linux-snps-arc.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: hch@lst.de (Christoph Hellwig)
To: linux-snps-arc@lists.infradead.org
Subject: [PATCH 16/26] asm-generic: don't provide ioremap for CONFIG_MMU
Date: Sat, 17 Aug 2019 09:32:43 +0200	[thread overview]
Message-ID: <20190817073253.27819-17-hch@lst.de> (raw)
In-Reply-To: <20190817073253.27819-1-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 at 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

  parent reply	other threads:[~2019-08-17  7:32 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-17  7:32 generic ioremap (and lots of cleanups) Christoph Hellwig
2019-08-17  7:32 ` [PATCH 01/26] mtd/maps/pxa2xx: use ioremap_cache insted of ioremap_cached Christoph Hellwig
2019-08-17  7:32 ` [PATCH 02/26] arm, unicore32: remove ioremap_cached Christoph Hellwig
2019-08-17  7:32 ` [PATCH 03/26] m68k, microblaze: remove ioremap_fullcache Christoph Hellwig
2019-08-19  8:50   ` Geert Uytterhoeven
2019-09-02 14:16   ` Michal Simek
2019-08-17  7:32 ` [PATCH 04/26] mips: remove ioremap_cachable Christoph Hellwig
2019-08-19 20:57   ` Paul Burton
2019-08-30 16:06     ` Christoph Hellwig
2019-09-03  8:57   ` Paul Burton
2019-08-17  7:32 ` [PATCH 05/26] openrisc: map as uncached in ioremap Christoph Hellwig
2019-08-23 13:55   ` Stafford Horne
2019-08-30 16:07     ` Christoph Hellwig
2019-08-30 21:45       ` Stafford Horne
2019-08-17  7:32 ` [PATCH 06/26] ia64: rename ioremap_nocache to ioremap_uc Christoph Hellwig
2019-08-17 16:00   ` Sergei Shtylyov
2019-08-17  7:32 ` [PATCH 07/26] hexagon: clean up ioremap Christoph Hellwig
2019-08-17  7:32 ` [PATCH 08/26] m68k: simplify ioremap_nocache Christoph Hellwig
2019-08-19  8:56   ` Geert Uytterhoeven
2019-08-19  9:18     ` Christoph Hellwig
2019-08-30 16:06     ` Christoph Hellwig
2019-09-02  7:53       ` Geert Uytterhoeven
2019-08-17  7:32 ` [PATCH 09/26] alpha: remove the unused __ioremap wrapper Christoph Hellwig
2019-08-17  7:32 ` [PATCH 10/26] nios2: remove __ioremap Christoph Hellwig
2019-08-17  7:32 ` [PATCH 11/26] parisc: " Christoph Hellwig
2019-08-17  7:32 ` [PATCH 12/26] x86: clean up ioremap Christoph Hellwig
2019-08-17 10:34   ` Ingo Molnar
2019-08-30 16:04     ` Christoph Hellwig
2019-08-17  7:32 ` [PATCH 13/26] xtensa: " Christoph Hellwig
2019-08-17  7:32 ` [PATCH 14/26] asm-generic: don't provide __ioremap Christoph Hellwig
2019-08-17 20:58   ` Paul Walmsley
2019-08-17 21:27     ` Paul Walmsley
2019-08-17  7:32 ` [PATCH 15/26] asm-generic: ioremap_uc should behave the same with and without MMU Christoph Hellwig
2019-08-17 21:07   ` Paul Walmsley
2019-08-17  7:32 ` Christoph Hellwig [this message]
2019-08-17 21:15   ` [PATCH 16/26] asm-generic: don't provide ioremap for CONFIG_MMU Paul Walmsley
2019-08-17  7:32 ` [PATCH 17/26] arch: rely on asm-generic/io.h for default ioremap_* definitions Christoph Hellwig
2019-08-17 21:13   ` Paul Walmsley
2019-08-17  7:32 ` [PATCH 18/26] m68k: rename __iounmap and mark it static Christoph Hellwig
2019-08-19  9:00   ` Geert Uytterhoeven
2019-08-17  7:32 ` [PATCH 19/26] arm64: remove __iounmap Christoph Hellwig
2019-08-19  7:36   ` Will Deacon
2019-08-30 16:05     ` Christoph Hellwig
2019-08-31 16:29       ` Will Deacon
2019-08-17  7:32 ` [PATCH 20/26] hexagon: " Christoph Hellwig
2019-08-17  7:32 ` [PATCH 21/26] nios2: " Christoph Hellwig
2019-08-17  7:32 ` [PATCH 22/26] sh: " Christoph Hellwig
2019-08-17  7:32 ` [PATCH 23/26] lib: provide a simple generic ioremap implementation Christoph Hellwig
2019-08-17  7:32 ` [PATCH 24/26] riscv: use the generic ioremap code Christoph Hellwig
2019-08-17 21:22   ` Paul Walmsley
2019-09-01  8:02     ` Christoph Hellwig
2019-08-17  7:32 ` [PATCH 25/26] csky: use generic ioremap Christoph Hellwig
2019-08-17  7:32 ` [PATCH 26/26] nds32: " Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190817073253.27819-17-hch@lst.de \
    --to=hch@lst.de \
    --cc=linux-snps-arc@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).