[PATCH v3 22/23] ARM: k3: Add DRAM size detection

[Sascha Hauer]

This adds support for reading the DRAM size back from the DDRSS memory
controller.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/mach-k3/Makefile |  1 +
 arch/arm/mach-k3/common.c |  1 +
 arch/arm/mach-k3/ddrss.c  | 76 +++++++++++++++++++++++++++++++++++++++++++++++
 include/mach/k3/common.h  |  4 +++
 4 files changed, 82 insertions(+)

diff --git a/arch/arm/mach-k3/Makefile b/arch/arm/mach-k3/Makefile
index 6e105095da..b9b987d211 100644
--- a/arch/arm/mach-k3/Makefile
+++ b/arch/arm/mach-k3/Makefile
@@ -1,5 +1,6 @@
 obj-y += common.o
 obj-pbl-$(CONFIG_MACH_K3_CORTEX_R5) += r5.o
+obj-pbl-y += ddrss.o
 
 extra-y += combined-dm-cfg-am625.k3cfg combined-sysfw-cfg-am625.k3cfg
 
diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
index d7b44f31e8..d8bed194d6 100644
--- a/arch/arm/mach-k3/common.c
+++ b/arch/arm/mach-k3/common.c
@@ -171,6 +171,7 @@ static int am625_init(void)
 
 	am625_get_bootsource(&src, &instance);
 	bootsource_set(src, instance);
+	am625_register_dram();
 
 	genpd_activate();
 
diff --git a/arch/arm/mach-k3/ddrss.c b/arch/arm/mach-k3/ddrss.c
new file mode 100644
index 0000000000..b51371d661
--- /dev/null
+++ b/arch/arm/mach-k3/ddrss.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <memory.h>
+#include <linux/bitfield.h>
+#include <mach/k3/common.h>
+#include <linux/bits.h>
+#include <io.h>
+#include <asm/memory.h>
+#include <linux/kernel.h>
+
+#define CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_0 0x0
+
+#define DRAM_CLASS	GENMASK(11, 8)
+
+#define CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_327 0x51c
+
+#define CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_317 0x4f4
+
+#define ROW_DIFF_0	GENMASK(2, 0)
+#define ROW_DIFF_1	GENMASK(10, 8)
+#define COL_DIFF_0	GENMASK(19, 16)
+#define COL_DIFF_1	GENMASK(27, 24)
+
+#define CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_3 0xc
+
+#define MAX_ROW		GENMASK(4, 0)
+#define MAX_COL		GENMASK(11, 8)
+
+#define AM625_DDRSS_BASE	0x0f308000
+
+#define DENALI_CTL_0_DRAM_CLASS_DDR4		0xa
+#define DENALI_CTL_0_DRAM_CLASS_LPDDR4		0xb
+
+u64 am625_sdram_size(void)
+{
+	void __iomem *base = IOMEM(AM625_DDRSS_BASE);
+	u32 ctl0 = readl(base + CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_0);
+	u32 ctl3 = readl(base + CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_3);
+	u32 ctl317 = readl(base + CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_317);
+	u32 ctl327 = readl(base + CTLPHY_CTL_CFG_CTLCFG_DENALI_CTL_327);
+	unsigned int cols, rows, banks;
+	u64 size = 0;
+
+	if (FIELD_GET(DRAM_CLASS, ctl0) == DENALI_CTL_0_DRAM_CLASS_LPDDR4)
+		banks = 8;
+	else if (FIELD_GET(DRAM_CLASS, ctl0) == DENALI_CTL_0_DRAM_CLASS_DDR4)
+		banks = 16;
+	else
+		return 0;
+
+	if (ctl327 & BIT(0)) {
+		cols = FIELD_GET(MAX_COL, ctl3) - FIELD_GET(COL_DIFF_0, ctl317);
+		rows = FIELD_GET(MAX_ROW, ctl3) - FIELD_GET(ROW_DIFF_0, ctl317);
+		size += memory_sdram_size(cols, rows, banks, 2);
+	}
+
+	if (ctl327 & BIT(1)) {
+		cols = FIELD_GET(MAX_COL, ctl3) - FIELD_GET(COL_DIFF_1, ctl317);
+		rows = FIELD_GET(MAX_ROW, ctl3) - FIELD_GET(ROW_DIFF_1, ctl317);
+		size += memory_sdram_size(cols, rows, banks, 2);
+	}
+
+	return size;
+}
+
+void am625_register_dram(void)
+{
+	u64 size = am625_sdram_size();
+	u64 lowmem = min_t(u64, size, SZ_2G);
+
+	arm_add_mem_device("ram0", 0x80000000, lowmem);
+
+#ifdef CONFIG_64BIT
+	if (size - lowmem)
+		arm_add_mem_device("ram0", 0x880000000ULL, size - lowmem);
+#endif
+}
diff --git a/include/mach/k3/common.h b/include/mach/k3/common.h
index 448ec1343c..d7ceea51d7 100644
--- a/include/mach/k3/common.h
+++ b/include/mach/k3/common.h
@@ -1,6 +1,10 @@
 #ifndef __MACH_K3_COMMON_H
 #define __MACH_K3_COMMON_H
 
+#include <bootsource.h>
+
 void am625_get_bootsource(enum bootsource *src, int *instance);
+u64 am625_sdram_size(void);
+void am625_register_dram(void);
 
 #endif /* __MACH_K3_COMMON_H */

-- 
2.39.5