Commit 620242ae authored by Myron Stowe's avatar Myron Stowe Committed by Len Brown

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: default avatarMyron Stowe <myron.stowe@hp.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent b3ba1efe
......@@ -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;
......@@ -514,6 +602,7 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width)
BUG();
}
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:
......@@ -540,6 +637,7 @@ acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
BUG();
}
if (unmap)
iounmap(virt_addr);
return AE_OK;
......
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