sh: SH-4A Privileged Space Mapping Buffer (PMB) support.

Add support for 32-bit physical addressing through the SH-4A
Privileged Space Mapping Buffer (PMB).

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

2 files changed, 271 insertions, 1 deletions

diff --git a/arch/sh/mm/Makefile b/arch/sh/mm/Makefile
index 9489a1424644..f4e32b3d24dc 100644
--- a/arch/sh/mm/Makefile
+++ b/arch/sh/mm/Makefile
@@ -22,4 +22,5 @@ obj-$(CONFIG_CPU_SH4)	+= tlb-sh4.o ioremap.o
 obj-$(CONFIG_SH7705_CACHE_32KB) += pg-sh7705.o
 endif
 
-obj-$(CONFIG_SH7705_CACHE_32KB) += cache-sh7705.o
+obj-$(CONFIG_SH7705_CACHE_32KB)	+= cache-sh7705.o
+obj-$(CONFIG_32BIT)		+= pmb.o
diff --git a/arch/sh/mm/pmb.c b/arch/sh/mm/pmb.c
new file mode 100644
index 000000000000..ff5bde745647
--- /dev/null
+++ b/arch/sh/mm/pmb.c
@@ -0,0 +1,269 @@
+/*
+ * arch/sh/mm/pmb.c
+ *
+ * Privileged Space Mapping Buffer (PMB) Support.
+ *
+ * Copyright (C) 2005 Paul Mundt
+ *
+ * P1/P2 Section mapping definitions from map32.h, which was:
+ *
+ *	Copyright 2003 (c) Lineo Solutions,Inc.
+ *
+ * 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/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/mmu.h>
+#include <asm/io.h>
+
+#define NR_PMB_ENTRIES	16
+
+static kmem_cache_t *pmb_cache;
+static unsigned long pmb_map;
+
+static struct pmb_entry pmb_init_map[] = {
+	/* vpn         ppn         flags (ub/sz/c/wt) */
+
+	/* P1 Section Mappings */
+	{ 0x80000000, 0x00000000, PMB_SZ_64M  | PMB_C, },
+	{ 0x84000000, 0x04000000, PMB_SZ_64M  | PMB_C, },
+	{ 0x88000000, 0x08000000, PMB_SZ_128M | PMB_C, },
+	{ 0x90000000, 0x10000000, PMB_SZ_64M  | PMB_C, },
+	{ 0x94000000, 0x14000000, PMB_SZ_64M  | PMB_C, },
+	{ 0x98000000, 0x18000000, PMB_SZ_64M  | PMB_C, },
+
+	/* P2 Section Mappings */
+	{ 0xa0000000, 0x00000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
+	{ 0xa4000000, 0x04000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
+	{ 0xa8000000, 0x08000000, PMB_UB | PMB_SZ_128M | PMB_WT, },
+	{ 0xb0000000, 0x10000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
+	{ 0xb4000000, 0x14000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
+	{ 0xb8000000, 0x18000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
+};
+
+static inline unsigned long mk_pmb_entry(unsigned int entry)
+{
+	return (entry & PMB_E_MASK) << PMB_E_SHIFT;
+}
+
+static inline unsigned long mk_pmb_addr(unsigned int entry)
+{
+	return mk_pmb_entry(entry) | PMB_ADDR;
+}
+
+static inline unsigned long mk_pmb_data(unsigned int entry)
+{
+	return mk_pmb_entry(entry) | PMB_DATA;
+}
+
+struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
+			    unsigned long flags)
+{
+	struct pmb_entry *pmbe;
+
+	pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
+	if (!pmbe)
+		return ERR_PTR(-ENOMEM);
+
+	pmbe->vpn	= vpn;
+	pmbe->ppn	= ppn;
+	pmbe->flags	= flags;
+
+	return pmbe;
+}
+
+void pmb_free(struct pmb_entry *pmbe)
+{
+	kmem_cache_free(pmb_cache, pmbe);
+}
+
+/*
+ * Must be in P2 for __set_pmb_entry()
+ */
+int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
+		    unsigned long flags, int *entry)
+{
+	unsigned int pos = *entry;
+
+	if (unlikely(pos == PMB_NO_ENTRY))
+		pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
+
+repeat:
+	if (unlikely(pos > NR_PMB_ENTRIES))
+		return -ENOSPC;
+
+	if (test_and_set_bit(pos, &pmb_map)) {
+		pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
+		goto repeat;
+	}
+
+	ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
+
+#ifdef CONFIG_SH_WRITETHROUGH
+	/*
+	 * When we are in 32-bit address extended mode, CCR.CB becomes
+	 * invalid, so care must be taken to manually adjust cacheable
+	 * translations.
+	 */
+	if (likely(flags & PMB_C))
+		flags |= PMB_WT;
+#endif
+
+	ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
+
+	*entry = pos;
+
+	return 0;
+}
+
+void set_pmb_entry(struct pmb_entry *pmbe)
+{
+	jump_to_P2();
+	__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &pmbe->entry);
+	back_to_P1();
+}
+
+void clear_pmb_entry(struct pmb_entry *pmbe)
+{
+	unsigned int entry = pmbe->entry;
+	unsigned long addr;
+
+	/*
+	 * Don't allow clearing of wired init entries, P1 or P2 access
+	 * without a corresponding mapping in the PMB will lead to reset
+	 * by the TLB.
+	 */
+	if (unlikely(entry < ARRAY_SIZE(pmb_init_map) ||
+		     entry >= NR_PMB_ENTRIES))
+		return;
+
+	jump_to_P2();
+
+	/* Clear V-bit */
+	addr = mk_pmb_addr(entry);
+	ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
+
+	addr = mk_pmb_data(entry);
+	ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
+
+	back_to_P1();
+
+	clear_bit(entry, &pmb_map);
+}
+
+static void pmb_cache_ctor(void *pmb, kmem_cache_t *cachep, unsigned long flags)
+{
+	memset(pmb, 0, sizeof(struct pmb_entry));
+
+	((struct pmb_entry *)pmb)->entry = PMB_NO_ENTRY;
+}
+
+static int __init pmb_init(void)
+{
+	unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
+	unsigned int entry;
+
+	BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
+
+	pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry),
+				      0, 0, pmb_cache_ctor, NULL);
+	BUG_ON(!pmb_cache);
+
+	jump_to_P2();
+
+	/*
+	 * Ordering is important, P2 must be mapped in the PMB before we
+	 * can set PMB.SE, and P1 must be mapped before we jump back to
+	 * P1 space.
+	 */
+	for (entry = 0; entry < nr_entries; entry++) {
+		struct pmb_entry *pmbe = pmb_init_map + entry;
+
+		__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &entry);
+	}
+
+	ctrl_outl(0, PMB_IRMCR);
+
+	/* PMB.SE and UB[7] */
+	ctrl_outl((1 << 31) | (1 << 7), PMB_PASCR);
+
+	back_to_P1();
+
+	return 0;
+}
+
+arch_initcall(pmb_init);
+
+#ifdef CONFIG_DEBUG_FS
+static int pmb_seq_show(struct seq_file *file, void *iter)
+{
+	int i;
+
+	seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
+			 "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
+	seq_printf(file, "ety   vpn  ppn  size   flags\n");
+
+	for (i = 0; i < NR_PMB_ENTRIES; i++) {
+		unsigned long addr, data;
+		unsigned int size;
+		char *sz_str = NULL;
+
+		addr = ctrl_inl(mk_pmb_addr(i));
+		data = ctrl_inl(mk_pmb_data(i));
+
+		size = data & PMB_SZ_MASK;
+		sz_str = (size == PMB_SZ_16M)  ? " 16MB":
+			 (size == PMB_SZ_64M)  ? " 64MB":
+			 (size == PMB_SZ_128M) ? "128MB":
+					         "512MB";
+
+		/* 02: V 0x88 0x08 128MB C CB  B */
+		seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
+			   i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
+			   (addr >> 24) & 0xff, (data >> 24) & 0xff,
+			   sz_str, (data & PMB_C) ? 'C' : ' ',
+			   (data & PMB_WT) ? "WT" : "CB",
+			   (data & PMB_UB) ? "UB" : " B");
+	}
+
+	return 0;
+}
+
+static int pmb_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pmb_seq_show, NULL);
+}
+
+static struct file_operations pmb_debugfs_fops = {
+	.owner		= THIS_MODULE,
+	.open		= pmb_debugfs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int __init pmb_debugfs_init(void)
+{
+	struct dentry *dentry;
+
+	dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
+				     NULL, NULL, &pmb_debugfs_fops);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	return 0;
+}
+
+postcore_initcall(pmb_debugfs_init);
+#endif