUP_RAM_SIZE];
+  struct {
+    volatile fuel_gauge_backup_storage_t fg;
+    // < Room for other data structures >
+  } data;
+} backup_ram_data_t;
+
+// Initialize backup RAM driver
+backup_ram_status_t backup_ram_init(void);
+
+// Deinitialize backup RAM driver
+backup_ram_status_t backup_ram_deinit(void);
+
+// Erase backup ram
+backup_ram_status_t backup_ram_erase(void);
+
+// Erase unused space in backup ram
+// This function clears the remaining part of the backup ram not alocated by
+// data struct.
+backup_ram_status_t backup_ram_erase_unused(void);
+
+// Store fuel gauge state in backup ram
+backup_ram_status_t backup_ram_store_fuel_gauge_state(
+    const fuel_gauge_backup_storage_t* fg_state);
+
+// Read fuel gauge state from backup ram
+backup_ram_status_t backup_ram_read_fuel_gauge_state(
+    fuel_gauge_backup_storage_t* fg_state);

core/embed/sys/bsp/stm32u5/stm32u5xx_hal_conf.h

@@ -84,7 +84,7 @@ extern "C" {
 #define HAL_SRAM_MODULE_ENABLED
 #define HAL_TIM_MODULE_ENABLED
 /*#define HAL_TSC_MODULE_ENABLED */
-/*#define HAL_RAMCFG_MODULE_ENABLED */
+#define HAL_RAMCFG_MODULE_ENABLED
 #define HAL_UART_MODULE_ENABLED
 /*#define HAL_USART_MODULE_ENABLED */
 /*#define HAL_WWDG_MODULE_ENABLED */

core/embed/sys/linker/stm32u5g/prodtest.ld

@@ -11,6 +11,7 @@ MEMORY {
   SAES_RAM (wal) : ORIGIN = SAES_RAM_START, LENGTH = SAES_RAM_SIZE
   FB1_RAM (wal) : ORIGIN = FB1_RAM_START, LENGTH = FB1_RAM_SIZE
   FB2_RAM (wal) : ORIGIN = FB2_RAM_START, LENGTH = FB2_RAM_SIZE
+  BACKUP_RAM (wal) : ORIGIN = BACKUP_RAM_START, LENGTH = BACKUP_RAM_SIZE
 }
 
 _stack_section_start = ADDR(.stack);
@@ -35,6 +36,9 @@ _accessible_ram_1_end = MCU_SRAM4 + MCU_SRAM4_SIZE;
 _bootargs_ram_start = BOOTARGS_START;
 _bootargs_ram_end = BOOTARGS_START + BOOTARGS_SIZE;
 
+_backup_ram_start = ORIGIN(BACKUP_RAM);
+_backup_ram_end = ORIGIN(BACKUP_RAM) + LENGTH(BACKUP_RAM);
+
 _codelen = SIZEOF(.padding) + SIZEOF(.flash) + SIZEOF(.data) + SIZEOF(.confidential);
 
 _flash_start = ORIGIN(FLASH);
@@ -113,6 +117,11 @@ SECTIONS {
     . = ALIGN(4);
   } >AUX1_RAM
 
+  .backup_ram (NOLOAD) : {
+    . = ALIGN(4);
+    *(.backup_ram)
+    . = ALIGN(4);
+  } > BACKUP_RAM
 
   .boot_args : ALIGN(8) {
     *(.boot_command*);

core/site_scons/models/T3W1/trezor_t3w1_revC.py

@@ -77,6 +77,10 @@ def configure(
     paths += ["embed/io/i2c_bus/inc"]
     defines += [("USE_I2C", "1")]
 
+    sources += ["embed/sys/backup_ram/backup_ram.c"]
+    paths += ["embed/sys/backup_ram/inc"]
+    defines += [("USE_BACKUP_RAM", "1")]
+
     if "haptic" in features_wanted:
         sources += [
             "embed/io/haptic/drv2625/drv2625.c",

core/site_scons/models/stm32u5_common.py

@@ -68,6 +68,7 @@ def stm32u5_common_files(env, defines, sources, paths):
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_pcd_ex.c",
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_pwr.c",
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_pwr_ex.c",
+        "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_ramcfg.c",
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_rcc.c",
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_rcc_ex.c",
         "vendor/stm32u5xx_hal_driver/Src/stm32u5xx_hal_rtc.c",