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SubjectRe: [PATCH 17/21] lib: provide a simple generic ioremap implementation
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On Mon, 28 Oct 2019 23:48:30 PDT (-0700), Christoph Hellwig wrote:
> 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 */

Reviewed-by: Palmer Dabbelt <palmer@dabbelt.com>

Thanks! This should let us get rid of arch/riscv/mm/ioremap.c.

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