Patch set updated for coreboot: 704d4ab drivers/spi: Reduce the per loop delay of spi_flash_cmd_poll_bit()

[Edward O'Callaghan]

Edward O'Callaghan ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5973

-gerrit

commit 704d4abad3f6d71d2272381c2ecd00ca52739a9b
Author: Dave Frodin 
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: Ia8b00879135f926c402bbd9d08953c77a2dcc84e
    Signed-off-by: Dave Frodin 
---
 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(&current);
+	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(&current);
+	} while (!mono_time_after(&current, &end));

-	/* Timed out */
-	printk(BIOS_DEBUG, "SF: time out!\n");
+	printk(BIOS_DEBUG, "SF: timeout at %ld msec\n",timeout);
    return -1;
 }