soc/mediatek/mt8195: Get DRAM size from DRAM calibration result

Signed-off-by: Ryan Chuang <ryan.chuang@mediatek.corp-partner.google.com>
Change-Id: Ic34f29d1692b94284b2cf6c5d91d323df736c76f
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56204
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/mediatek/mt8195/emi.c

@@ -1,8 +1,25 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <console/console.h>
+#include <emi.h>
 #include <soc/emi.h>
 
 size_t sdram_size(void)
 {
-	return (size_t)4 * GiB;
+	int rank_num;
+	u64 rank_size[RANK_MAX];
+	static size_t dram_size = 0;
+
+	if (dram_size)
+		return dram_size;
+
+	get_rank_size_by_emi(rank_size);
+	rank_num = get_rank_nr_by_emi();
+
+	for (int i = 0; i < rank_num; i++)
+		dram_size += rank_size[i];
+
+	printk(BIOS_INFO, "dram size = %#lx\n", dram_size);
+
+	return dram_size;
 }