[V1 PATCH 1/2] rockchip: sdram: Support getting banks from TPL for rk3568 and rk3588

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

Allow RK3568 and RK3588 based boards to get the RAM bank configuration
from the ROCKCHIP_TPL stage instead of the current logic. This fixes
both an issue where 256MB of RAM is blocked for devices with >= 4GB
of RAM and where memory holes need to be defined for devices with
>= 16GB of RAM. In the event that neither SOC is used and the
ROCKCHIP_TPL stage is not used, fall back to existing logic.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 arch/arm/mach-rockchip/sdram.c | 100 +++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

diff --git a/arch/arm/mach-rockchip/sdram.c b/arch/arm/mach-rockchip/sdram.c
index 0d9a0aef6f..e02fb03c5f 100644
--- a/arch/arm/mach-rockchip/sdram.c
+++ b/arch/arm/mach-rockchip/sdram.c
@@ -12,6 +12,7 @@
 #include <asm/io.h>
 #include <asm/arch-rockchip/sdram.h>
 #include <dm/uclass-internal.h>
+#include <linux/errno.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -35,11 +36,110 @@ struct tos_parameter_t {
 	s64 reserve[8];
 };
 
+/* Tag magic */
+#define ATAGS_CORE_MAGIC	0x54410001
+#define ATAGS_DDR_MEM_MAGIC	0x54410052
+
+/* Tag size and offset */
+#define ATAGS_SIZE		SZ_8K
+#define ATAGS_OFFSET		(SZ_2M - ATAGS_SIZE)
+#define ATAGS_PHYS_BASE		(CFG_SYS_SDRAM_BASE + ATAGS_OFFSET)
+
+/* ATAGS memory structure. */
+struct tag_ddr_mem {
+	u32 count;
+	u32 version;
+	u64 bank[20];
+	u32 flags;
+	u32 data[2];
+	u32 hash;
+} __packed;
+
+/**
+ * rockchip_dram_init_banksize() - Get RAM banks from Rockchip TPL
+ *
+ * Iterate through the defined ATAGS memory location to first find a
+ * valid core header, then find a valid ddr_info header. Sanity check
+ * the number of banks found. Then, iterate through the data to add
+ * each individual memory bank. Perform fixups on memory banks that
+ * overlap with a reserved space. If an error condition is received,
+ * it is expected that memory bank setup will fall back on existing
+ * logic. If ROCKCHIP_EXTERNAL_TPL is false then immediately return,
+ * and if neither ROCKCHIP_RK3588 or ROCKCHIP_RK3568 is enabled
+ * immediately return.
+ *
+ * Return number of banks found on success or negative on error.
+ */
+__weak int rockchip_dram_init_banksize(void)
+{
+	struct tag_ddr_mem *ddr_info;
+	size_t val;
+	size_t addr = ATAGS_PHYS_BASE;
+	int i;
+
+	if (!IS_ENABLED(CONFIG_ROCKCHIP_EXTERNAL_TPL))
+		return 0;
+	if (!IS_ENABLED(CONFIG_ROCKCHIP_RK3588) &&
+	    !IS_ENABLED(CONFIG_ROCKCHIP_RK3568))
+		return 0;
+
+	if (!IS_ENABLED(CONFIG_ROCKCHIP_EXTERNAL_TPL))
+		return -EPERM;
+
+	while (addr < (ATAGS_PHYS_BASE + ATAGS_SIZE)) {
+		val = readl(addr);
+		if (val == ATAGS_CORE_MAGIC)
+			break;
+		addr += 4;
+	}
+	if (addr >= (ATAGS_PHYS_BASE + ATAGS_SIZE))
+		return -ENODATA;
+
+	while (addr < (ATAGS_PHYS_BASE + ATAGS_SIZE)) {
+		val = readl(addr);
+		if (val == ATAGS_DDR_MEM_MAGIC)
+			break;
+		addr += 4;
+	}
+	if (addr >= (ATAGS_PHYS_BASE + ATAGS_SIZE))
+		return -ENODATA;
+
+	ddr_info = (void *)addr + 4;
+	if (!ddr_info->count || ddr_info->count > CONFIG_NR_DRAM_BANKS)
+		return -ENODATA;
+
+	for (i = 0; i < (ddr_info->count); i++) {
+		size_t start_addr = ddr_info->bank[i];
+		size_t size = ddr_info->bank[(i + ddr_info->count)];
+		size_t tmp;
+
+		if (start_addr < SZ_2M) {
+			tmp = SZ_2M - start_addr;
+			start_addr = SZ_2M;
+			size = size - tmp;
+		}
+
+		if (start_addr >= SDRAM_MAX_SIZE && start_addr < SZ_4G)
+			start_addr = SZ_4G;
+
+		tmp = start_addr + size;
+		if (tmp > SDRAM_MAX_SIZE && tmp < SZ_4G)
+			size = SDRAM_MAX_SIZE - start_addr;
+
+		gd->bd->bi_dram[i].start = start_addr;
+		gd->bd->bi_dram[i].size = size;
+	}
+
+	return i;
+}
+
 int dram_init_banksize(void)
 {
 	size_t ram_top = (unsigned long)(gd->ram_size + CFG_SYS_SDRAM_BASE);
 	size_t top = min((unsigned long)ram_top, (unsigned long)(gd->ram_top));
 
+	if (rockchip_dram_init_banksize() > 0)
+		return 0;
 #ifdef CONFIG_ARM64
 	/* Reserve 0x200000 for ATF bl31 */
 	gd->bd->bi_dram[0].start = 0x200000;
-- 
2.34.1