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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 17/21] lib: provide a simple generic ioremap implementation
Date: Tue, 29 Oct 2019 07:48:30 +0100
Message-ID: <20191029064834.23438-18-hch@lst.de> (raw)
In-Reply-To: <20191029064834.23438-1-hch@lst.de>

A lot of architectures reuse the same simple ioremap implementation, so
start lifting the most simple variant to lib/ioremap.c.  It provides
ioremap_prot and iounmap, plus a default ioremap that uses prot_noncached,
although that can be overridden by asm/io.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/asm-generic/io.h | 20 ++++++++++++++++----
 lib/Kconfig              |  3 +++
 lib/ioremap.c            | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 4e45e1cb6560..4a661fdd1937 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -923,9 +923,10 @@ static inline void *phys_to_virt(unsigned long address)
  * DOC: ioremap() and ioremap_*() variants
  *
  * 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.
+ * themselves or rely on GENERIC_IOREMAP.  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.
  *
  * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes
  * for specific drivers if the architecture choses to implement them.  If they
@@ -946,7 +947,18 @@ static inline void iounmap(void __iomem *addr)
 {
 }
 #endif
-#endif /* CONFIG_MMU */
+#elif defined(CONFIG_GENERIC_IOREMAP)
+#include <asm/pgtable.h>
+
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot);
+void iounmap(volatile void __iomem *addr);
+
+static inline void __iomem *ioremap(phys_addr_t addr, size_t size)
+{
+	/* _PAGE_IOREMAP needs to be supplied by the architecture */
+	return ioremap_prot(addr, size, _PAGE_IOREMAP);
+}
+#endif /* !CONFIG_MMU || CONFIG_GENERIC_IOREMAP */
 
 #ifndef ioremap_nocache
 #define ioremap_nocache ioremap
diff --git a/lib/Kconfig b/lib/Kconfig
index 183f92a297ca..afc78aaf2b25 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -638,6 +638,9 @@ config STRING_SELFTEST
 
 endmenu
 
+config GENERIC_IOREMAP
+	bool
+
 config GENERIC_LIB_ASHLDI3
 	bool
 
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 0a2ffadc6d71..3f0e18543de8 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -231,3 +231,42 @@ int ioremap_page_range(unsigned long addr,
 
 	return err;
 }
+
+#ifdef CONFIG_GENERIC_IOREMAP
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
+{
+	unsigned long offset, vaddr;
+	phys_addr_t last_addr;
+	struct vm_struct *area;
+
+	/* Disallow wrap-around or zero size */
+	last_addr = addr + size - 1;
+	if (!size || last_addr < addr)
+		return NULL;
+
+	/* Page-align mappings */
+	offset = addr & (~PAGE_MASK);
+	addr -= offset;
+	size = PAGE_ALIGN(size + offset);
+
+	area = get_vm_area_caller(size, VM_IOREMAP,
+			__builtin_return_address(0));
+	if (!area)
+		return NULL;
+	vaddr = (unsigned long)area->addr;
+
+	if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
+		free_vm_area(area);
+		return NULL;
+	}
+
+	return (void __iomem *)(vaddr + offset);
+}
+EXPORT_SYMBOL(ioremap_prot);
+
+void iounmap(volatile void __iomem *addr)
+{
+	vunmap((void *)((unsigned long)addr & PAGE_MASK));
+}
+EXPORT_SYMBOL(iounmap);
+#endif /* CONFIG_GENERIC_IOREMAP */
-- 
2.20.1


  parent reply index

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 ` [PATCH 11/21] asm-generic: don't provide ioremap for CONFIG_MMU Christoph Hellwig
2019-11-06 18:11   ` 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 ` Christoph Hellwig [this message]
2019-11-07 15:29   ` [PATCH 17/21] lib: provide a simple generic ioremap implementation 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 17/21] lib: provide a simple generic ioremap implementation Christoph Hellwig

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