src/mediatek/mt8186: Implement sdram_size() to get real dram size

Originally, dram size is hard-coded to 4GB by default. To support
different dram size, calculate it from the mem chip info stored
in CBMEM.

BUG=b:206014043
TEST=Output "dram size: 0x100000000" on Kingler

Signed-off-by: Xi Chen <xixi.chen@mediatek.corp-partner.google.com>
Change-Id: I017e9d1a2d6e26f1fc21b67b5962dfb5c6ade8a5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62065
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/src/soc/mediatek/mt8186/emi.c b/src/soc/mediatek/mt8186/emi.c
index 48a7b3ef07..6e2544185e 100644
--- a/src/soc/mediatek/mt8186/emi.c
+++ b/src/soc/mediatek/mt8186/emi.c
@@ -5,11 +5,30 @@
  * Chapter number: 4.8
  */
 
+#include <assert.h>
+#include <cbmem.h>
+#include <commonlib/bsd/mem_chip_info.h>
 #include <soc/emi.h>
 
 size_t sdram_size(void)
 {
-	return (size_t)4 * GiB;
+	const struct mem_chip_info *mc;
+	size_t size = 0;
+
+	if (ENV_ROMSTAGE) {
+		size = mtk_dram_size();
+		printk(BIOS_INFO, "dram size (romstage): %#lx\n", size);
+		return size;
+	}
+
+	mc = cbmem_find(CBMEM_ID_MEM_CHIP_INFO);
+	assert(mc);
+
+	for (unsigned int i = 0; i < mc->num_channels; ++i)
+		size += mc->channel[i].density;
+
+	printk(BIOS_INFO, "dram size: %#lx\n", size);
+	return size;
 }
 
 void mt_set_emi(struct dramc_param *dparam)