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