1 files changed, 55 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/mmdc_size.c b/arch/arm/mach-imx/mmdc_size.c
new file mode 100644
index 0000000000..8a3c6bdea6
--- /dev/null
+++ b/arch/arm/mach-imx/mmdc_size.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <common.h>
+#include <asm/io.h>
+
+#if defined(CONFIG_MX53)
+#define MEMCTL_BASE	ESDCTL_BASE_ADDR
+#else
+#define MEMCTL_BASE	MMDC_P0_BASE_ADDR
+#endif
+static const unsigned char col_lookup[] = {9, 10, 11, 8, 12, 9, 9, 9};
+static const unsigned char bank_lookup[] = {3, 2};
+
+/* these MMDC registers are common to the IMX53 and IMX6 */
+struct esd_mmdc_regs {
+	uint32_t	ctl;
+	uint32_t	pdc;
+	uint32_t	otc;
+	uint32_t	cfg0;
+	uint32_t	cfg1;
+	uint32_t	cfg2;
+	uint32_t	misc;
+};
+
+#define ESD_MMDC_CTL_GET_ROW(mdctl)	((ctl >> 24) & 7)
+#define ESD_MMDC_CTL_GET_COLUMN(mdctl)	((ctl >> 20) & 7)
+#define ESD_MMDC_CTL_GET_WIDTH(mdctl)	((ctl >> 16) & 3)
+#define ESD_MMDC_CTL_GET_CS1(mdctl)	((ctl >> 30) & 1)
+#define ESD_MMDC_MISC_GET_BANK(mdmisc)	((misc >> 5) & 1)
+
+/*
+ * imx_ddr_size - return size in bytes of DRAM according MMDC config
+ * The MMDC MDCTL register holds the number of bits for row, col, and data
+ * width and the MMDC MDMISC register holds the number of banks. Combine
+ * all these bits to determine the meme size the MMDC has been configured for
+ */
+unsigned imx_ddr_size(void)
+{
+	struct esd_mmdc_regs *mem = (struct esd_mmdc_regs *)MEMCTL_BASE;
+	unsigned ctl = readl(&mem->ctl);
+	unsigned misc = readl(&mem->misc);
+	int bits = 11 + 0 + 0 + 1;      /* row + col + bank + width */
+
+	bits += ESD_MMDC_CTL_GET_ROW(ctl);
+	bits += col_lookup[ESD_MMDC_CTL_GET_COLUMN(ctl)];
+	bits += bank_lookup[ESD_MMDC_MISC_GET_BANK(misc)];
+	bits += ESD_MMDC_CTL_GET_WIDTH(ctl);
+	bits += ESD_MMDC_CTL_GET_CS1(ctl);
+
+	/* The MX6 can do only 3840 MiB of DRAM */
+	if (bits == 32)
+		return 0xf0000000;
+
+	return 1 << bits;
+}