dfu: introduce progressive erasing

Patch adds option for progressive erase of firmware image.
When using this, flash is erased as necessary when receiving
new firmware, instead of erasing the whole image slot at once.
This is useful on some hardware (like nRF52840) that has
long erase times, to prevent long wait times at the beginning
of the DFU process.

Signed-off-by: Andrzej Puzdrowski <[email protected]>

Author: nvlsianpu

include/dfu/flash_img.h

@@ -19,6 +19,9 @@ struct flash_img_context {
 	const struct flash_area *flash_area;
 	size_t bytes_written;
 	u16_t buf_bytes;
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+	off_t off_last;
+#endif
 };
 
 /**

include/dfu/mcuboot.h

@@ -30,6 +30,13 @@
 
 #define BOOT_IMG_VER_STRLEN_MAX 25  /* 255.255.65535.4294967295\0 */
 
+/* Trailer: */
+#define BOOT_MAX_ALIGN		8
+#define BOOT_MAGIC_SZ		16
+
+#define BOOT_TRAILER_IMG_STATUS_OFFS(bank_area) ((bank_area)->fa_size -\
+						  BOOT_MAGIC_SZ -\
+						  BOOT_MAX_ALIGN * 2)
 /**
  * @brief MCUboot image header representation for image version
  *

subsys/dfu/Kconfig

@@ -41,6 +41,16 @@ config IMG_BLOCK_BUF_SIZE
 	  Size (in Bytes) of buffer for image writer. Must be a multiple of
 	  the access alignment required by used flash driver.
 
+config 	IMG_ERASE_PROGRESSIVELY
+	bool "Erase flash progressively when receiving new firmware"
+	depends on MCUBOOT_IMG_MANAGER
+	select FLASH_PAGE_LAYOUT
+	help
+	 If enabled, flash is erased as necessary when receiving new firmware,
+	 instead of erasing the whole image slot at once. This is necessary
+	 on some hardware that has long erase times, to prevent long wait
+	 times at the beginning of the DFU process.
+
 module = IMG_MANAGER
 module-str = image manager
 source "subsys/logging/Kconfig.template.log_config"

subsys/dfu/boot/mcuboot.c

@@ -32,8 +32,6 @@
 #define BOOT_HEADER_SIZE_V1 32
 
 /* Trailer: */
-#define BOOT_MAX_ALIGN 8
-#define BOOT_MAGIC_SZ  16
 #define BOOT_FLAG_SET 0x01
 #define BOOT_FLAG_UNSET 0xff
 

subsys/dfu/img_util/flash_img.c

@@ -18,6 +18,11 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #include <dfu/flash_img.h>
 #include <inttypes.h>
 
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+#include <dfu/mcuboot.h>
+#include <flash.h>
+#endif
+
 BUILD_ASSERT_MSG((CONFIG_IMG_BLOCK_BUF_SIZE % DT_FLASH_WRITE_BLOCK_SIZE == 0),
 		 "CONFIG_IMG_BLOCK_BUF_SIZE is not a multiple of "
 		 "DT_FLASH_WRITE_BLOCK_SIZE");
@@ -52,6 +57,63 @@ static bool flash_verify(const struct flash_area *fa, off_t offset,
 	return (len == 0) ? true : false;
 }
 
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+
+static int flash_sector_from_off(struct flash_area const *fap, off_t off,
+				 struct flash_sector *sector)
+{
+	struct flash_pages_info page;
+	struct device *flash_dev;
+	int rc = -ENODEV;
+
+	flash_dev = flash_area_get_device(fap);
+	if (flash_dev) {
+		rc = flash_get_page_info_by_offs(flash_dev, off, &page);
+		if (rc == 0) {
+			sector->fs_off = page.start_offset;
+			sector->fs_size = page.size;
+		}
+	}
+
+	return rc;
+}
+
+/**
+ * Erase the image slot progressively
+ *
+ * This function erases a flash page to which offset belongs if only this page
+ * wasn't erased before.
+ *
+ * @param[in] ctx context of the image collection process.
+ * @param[in] off offset from the beginning of the image flash area beginning
+ *
+ * @return  0 on success, negative errno code on fail.
+ */
+static int flash_progressive_erase(struct flash_img_context *ctx, off_t off)
+{
+	struct flash_sector sector;
+	int rc;
+
+	rc = flash_sector_from_off(ctx->flash_area, off, &sector);
+	if (rc) {
+		LOG_ERR("Unable to determine flash sector size");
+	} else {
+		if (ctx->off_last != sector.fs_off) {
+			ctx->off_last = sector.fs_off;
+			LOG_INF("Erasing sector at offset 0x%x", sector.fs_off);
+			rc = flash_area_erase(ctx->flash_area, sector.fs_off,
+					      sector.fs_size);
+			if (rc) {
+				LOG_ERR("Error %d while erasing sector", rc);
+			}
+		}
+	}
+
+	return rc;
+}
+
+#endif /* CONFIG_IMG_ERASE_PROGRESSIVELY */
+
 static int flash_sync(struct flash_img_context *ctx)
 {
 	int rc = 0;
@@ -61,6 +123,11 @@ static int flash_sync(struct flash_img_context *ctx)
 			     CONFIG_IMG_BLOCK_BUF_SIZE - ctx->buf_bytes);
 	}
 
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+	flash_progressive_erase(ctx, ctx->bytes_written +
+				CONFIG_IMG_BLOCK_BUF_SIZE);
+#endif
+
 	rc = flash_area_write(ctx->flash_area, ctx->bytes_written, ctx->buf,
 			      CONFIG_IMG_BLOCK_BUF_SIZE);
 	if (rc) {
@@ -121,6 +188,11 @@ int flash_img_buffered_write(struct flash_img_context *ctx, u8_t *data,
 			return rc;
 		}
 	}
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+	/* erase the image trailer area if it was not erased */
+	flash_progressive_erase(ctx,
+				BOOT_TRAILER_IMG_STATUS_OFFS(ctx->flash_area));
+#endif
 
 	flash_area_close(ctx->flash_area);
 	ctx->flash_area = NULL;
@@ -137,6 +209,9 @@ int flash_img_init(struct flash_img_context *ctx)
 {
 	ctx->bytes_written = 0;
 	ctx->buf_bytes = 0U;
+#ifdef CONFIG_IMG_ERASE_PROGRESSIVELY
+	ctx->off_last = -1;
+#endif
 	return flash_area_open(DT_FLASH_AREA_IMAGE_1_ID,
 			       (const struct flash_area **)&(ctx->flash_area));
 }