chromeos: Provide common watchdog reboot support

Many ChromeOS devices use a GPIO to reset the system, in order to
guarantee that the TPM cannot be reset without also resetting the CPU.
Often chipset/SoC hardware watchdogs trigger some kind of built-in
CPU reset, bypassing this GPIO and thus leaving the TPM locked. These
ChromeOS devices need to detect that condition in their bootblock and
trigger a second (proper) reboot.

This patch adds some code to generalize this previously
mainboard-specific functionality and uses it on Veyron boards. It also
provides some code to add the proper eventlog entry for a watchdog
reset. Since the second reboot has to happen before firmware
verification and the eventlog is usually only initialized afterwards, we
provide the functionality to place a tombstone in a memlayout-defined
location (which could be SRAM or some MMIO register that is preserved
across reboots).

[pg: Integrates
 'mips: Temporarily work around build error caused by <arch/io.h> mismatch]

BRANCH=veyron
BUG=chrome-os-partner:35705
TEST=Run 'mem w 0xff800000 0x9' on a Jerry, watch how a "Hardware
watchdog reset" event appears in the eventlog after the reboot.

Change-Id: I0a33820b236c9328b2f9b20905b69cb934326f2a
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: fffc484bb89f5129d62739dcb44d08d7f5b30b33
Original-Change-Id: I7ee1d02676e9159794d29e033d71c09fdf4620fd
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/242404
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Id: c919c72ddc9d2e1e18858c0bf49c0ce79f2bc506
Original-Change-Id: I509c842d3393bd810e89ebdf0dc745275c120c1d
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/242504
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/9749
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/soc/rockchip/rk3288/include/soc/memlayout.ld b/src/soc/rockchip/rk3288/include/soc/memlayout.ld
index 8a12aba926..632384c069 100644
--- a/src/soc/rockchip/rk3288/include/soc/memlayout.ld
+++ b/src/soc/rockchip/rk3288/include/soc/memlayout.ld
@@ -47,5 +47,6 @@ SECTIONS
 	/* 4K of special SRAM in PMU power domain.
 	 * Careful: only supports 32-bit wide write accesses! */
 	SYMBOL(pmu_sram, 0xFF720000)
+	WATCHDOG_TOMBSTONE(0xFF720FFC, 4)
 	SYMBOL(epmu_sram, 0xFF721000)
 }