[U-Boot] [PATCH] kirkwood: implement kw_sdram_bs_set()

[Gerlando Falauto]

Some boards might be equipped with different SDRAM configurations.
When that is the case, CPU CS Window Size Register (CS[0]n Size) should
be set to the biggest value through board.cfg file; then its value
can be fixed at runtime according to the detected SDRAM size.

Therefore, implement kw_sdram_bs_set(), to be called for instance within
board_early_init_f().

Signed-off-by: Gerlando Falauto <gerlando.falauto at keymile.com>
Cc: Marek Vasut <marex at denx.de>
Cc: Prafulla Wadaskar <prafulla at marvell.com>
Cc: Wolfgang Denk <wd at denx.de>
Cc: Valentin Longchamp <valentin.longchamp at keymile.com>
Cc: Holger Brunck <holger.brunck at keymile.com>
---
 arch/arm/cpu/arm926ejs/kirkwood/dram.c   |   28 ++++++++++++++++++++++++++--
 arch/arm/include/asm/arch-kirkwood/cpu.h |    2 ++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/arm926ejs/kirkwood/dram.c b/arch/arm/cpu/arm926ejs/kirkwood/dram.c
index 2441554..e5409f1 100644
--- a/arch/arm/cpu/arm926ejs/kirkwood/dram.c
+++ b/arch/arm/cpu/arm926ejs/kirkwood/dram.c
@@ -28,8 +28,15 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define KW_REG_CPUCS_WIN_BAR(x)		(KW_REGISTER(0x1500) + (x * 0x08))
-#define KW_REG_CPUCS_WIN_SZ(x)		(KW_REGISTER(0x1504) + (x * 0x08))
+/* Kirkwood memory registers */
+#define KW_REG_CPUCS_WIN_BAR(x)		(KW_REGISTER(0x1500) + ((x) * 0x08))
+#define KW_REG_CPUCS_WIN_SZ(x)		(KW_REGISTER(0x1504) + ((x) * 0x08))
+
+#define KW_REG_CPUCS_WIN_ENABLE		(1 << 0)
+#define KW_REG_CPUCS_WIN_WR_PROTECT	(1 << 1)
+#define KW_REG_CPUCS_WIN_WIN0_CS(x)	(((x) & 0x3) << 2)
+#define KW_REG_CPUCS_WIN_SIZE(x)	(((x) & 0xff) << 24)
+
 /*
  * kw_sdram_bar - reads SDRAM Base Address Register
  */
@@ -60,6 +67,23 @@ u32 kw_sdram_bs(enum memory_bank bank)
 	return result;
 }
 
+/*
+ * kw_sdram_bs_set - writes SDRAM Bank size
+ */
+void kw_sdram_bs_set(enum memory_bank bank, u32 size)
+{
+	/* Read current register value */
+	u32 reg = readl(KW_REG_CPUCS_WIN_SZ(bank));
+
+	/* Clear window size */
+	reg &= ~KW_REG_CPUCS_WIN_SIZE(0xFF);
+
+	/* Set new window size */
+	reg |= KW_REG_CPUCS_WIN_SIZE((size - 1) >> 24);
+
+	writel(reg, KW_REG_CPUCS_WIN_SZ(bank));
+}
+
 #ifndef CONFIG_SYS_BOARD_DRAM_INIT
 int dram_init(void)
 {
diff --git a/arch/arm/include/asm/arch-kirkwood/cpu.h b/arch/arm/include/asm/arch-kirkwood/cpu.h
index d28c51a..807154e 100644
--- a/arch/arm/include/asm/arch-kirkwood/cpu.h
+++ b/arch/arm/include/asm/arch-kirkwood/cpu.h
@@ -159,6 +159,8 @@ void reset_cpu(unsigned long ignored);
 unsigned char get_random_hex(void);
 unsigned int kw_sdram_bar(enum memory_bank bank);
 unsigned int kw_sdram_bs(enum memory_bank bank);
+void kw_sdram_bs_set(enum memory_bank bank, u32 size);
+
 int kw_config_adr_windows(void);
 void kw_config_gpio(unsigned int gpp0_oe_val, unsigned int gpp1_oe_val,
 		unsigned int gpp0_oe, unsigned int gpp1_oe);
-- 
1.7.1