From 6edde0247644db475f68f25dcb1bf72260600081 Mon Sep 17 00:00:00 2001 From: Maarten ter Huurne Date: Mon, 2 May 2011 11:47:00 +0200 Subject: [PATCH] MIPS: JZ4740: setup: Autodetect physical memory. Assume that the boot loader knows the physical memory of the system and deduce that information from the contents of the SDRAM control register. It is still possible to override with with the "mem=" parameter, but we have a sensible default now. Signed-off-by: Maarten ter Huurne Acked-by: Lars-Peter Clausen Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2319/ Signed-off-by: Ralf Baechle --- arch/mips/jz4740/setup.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/mips/jz4740/setup.c b/arch/mips/jz4740/setup.c index 6a9e14dab91e..d97cfbf882f5 100644 --- a/arch/mips/jz4740/setup.c +++ b/arch/mips/jz4740/setup.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2009-2010, Lars-Peter Clausen + * Copyright (C) 2011, Maarten ter Huurne * JZ4740 setup code * * This program is free software; you can redistribute it and/or modify it @@ -14,13 +15,44 @@ */ #include +#include #include +#include + +#include + #include "reset.h" + +#define JZ4740_EMC_SDRAM_CTRL 0x80 + + +static void __init jz4740_detect_mem(void) +{ + void __iomem *jz_emc_base; + u32 ctrl, bus, bank, rows, cols; + phys_t size; + + jz_emc_base = ioremap(JZ4740_EMC_BASE_ADDR, 0x100); + ctrl = readl(jz_emc_base + JZ4740_EMC_SDRAM_CTRL); + bus = 2 - ((ctrl >> 31) & 1); + bank = 1 + ((ctrl >> 19) & 1); + cols = 8 + ((ctrl >> 26) & 7); + rows = 11 + ((ctrl >> 20) & 3); + printk(KERN_DEBUG + "SDRAM preconfigured: bus:%u bank:%u rows:%u cols:%u\n", + bus, bank, rows, cols); + iounmap(jz_emc_base); + + size = 1 << (bus + bank + cols + rows); + add_memory_region(0, size, BOOT_MEM_RAM); +} + void __init plat_mem_setup(void) { jz4740_reset_init(); + jz4740_detect_mem(); } const char *get_system_type(void)