[coreboot-gerrit] Change in coreboot[master]: mainboard/google/kahlee: Use 66MHz SPI clock for fast read

Martin Roth (Code Review) gerrit at coreboot.org
Fri Jun 8 18:12:58 CEST 2018


Martin Roth has submitted this change and it was merged. ( https://review.coreboot.org/26950 )

Change subject: mainboard/google/kahlee: Use 66MHz SPI clock for fast read
......................................................................

mainboard/google/kahlee: Use 66MHz SPI clock for fast read

Looking at the 100MHz signal, we were violating the timing requirements.
66MHz still isn't great, but it's a good tradeoff between improving
the signal and losing boot speed time.

This slows down the boot time by about 20mS.

BUG=b:109583457
TEST=Boot grunt, look at signal on scope

Change-Id: I7ce70c992822dd17c5877226e74c1890660768c6
Signed-off-by: Martin Roth <martinroth at google.com>
Reviewed-on: https://review.coreboot.org/26950
Tested-by: build bot (Jenkins) <no-reply at coreboot.org>
Reviewed-by: Raul Rangel <rrangel at chromium.org>
---
M src/mainboard/google/kahlee/bootblock/bootblock.c
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Raul Rangel: Looks good to me, approved



diff --git a/src/mainboard/google/kahlee/bootblock/bootblock.c b/src/mainboard/google/kahlee/bootblock/bootblock.c
index 8f124b3..7e6524d 100644
--- a/src/mainboard/google/kahlee/bootblock/bootblock.c
+++ b/src/mainboard/google/kahlee/bootblock/bootblock.c
@@ -44,7 +44,7 @@
 
 	/* Set SPI speeds before verstage. Needed for TPM */
 	sb_set_spi100(SPI_SPEED_33M,		/* Normal */
-			SPI_SPEED_100M,		/* Fast   */
+			SPI_SPEED_66M,		/* Fast   */
 			SPI_SPEED_66M,		/* AltIO  */
 			SPI_SPEED_66M);		/* TPM    */
 

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Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: I7ce70c992822dd17c5877226e74c1890660768c6
Gerrit-Change-Number: 26950
Gerrit-PatchSet: 2
Gerrit-Owner: Martin Roth <martinroth at google.com>
Gerrit-Reviewer: Martin Roth <martinroth at google.com>
Gerrit-Reviewer: Raul Rangel <rrangel at chromium.org>
Gerrit-Reviewer: Raul Rangel <rrangel at google.com>
Gerrit-Reviewer: Richard Spiegel <richard.spiegel at silverbackltd.com>
Gerrit-Reviewer: build bot (Jenkins) <no-reply at coreboot.org>
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