Commit 80b0ca98 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

lib: provide a simple generic ioremap implementation 



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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarPalmer Dabbelt <palmer@dabbelt.com>
parent 98c90e5e

include/asm-generic/io.h

+16 −4
Original line number Diff line number Diff line
@@ -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

lib/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -637,6 +637,9 @@ config STRING_SELFTEST 


endmenu



config GENERIC_IOREMAP

	bool



config GENERIC_LIB_ASHLDI3

	bool

lib/ioremap.c

+39 −0
Original line number Diff line number Diff line
@@ -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 */

CRA Git | Maintained and supported by SUSTech CRA and CCSE