lpc: Add function for host reset without RCIN GPIO

Prior x86 boards have had GPIO for toggling RCIN directly on the PCH,
although many likely had HW-assisted methods as well.

With eve we need to generate an eSPI Virtual Wire for RCIN, but in reality
software control over RCIN Virtual Wire is not available with the npcx EC,
so the legacy LPC interface for pulsing KBRST must be used instead as this
is the only way to generate RCIN.

This method will likely vary on different EC chips, but for skylake it
can just be abstracted into the LPC module.

BUG=chrome-os-partner:58666
BRANCH=none
TEST=successful 'apreset warm' on eve EC console

Change-Id: I7f9e7544a72877f75d05593b5e41f2f09a50e1c9
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/400037
Reviewed-by: Mulin Chao <mlchao@nuvoton.com>
Reviewed-by: Shawn N <shawnn@chromium.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/lpc.h b/include/lpc.h
index 3b77736f00..4408b71327 100644
--- a/include/lpc.h
+++ b/include/lpc.h
@@ -113,6 +113,10 @@ void lpc_clear_acpi_status_mask(uint8_t mask);
  */
 int lpc_get_pltrst_asserted(void);
 
+/**
+ * Reset the host with KBRST# or RCIN#
+ */
+void lpc_host_reset(void);
 
 /* Disable LPC ACPI interrupts */
 void lpc_disable_acpi_interrupts(void);