Re: [PATCH v3 01/11] hexagon: mm: Convert to GENERIC_IOREMAP

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 09/10/2022 à 12:31, Baoquan He a écrit :
> By taking GENERIC_IOREMAP method, the generic ioremap_prot() and
> iounmap() are visible and available to arch. Arch only needs to
> provide implementation of arch_ioremap() or arch_iounmap() if there's
> arch specific handling needed in its ioremap() or iounmap(). This
> change will simplify implementation by removing duplicated codes with
> generic ioremap() and iounmap(), and has the equivalent functioality.
> 
> For hexagon, the current ioremap() and iounmap() are the same as
> generic version. After taking GENERIC_IOREMAP way, the old ioremap()
> and iounmap() can be completely removed.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: Brian Cain <bcain@quicinc.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: linux-hexagon@vger.kernel.org
> ---
> v2->v3:
>    Rewrite patch log.
>    Put it at the beginning of patchset since it doesn't introduce new
>    arch_ioremap()/arch_iounmap().
> 
>   arch/hexagon/Kconfig          |  1 +
>   arch/hexagon/include/asm/io.h |  9 +++++--
>   arch/hexagon/mm/ioremap.c     | 44 -----------------------------------
>   3 files changed, 8 insertions(+), 46 deletions(-)
>   delete mode 100644 arch/hexagon/mm/ioremap.c
> 
> diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
> index 54eadf265178..17afffde1a7f 100644
> --- a/arch/hexagon/Kconfig
> +++ b/arch/hexagon/Kconfig
> @@ -25,6 +25,7 @@ config HEXAGON
>   	select NEED_SG_DMA_LENGTH
>   	select NO_IOPORT_MAP
>   	select GENERIC_IOMAP
> +	select GENERIC_IOREMAP
>   	select GENERIC_SMP_IDLE_THREAD
>   	select STACKTRACE_SUPPORT
>   	select GENERIC_CLOCKEVENTS_BROADCAST
> diff --git a/arch/hexagon/include/asm/io.h b/arch/hexagon/include/asm/io.h
> index 46a099de85b7..dcd9cbbf5934 100644
> --- a/arch/hexagon/include/asm/io.h
> +++ b/arch/hexagon/include/asm/io.h
> @@ -170,8 +170,13 @@ static inline void writel(u32 data, volatile void __iomem *addr)
>   #define writew_relaxed __raw_writew
>   #define writel_relaxed __raw_writel
>   
> -void __iomem *ioremap(unsigned long phys_addr, unsigned long size);
> -#define ioremap_uc(X, Y) ioremap((X), (Y))
> +/*
> + * I/O memory mapping functions.
> + */
> +#define _PAGE_IOREMAP (_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
> +		       (__HEXAGON_C_DEV << 6))
> +
> +#define ioremap_uc(addr, size) ioremap((addr), (size))

Why do you need to change this macro ?

>   
>   
>   #define __raw_writel writel
> diff --git a/arch/hexagon/mm/ioremap.c b/arch/hexagon/mm/ioremap.c
> deleted file mode 100644
> index 255c5b1ee1a7..000000000000
> --- a/arch/hexagon/mm/ioremap.c
> +++ /dev/null
> @@ -1,44 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * I/O remap functions for Hexagon
> - *
> - * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
> - */
> -
> -#include <linux/io.h>
> -#include <linux/vmalloc.h>
> -#include <linux/mm.h>
> -
> -void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
> -{
> -	unsigned long last_addr, addr;
> -	unsigned long offset = phys_addr & ~PAGE_MASK;
> -	struct vm_struct *area;
> -
> -	pgprot_t prot = __pgprot(_PAGE_PRESENT|_PAGE_READ|_PAGE_WRITE
> -					|(__HEXAGON_C_DEV << 6));
> -
> -	last_addr = phys_addr + size - 1;
> -
> -	/*  Wrapping not allowed  */
> -	if (!size || (last_addr < phys_addr))
> -		return NULL;
> -
> -	/*  Rounds up to next page size, including whole-page offset */
> -	size = PAGE_ALIGN(offset + size);
> -
> -	area = get_vm_area(size, VM_IOREMAP);
> -	addr = (unsigned long)area->addr;
> -
> -	if (ioremap_page_range(addr, addr+size, phys_addr, prot)) {
> -		vunmap((void *)addr);
> -		return NULL;
> -	}
> -
> -	return (void __iomem *) (offset + addr);
> -}
> -
> -void iounmap(const volatile void __iomem *addr)
> -{
> -	vunmap((void *) ((unsigned long) addr & PAGE_MASK));
> -}