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>
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@ -95,6 +95,20 @@ struct acpi_res_list {
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static LIST_HEAD(resource_list_head);
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static DEFINE_SPINLOCK(acpi_res_lock);
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/*
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* This list of permanent mappings is for memory that may be accessed from
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* interrupt context, where we can't do the ioremap().
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*/
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struct acpi_ioremap {
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struct list_head list;
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void __iomem *virt;
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acpi_physical_address phys;
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acpi_size size;
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};
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static LIST_HEAD(acpi_ioremaps);
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static DEFINE_SPINLOCK(acpi_ioremap_lock);
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#define OSI_STRING_LENGTH_MAX 64 /* arbitrary */
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static char osi_additional_string[OSI_STRING_LENGTH_MAX];
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@ -260,29 +274,95 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
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}
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}
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/* Must be called with 'acpi_ioremap_lock' lock held. */
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static void __iomem *
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acpi_map_vaddr_lookup(acpi_physical_address phys, acpi_size size)
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{
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struct acpi_ioremap *map;
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list_for_each_entry(map, &acpi_ioremaps, list)
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if (map->phys <= phys &&
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phys + size <= map->phys + map->size)
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return map->virt + (phys - map->phys);
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return NULL;
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}
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/* Must be called with 'acpi_ioremap_lock' lock held. */
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static struct acpi_ioremap *
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acpi_map_lookup_virt(void __iomem *virt, acpi_size size)
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{
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struct acpi_ioremap *map;
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list_for_each_entry(map, &acpi_ioremaps, list)
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if (map->virt == virt && map->size == size)
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return map;
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return NULL;
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}
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void __iomem *__init_refok
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acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
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{
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struct acpi_ioremap *map;
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unsigned long flags;
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void __iomem *virt;
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if (phys > ULONG_MAX) {
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printk(KERN_ERR PREFIX "Cannot map memory that high\n");
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return NULL;
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}
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if (acpi_gbl_permanent_mmap)
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/*
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* ioremap checks to ensure this is in reserved space
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*/
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return ioremap((unsigned long)phys, size);
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else
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if (!acpi_gbl_permanent_mmap)
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return __acpi_map_table((unsigned long)phys, size);
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map = kzalloc(sizeof(*map), GFP_KERNEL);
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if (!map)
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return NULL;
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virt = ioremap(phys, size);
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if (!virt) {
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kfree(map);
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return NULL;
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}
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INIT_LIST_HEAD(&map->list);
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map->virt = virt;
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map->phys = phys;
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map->size = size;
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spin_lock_irqsave(&acpi_ioremap_lock, flags);
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list_add_tail(&map->list, &acpi_ioremaps);
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spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
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return virt;
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}
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EXPORT_SYMBOL_GPL(acpi_os_map_memory);
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void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
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{
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if (acpi_gbl_permanent_mmap)
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iounmap(virt);
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else
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struct acpi_ioremap *map;
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unsigned long flags;
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if (!acpi_gbl_permanent_mmap) {
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__acpi_unmap_table(virt, size);
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return;
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}
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spin_lock_irqsave(&acpi_ioremap_lock, flags);
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map = acpi_map_lookup_virt(virt, size);
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if (!map) {
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spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
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printk(KERN_ERR PREFIX "%s: bad address %p\n", __func__, virt);
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dump_stack();
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return;
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}
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list_del(&map->list);
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spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
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iounmap(map->virt);
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kfree(map);
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}
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EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
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@ -495,8 +575,16 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width)
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{
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u32 dummy;
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void __iomem *virt_addr;
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int size = width / 8, unmap = 0;
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unsigned long flags;
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virt_addr = ioremap(phys_addr, width / 8);
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spin_lock_irqsave(&acpi_ioremap_lock, flags);
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virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
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spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
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if (!virt_addr) {
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virt_addr = ioremap(phys_addr, size);
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unmap = 1;
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}
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if (!value)
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value = &dummy;
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@ -514,6 +602,7 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width)
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BUG();
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}
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if (unmap)
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iounmap(virt_addr);
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return AE_OK;
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@ -523,8 +612,16 @@ acpi_status
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acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
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{
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void __iomem *virt_addr;
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int size = width / 8, unmap = 0;
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unsigned long flags;
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virt_addr = ioremap(phys_addr, width / 8);
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spin_lock_irqsave(&acpi_ioremap_lock, flags);
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virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
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spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
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if (!virt_addr) {
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virt_addr = ioremap(phys_addr, size);
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unmap = 1;
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}
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switch (width) {
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case 8:
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@ -540,6 +637,7 @@ acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
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BUG();
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}
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if (unmap)
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iounmap(virt_addr);
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return AE_OK;
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