From 3316cf2ff80f379b609115f375f73ef4b9e7d8f4 Mon Sep 17 00:00:00 2001 From: Martin Roth Date: Wed, 5 Dec 2012 16:22:54 -0700 Subject: Claim the SPI bus before writes if the IMC ROM is present The SB800 and Hudson now support adding the IMC ROM which runs from the same chip as coreboot. When the IMC is running, write or erase commands sent to the spi bus will fail, and the IMC will die. To fix this, we send a request to the IMC to stop fetching from the SPI rom while we write to it. This process (in one form or another) is required for writes to the SPI bus while the IMC is running. Because the IMC can take up to 500ms to respond every time we claim the bus, this patch tries to keep the number of times we need to do that to a minimum. We only need to claim the bus on writes, and using a counter for the semaphore allows us to call in once to claim the bus at the beginning of a number of transactions and it will stay claimed until we release it at the end of the transactions. Claim() - takes up to 500ms hit claim() - no delay erase() release() claim() - no delay write() release() Release() Change-Id: I4e003c5122a2ed47abce57ab8b92dee6aa4713ed Signed-off-by: Martin Roth Reviewed-on: http://review.coreboot.org/1976 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/drivers/spi/spi_flash.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'src/drivers/spi/spi_flash.c') diff --git a/src/drivers/spi/spi_flash.c b/src/drivers/spi/spi_flash.c index 75a5c21619..6b658f894d 100644 --- a/src/drivers/spi/spi_flash.c +++ b/src/drivers/spi/spi_flash.c @@ -69,6 +69,7 @@ int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd, struct spi_slave *spi = flash->spi; int ret; + spi->rw = SPI_READ_FLAG; spi_claim_bus(spi); ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len); spi_release_bus(spi); @@ -148,6 +149,7 @@ int spi_flash_cmd_erase(struct spi_flash *flash, u8 erase_cmd, return -1; } + flash->spi->rw = SPI_WRITE_FLAG; ret = spi_claim_bus(flash->spi); if (ret) { printk(BIOS_WARNING, "SF: Unable to claim SPI bus\n"); @@ -258,6 +260,7 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs, return NULL; } + spi->rw = SPI_READ_FLAG; ret = spi_claim_bus(spi); if (ret) { printk(BIOS_WARNING, "SF: Failed to claim SPI bus: %d\n", ret); -- cgit v1.2.3