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Enable continuous SPI reads

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Previous unnecessary page-by-page reading is repurposed to
read by big naturally aligned areas (now chip size limited
to 16MB for future-proofing of 4 byte addressed multi-die chips)
and serprog hack for continuous reads is removed.

Change-Id: Iadf909c9216578b1c5dacd4c4991bb436e32edc9
Signed-off-by: Urja Rannikko <urjaman@gmail.com>
Reviewed-on: https://review.coreboot.org/20223
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Urja Rannikko
2017-06-15 13:32:01 +03:00
committed by Nico Huber
parent 026c741651
commit 731316a912
2 changed files with 15 additions and 35 deletions
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27
spi25.c
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@ -940,30 +940,31 @@ int spi_nbyte_read(struct flashctx *flash, unsigned int address, uint8_t *bytes,
/*
* Read a part of the flash chip.
* FIXME: Use the chunk code from Michael Karcher instead.
* Each page is read separately in chunks with a maximum size of chunksize.
* Each naturally aligned area is read separately in chunks with a maximum size of chunksize.
*/
int spi_read_chunked(struct flashctx *flash, uint8_t *buf, unsigned int start,
unsigned int len, unsigned int chunksize)
{
int rc = 0;
unsigned int i, j, starthere, lenhere, toread;
unsigned int page_size = flash->chip->page_size;
/* Limit for multi-die 4-byte-addressing chips. */
unsigned int area_size = min(flash->chip->total_size * 1024, 16 * 1024 * 1024);
/* 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
* The loop needs to go through each area with at least one affected
* byte. The lowest area number is (start / area_size) since that
* division rounds down. The highest area number we want is the area
* 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 <=.
* address (start + len - 1), thus the highest area number is
* (start + len - 1) / area_size. Since we want to include that last
* area 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. */
for (i = start / area_size; i <= (start + len - 1) / area_size; i++) {
/* Byte position of the first byte in the range in this area. */
/* 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;
starthere = max(start, i * area_size);
/* Length of bytes in the range in this area. */
lenhere = min(start + len, (i + 1) * area_size) - starthere;
for (j = 0; j < lenhere; j += chunksize) {
toread = min(chunksize, lenhere - j);
rc = spi_nbyte_read(flash, starthere + j, buf + starthere - start + j, toread);