imx-common: cpu: add imx_ddr_size

Read memory setup registers to determine size
of available ram. This routine works for mx53/mx6x

I need this because when mx6solo called get_ram_size
with a too large maximum size, the system hanged.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

arch/arm/imx-common/cpu.c

@@ -65,6 +65,56 @@ char *get_reset_cause(void)
 	}
 }
 
+#if defined(CONFIG_MX53) || defined(CONFIG_MX6)
+#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};
+
+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;
+	uint32_t	scr;
+	uint32_t	ref;
+	uint32_t	rsvd1;
+	uint32_t	rsvd2;
+	uint32_t	rwd;
+	uint32_t	or;
+	uint32_t	mrr;
+	uint32_t	cfg3lp;
+	uint32_t	mr4;
+};
+
+#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)
+
+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);
+	return 1 << bits;
+}
+#endif
+
 #if defined(CONFIG_DISPLAY_CPUINFO)
 
 const char *get_imx_type(u32 imxtype)

arch/arm/include/asm/arch-mx5/sys_proto.h

@@ -33,6 +33,7 @@
 
 #define is_soc_rev(rev)	((get_cpu_rev() & 0xFF) - rev)
 u32 get_cpu_rev(void);
+unsigned imx_ddr_size(void);
 void sdelay(unsigned long);
 void set_chipselect_size(int const);
 

arch/arm/include/asm/arch-mx6/sys_proto.h

@@ -34,6 +34,7 @@
 #define is_soc_rev(rev)	((get_cpu_rev() & 0xFF) - rev)
 u32 get_cpu_rev(void);
 const char *get_imx_type(u32 imxtype);
+unsigned imx_ddr_size(void);
 
 void set_vddsoc(u32 mv);