[PATCH] riscv: spacemit: k1: probe dram size during boot phase.

[Huan Zhou]

---
This patch introduce improvement for get dram size on bananapi BPI-F3,
retrieving the dram size dynamically.
Have tested on bananapi BPIF3 4G and jupiter 8G.

Signed-off-by: Huan Zhou <me at per1cycle.org>
---
 arch/riscv/cpu/k1/dram.c | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/cpu/k1/dram.c b/arch/riscv/cpu/k1/dram.c
index c477c15cbfb19f0e3a0ee72985b602f5bda352d7..095217f2a4c053f7477d62c0776bcb51e623db47 100644
--- a/arch/riscv/cpu/k1/dram.c
+++ b/arch/riscv/cpu/k1/dram.c
@@ -4,17 +4,53 @@
  */
 
 #include <asm/global_data.h>
+#include <asm/io.h>
 #include <config.h>
+#include <bitfield.h>
 #include <fdt_support.h>
 #include <linux/sizes.h>
 
+#define DDR_BASE 0xC0000000
 DECLARE_GLOBAL_DATA_PTR;
 
+static inline u32 map_format_size(u32 val)
+{
+	u32 tmp;
+
+	if (val & 0x1 == 0)
+		return 0;
+
+	tmp = bitfield_extract(val, 16, 5);
+	switch (tmp) {
+	case 0xd:
+		return 512;
+	case 0xe:
+		return 1024;
+	case 0xf:
+		return 2048;
+	case 0x10:
+		return 4096;
+	case 0x11:
+		return 8192;
+	default:
+		pr_info("Invalid DRAM density %x\n", val);
+		return 0;
+	}
+}
+
+u32 ddr_get_density(void)
+{
+	u32 cs0_size = map_format_size(readl((void *)DDR_BASE + 0x200));
+	u32 cs1_size = map_format_size(readl((void *)DDR_BASE + 0x208));
+	u32 ddr_size = cs0_size + cs1_size;
+
+	return ddr_size;
+}
+
 int dram_init(void)
 {
 	gd->ram_base = CFG_SYS_SDRAM_BASE;
-	/* TODO get ram size from ddr controller */
-	gd->ram_size = SZ_4G;
+	gd->ram_size = (u64)ddr_get_density() * SZ_1M;
 	return 0;
 }
 

---
base-commit: 19fc0b7f7d907119a13e9c207991899f0817f8fc
change-id: 20250108-get-dram-size-65cf59a15201

Best regards,
-- 
Huan Zhou <me at per1cycle.org>