diff options
author | Myron Stowe <myron.stowe@hp.com> | 2010-10-22 00:23:53 +0400 |
---|---|---|
committer | Len Brown <len.brown@intel.com> | 2010-10-25 07:25:52 +0400 |
commit | 620242ae8c3d9c0b1a77451744fb2d855d1e7342 (patch) | |
tree | 33271319c7628aa51998fadf5df0f492c36abb4f /drivers/acpi/osl.c | |
parent | b3ba1efec2a58f4dc0647f4c0099c27d6ab92595 (diff) | |
download | linux-620242ae8c3d9c0b1a77451744fb2d855d1e7342.tar.xz |
ACPI: Maintain a list of ACPI memory mapped I/O remappings
For memory mapped I/O (MMIO) remappings, add a list to maintain the
remappings and augment the corresponding mapping and unmapping interface
routines (acpi_os_map_memory() and acpi_os_unmap_memory()) to
dynamically add to, and delete from, the list.
The current ACPI I/O accessing methods - acpi_read() and acpi_write() -
end up calling ioremap() when accessing MMIO. This prevents use of these
methods within interrupt context (IRQ and/or NMI), since ioremap() may
block to allocate memory. Maintaining a list of MMIO remappings enables
accesses to such areas from within interrupt context provided they have
been pre-mapped.
Signed-off-by: Myron Stowe <myron.stowe@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/osl.c')
-rw-r--r-- | drivers/acpi/osl.c | 128 |
1 files changed, 113 insertions, 15 deletions
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 58842fb9fd90..bd72129e35f2 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -95,6 +95,20 @@ struct acpi_res_list { static LIST_HEAD(resource_list_head); static DEFINE_SPINLOCK(acpi_res_lock); +/* + * This list of permanent mappings is for memory that may be accessed from + * interrupt context, where we can't do the ioremap(). + */ +struct acpi_ioremap { + struct list_head list; + void __iomem *virt; + acpi_physical_address phys; + acpi_size size; +}; + +static LIST_HEAD(acpi_ioremaps); +static DEFINE_SPINLOCK(acpi_ioremap_lock); + #define OSI_STRING_LENGTH_MAX 64 /* arbitrary */ static char osi_additional_string[OSI_STRING_LENGTH_MAX]; @@ -260,29 +274,95 @@ acpi_physical_address __init acpi_os_get_root_pointer(void) } } +/* Must be called with 'acpi_ioremap_lock' lock held. */ +static void __iomem * +acpi_map_vaddr_lookup(acpi_physical_address phys, acpi_size size) +{ + struct acpi_ioremap *map; + + list_for_each_entry(map, &acpi_ioremaps, list) + if (map->phys <= phys && + phys + size <= map->phys + map->size) + return map->virt + (phys - map->phys); + + return NULL; +} + +/* Must be called with 'acpi_ioremap_lock' lock held. */ +static struct acpi_ioremap * +acpi_map_lookup_virt(void __iomem *virt, acpi_size size) +{ + struct acpi_ioremap *map; + + list_for_each_entry(map, &acpi_ioremaps, list) + if (map->virt == virt && map->size == size) + return map; + + return NULL; +} + void __iomem *__init_refok acpi_os_map_memory(acpi_physical_address phys, acpi_size size) { + struct acpi_ioremap *map; + unsigned long flags; + void __iomem *virt; + if (phys > ULONG_MAX) { printk(KERN_ERR PREFIX "Cannot map memory that high\n"); return NULL; } - if (acpi_gbl_permanent_mmap) - /* - * ioremap checks to ensure this is in reserved space - */ - return ioremap((unsigned long)phys, size); - else + + if (!acpi_gbl_permanent_mmap) return __acpi_map_table((unsigned long)phys, size); + + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (!map) + return NULL; + + virt = ioremap(phys, size); + if (!virt) { + kfree(map); + return NULL; + } + + INIT_LIST_HEAD(&map->list); + map->virt = virt; + map->phys = phys; + map->size = size; + + spin_lock_irqsave(&acpi_ioremap_lock, flags); + list_add_tail(&map->list, &acpi_ioremaps); + spin_unlock_irqrestore(&acpi_ioremap_lock, flags); + + return virt; } EXPORT_SYMBOL_GPL(acpi_os_map_memory); void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size) { - if (acpi_gbl_permanent_mmap) - iounmap(virt); - else + struct acpi_ioremap *map; + unsigned long flags; + + if (!acpi_gbl_permanent_mmap) { __acpi_unmap_table(virt, size); + return; + } + + spin_lock_irqsave(&acpi_ioremap_lock, flags); + map = acpi_map_lookup_virt(virt, size); + if (!map) { + spin_unlock_irqrestore(&acpi_ioremap_lock, flags); + printk(KERN_ERR PREFIX "%s: bad address %p\n", __func__, virt); + dump_stack(); + return; + } + + list_del(&map->list); + spin_unlock_irqrestore(&acpi_ioremap_lock, flags); + + iounmap(map->virt); + kfree(map); } EXPORT_SYMBOL_GPL(acpi_os_unmap_memory); @@ -495,8 +575,16 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width) { u32 dummy; void __iomem *virt_addr; - - virt_addr = ioremap(phys_addr, width / 8); + int size = width / 8, unmap = 0; + unsigned long flags; + + spin_lock_irqsave(&acpi_ioremap_lock, flags); + virt_addr = acpi_map_vaddr_lookup(phys_addr, size); + spin_unlock_irqrestore(&acpi_ioremap_lock, flags); + if (!virt_addr) { + virt_addr = ioremap(phys_addr, size); + unmap = 1; + } if (!value) value = &dummy; @@ -514,7 +602,8 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width) BUG(); } - iounmap(virt_addr); + if (unmap) + iounmap(virt_addr); return AE_OK; } @@ -523,8 +612,16 @@ acpi_status acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width) { void __iomem *virt_addr; - - virt_addr = ioremap(phys_addr, width / 8); + int size = width / 8, unmap = 0; + unsigned long flags; + + spin_lock_irqsave(&acpi_ioremap_lock, flags); + virt_addr = acpi_map_vaddr_lookup(phys_addr, size); + spin_unlock_irqrestore(&acpi_ioremap_lock, flags); + if (!virt_addr) { + virt_addr = ioremap(phys_addr, size); + unmap = 1; + } switch (width) { case 8: @@ -540,7 +637,8 @@ acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width) BUG(); } - iounmap(virt_addr); + if (unmap) + iounmap(virt_addr); return AE_OK; } |