Simplify OTA API

src/flash.c

@@ -0,0 +1,65 @@
+#include "arch.h"
+#include "flash.h"
+#include "log.h"
+#include "ota.h"
+
+static char *s_addr;      // Current address to write to
+static size_t s_size;     // Firmware size to flash. In-progress indicator
+static uint32_t s_crc32;  // Firmware checksum
+
+bool mg_ota_flash_begin(size_t new_firmware_size, struct mg_flash *flash) {
+  bool ok = false;
+  if (s_size) {
+    MG_ERROR(("OTA already in progress. Call mg_ota_end()"));
+  } else {
+    size_t half = flash->size / 2;
+    s_crc32 = 0;
+    s_addr = (char *) flash->start + half;
+    MG_DEBUG(("FW %lu bytes, max %lu", new_firmware_size, half));
+    if (new_firmware_size < half) {
+      ok = true;
+      s_size = new_firmware_size;
+      MG_INFO(("Starting OTA, firmware size %lu", s_size));
+    } else {
+      MG_ERROR(("Firmware %lu is too big to fit %lu", new_firmware_size, half));
+    }
+  }
+  return ok;
+}
+
+bool mg_ota_flash_write(const void *buf, size_t len, struct mg_flash *flash) {
+  bool ok = false;
+  if (s_size == 0) {
+    MG_ERROR(("OTA is not started, call mg_ota_begin()"));
+  } else {
+    size_t len_aligned_down = MG_ROUND_DOWN(len, flash->align);
+    if (len_aligned_down) ok = flash->write_fn(s_addr, buf, len_aligned_down);
+    if (len_aligned_down < len) {
+      size_t left = len - len_aligned_down;
+      char tmp[flash->align];
+      memset(tmp, 0xff, sizeof(tmp));
+      memcpy(tmp, (char *) buf + len_aligned_down, left);
+      ok = flash->write_fn(s_addr + len_aligned_down, tmp, sizeof(tmp));
+    }
+    s_crc32 = mg_crc32(s_crc32, (char *) buf, len);  // Update CRC
+    MG_DEBUG(("%#x %p %lu -> %d", s_addr - len, buf, len, ok));
+    s_addr += len;
+  }
+  return ok;
+}
+
+bool mg_ota_flash_end(struct mg_flash *flash) {
+  char *base = (char *) flash->start + flash->size / 2;
+  bool ok = false;
+  if (s_size) {
+    size_t size = (size_t) (s_addr - base);
+    uint32_t crc32 = mg_crc32(0, base, s_size);
+    if (size == s_size && crc32 == s_crc32) ok = true;
+    MG_DEBUG(("CRC: %x/%x, size: %lu/%lu, status: %s", s_crc32, crc32, s_size,
+              size, ok ? "ok" : "fail"));
+    s_size = 0;
+    if (ok) ok = flash->swap_fn();
+  }
+  MG_INFO(("Finishing OTA: %s", ok ? "ok" : "fail"));
+  return ok;
+}