From c50c0ab4566a031a0420d762f2403126635bba93 Mon Sep 17 00:00:00 2001 From: Dave Frodin Date: Wed, 11 Jun 2014 12:53:47 -0600 Subject: [PATCH] drivers/spi: Reduce the per loop delay of spi_flash_cmd_poll_bit() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit At the end of some SPI operations the SPI device needs to be polled to determine if it is done with the operation. For SPI data writes the predicted time of that operation could be less than 10us. The current per loop delay of 500us is adding too much delay. This change replaces the delay(x) in the do-while loop with a timer so that the actual timeout value won't be lengthened by the delay of reading the SPI device. Change-Id: Ia8b00879135f926c402bbd9d08953c77a2dcc84e Signed-off-by: Dave Frodin Reviewed-on: http://review.coreboot.org/5973 Tested-by: build bot (Jenkins) Reviewed-by: David Hendricks Reviewed-by: Edward O'Callaghan Reviewed-by: Kyösti Mälkki --- src/drivers/spi/spi_flash.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/src/drivers/spi/spi_flash.c b/src/drivers/spi/spi_flash.c index 33588d5f47..6d92836c13 100644 --- a/src/drivers/spi/spi_flash.c +++ b/src/drivers/spi/spi_flash.c @@ -16,6 +16,7 @@ #include #endif #include "spi_flash_internal.h" +#include static void spi_flash_addr(u32 addr, u8 *cmd) { @@ -106,27 +107,24 @@ int spi_flash_cmd_poll_bit(struct spi_flash *flash, unsigned long timeout, u8 cmd, u8 poll_bit) { struct spi_slave *spi = flash->spi; - unsigned long timebase; int ret; u8 status; + struct mono_time current, end; + + timer_monotonic_get(¤t); + end = current; + mono_time_add_msecs(&end, timeout); - timebase = timeout; do { ret = spi_flash_cmd_read(spi, &cmd, 1, &status, 1); if (ret) return -1; - if ((status & poll_bit) == 0) - break; + return 0; + timer_monotonic_get(¤t); + } while (!mono_time_after(¤t, &end)); - udelay(500); - } while (timebase--); - - if ((status & poll_bit) == 0) - return 0; - - /* Timed out */ - printk(BIOS_DEBUG, "SF: time out!\n"); + printk(BIOS_DEBUG, "SF: timeout at %ld msec\n",timeout); return -1; }