[PATCH v2] arm/imx: provide command to add ram device with autodetected size

[Uwe Kleine-König]

The amount of available ram is determined by the ESDCTL register, so
better don't hardcode the value.

This commit provides a command that can be used instead of
arm_add_mem_device and convertes pcm043 (on which this patch was tested)
to it.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
changes since implicit v1:
 - support 2nd sdram chip select
 - move implementation to arch/arm/mach-imx/esdctl.c

 arch/arm/boards/pcm043/pcm043.c         |    3 ++-
 arch/arm/mach-imx/Makefile              |    2 +-
 arch/arm/mach-imx/esdctl.c              |   45 +++++++++++++++++++++++++++++++
 arch/arm/mach-imx/include/mach/esdctl.h |    3 +++
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/mach-imx/esdctl.c

diff --git a/arch/arm/boards/pcm043/pcm043.c b/arch/arm/boards/pcm043/pcm043.c
index 65e0586..3a309c4 100644
--- a/arch/arm/boards/pcm043/pcm043.c
+++ b/arch/arm/boards/pcm043/pcm043.c
@@ -46,6 +46,7 @@
 #include <mach/imx-pll.h>
 #include <mach/iomux-mx35.h>
 #include <mach/devices-imx35.h>
+#include <mach/esdctl.h>
 
 static struct fec_platform_data fec_info = {
 	.xcv_type = MII100,
@@ -103,7 +104,7 @@ static struct imx_ipu_fb_platform_data ipu_fb_data = {
 
 static int pcm043_mem_init(void)
 {
-	arm_add_mem_device("ram0", IMX_SDRAM_CS0, SZ_128M);
+	imx_add_ram0();
 
 	return 0;
 }
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index 03e2421..cc6fa5e 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -1,4 +1,4 @@
-obj-y += clocksource.o gpio.o
+obj-y += clocksource.o gpio.o esdctl.o
 obj-$(CONFIG_ARCH_IMX1)  += speed-imx1.o  imx1.o  iomux-v1.o
 obj-$(CONFIG_ARCH_IMX25) += speed-imx25.o imx25.o iomux-v3.o
 obj-$(CONFIG_ARCH_IMX21) += speed-imx21.o imx21.o iomux-v1.o
diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
new file mode 100644
index 0000000..8695c12
--- /dev/null
+++ b/arch/arm/mach-imx/esdctl.c
@@ -0,0 +1,45 @@
+#include <mach/esdctl.h>
+#include <mach/imx-regs.h>
+#include <asm/io.h>
+#include <asm/memory.h>
+
+static void imx_add_ram(const char* name, resource_size_t base,
+		void __iomem *esdctladdr)
+{
+	u32 esdctl = readl(esdctladdr);
+	/*
+	 * with the fields ROW, COL and DSIZ all zero we have 11 rows, 8 cols
+	 * and 2 bytes bus width on 4 banks.
+	 */
+	resource_size_t size = 4 << (11 + 8 + 1);
+
+	if (!(esdctl & ESDCTL0_SDE))
+		/* SDRAM controller disabled, so no RAM here */
+		return;
+
+	/* calculate memory size: 4 banks * 2^#rows * 2^#cols * bytes/word */
+	size <<= (esdctl & ESDCTL0_ROW_MASK) >> 24;
+	size <<= (esdctl & ESDCTL0_COL_MASK) >> 20;
+
+	if ((esdctl & ESDCTL0_DSIZ_MASK) == ESDCTL0_DSIZ_31_0)
+		/* 4 bytes bus width */
+		size <<= 1;
+
+	arm_add_mem_device(name, base, size);
+}
+
+void imx_add_ram0(void)
+{
+	imx_add_ram("ram0", (resource_size_t)IMX_SDRAM_CS0, (void __iomem *)ESDCTL0);
+}
+
+void imx_add_ram1(void)
+{
+	imx_add_ram("ram1", (resource_size_t)IMX_SDRAM_CS1, (void __iomem *)ESDCTL1);
+}
+
+void imx_add_ram_auto(void)
+{
+	imx_add_ram0();
+	imx_add_ram1();
+}
diff --git a/arch/arm/mach-imx/include/mach/esdctl.h b/arch/arm/mach-imx/include/mach/esdctl.h
index 10c8b9b..688f799 100644
--- a/arch/arm/mach-imx/include/mach/esdctl.h
+++ b/arch/arm/mach-imx/include/mach/esdctl.h
@@ -26,6 +26,7 @@
 #define ESDCTL0_DSIZ_31_16			(0 << 16)
 #define ESDCTL0_DSIZ_15_0			(1 << 16)
 #define ESDCTL0_DSIZ_31_0			(2 << 16)
+#define ESDCTL0_DSIZ_MASK			(3 << 16)
 #define ESDCTL0_REF1				(1 << 13)
 #define ESDCTL0_REF2				(2 << 13)
 #define ESDCTL0_REF4				(3 << 13)
@@ -124,3 +125,5 @@
 //#define ESDCFGx_tRC_14		0x0000000e	// 15 seems to not exist
 #define ESDCFGx_tRC_16			0x0000000f
 
+void imx_add_ram0(void);
+void imx_add_ram1(void);
-- 
1.7.10.4