From: Christoph Hellwig <hch@lst.de>
To: Arnd Bergmann <arnd@arndb.de>, Guo Ren <guoren@kernel.org>,
Michal Simek <monstr@monstr.eu>,
Greentime Hu <green.hu@gmail.com>,
Vincent Chen <deanbo422@gmail.com>, Guan Xuetao <gxt@pku.edu.cn>,
x86@kernel.org
Cc: linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org,
linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org,
linux-mtd@lists.infradead.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 11/21] asm-generic: don't provide ioremap for CONFIG_MMU
Date: Tue, 29 Oct 2019 07:48:24 +0100 [thread overview]
Message-ID: <20191029064834.23438-12-hch@lst.de> (raw)
In-Reply-To: <20191029064834.23438-1-hch@lst.de>
All MMU-enabled ports have a non-trivial ioremap and should thus provide
the prototype for their implementation instead of providing a generic
one unless a different symbol is not defined. Note that this only
affects sparc32 nds32 as all others do provide their own version.
Also update the kerneldoc comments in asm-generic/io.h to explain the
situation around the default ioremap* implementations correctly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/nds32/include/asm/io.h | 2 ++
arch/sparc/include/asm/io_32.h | 1 +
include/asm-generic/io.h | 29 ++++++++---------------------
3 files changed, 11 insertions(+), 21 deletions(-)
diff --git a/arch/nds32/include/asm/io.h b/arch/nds32/include/asm/io.h
index 16f262322b8f..fb0e8a24c7af 100644
--- a/arch/nds32/include/asm/io.h
+++ b/arch/nds32/include/asm/io.h
@@ -6,6 +6,7 @@
#include <linux/types.h>
+void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
extern void iounmap(volatile void __iomem *addr);
#define __raw_writeb __raw_writeb
static inline void __raw_writeb(u8 val, volatile void __iomem *addr)
@@ -80,4 +81,5 @@ static inline u32 __raw_readl(const volatile void __iomem *addr)
#define writew(v,c) ({ __iowmb(); writew_relaxed((v),(c)); })
#define writel(v,c) ({ __iowmb(); writel_relaxed((v),(c)); })
#include <asm-generic/io.h>
+
#endif /* __ASM_NDS32_IO_H */
diff --git a/arch/sparc/include/asm/io_32.h b/arch/sparc/include/asm/io_32.h
index df2dc1784673..9a52d9506f80 100644
--- a/arch/sparc/include/asm/io_32.h
+++ b/arch/sparc/include/asm/io_32.h
@@ -127,6 +127,7 @@ static inline void sbus_memcpy_toio(volatile void __iomem *dst,
* Bus number may be embedded in the higher bits of the physical address.
* This is why we have no bus number argument to ioremap().
*/
+void __iomem *ioremap(phys_addr_t offset, size_t size);
void iounmap(volatile void __iomem *addr);
/* Create a virtual mapping cookie for an IO port range */
void __iomem *ioport_map(unsigned long port, unsigned int nr);
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index a98ed6325727..6a5edc23afe2 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -922,28 +922,16 @@ static inline void *phys_to_virt(unsigned long address)
/**
* DOC: ioremap() and ioremap_*() variants
*
- * If you have an IOMMU your architecture is expected to have both ioremap()
- * and iounmap() implemented otherwise the asm-generic helpers will provide a
- * direct mapping.
+ * 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.
*
- * There are ioremap_*() call variants, if you have no IOMMU we naturally will
- * default to direct mapping for all of them, you can override these defaults.
- * If you have an IOMMU you are highly encouraged to provide your own
- * ioremap variant implementation as there currently is no safe architecture
- * agnostic default. To avoid possible improper behaviour default asm-generic
- * ioremap_*() variants all return NULL when an IOMMU is available. If you've
- * defined your own ioremap_*() variant you must then declare your own
- * ioremap_*() variant as defined to itself to avoid the default NULL return.
+ * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes
+ * for specific drivers if the architecture choses to implement them. If they
+ * are not implemented we fall back to plain ioremap.
*/
#ifndef CONFIG_MMU
-
-/*
- * Change "struct page" to physical address.
- *
- * This implementation is for the no-MMU case only... if you have an MMU
- * you'll need to provide your own definitions.
- */
-
#ifndef ioremap
#define ioremap ioremap
static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
@@ -954,14 +942,13 @@ static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
#ifndef iounmap
#define iounmap iounmap
-
static inline void iounmap(void __iomem *addr)
{
}
#endif
#endif /* CONFIG_MMU */
+
#ifndef ioremap_nocache
-void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
#define ioremap_nocache ioremap_nocache
static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size)
{
--
2.20.1
next prev parent reply other threads:[~2019-10-29 6:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 6:48 generic ioremap (and lots of cleanups) v3 Christoph Hellwig
2019-10-29 6:48 ` [PATCH 01/21] arm: remove ioremap_cached Christoph Hellwig
2019-11-11 10:33 ` Arnd Bergmann
2019-10-29 6:48 ` [PATCH 02/21] unicore32: " Christoph Hellwig
2019-10-29 6:48 ` [PATCH 03/21] ia64: rename ioremap_nocache to ioremap_uc Christoph Hellwig
2019-11-11 10:36 ` Arnd Bergmann
2019-10-29 6:48 ` [PATCH 04/21] hexagon: clean up ioremap Christoph Hellwig
2019-10-29 6:48 ` [PATCH 05/21] alpha: remove the unused __ioremap wrapper Christoph Hellwig
2019-10-29 6:48 ` [PATCH 06/21] nios2: remove __ioremap Christoph Hellwig
2019-10-29 6:48 ` [PATCH 07/21] parisc: " Christoph Hellwig
2019-11-05 14:29 ` Helge Deller
2019-10-29 6:48 ` [PATCH 08/21] x86: Clean up ioremap() Christoph Hellwig
2019-10-30 10:39 ` Thomas Gleixner
2019-10-29 6:48 ` [PATCH 09/21] xtensa: clean up ioremap Christoph Hellwig
2019-10-29 6:48 ` [PATCH 10/21] asm-generic: ioremap_uc should behave the same with and without MMU Christoph Hellwig
2019-11-06 17:56 ` Palmer Dabbelt
2019-11-11 10:09 ` Arnd Bergmann
2019-11-11 10:15 ` Christoph Hellwig
2019-11-11 10:27 ` Arnd Bergmann
2019-11-11 10:29 ` Christoph Hellwig
2019-11-11 19:33 ` Arnd Bergmann
2019-10-29 6:48 ` Christoph Hellwig [this message]
2019-11-06 18:11 ` [PATCH 11/21] asm-generic: don't provide ioremap for CONFIG_MMU Palmer Dabbelt
2019-11-06 18:16 ` Geert Uytterhoeven
2019-11-06 18:28 ` Christoph Hellwig
2019-11-11 10:31 ` Arnd Bergmann
2019-11-11 10:29 ` Arnd Bergmann
2019-10-29 6:48 ` [PATCH 12/21] arch: rely on asm-generic/io.h for default ioremap_* definitions Christoph Hellwig
2019-11-07 15:29 ` Palmer Dabbelt
2019-11-11 10:10 ` Arnd Bergmann
2019-10-29 6:48 ` [PATCH 13/21] m68k: rename __iounmap and mark it static Christoph Hellwig
2019-10-30 8:51 ` Geert Uytterhoeven
2019-10-29 6:48 ` [PATCH 14/21] hexagon: remove __iounmap Christoph Hellwig
2019-10-29 6:48 ` [PATCH 15/21] nios2: " Christoph Hellwig
2019-10-29 6:48 ` [PATCH 16/21] sh: " Christoph Hellwig
2019-10-29 6:48 ` [PATCH 17/21] lib: provide a simple generic ioremap implementation Christoph Hellwig
2019-11-07 15:29 ` Palmer Dabbelt
2019-11-11 10:10 ` Arnd Bergmann
2019-10-29 6:48 ` [PATCH 18/21] riscv: use the generic ioremap code Christoph Hellwig
2019-10-29 6:48 ` [PATCH 19/21] nds32: use generic ioremap Christoph Hellwig
2019-11-12 8:51 ` Greentime Hu
2019-10-29 6:48 ` [PATCH 20/21] csky: remove ioremap_cache Christoph Hellwig
2019-10-29 6:48 ` [PATCH 21/21] csky: use generic ioremap Christoph Hellwig
2019-11-05 1:31 ` generic ioremap (and lots of cleanups) v3 Christoph Hellwig
2019-11-07 20:47 ` generic-iomap tree for linux-next Christoph Hellwig
2019-11-08 2:20 ` Stephen Rothwell
2019-11-08 4:52 ` Stephen Rothwell
2019-11-08 5:14 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2019-10-17 17:45 generic ioremap (and lots of cleanups) v2 Christoph Hellwig
2019-10-17 17:45 ` [PATCH 11/21] asm-generic: don't provide ioremap for CONFIG_MMU Christoph Hellwig
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