/*
* arch/sh/mm/pmb.c
*
* Privileged Space Mapping Buffer (PMB) Support.
*
* Copyright (C) 2005 - 2011 Paul Mundt
* Copyright (C) 2010 Matt Fleming
*
* 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/syscore_ops.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <asm/cacheflush.h>
#include <asm/sizes.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
struct pmb_entry;
struct pmb_entry {
unsigned long vpn;
unsigned long ppn;
unsigned long flags;
unsigned long size;
raw_spinlock_t lock;
/*
* 0 .. NR_PMB_ENTRIES for specific entry selection, or
* PMB_NO_ENTRY to search for a free one
*/
int entry;
/* Adjacent entry link for contiguous multi-entry mappings */
struct pmb_entry *link;
};
static struct {
unsigned long size;
int flag;
} pmb_sizes[] = {
{ .size = SZ_512M, .flag = PMB_SZ_512M, },
{ .size = SZ_128M, .flag = PMB_SZ_128M, },
{ .size = SZ_64M, .flag = PMB_SZ_64M, },
{ .size = SZ_16M, .flag = PMB_SZ_16M, },
};
static void pmb_unmap_entry(struct pmb_entry *, int depth);
static DEFINE_RWLOCK(pmb_rwlock);
static struct pmb_entry pmb_entry_list[NR_PMB_ENTRIES];
static DECLARE_BITMAP(pmb_map, NR_PMB_ENTRIES);
static unsigned int pmb_iomapping_enabled;
static __always_inline unsigned long mk_pmb_entry(unsigned int entry)
{
return (entry & PMB_E_MASK) << PMB_E_SHIFT;
}
static __always_inline unsigned long mk_pmb_addr(unsigned int entry)
{
return mk_pmb_entry(entry) | PMB_ADDR;
}
static __always_inline unsigned long mk_pmb_data(unsigned int entry)
{
return mk_pmb_entry(entry) | PMB_DATA;
}
static __always_inline unsigned int pmb_ppn_in_range(unsigned long ppn)
{
return ppn >= __pa(memory_start) && ppn < __pa(memory_end);
}
/*
* Ensure that the PMB entries match our cache configuration.
*
* When we are in 32-bit address extended mode, CCR.CB becomes
* invalid, so care must be taken to manually adjust cacheable
* translations.
*/
static __always_inline unsigned long pmb_cache_flags(void)
{
unsigned long flags = 0;
#if defined(CONFIG_CACHE_OFF)
flags |= PMB_WT | PMB_UB;
#elif defined(CONFIG_CACHE_WRITETHROUGH)
flags |= PMB_C | PMB_WT | PMB_UB;
#elif defined(CONFIG_CACHE_WRITEBACK)
flags |= PMB_C;
#endif
return flags;
}
/*
* Convert typical pgprot value to the PMB equivalent
*/
static inline unsigned long pgprot_to_pmb_flags(pgprot_t prot)
{
unsigned long pmb_flags = 0;
u64 flags = pgprot_val(prot);
if (flags & _PAGE_CACHABLE)
pmb_flags |= PMB_C;
if (flags & _PAGE_WT)
pmb_flags |= PMB_WT | PMB_UB;
return pmb_flags;
}
static inline bool pmb_can_merge(struct pmb_entry *a, struct pmb_entry *b)
{
return (b->vpn == (a->vpn + a->size)) &&
(b->ppn == (a->ppn + a->size)) &&
(b->flags == a->flags);
}
static bool pmb_mapping_exists(unsigned long vaddr, phys_addr_t phys,
unsigned long size)
{
int i;
read_lock(&pmb_rwlock);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
struct pmb_entry *pmbe, *iter;
unsigned long span;
if (!test_bit(i, pmb_map))
continue;
pmbe = &pmb_entry_list[i];
/*
* See if VPN and PPN are bounded by an existing mapping.
*/
if ((vaddr < pmbe->vpn) || (vaddr >= (pmbe->vpn + pmbe->size)))
continue;
if ((phys < pmbe->ppn) || (phys >= (pmbe->ppn + pmbe->size)))
continue;
/*
* Now see if we're in range of a simple mapping.
*/
if (size <= pmbe->size) {
read_unlock(&pmb_rwlock);
return true;
}
span = pmbe->size;
/*
* Finally for sizes that involve compound mappings, walk
* the chain.
*/
for (iter = pmbe->link; iter; iter = iter->link)
span += iter->size;
/*
* Nothing else to do if the range requirements are met.
*/
if (size <= span) {
read_unlock(&pmb_rwlock);
return true