[PATCH v3 2/2] arch/*/io.h: remove ioremap_uc in some architectures

Baoquan He
2023-03-03T10:29:38Z

ioremap_uc() is only meaningful on old x86-32 systems with the PAT
extension, and on ia64 with its slightly unconventional ioremap()
behavior, everywhere else this is the same as ioremap() anyway.

Here, 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.

Note: This changes the existing behaviour and could break code
calling ioremap_uc(). If any ARCH meets this breakage and really
needs a specific ioremap_uc() for its own usage, one ioremap_uc()
can be added in the ARCH.

Link: https://lore.kernel.org/all/20191112105507.GA7122@lst.de/#t
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-hexagon@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org

---
Documentation/driver-api/device-io.rst | 14 +++++++++-----
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, 9 insertions(+), 17 deletions(-)

diff --git a/Documentation/driver-api/device-io.rst b/Documentation/driver-api/device-io.rst
index 4d2baac0311c..12c2ebbaa41e 100644
--- a/Documentation/driver-api/device-io.rst
+++ b/Documentation/driver-api/device-io.rst
@@ -408,11 +408,15 @@ functions for details on the CPU side of things.
ioremap_uc()
------------

-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/x86/pat.rst.
-
-Portable drivers should avoid the use of ioremap_uc().
+ioremap_uc() will be obsoleted since it's only expected on x86 and ia64.
+X86 non-PAT system marks memory as uncached even when the MTRR has designated
+it as cacheable in ioremap_uc()(see Documentation/x86/pat.rst). Ia64 system
+need check if attributes match, otherwise fails. Other than these two
+architectures, ioremap_uc() will default to NULL. Any architectures which
+meets breakage by ioremap_uc() returning NULL should provide a specific
+implementation to override the default version.
+
+Portable drivers should avoid the use of ioremap_uc(), use ioremap() instead.

ioremap_cache()
---------------
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 dcd9cbbf5934..b9847472f25c 100644
--- a/arch/hexagon/include/asm/io.h
+++ b/arch/hexagon/include/asm/io.h
@@ -176,9 +176,6 @@ static inline void writel(u32 data, volatile void __iomem *addr)
#define _PAGE_IOREMAP (_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
(__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 6756baadba6c..da0a625c3c6d 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -167,7 +167,6 @@ 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 978d687edf32..7873fc83c82c 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -863,7 +863,6 @@ void __iomem *ioremap_wt(phys_addr_t address, unsigned long size);
#endif

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 b3a26b405c8d..12a892804082 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -278,8 +278,6 @@ 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)
--
2.34.1