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lib: provide a simple generic ioremap implementation

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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>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Christoph Hellwig 2019-08-13 11:24:04 +02:00
parent 98c90e5ea3
commit 80b0ca98f9
3 changed files with 58 additions and 4 deletions
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20
include/asm-generic/io.h
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@ -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

3
lib/Kconfig
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@ -637,6 +637,9 @@ config STRING_SELFTEST
endmenu
config GENERIC_IOREMAP
bool
config GENERIC_LIB_ASHLDI3
bool

39
lib/ioremap.c
View File

@ -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 */