sravan/system76-coreboot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

spi_flash: Move (de-)assertion of /CS to single location

Browse Source 
This consolidates all calls to spi_claim_bus() and spi_release_bus()
to a single location where spi_xfer() is called. This avoids confusing
(and potentially redundant) calls that were being done throughout the
generic spi_flash.c functions and chip-specific functions.

I don't think the current approach could even work since many chip
drivers assert /CS once and then issue multiple commands such as page
program followed by reading the status register. I suspect the reason
we didn't notice it on x86 is because the ICH/PCH handled each
individual command correctly (spi_claim_bus() and spi_release_bus()
are noops) in spite of the broken code.

BUG=none
BRANCH=none
TEST=tested on nyan and link
Signed-off-by: David Hendricks <dhendrix@chromium.org>

Original-Change-Id: I3257e2f6a2820834f4c9018069f90fcf2bab05f6
Original-Reviewed-on: https://chromium-review.googlesource.com/194510
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: David Hendricks <dhendrix@chromium.org>
Original-Tested-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit d3394d34fb49e9e252f67371674d5b3aa220bc9e)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ieb62309b18090d8f974f91a6e448af3d65dd3d1d
Reviewed-on: http://review.coreboot.org/7829
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
David Hendricks
2014-04-11 19:48:55 -07:00
committed by Marc Jones
parent f101bbe4f0
commit 032c843817
8 changed files with 11 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
src/drivers/spi/eon.c
View File

@@ -73,7 +73,7 @@ static int eon_write(struct spi_flash *flash,
unsigned long page_size;
size_t chunk_len;
size_t actual;
int ret;
int ret = 0;
u8 cmd[4];
page_size = eon->params->page_size;
@@ -81,13 +81,7 @@ static int eon_write(struct spi_flash *flash,
byte_addr = offset % page_size;
flash->spi->rw = SPI_WRITE_FLAG;
ret = spi_claim_bus(flash->spi);
if (ret) {
printk(BIOS_WARNING, "SF: Unable to claim SPI bus\n");
return ret;
}
ret = 0;
for (actual = 0; actual < len; actual += chunk_len) {
chunk_len = min(len - actual, page_size - byte_addr);
@@ -128,7 +122,6 @@ static int eon_write(struct spi_flash *flash,
len, offset);
#endif
spi_release_bus(flash->spi);
return ret;
}