Import of the watch repository from Pebble

src/fw/mfg/snowy/boot_fpga.c

@@ -0,0 +1,54 @@
+/*
+ * 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 "mfg/snowy/mfg_private.h"
+
+#include "drivers/flash.h"
+#include "flash_region/flash_region.h"
+#include "mfg/snowy/snowy_boot.fpga.auto.h"
+#include "util/attributes.h"
+
+#define BOOT_FPGA_FLASH_ADDR (FLASH_REGION_MFG_INFO_BEGIN + 0x10000)
+
+typedef struct PACKED {
+  uint16_t fpga_len;
+  uint16_t fpga_len_complemented;
+} BootFPGAHeader;
+
+bool mfg_info_is_boot_fpga_bitstream_written(void) {
+  BootFPGAHeader header;
+  flash_read_bytes((void *)&header, BOOT_FPGA_FLASH_ADDR, sizeof header);
+  return (header.fpga_len != 0xffff &&
+          header.fpga_len_complemented != 0xffff);
+}
+
+void mfg_info_write_boot_fpga_bitstream(void) {
+  // Store the bootloader FPGA in the MFG info flash region so that the
+  // bootloader can find it.
+  _Static_assert(sizeof s_boot_fpga < 1<<16, "FPGA bitstream too big");
+  BootFPGAHeader fpga_header = { (uint16_t)sizeof s_boot_fpga,
+                                 (uint16_t)~sizeof s_boot_fpga };
+
+  _Static_assert(
+      (BOOT_FPGA_FLASH_ADDR + sizeof fpga_header + sizeof s_boot_fpga)
+      < FLASH_REGION_MFG_INFO_END,
+      "FPGA bitstream will overflow FLASH_REGION_MFG_INFO!");
+  flash_write_bytes((const uint8_t *)&fpga_header,
+                    BOOT_FPGA_FLASH_ADDR, sizeof fpga_header);
+  flash_write_bytes((const uint8_t *)s_boot_fpga,
+                    BOOT_FPGA_FLASH_ADDR + sizeof fpga_header,
+                    sizeof s_boot_fpga);
+}