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author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-09-16 01:14:23 -0400 |
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committer | Nicolas Pitre <nico@fluxnic.net> | 2011-11-26 19:21:28 -0500 |
commit | 576d2f2525612ecb5af029a76f21f22a3b82563d (patch) | |
tree | 81f9564c432ceeb4068dd3a5de204134a32c98f3 /arch/arm/mm/ioremap.c | |
parent | 6ee723a6570a897208b76ab3e9a495e9106b2f8c (diff) | |
download | linux-stable-576d2f2525612ecb5af029a76f21f22a3b82563d.tar.gz linux-stable-576d2f2525612ecb5af029a76f21f22a3b82563d.tar.bz2 linux-stable-576d2f2525612ecb5af029a76f21f22a3b82563d.zip |
ARM: add generic ioremap optimization by reusing static mappings
Now that we have all the static mappings from iotable_init() located
in the vmalloc area, it is trivial to optimize ioremap by reusing those
static mappings when the requested physical area fits in one of them,
and so in a generic way for all platforms.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Tested-by: Jamie Iles <jamie@jamieiles.com>
Diffstat (limited to 'arch/arm/mm/ioremap.c')
-rw-r--r-- | arch/arm/mm/ioremap.c | 72 |
1 files changed, 48 insertions, 24 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index bc7d9bd766d1..12c7ad215ce7 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -36,12 +36,6 @@ #include <asm/mach/map.h> #include "mm.h" -/* - * Used by ioremap() and iounmap() code to mark (super)section-mapped - * I/O regions in vm_struct->flags field. - */ -#define VM_ARM_SECTION_MAPPING 0x80000000 - int ioremap_page(unsigned long virt, unsigned long phys, const struct mem_type *mtype) { @@ -201,12 +195,6 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) return NULL; - /* - * Don't allow RAM to be mapped - this causes problems with ARMv6+ - */ - if (WARN_ON(pfn_valid(pfn))) - return NULL; - type = get_mem_type(mtype); if (!type) return NULL; @@ -216,6 +204,34 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, */ size = PAGE_ALIGN(offset + size); + /* + * Try to reuse one of the static mapping whenever possible. + */ + read_lock(&vmlist_lock); + for (area = vmlist; area; area = area->next) { + if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) + break; + if (!(area->flags & VM_ARM_STATIC_MAPPING)) + continue; + if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) + continue; + if (__phys_to_pfn(area->phys_addr) > pfn || + __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1) + continue; + /* we can drop the lock here as we know *area is static */ + read_unlock(&vmlist_lock); + addr = (unsigned long)area->addr; + addr += __pfn_to_phys(pfn) - area->phys_addr; + return (void __iomem *) (offset + addr); + } + read_unlock(&vmlist_lock); + + /* + * Don't allow RAM to be mapped - this causes problems with ARMv6+ + */ + if (WARN_ON(pfn_valid(pfn))) + return NULL; + area = get_vm_area_caller(size, VM_IOREMAP, caller); if (!area) return NULL; @@ -313,26 +329,34 @@ __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached) void __iounmap(volatile void __iomem *io_addr) { void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); -#ifndef CONFIG_SMP struct vm_struct *vm; - /* - * If this is a section based mapping we need to handle it - * specially as the VM subsystem does not know how to handle - * such a beast. - */ read_lock(&vmlist_lock); for (vm = vmlist; vm; vm = vm->next) { - if ((vm->flags & VM_IOREMAP) && (vm->addr == addr)) { - if (vm->flags & VM_ARM_SECTION_MAPPING) { - unmap_area_sections((unsigned long)vm->addr, - vm->size); - } + if (vm->addr > addr) break; + if (!(vm->flags & VM_IOREMAP)) + continue; + /* If this is a static mapping we must leave it alone */ + if ((vm->flags & VM_ARM_STATIC_MAPPING) && + (vm->addr <= addr) && (vm->addr + vm->size > addr)) { + read_unlock(&vmlist_lock); + return; } +#ifndef CONFIG_SMP + /* + * If this is a section based mapping we need to handle it + * specially as the VM subsystem does not know how to handle + * such a beast. + */ + if ((vm->addr == addr) && + (vm->flags & VM_ARM_SECTION_MAPPING)) { + unmap_area_sections((unsigned long)vm->addr, vm->size); + break; + } +#endif } read_unlock(&vmlist_lock); -#endif vunmap(addr); } |