[S] Change in coreboot[master]: soc/mediatek/mt8188: Support ARM arch timer

[Yidi Lin (Code Review)]

Yidi Lin has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/76919?usp=email )

Change subject: soc/mediatek/mt8188: Support ARM arch timer
......................................................................

soc/mediatek/mt8188: Support ARM arch timer

Use ARM architectual timer by initializing frequency to 13 MHz. Since
system timer is the source of the architectual timer, we also call
`timer_prepare` in `init_timer`.

BUG=b:229800119
TEST=run `suite:faft_bios` to verify the firmware stability.
     check timestamps by cbmem.

Change-Id: I8b1348044e4c92984510604b7f61611e13284d86
Signed-off-by: Yidi Lin 
---
M src/soc/mediatek/mt8188/Kconfig
M src/soc/mediatek/mt8188/Makefile.inc
A src/soc/mediatek/mt8188/timer.c
3 files changed, 15 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/19/76919/1

diff --git a/src/soc/mediatek/mt8188/Kconfig b/src/soc/mediatek/mt8188/Kconfig
index 6d3c659..0568cd6 100644
--- a/src/soc/mediatek/mt8188/Kconfig
+++ b/src/soc/mediatek/mt8188/Kconfig
@@ -13,6 +13,7 @@
    select MEDIATEK_DRAM_BLOB_FAST_INIT
    select USE_CBMEM_DRAM_INFO
    select DPM_FOUR_CHANNEL
+	select ARM64_USE_ARCH_TIMER

if SOC_MEDIATEK_MT8188

diff --git a/src/soc/mediatek/mt8188/Makefile.inc b/src/soc/mediatek/mt8188/Makefile.inc
index 67c2d7a..1426b83 100644
--- a/src/soc/mediatek/mt8188/Makefile.inc
+++ b/src/soc/mediatek/mt8188/Makefile.inc
@@ -6,7 +6,7 @@
 all-y += ../common/i2c.c i2c.c
 all-y += ../common/pll.c pll.c
 all-$(CONFIG_SPI_FLASH) += ../common/spi.c spi.c
-all-y += ../common/timer.c ../common/timer_prepare.c
+all-y += timer.c ../common/timer_prepare.c
 all-y += ../common/uart.c

bootblock-y += bootblock.c
diff --git a/src/soc/mediatek/mt8188/timer.c b/src/soc/mediatek/mt8188/timer.c
new file mode 100644
index 0000000..00aaa40
--- /dev/null
+++ b/src/soc/mediatek/mt8188/timer.c
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/lib_helpers.h>
+#include <commonlib/helpers.h>
+#include <delay.h>
+#include <soc/timer_common.h>
+
+void init_timer(void)
+{
+	timer_prepare();
+
+	raw_write_cntfrq_el0(13 * MHz);
+}