openwrtv4/target/linux/ramips/patches-3.9/0121-MIPS-add-detect_memory_region.patch

From 2ccca2ac0b54eb21890412c888cf5a5bda656bba Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sat, 13 Apr 2013 13:15:47 +0200
Subject: [PATCH 121/164] MIPS: add detect_memory_region()

Add a generic way of detecting the available RAM. This function is based on the
implementation already used by ath79.

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5178/
---
 arch/mips/include/asm/bootinfo.h |    1 +
 arch/mips/kernel/setup.c         |   20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/arch/mips/include/asm/bootinfo.h b/arch/mips/include/asm/bootinfo.h
index b71dd5b..4d2cdea 100644
--- a/arch/mips/include/asm/bootinfo.h
+++ b/arch/mips/include/asm/bootinfo.h
@@ -104,6 +104,7 @@ struct boot_mem_map {
 extern struct boot_mem_map boot_mem_map;
 
 extern void add_memory_region(phys_t start, phys_t size, long type);
+extern void detect_memory_region(phys_t start, phys_t sz_min,  phys_t sz_max);
 
 extern void prom_init(void);
 extern void prom_free_prom_memory(void);
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 4c774d5..7325793 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -23,6 +23,7 @@
 #include <linux/pfn.h>
 #include <linux/debugfs.h>
 #include <linux/kexec.h>
+#include <linux/sizes.h>
 
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
@@ -122,6 +123,25 @@ void __init add_memory_region(phys_t start, phys_t size, long type)
 	boot_mem_map.nr_map++;
 }
 
+void __init detect_memory_region(phys_t start, phys_t sz_min, phys_t sz_max)
+{
+	phys_t size;
+
+	for (size = sz_min; size < sz_max; size <<= 1) {
+		if (!memcmp(detect_memory_region,
+				detect_memory_region + size, 1024))
+			break;
+	}
+
+	pr_debug("Memory: %lluMB of RAM detected at 0x%llx (min: %lluMB, max: %lluMB)\n",
+		((unsigned long long) size) / SZ_1M,
+		(unsigned long long) start,
+		((unsigned long long) sz_min) / SZ_1M,
+		((unsigned long long) sz_max) / SZ_1M);
+
+	add_memory_region(start, size, BOOT_MEM_RAM);
+}
+
 static void __init print_memory_map(void)
 {
 	int i;
-- 
1.7.10.4