4 files changed, 33 insertions, 1 deletions
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index c6af40ce03be..082e0c96db6e 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -942,7 +942,9 @@ static inline void *phys_to_virt(unsigned long address)
  *
  * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes
  * for specific drivers if the architecture choses to implement them.  If they
- * are not implemented we fall back to plain ioremap.
+ * are not implemented we fall back to plain ioremap. Conversely, ioremap_np()
+ * can provide stricter non-posted write semantics if the architecture
+ * implements them.
  */
 #ifndef CONFIG_MMU
 #ifndef ioremap
@@ -993,6 +995,24 @@ static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size)
 {
 	return NULL;
 }
+
+/*
+ * ioremap_np needs an explicit architecture implementation, as it
+ * requests stronger semantics than regular ioremap(). Portable drivers
+ * should instead use one of the higher-level abstractions, like
+ * devm_ioremap_resource(), to choose the correct variant for any given
+ * device and bus. Portable drivers with a good reason to want non-posted
+ * write semantics should always provide an ioremap() fallback in case
+ * ioremap_np() is not available.
+ */
+#ifndef ioremap_np
+#define ioremap_np ioremap_np
+static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)
+{
+	return NULL;
+}
+#endif
+
 #endif
 
 #ifdef CONFIG_HAS_IOPORT_MAP
diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
index 649224664969..9b3eb6d86200 100644
--- a/include/asm-generic/iomap.h
+++ b/include/asm-generic/iomap.h
@@ -101,6 +101,15 @@ extern void ioport_unmap(void __iomem *);
 #define ioremap_wt ioremap
 #endif
 
+#ifndef ARCH_HAS_IOREMAP_NP
+/* See the comment in asm-generic/io.h about ioremap_np(). */
+#define ioremap_np ioremap_np
+static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)
+{
+	return NULL;
+}
+#endif
+
 #ifdef CONFIG_PCI
 /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */
 struct pci_dev;
diff --git a/include/linux/io.h b/include/linux/io.h
index 8394c56babc2..d718354ed3e1 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -68,6 +68,8 @@ void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset,
 				   resource_size_t size);
 void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,
 				   resource_size_t size);
+void __iomem *devm_ioremap_np(struct device *dev, resource_size_t offset,
+				   resource_size_t size);
 void devm_iounmap(struct device *dev, void __iomem *addr);
 int check_signature(const volatile void __iomem *io_addr,
 			const unsigned char *signature, int length);
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 55de385c839c..1de6c2e40c32 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -108,6 +108,7 @@ struct resource {
 #define IORESOURCE_MEM_32BIT		(3<<3)
 #define IORESOURCE_MEM_SHADOWABLE	(1<<5)	/* dup: IORESOURCE_SHADOWABLE */
 #define IORESOURCE_MEM_EXPANSIONROM	(1<<6)
+#define IORESOURCE_MEM_NONPOSTED	(1<<7)
 
 /* PnP I/O specific bits (IORESOURCE_BITS) */
 #define IORESOURCE_IO_16BIT_ADDR	(1<<0)