From 026246f114d925b2ab97a60e8b4a5506bd035e9c Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 21 Sep 2023 19:04:23 +0800 Subject: arch/*/io.h: remove ioremap_uc in some architectures 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 Acked-by: Geert Uytterhoeven Acked-by: Michael Ellerman (powerpc) Acked-by: Helge Deller # parisc Acked-by: Arnd Bergmann Acked-by: Thomas Bogendoerfer Acked-by: John Paul Adrian Glaubitz (SuperH) 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 Signed-off-by: Arnd Bergmann --- Documentation/driver-api/device-io.rst | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'Documentation/driver-api') 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() ------------ -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. ioremap_cache() --------------- -- cgit v1.2.3