native/mtd: implement .write_page()

cpu/native/mtd/mtd_native.c

@@ -27,6 +27,8 @@
 #define ENABLE_DEBUG 0
 #include "debug.h"
 
+#define MIN(a, b) ((a) > (b) ? (b) : (a))
+
 static int _init(mtd_dev_t *dev)
 {
     mtd_native_dev_t *_dev = (mtd_native_dev_t*) dev;
@@ -103,6 +105,41 @@ static int _write(mtd_dev_t *dev, const void *buff, uint32_t addr, uint32_t size
     return 0;
 }
 
+static int _write_page(mtd_dev_t *dev, const void *buff, uint32_t page, uint32_t offset,
+                       uint32_t size)
+{
+    mtd_native_dev_t *_dev = (mtd_native_dev_t*) dev;
+    uint32_t addr = page * dev->page_size + offset;
+
+    DEBUG("mtd_native: write from page %" PRIx32 ", offset 0x%" PRIx32 " count %" PRIu32 "\n",
+          page, offset, size);
+
+    if (page > dev->sector_count * dev->pages_per_sector) {
+        return -EOVERFLOW;
+    }
+
+    if (offset > dev->page_size) {
+        return -EOVERFLOW;
+    }
+
+    uint32_t remaining = dev->page_size - offset;
+    size = MIN(remaining, size);
+
+    FILE *f = real_fopen(_dev->fname, "r+");
+    if (!f) {
+        return -EIO;
+    }
+    real_fseek(f, addr, SEEK_SET);
+    for (size_t i = 0; i < size; i++) {
+        uint8_t c = real_fgetc(f);
+        real_fseek(f, -1, SEEK_CUR);
+        real_fputc(c & ((uint8_t*)buff)[i], f);
+    }
+    real_fclose(f);
+
+    return size;
+}
+
 static int _erase(mtd_dev_t *dev, uint32_t addr, uint32_t size)
 {
     mtd_native_dev_t *_dev = (mtd_native_dev_t*) dev;
@@ -144,6 +181,7 @@ const mtd_desc_t native_flash_driver = {
     .read = _read,
     .power = _power,
     .write = _write,
+    .write_page = _write_page,
     .erase = _erase,
     .init = _init,
 };