drivers/mtd/ubi/upd.c

Source file repositories/reference/linux-study-clean/drivers/mtd/ubi/upd.c

File Facts

System
Linux kernel
Corpus path
drivers/mtd/ubi/upd.c
Extension
.c
Size
12246 bytes
Lines
421
Domain
Driver Families
Bucket
drivers/mtd
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (len == 0) {
			dbg_gen("all %d bytes contain 0xFF - skip", len);
			return 0;
		}

		err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len);
	} else {
		/*
		 * When writing static volume, and this is the last logical
		 * eraseblock, the length (@len) does not have to be aligned to
		 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
		 * function accepts exact (unaligned) length and stores it in
		 * the VID header. And it takes care of proper alignment by
		 * padding the buffer. Here we just make sure the padding will
		 * contain zeros, not random trash.
		 */
		memset(buf + len, 0, vol->usable_leb_size - len);
		err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs);
	}

	return err;
}

/**
 * ubi_more_update_data - write more update data.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @buf: write data (user-space memory buffer)
 * @count: how much bytes to write
 *
 * This function writes more data to the volume which is being updated. It may
 * be called arbitrary number of times until all the update data arriveis. This
 * function returns %0 in case of success, number of bytes written during the
 * last call if the whole volume update has been successfully finished, and a
 * negative error code in case of failure.
 */
int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
			 const void __user *buf, int count)
{
	int lnum, offs, err = 0, len, to_write = count;

	dbg_gen("write %d of %lld bytes, %lld already passed",
		count, vol->upd_bytes, vol->upd_received);

	if (ubi->ro_mode)
		return -EROFS;

	lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
	if (vol->upd_received + count > vol->upd_bytes)
		to_write = count = vol->upd_bytes - vol->upd_received;

	/*
	 * When updating volumes, we accumulate whole logical eraseblock of
	 * data and write it at once.
	 */
	if (offs != 0) {
		/*
		 * This is a write to the middle of the logical eraseblock. We
		 * copy the data to our update buffer and wait for more data or
		 * flush it if the whole eraseblock is written or the update
		 * is finished.
		 */

		len = vol->usable_leb_size - offs;
		if (len > count)
			len = count;

		err = copy_from_user(vol->upd_buf + offs, buf, len);
		if (err)
			return -EFAULT;

		if (offs + len == vol->usable_leb_size ||
		    vol->upd_received + len == vol->upd_bytes) {
			int flush_len = offs + len;

			/*
			 * OK, we gathered either the whole eraseblock or this
			 * is the last chunk, it's time to flush the buffer.
			 */
			ubi_assert(flush_len <= vol->usable_leb_size);
			err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
					vol->upd_ebs);
			if (err)
				return err;
		}

		vol->upd_received += len;
		count -= len;
		buf += len;
		lnum += 1;

Annotation

Implementation Notes