lib: provide a simple generic ioremap implementation

A lot of architectures reuse the same simple ioremap implementation, so
start lifting the most simple variant to lib/ioremap.c.  It provides
ioremap_prot and iounmap, plus a default ioremap that uses prot_noncached,
although that can be overridden by asm/io.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Palmer Dabbelt <palmer@dabbelt.com>

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index bd676f21b5bd6569ba44364388afc72a5ccb59a4..325fc98cc9ff75109702c8e9bcf8f26fb82fa5c5 100644 (file)
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -923,9 +923,10 @@ static inline void *phys_to_virt(unsigned long address)
  * DOC: ioremap() and ioremap_*() variants
  *
  * Architectures with an MMU are expected to provide ioremap() and iounmap()
- * themselves.  For NOMMU architectures we provide a default nop-op
- * implementation that expect that the physical address used for MMIO are
- * already marked as uncached, and can be used as kernel virtual addresses.
+ * themselves or rely on GENERIC_IOREMAP.  For NOMMU architectures we provide
+ * a default nop-op implementation that expect that the physical address used
+ * for MMIO are already marked as uncached, and can be used as kernel virtual
+ * addresses.
  *
  * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes
  * for specific drivers if the architecture choses to implement them.  If they
@@ -946,7 +947,18 @@ static inline void iounmap(void __iomem *addr)
 {
 }
 #endif
-#endif /* CONFIG_MMU */
+#elif defined(CONFIG_GENERIC_IOREMAP)
+#include <asm/pgtable.h>
+
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot);
+void iounmap(volatile void __iomem *addr);
+
+static inline void __iomem *ioremap(phys_addr_t addr, size_t size)
+{
+       /* _PAGE_IOREMAP needs to be supplied by the architecture */
+       return ioremap_prot(addr, size, _PAGE_IOREMAP);
+}
+#endif /* !CONFIG_MMU || CONFIG_GENERIC_IOREMAP */
 
 #ifndef ioremap_nocache
 #define ioremap_nocache ioremap

diff --git a/lib/Kconfig b/lib/Kconfig
index 3321d04dfa5a5a703909d1f201ffecf75a7767fa..cb571767d080c733eaeea95096b525f900b26e47 100644 (file)
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -637,6 +637,9 @@ config STRING_SELFTEST
 
 endmenu
 
+config GENERIC_IOREMAP
+       bool
+
 config GENERIC_LIB_ASHLDI3
        bool
 

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 0a2ffadc6d71e4f0444f63cd6f6900ad10ff02da..3f0e18543de84f9b94d64a8a6d79ef5e35ea8d7a 100644 (file)
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -231,3 +231,42 @@ int ioremap_page_range(unsigned long addr,
 
        return err;
 }
+
+#ifdef CONFIG_GENERIC_IOREMAP
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
+{
+       unsigned long offset, vaddr;
+       phys_addr_t last_addr;
+       struct vm_struct *area;
+
+       /* Disallow wrap-around or zero size */
+       last_addr = addr + size - 1;
+       if (!size || last_addr < addr)
+               return NULL;
+
+       /* Page-align mappings */
+       offset = addr & (~PAGE_MASK);
+       addr -= offset;
+       size = PAGE_ALIGN(size + offset);
+
+       area = get_vm_area_caller(size, VM_IOREMAP,
+                       __builtin_return_address(0));
+       if (!area)
+               return NULL;
+       vaddr = (unsigned long)area->addr;
+
+       if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
+               free_vm_area(area);
+               return NULL;
+       }
+
+       return (void __iomem *)(vaddr + offset);
+}
+EXPORT_SYMBOL(ioremap_prot);
+
+void iounmap(volatile void __iomem *addr)
+{
+       vunmap((void *)((unsigned long)addr & PAGE_MASK));
+}
+EXPORT_SYMBOL(iounmap);
+#endif /* CONFIG_GENERIC_IOREMAP */