ARM: sort the meminfo array earlier

The meminfo array has to be sorted before sanity_check_meminfo() in
arch/arm/mm/mmu.c is called for it to work properly.  This also allows
for a simpler find_limits() in arch/arm/mm/init.c.

The sort is moved to arch/arm/kernel/setup.c because that's where the
meminfo array is populated.  Eventually this should be improved upon
to make the memory bank parser a bit more robust against problems
such as overlapping memory ranges.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>

arch/arm/kernel/setup.c

@@ -31,6 +31,7 @@
 #include <linux/memblock.h>
 #include <linux/bug.h>
 #include <linux/compiler.h>
+#include <linux/sort.h>
 
 #include <asm/unified.h>
 #include <asm/cpu.h>
@@ -888,6 +889,12 @@ static struct machine_desc * __init setup_machine_tags(unsigned int nr)
 	return mdesc;
 }
 
+static int __init meminfo_cmp(const void *_a, const void *_b)
+{
+	const struct membank *a = _a, *b = _b;
+	long cmp = bank_pfn_start(a) - bank_pfn_start(b);
+	return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
+}
 
 void __init setup_arch(char **cmdline_p)
 {
@@ -916,6 +923,7 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
 	sanity_check_meminfo();
 	arm_memblock_init(&meminfo, mdesc);