Import of the watch repository from Pebble

2025-07-04 22:26:21 +00:00 · 2024-12-12 16:43:03 -08:00 · 2024-12-12 16:43:03 -08:00 · 3b92768480
commit 3b92768480
10334 changed files with 2564465 additions and 0 deletions
--- a/python_libs/pblprog/loader/src/main.c
+++ b/python_libs/pblprog/loader/src/main.c
@ -0,0 +1,112 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+
+#define HEADER_ADDR (0x20000400)
+#define DATA_ADDR   (0x20000800)
+#define FLASH_SR_ADDR (0x40023C0C)
+
+#define STATE_WAITING (0)
+#define STATE_WRITE (1)
+#define STATE_CRC (2)
+
+// typedef to make it easy to change the program size
+typedef uint8_t p_size_t;
+
+typedef struct __attribute__((__packed__)) {
+  uint32_t state;
+  volatile p_size_t *addr;
+  uint32_t length;
+} Header;
+
+static uint8_t prv_crc8(const uint8_t *data, uint32_t data_len) {
+  uint8_t crc = 0;
+
+  // nibble lookup table for (x^8 + x^5 + x^3 + x^2 + x + 1)
+  static const uint8_t lookup_table[] =
+    { 0, 47, 94, 113, 188, 147, 226, 205, 87, 120, 9, 38, 235, 196, 181, 154 };
+
+  for (uint32_t i = 0; i < data_len * 2; i++) {
+    uint8_t nibble = data[i / 2];
+
+    if (i % 2 == 0) {
+      nibble >>= 4;
+    }
+
+    uint8_t index = nibble ^ (crc >> 4);
+    crc = lookup_table[index & 0xf] ^ ((crc << 4) & 0xf0);
+  }
+
+  return crc;
+}
+
+static void prv_wait_for_flash_not_busy(void) {
+  while ((*(volatile uint32_t *)FLASH_SR_ADDR) & (1 << 16)); // BSY flag in FLASH_SR
+}
+
+__attribute__((__noreturn__)) void Reset_Handler(void) {
+  // Disable all interrupts
+  __asm__("cpsid i" : : : "memory");
+
+  volatile uint32_t *flash_sr = (volatile uint32_t *)FLASH_SR_ADDR;
+  volatile p_size_t *data = (volatile p_size_t *)DATA_ADDR;
+  volatile Header *header = (volatile Header *)HEADER_ADDR;
+  header->state = STATE_WAITING;
+
+  while(1) {
+    switch (header->state) {
+      case STATE_WRITE:
+        prv_wait_for_flash_not_busy();
+        for (uint32_t i = 0; i < header->length / sizeof(p_size_t); i++) {
+          header->addr[i] = data[i];
+          __asm__("isb 0xF":::"memory");
+          __asm__("dsb 0xF":::"memory");
+          /// Wait until flash isn't busy
+          prv_wait_for_flash_not_busy();
+          if (*flash_sr & (0x1f << 4)) {
+            // error raised, set bad state
+            header->state = *flash_sr;
+          }
+          if (header->addr[i] != data[i]) {
+            header->state = 0xbd;
+          }
+        }
+        header->addr += header->length / sizeof(p_size_t);
+        header->state = STATE_WAITING;
+        break;
+      case STATE_CRC:
+        *data = prv_crc8((uint8_t *)header->addr, header->length);
+        header->state = STATE_WAITING;
+        break;
+      default:
+        break;
+    }
+  }
+
+  __builtin_unreachable();
+}
+
+//! These symbols are defined in the linker script for use in initializing
+//! the data sections. uint8_t since we do arithmetic with section lengths.
+//! These are arrays to avoid the need for an & when dealing with linker symbols.
+extern uint8_t _estack[];
+
+
+__attribute__((__section__(".isr_vector"))) const void * const vector_table[] = {
+  _estack,
+  Reset_Handler
+};