[PATCH v5 3/4] arch/*/io.h: remove ioremap_uc in some architectures

Baoquan He bhe at redhat.com
Thu Sep 21 21:04:23 AEST 2023

ioremap_uc() is only meaningful on old x86-32 systems with the PAT
extension, and on ia64 with its slightly unconventional ioremap()
behavior. So remove the ioremap_uc() definition in architecutures
other than x86 and ia64. These architectures all have asm-generic/io.h
included and will have the default ioremap_uc() definition which
returns NULL.

This changes the existing behaviour, while no need to worry about
any breakage because in the only callsite of ioremap_uc(), code
has been adjusted to eliminate the impact. Please see
atyfb_setup_generic() of drivers/video/fbdev/aty/atyfb_base.c.

If any new invocation of ioremap_uc() need be added, please consider
using ioremap() intead or adding a ARCH specific version if necessary.

Signed-off-by: Baoquan He <bhe at redhat.com>
Acked-by: Geert Uytterhoeven <geert at linux-m68k.org>
Acked-by: Michael Ellerman <mpe at ellerman.id.au> (powerpc)
Acked-by: Helge Deller <deller at gmx.de>  # parisc
Cc: linux-alpha at vger.kernel.org
Cc: linux-hexagon at vger.kernel.org
Cc: linux-m68k at lists.linux-m68k.org
Cc: linux-mips at vger.kernel.org
Cc: linux-parisc at vger.kernel.org
Cc: linuxppc-dev at lists.ozlabs.org
Cc: linux-sh at vger.kernel.org
Cc: sparclinux at vger.kernel.org
 Documentation/driver-api/device-io.rst | 9 +++++----
 arch/alpha/include/asm/io.h            | 1 -
 arch/hexagon/include/asm/io.h          | 3 ---
 arch/m68k/include/asm/kmap.h           | 1 -
 arch/mips/include/asm/io.h             | 1 -
 arch/parisc/include/asm/io.h           | 2 --
 arch/powerpc/include/asm/io.h          | 1 -
 arch/sh/include/asm/io.h               | 2 --
 arch/sparc/include/asm/io_64.h         | 1 -
 9 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/Documentation/driver-api/device-io.rst b/Documentation/driver-api/device-io.rst
index 2c7abd234f4e..d55384b106bd 100644
--- a/Documentation/driver-api/device-io.rst
+++ b/Documentation/driver-api/device-io.rst
@@ -408,11 +408,12 @@ functions for details on the CPU side of things.
-ioremap_uc() behaves like ioremap() except that on the x86 architecture without
-'PAT' mode, it marks memory as uncached even when the MTRR has designated
-it as cacheable, see Documentation/arch/x86/pat.rst.
+ioremap_uc() is only meaningful on old x86-32 systems with the PAT extension,
+and on ia64 with its slightly unconventional ioremap() behavior, everywhere
+elss ioremap_uc() defaults to return NULL.
-Portable drivers should avoid the use of ioremap_uc().
+Portable drivers should avoid the use of ioremap_uc(), use ioremap() instead.
diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
index 7aeaf7c30a6f..076f0e4e7f1e 100644
--- a/arch/alpha/include/asm/io.h
+++ b/arch/alpha/include/asm/io.h
@@ -308,7 +308,6 @@ static inline void __iomem *ioremap(unsigned long port, unsigned long size)
 #define ioremap_wc ioremap
-#define ioremap_uc ioremap
 static inline void iounmap(volatile void __iomem *addr)
diff --git a/arch/hexagon/include/asm/io.h b/arch/hexagon/include/asm/io.h
index e2b308e32a37..b7bc246dbcb1 100644
--- a/arch/hexagon/include/asm/io.h
+++ b/arch/hexagon/include/asm/io.h
@@ -174,9 +174,6 @@ static inline void writel(u32 data, volatile void __iomem *addr)
 		       (__HEXAGON_C_DEV << 6))
-#define ioremap_uc(addr, size) ioremap((addr), (size))
 #define __raw_writel writel
 static inline void memcpy_fromio(void *dst, const volatile void __iomem *src,
diff --git a/arch/m68k/include/asm/kmap.h b/arch/m68k/include/asm/kmap.h
index 4efb3efa593a..b778f015c917 100644
--- a/arch/m68k/include/asm/kmap.h
+++ b/arch/m68k/include/asm/kmap.h
@@ -25,7 +25,6 @@ static inline void __iomem *ioremap(unsigned long physaddr, unsigned long size)
 	return __ioremap(physaddr, size, IOMAP_NOCACHE_SER);
-#define ioremap_uc ioremap
 #define ioremap_wt ioremap_wt
 static inline void __iomem *ioremap_wt(unsigned long physaddr,
 				       unsigned long size)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 41d8bd5adef8..1ecf255efb40 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -170,7 +170,6 @@ void iounmap(const volatile void __iomem *addr);
 #define ioremap(offset, size)						\
 	ioremap_prot((offset), (size), _CACHE_UNCACHED)
-#define ioremap_uc		ioremap
  * ioremap_cache -	map bus memory into CPU space
diff --git a/arch/parisc/include/asm/io.h b/arch/parisc/include/asm/io.h
index 366537042465..48630c78714a 100644
--- a/arch/parisc/include/asm/io.h
+++ b/arch/parisc/include/asm/io.h
@@ -132,8 +132,6 @@ static inline void gsc_writeq(unsigned long long val, unsigned long addr)
 #define ioremap_wc(addr, size)  \
 	ioremap_prot((addr), (size), _PAGE_IOREMAP)
-#define ioremap_uc(addr, size)  \
-	ioremap_prot((addr), (size), _PAGE_IOREMAP)
 #define pci_iounmap			pci_iounmap
diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 0732b743e099..21bd3e8bffce 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -900,7 +900,6 @@ void __iomem *ioremap_wt(phys_addr_t address, unsigned long size);
 void __iomem *ioremap_coherent(phys_addr_t address, unsigned long size);
-#define ioremap_uc(addr, size)		ioremap((addr), (size))
 #define ioremap_cache(addr, size) \
 	ioremap_prot((addr), (size), pgprot_val(PAGE_KERNEL))
diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index f2f38e9d489a..790bea22c9b5 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -302,8 +302,6 @@ unsigned long long poke_real_address_q(unsigned long long addr,
 	ioremap_prot((addr), (size), pgprot_val(PAGE_KERNEL))
 #endif /* CONFIG_MMU */
-#define ioremap_uc	ioremap
  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
  * access
diff --git a/arch/sparc/include/asm/io_64.h b/arch/sparc/include/asm/io_64.h
index 9303270b22f3..d8ee1442f303 100644
--- a/arch/sparc/include/asm/io_64.h
+++ b/arch/sparc/include/asm/io_64.h
@@ -423,7 +423,6 @@ static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
 	return (void __iomem *)offset;
-#define ioremap_uc(X,Y)			ioremap((X),(Y))
 #define ioremap_wc(X,Y)			ioremap((X),(Y))
 #define ioremap_wt(X,Y)			ioremap((X),(Y))
 static inline void __iomem *ioremap_np(unsigned long offset, unsigned long size)

More information about the Linuxppc-dev mailing list