[coreboot-gerrit] Patch set updated for coreboot: 491ad69 drivers/spi: Reduce the per loop delay of spi_flash_cmd_poll_bit()
Edward O'Callaghan (eocallaghan@alterapraxis.com)
gerrit at coreboot.org
Fri Jun 27 07:06:08 CEST 2014
Edward O'Callaghan (eocallaghan at alterapraxis.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/6137
-gerrit
commit 491ad696acc481f3f18967097b58b8729bdf133f
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: Idf5a70182d66fc6a4b760ddae5f15a9fb654c9ff
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;
}
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