iomap: constify ioreadX() iomem argument (as in generic implementation)

Patch series "iomap: Constify ioreadX() iomem argument", v3.

The ioread8/16/32() and others have inconsistent interface among the
architectures: some taking address as const, some not.

It seems there is nothing really stopping all of them to take pointer to
const.

This patch (of 4):

The ioreadX() and ioreadX_rep() helpers have inconsistent interface.  On
some architectures void *__iomem address argument is a pointer to const,
on some not.

Implementations of ioreadX() do not modify the memory under the address so
they can be converted to a "const" version for const-safety and
consistency among architectures.

[krzk@kernel.org: sh: clk: fix assignment from incompatible pointer type for ioreadX()]
  Link: http://lkml.kernel.org/r/20200723082017.24053-1-krzk@kernel.org
[akpm@linux-foundation.org: fix drivers/mailbox/bcm-pdc-mailbox.c]
  Link: http://lkml.kernel.org/r/202007132209.Rxmv4QyS%25lkp@intel.com

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Allen Hubbe <allenbh@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/20200709072837.5869-1-krzk@kernel.org
Link: http://lkml.kernel.org/r/20200709072837.5869-2-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
index 640e1a2f57b4..1f6a909d1fa5 100644
--- a/arch/alpha/include/asm/io.h
+++ b/arch/alpha/include/asm/io.h
@@ -150,9 +150,9 @@ static inline void generic_##NAME(TYPE b, QUAL void __iomem *addr)	\
 	alpha_mv.mv_##NAME(b, addr);					\
 }
 
-REMAP1(unsigned int, ioread8, /**/)
-REMAP1(unsigned int, ioread16, /**/)
-REMAP1(unsigned int, ioread32, /**/)
+REMAP1(unsigned int, ioread8, const)
+REMAP1(unsigned int, ioread16, const)
+REMAP1(unsigned int, ioread32, const)
 REMAP1(u8, readb, const volatile)
 REMAP1(u16, readw, const volatile)
 REMAP1(u32, readl, const volatile)
@@ -307,7 +307,7 @@ static inline int __is_mmio(const volatile void __iomem *addr)
  */
 
 #if IO_CONCAT(__IO_PREFIX,trivial_io_bw)
-extern inline unsigned int ioread8(void __iomem *addr)
+extern inline unsigned int ioread8(const void __iomem *addr)
 {
 	unsigned int ret;
 	mb();
@@ -316,7 +316,7 @@ extern inline unsigned int ioread8(void __iomem *addr)
 	return ret;
 }
 
-extern inline unsigned int ioread16(void __iomem *addr)
+extern inline unsigned int ioread16(const void __iomem *addr)
 {
 	unsigned int ret;
 	mb();
@@ -359,7 +359,7 @@ extern inline void outw(u16 b, unsigned long port)
 #endif
 
 #if IO_CONCAT(__IO_PREFIX,trivial_io_lq)
-extern inline unsigned int ioread32(void __iomem *addr)
+extern inline unsigned int ioread32(const void __iomem *addr)
 {
 	unsigned int ret;
 	mb();