From: Myron Stowe Date: Thu, 21 Oct 2010 20:23:53 +0000 (-0600) Subject: ACPI: Maintain a list of ACPI memory mapped I/O remappings X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=620242a;p=linux-beck.git 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 Signed-off-by: Len Brown --- 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; }