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cr50: use plt_rst_l low level as a sleep wake trigger

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When an x86 based system is reset, a pulse on the plt_rst_l line is
generated. This pulse is supposed to reset the system and the pulse'
rising edge is an interrupt trigger for H1 to reset the TPM. If H1 is
in sleep state at the time of the rising edge, the interrupt request
could be lost.

Luckily, the minimum plt_rst_l pulse duration is 1 ms, and the worst
case max time to wake up from sleep for H1 150 us. Let's wake up on
low level of plt_rst_l, this way by the time the rising edge comes
along the H1 would be awake and ready to process the interrupt.

BRANCH=cr50
BUG=b:35995492

TEST=verified that platform_KernelErrorPaths.CORRUPT_STACK passes
     hundreds of times on a system were it was failing after a few
     runs before this fix.

    - verified that suspend_stress_test still succeeds at least 300
      iterations

Change-Id: Ib9984efa08bdd185a95716dc9e48077cf4bb3c2a
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/455579
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Vadim Bendebury
2017-03-15 10:13:10 -07:00
parent 597a3bc943
commit 43abc6d9de
1 changed files with 13 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
board/cr50/board.c
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@@ -473,10 +473,19 @@ static void configure_board_specific_gpios(void)
/* Enbale the input */
GWRITE_FIELD(PINMUX, DIOM3_CTL, IE, 1);
/* Set to be edge sensitive */
GWRITE_FIELD(PINMUX, EXITEDGE0, DIOM3, 1);
/* Select rising edge polarity */
GWRITE_FIELD(PINMUX, EXITINV0, DIOM3, 0);
/*
* Make plt_rst_l routed to DIOM3 a low level sensitive wake
* source. This way when a plt_rst_l pulse comes along while
* H1 is in sleep, the H1 wakes from sleep first, enabling all
* necessary clocks, and becomes ready to generate an
* interrupt on the rising edge of plt_rst_l.
*
* It takes at most 150 us to wake up, and the pulse is at
* least 1ms long.
*/
GWRITE_FIELD(PINMUX, EXITEDGE0, DIOM3, 0);
GWRITE_FIELD(PINMUX, EXITINV0, DIOM3, 1);
/* Enable powerdown exit on DIOM3 */
GWRITE_FIELD(PINMUX, EXITEN0, DIOM3, 1);
} else {