[coreboot-gerrit] New patch to review for coreboot: 8de2843 drivers/spi: Reduce the per loop delay of spi_flash_cmd_poll_bit()
David Hendricks (dhendrix@chromium.org)
gerrit at coreboot.org
Fri Jul 4 03:22:55 CEST 2014
David Hendricks (dhendrix at chromium.org) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/6177
-gerrit
commit 8de284388fb3eeb7e5c743b33183148dcf6781aa
Author: Dave Frodin <dave.frodin at se-eng.com>
Date: Wed Jun 11 12:53:47 2014 -0600
drivers/spi: Reduce the per loop delay of spi_flash_cmd_poll_bit()
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: Icddb9953d7065d9ef789f941ea1a93ce9305a33a
Signed-off-by: Dave Frodin <dave.frodin at se-eng.com>
---
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 33588d5..6d92836 100644
--- a/src/drivers/spi/spi_flash.c
+++ b/src/drivers/spi/spi_flash.c
@@ -16,6 +16,7 @@
#include <cpu/x86/smm.h>
#endif
#include "spi_flash_internal.h"
+#include <timer.h>
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;
-
- udelay(500);
- } while (timebase--);
-
- if ((status & poll_bit) == 0)
- return 0;
+ return 0;
+ timer_monotonic_get(¤t);
+ } while (!mono_time_after(¤t, &end));
- /* Timed out */
- printk(BIOS_DEBUG, "SF: time out!\n");
+ printk(BIOS_DEBUG, "SF: timeout at %ld msec\n",timeout);
return -1;
}
More information about the coreboot-gerrit
mailing list