[MIPS] 64-bit Sibyte kernels need DMA32.

Sibyte SOCs only have 32-bit PCI.  Due to the sparse use of the address
space only the first 1GB of memory is mapped at physical addresses
below 1GB.  If a system has more than 1GB of memory 32-bit DMA will
not be able to reach all of it.

For now this patch is good enough to keep Sibyte users happy but it seems
eventually something like swiotlb will be needed for Sibyte.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 16 insertions, 27 deletions

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index ec3b9e9f30f4..480dec04f552 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -347,11 +347,8 @@ static int __init page_is_ram(unsigned long pagenr)
 
 void __init paging_init(void)
 {
-	unsigned long zones_size[MAX_NR_ZONES] = { 0, };
-#ifndef CONFIG_FLATMEM
-	unsigned long zholes_size[MAX_NR_ZONES] = { 0, };
-	unsigned long i, j, pfn;
-#endif
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	unsigned long lastpfn;
 
 	pagetable_init();
 
@@ -361,35 +358,27 @@ void __init paging_init(void)
 	kmap_coherent_init();
 
 #ifdef CONFIG_ZONE_DMA
-	if (min_low_pfn < MAX_DMA_PFN && MAX_DMA_PFN <= max_low_pfn) {
-		zones_size[ZONE_DMA] = MAX_DMA_PFN - min_low_pfn;
-		zones_size[ZONE_NORMAL] = max_low_pfn - MAX_DMA_PFN;
-	} else if (max_low_pfn < MAX_DMA_PFN)
-		zones_size[ZONE_DMA] = max_low_pfn - min_low_pfn;
-	else
+	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
 #endif
-	zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
-
+#ifdef CONFIG_ZONE_DMA32
+	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
+#endif
+	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+	lastpfn = max_low_pfn;
 #ifdef CONFIG_HIGHMEM
-	zones_size[ZONE_HIGHMEM] = highend_pfn - highstart_pfn;
+	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
+	lastpfn = highend_pfn;
 
-	if (cpu_has_dc_aliases && zones_size[ZONE_HIGHMEM]) {
+	if (cpu_has_dc_aliases && max_low_pfn != highend_pfn) {
 		printk(KERN_WARNING "This processor doesn't support highmem."
-		       " %ldk highmem ignored\n", zones_size[ZONE_HIGHMEM]);
-		zones_size[ZONE_HIGHMEM] = 0;
+		       " %ldk highmem ignored\n",
+		       (highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
+		max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
+		lastpfn = max_low_pfn;
 	}
 #endif
 
-#ifdef CONFIG_FLATMEM
-	free_area_init(zones_size);
-#else
-	pfn = min_low_pfn;
-	for (i = 0; i < MAX_NR_ZONES; i++)
-		for (j = 0; j < zones_size[i]; j++, pfn++)
-			if (!page_is_ram(pfn))
-				zholes_size[i]++;
-	free_area_init_node(0, NODE_DATA(0), zones_size, 0, zholes_size);
-#endif
+	free_area_init_nodes(max_zone_pfns);
 }
 
 static struct kcore_list kcore_mem, kcore_vmalloc;