1 files changed, 26 insertions, 16 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index db78d353bab1..3bb46cb24a99 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -663,6 +663,29 @@ acpi_status acpi_os_write_port(acpi_io_address port, u32 value, u32 width)
 
 EXPORT_SYMBOL(acpi_os_write_port);
 
+int acpi_os_read_iomem(void __iomem *virt_addr, u64 *value, u32 width)
+{
+
+        switch (width) {
+        case 8:
+                *(u8 *) value = readb(virt_addr);
+                break;
+        case 16:
+                *(u16 *) value = readw(virt_addr);
+                break;
+        case 32:
+                *(u32 *) value = readl(virt_addr);
+                break;
+        case 64:
+                *(u64 *) value = readq(virt_addr);
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
 acpi_status
 acpi_os_read_memory(acpi_physical_address phys_addr, u64 *value, u32 width)
 {
@@ -670,6 +693,7 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u64 *value, u32 width)
         unsigned int size = width / 8;
         bool unmap = false;
         u64 dummy;
+        int error;
 
         rcu_read_lock();
         virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
@@ -684,22 +708,8 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u64 *value, u32 width)
         if (!value)
                 value = &dummy;
 
-        switch (width) {
-        case 8:
-                *(u8 *) value = readb(virt_addr);
-                break;
-        case 16:
-                *(u16 *) value = readw(virt_addr);
-                break;
-        case 32:
-                *(u32 *) value = readl(virt_addr);
-                break;
-        case 64:
-                *(u64 *) value = readq(virt_addr);
-                break;
-        default:
-                BUG();
-        }
+        error = acpi_os_read_iomem(virt_addr, value, width);
+        BUG_ON(error);
 
         if (unmap)
                 iounmap(virt_addr);