mb/google/skyrim: Fix ESPI communication issues
* Use dedicated ALERT pin to resolve NO_RESPONSE error/status while
getting target configuration.
* Configure the ESPI to operate at 16 MHZ since operating at 33 MHz
causes boot stall.
BUG=b:226635441
TEST=Build and Boot to OS in Skyrim. Ensure that EC <-> AP communication
is working fine through Host Command debug logs in EC console, ectool
version command.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Change-Id: I951afdada8ee4f917cdeba8e287e5a2ae77c97ee
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63286
Reviewed-by: Jon Murphy <jpmurphy@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/skyrim/variants/baseboard/devicetree.cb b/src/mainboard/google/skyrim/variants/baseboard/devicetree.cb
index 8fa6ba5..7f74d6d 100644
--- a/src/mainboard/google/skyrim/variants/baseboard/devicetree.cb
+++ b/src/mainboard/google/skyrim/variants/baseboard/devicetree.cb
@@ -27,9 +27,9 @@
},
.io_mode = ESPI_IO_MODE_QUAD,
- .op_freq_mhz = ESPI_OP_FREQ_33_MHZ,
+ .op_freq_mhz = ESPI_OP_FREQ_16_MHZ,
.crc_check_enable = 1,
- .alert_pin = ESPI_ALERT_PIN_IN_BAND,
+ .alert_pin = ESPI_ALERT_PIN_OPEN_DRAIN,
.periph_ch_en = 1,
.vw_ch_en = 1,
.oob_ch_en = 0,