mb/google/asurada: Init dram in romstage

Signed-off-by: Huayang Duan <huayang.duan@mediatek.com>
Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
Change-Id: Ied350570a695cca1424a6562e41120bcaf467797
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44568
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/asurada/Makefile.inc

@@ -8,6 +8,7 @@ verstage-y += reset.c
 
 romstage-y += memlayout.ld
 romstage-y += boardid.c
+romstage-y += romstage.c
 romstage-y += sdram_configs.c
 
 ramstage-y += memlayout.ld

src/mainboard/google/asurada/romstage.c

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/stages.h>
+#include <console/console.h>
+#include <fmap.h>
+#include <soc/dramc_param.h>
+#include <soc/emi.h>
+#include <soc/mmu_operations.h>
+
+/* This must be defined in chromeos.fmd in same name and size. */
+#define CALIBRATION_REGION		"RW_DDR_TRAINING"
+#define CALIBRATION_REGION_SIZE		0x2000
+
+_Static_assert(sizeof(struct dramc_param) <= CALIBRATION_REGION_SIZE,
+	       "sizeof(struct dramc_param) exceeds " CALIBRATION_REGION);
+
+static bool read_calibration_data_from_flash(struct dramc_param *dparam)
+{
+	const size_t length = sizeof(*dparam);
+	size_t ret = fmap_read_area(CALIBRATION_REGION, dparam, length);
+	printk(BIOS_DEBUG, "read data from flash, ret=%#zx, length=%#zx\n", ret, length);
+
+	return ret == length;
+}
+
+static bool write_calibration_data_to_flash(const struct dramc_param *dparam)
+{
+	const size_t length = sizeof(*dparam);
+	size_t ret = fmap_overwrite_area(CALIBRATION_REGION, dparam, length);
+	printk(BIOS_DEBUG, "write data from flash, ret=%#zx, length=%#zx\n", ret, length);
+
+	return ret == length;
+}
+
+/* dramc_param is ~2K and too large to fit in stack. */
+static struct dramc_param dramc_parameter;
+
+static struct dramc_param_ops dparam_ops = {
+	.param = &dramc_parameter,
+	.read_from_flash = &read_calibration_data_from_flash,
+	.write_to_flash = &write_calibration_data_to_flash,
+};
+
+void platform_romstage_main(void)
+{
+	mt_mem_init(&dparam_ops);
+	mtk_mmu_after_dram();
+}