sh: Support for multiple nodes.

This adds basic support for multiple nodes on SH machines.
This is primarily useful for boards with many different
memory blocks that are otherwise unused (SH7722/SH7785 URAM
and so forth).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/Kconfig

@@ -293,6 +293,17 @@ config VSYSCALL
 	  For systems with an MMU that can afford to give up a page,
 	  (the default value) say Y.
 
+config NUMA
+	bool "Non Uniform Memory Access (NUMA) Support"
+	depends on MMU && EXPERIMENTAL
+	default n
+	help
+	  Some SH systems have many various memories scattered around
+	  the address space, each with varying latencies. This enables
+	  support for these blocks by binding them to nodes and allowing
+	  memory policies to be used for prioritizing and controlling
+	  allocation behaviour.
+
 config NODES_SHIFT
 	int
 	default "1"

arch/sh/mm/Makefile

@@ -29,3 +29,4 @@ endif
 
 obj-$(CONFIG_SH7705_CACHE_32KB)	+= cache-sh7705.o
 obj-$(CONFIG_32BIT)		+= pmb.o
+obj-$(CONFIG_NUMA)		+= numa.o

arch/sh/mm/numa.c

@@ -0,0 +1,92 @@
+/*
+ * arch/sh/mm/numa.c - Multiple node support for SH machines
+ *
+ *  Copyright (C) 2007  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/module.h>
+#include <linux/bootmem.h>
+#include <linux/mm.h>
+#include <linux/numa.h>
+#include <linux/pfn.h>
+#include <asm/sections.h>
+
+static bootmem_data_t plat_node_bdata[MAX_NUMNODES];
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
+EXPORT_SYMBOL_GPL(node_data);
+
+/*
+ * On SH machines the conventional approach is to stash system RAM
+ * in node 0, and other memory blocks in to node 1 and up, ordered by
+ * latency. Each node's pgdat is node-local at the beginning of the node,
+ * immediately followed by the node mem map.
+ */
+void __init setup_memory(void)
+{
+	unsigned long free_pfn = PFN_UP(__pa(_end));
+
+	/*
+	 * Node 0 sets up its pgdat at the first available pfn,
+	 * and bumps it up before setting up the bootmem allocator.
+	 */
+	NODE_DATA(0) = pfn_to_kaddr(free_pfn);
+	memset(NODE_DATA(0), 0, sizeof(struct pglist_data));
+	free_pfn += PFN_UP(sizeof(struct pglist_data));
+	NODE_DATA(0)->bdata = &plat_node_bdata[0];
+
+	/* Set up node 0 */
+	setup_bootmem_allocator(free_pfn);
+
+	/* Give the platforms a chance to hook up their nodes */
+	plat_mem_setup();
+}
+
+void __init setup_bootmem_node(int nid, unsigned long start, unsigned long end)
+{
+	unsigned long bootmap_pages, bootmap_start, bootmap_size;
+	unsigned long start_pfn, free_pfn, end_pfn;
+
+	/* Don't allow bogus node assignment */
+	BUG_ON(nid > MAX_NUMNODES || nid == 0);
+
+	/*
+	 * The free pfn starts at the beginning of the range, and is
+	 * advanced as necessary for pgdat and node map allocations.
+	 */
+	free_pfn = start_pfn = start >> PAGE_SHIFT;
+	end_pfn = end >> PAGE_SHIFT;
+
+	add_active_range(nid, start_pfn, end_pfn);
+
+	/* Node-local pgdat */
+	NODE_DATA(nid) = pfn_to_kaddr(free_pfn);
+	free_pfn += PFN_UP(sizeof(struct pglist_data));
+	memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));
+
+	NODE_DATA(nid)->bdata = &plat_node_bdata[nid];
+	NODE_DATA(nid)->node_start_pfn = start_pfn;
+	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
+
+	/* Node-local bootmap */
+	bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
+	bootmap_start = (unsigned long)pfn_to_kaddr(free_pfn);
+	bootmap_size = init_bootmem_node(NODE_DATA(nid), free_pfn, start_pfn,
+				    end_pfn);
+
+	free_bootmem_with_active_regions(nid, end_pfn);
+
+	/* Reserve the pgdat and bootmap space with the bootmem allocator */
+	reserve_bootmem_node(NODE_DATA(nid), start_pfn << PAGE_SHIFT,
+			     sizeof(struct pglist_data));
+	reserve_bootmem_node(NODE_DATA(nid), free_pfn << PAGE_SHIFT,
+			     bootmap_pages << PAGE_SHIFT);
+
+	/* It's up */
+	node_set_online(nid);
+
+	/* Kick sparsemem */
+	sparse_memory_present_with_active_regions(nid);
+}

include/asm-sh/mmzone.h

@@ -0,0 +1,46 @@
+#ifndef __ASM_SH_MMZONE_H
+#define __ASM_SH_MMZONE_H
+
+#ifdef __KERNEL__
+
+#ifdef CONFIG_NEED_MULTIPLE_NODES
+extern struct pglist_data *node_data[];
+#define NODE_DATA(nid)		(node_data[nid])
+
+#define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
+#define node_end_pfn(nid)	(NODE_DATA(nid)->node_start_pfn + \
+				 NODE_DATA(nid)->node_spanned_pages)
+
+static inline int pfn_to_nid(unsigned long pfn)
+{
+	int nid;
+
+	for (nid = 0; nid < MAX_NUMNODES; nid++)
+		if (pfn >= node_start_pfn(nid) && pfn <= node_end_pfn(nid))
+			break;
+
+	return nid;
+}
+
+static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
+{
+	return NODE_DATA(pfn_to_nid(pfn));
+}
+
+/* arch/sh/mm/numa.c */
+void __init setup_bootmem_node(int nid, unsigned long start, unsigned long end);
+#else
+static inline void
+setup_bootmem_node(int nid, unsigned long start, unsigned long end)
+{
+}
+#endif /* CONFIG_NEED_MULTIPLE_NODES */
+
+/* Platform specific mem init */
+void __init plat_mem_setup(void);
+
+/* arch/sh/kernel/setup.c */
+void __init setup_bootmem_allocator(unsigned long start_pfn);
+
+#endif /* __KERNEL__ */
+#endif /* __ASM_SH_MMZONE_H */

include/asm-sh/topology.h

@@ -1,6 +1,36 @@
 #ifndef _ASM_SH_TOPOLOGY_H
 #define _ASM_SH_TOPOLOGY_H
 
+#ifdef CONFIG_NUMA
+
+/* sched_domains SD_NODE_INIT for sh machines */
+#define SD_NODE_INIT (struct sched_domain) {		\
+	.span			= CPU_MASK_NONE,	\
+	.parent			= NULL,			\
+	.child			= NULL,			\
+	.groups			= NULL,			\
+	.min_interval		= 8,			\
+	.max_interval		= 32,			\
+	.busy_factor		= 32,			\
+	.imbalance_pct		= 125,			\
+	.cache_nice_tries	= 2,			\
+	.busy_idx		= 3,			\
+	.idle_idx		= 2,			\
+	.newidle_idx		= 0,			\
+	.wake_idx		= 1,			\
+	.forkexec_idx		= 1,			\
+	.flags			= SD_LOAD_BALANCE	\
+				| SD_BALANCE_FORK	\
+				| SD_BALANCE_EXEC	\
+				| SD_SERIALIZE		\
+				| SD_WAKE_BALANCE,	\
+	.last_balance		= jiffies,		\
+	.balance_interval	= 1,			\
+	.nr_balance_failed	= 0,			\
+}
+
+#endif
+
 #include <asm-generic/topology.h>
 
 #endif /* _ASM_SH_TOPOLOGY_H */