Support reads of arbitrary range
That means you can tell flashrom to read exactly bytes 12345-56789
(start 12345, length 44445) and it will not fetch a single byte more.
Uwe tested this on one LPC, one SPI, and one parallel flash board.
Corresponding to flashrom svn r596.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/spi.c b/spi.c
index e9319d7..f625da7 100644
--- a/spi.c
+++ b/spi.c
@@ -678,19 +678,31 @@
* Read a complete flash chip.
* Each page is read separately in chunks with a maximum size of chunksize.
*/
-int spi_read_chunked(struct flashchip *flash, uint8_t *buf, int chunksize)
+int spi_read_chunked(struct flashchip *flash, uint8_t *buf, int start, int len, int chunksize)
{
int rc = 0;
- int i, j;
- int total_size = flash->total_size * 1024;
+ int i, j, starthere, lenhere;
int page_size = flash->page_size;
int toread;
- for (j = 0; j < total_size / page_size; j++) {
- for (i = 0; i < page_size; i += chunksize) {
- toread = min(chunksize, page_size - i);
- rc = spi_nbyte_read(j * page_size + i,
- buf + j * page_size + i, toread);
+ /* Warning: This loop has a very unusual condition and body.
+ * The loop needs to go through each page with at least one affected
+ * byte. The lowest page number is (start / page_size) since that
+ * division rounds down. The highest page number we want is the page
+ * where the last byte of the range lives. That last byte has the
+ * address (start + len - 1), thus the highest page number is
+ * (start + len - 1) / page_size. Since we want to include that last
+ * page as well, the loop condition uses <=.
+ */
+ for (i = start / page_size; i <= (start + len - 1) / page_size; i++) {
+ /* Byte position of the first byte in the range in this page. */
+ /* starthere is an offset to the base address of the chip. */
+ starthere = max(start, i * page_size);
+ /* Length of bytes in the range in this page. */
+ lenhere = min(start + len, (i + 1) * page_size) - starthere;
+ for (j = 0; j < lenhere; j += chunksize) {
+ toread = min(chunksize, lenhere - j);
+ rc = spi_nbyte_read(starthere + j, buf + starthere - start + j, toread);
if (rc)
break;
}
@@ -701,19 +713,19 @@
return rc;
}
-int spi_chip_read(struct flashchip *flash, uint8_t *buf)
+int spi_chip_read(struct flashchip *flash, uint8_t *buf, int start, int len)
{
switch (spi_controller) {
case SPI_CONTROLLER_IT87XX:
- return it8716f_spi_chip_read(flash, buf);
+ return it8716f_spi_chip_read(flash, buf, start, len);
case SPI_CONTROLLER_SB600:
- return sb600_spi_read(flash, buf);
+ return sb600_spi_read(flash, buf, start, len);
case SPI_CONTROLLER_ICH7:
case SPI_CONTROLLER_ICH9:
case SPI_CONTROLLER_VIA:
- return ich_spi_read(flash, buf);
+ return ich_spi_read(flash, buf, start, len);
case SPI_CONTROLLER_WBSIO:
- return wbsio_spi_read(flash, buf);
+ return wbsio_spi_read(flash, buf, start, len);
default:
printf_debug
("%s called, but no SPI chipset/strapping detected\n",