veyron: Trigger hard reset (via GPIO) if last reboot was caused by watchdog

Like Nyan, Veyron boards use a GPIO to reset the system so that we can
make the accompanying TPM reset secure and unforgeable. The normal
kernel reboot driver knows that, but the SoC-internal watchdog doesn't.

This patch implements a check for the global reset status register in
the early bootblock and triggers a hard_reset() when it matches "first
global watchdog reset" or "second global watchdog reset". Seems that
the difference between the two is is a choice controlled by
wdt_glb_srst_ctrl (unconfirmed), and we want this code to run in both
cases.

BRANCH=None
BUG=chrome-os-partner:33141
TEST=Run 'mem w 0xff800000 0x9' from the command line, watch how you end
up in recovery without this patch but can boot normally with it.

Change-Id: Ice79648831e1e97d22325711da9e82bbf6bf3c75
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: 5d7cb52b2c2dcb2fff0bf83fc168439dade4b1b7
Original-Change-Id: I2581bde84f0445c15896060544e9acb60de91c8c
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/231734
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/9629
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/soc/rockchip/rk3288/clock.c b/src/soc/rockchip/rk3288/clock.c
index fe42910dde..ab12e8c896 100644
--- a/src/soc/rockchip/rk3288/clock.c
+++ b/src/soc/rockchip/rk3288/clock.c
@@ -640,3 +640,9 @@ int rkclk_configure_vop_dclk(u32 vop_id, u32 dclk_hz)
 	}
 	return 0;
 }
+
+int rkclk_was_watchdog_reset(void)
+{
+	/* Bits 5 and 4 are "second" and "first" global watchdog reset. */
+	return readl(&cru_ptr->cru_glb_rst_st) & 0x30;
+}