Re: [v4,5/6] fbdev: Move framebuffer I/O helpers into <asm/fb.h>

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 04.05.23 um 13:59 schrieb Sui Jingfeng:
> Hi,
> 
> I tested the whole patch set on a LS3A5000(LoongArch)machine with efifb 
> driver,
> 
> with both fbtest and fbdev of IGT,  The test result say passed and I can 
> not see anything wired happen.
> 
> 
> Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>

Thanks for testing.

> 
> 
> On 2023/5/4 15:45, Thomas Zimmermann wrote:
>> Implement framebuffer I/O helpers, such as fb_read*() and fb_write*(),
>> in the architecture's <asm/fb.h> header file or the generic one.
>>
>> The common case has been the use of regular I/O functions, such as
>> __raw_readb() or memset_io(). A few architectures used plain system-
>> memory reads and writes. Sparc used helpers for its SBus.
>>
>> The architectures that used special cases provide the same code in
>> their __raw_*() I/O helpers. So the patch replaces this code with the
>> __raw_*() functions and moves it to <asm-generic/fb.h> for all
>> architectures.
>>
>> v4:
>>     * ia64, loongarch, sparc64: add fb_mem*() to arch headers
>>       to keep current semantics (Arnd)
>> v3:
>>     * implement all architectures with generic helpers
>>     * support reordering and native byte order (Geert, Arnd)
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   arch/ia64/include/asm/fb.h      |  20 +++++++
>>   arch/loongarch/include/asm/fb.h |  21 +++++++
>>   arch/sparc/include/asm/fb.h     |  20 +++++++
>>   include/asm-generic/fb.h        | 101 ++++++++++++++++++++++++++++++++
>>   include/linux/fb.h              |  53 -----------------
>>   5 files changed, 162 insertions(+), 53 deletions(-)
>>
>> diff --git a/arch/ia64/include/asm/fb.h b/arch/ia64/include/asm/fb.h
>> index 0208f64a0da0..bcf982043a5c 100644
>> --- a/arch/ia64/include/asm/fb.h
>> +++ b/arch/ia64/include/asm/fb.h
>> @@ -2,7 +2,9 @@
>>   #ifndef _ASM_FB_H_
>>   #define _ASM_FB_H_
>> +#include <linux/compiler.h>
>>   #include <linux/efi.h>
>> +#include <linux/string.h>
>>   #include <asm/page.h>
>> @@ -18,6 +20,24 @@ static inline void fb_pgprotect(struct file *file, 
>> struct vm_area_struct *vma,
>>   }
>>   #define fb_pgprotect fb_pgprotect
>> +static inline void fb_memcpy_fromfb(void *to, const volatile void 
>> __iomem *from, size_t n)
>> +{
>> +    memcpy(to, (void __force *)from, n);
>> +}
>> +#define fb_memcpy_fromfb fb_memcpy_fromfb
>> +
>> +static inline void fb_memcpy_tofb(volatile void __iomem *to, const 
>> void *from, size_t n)
>> +{
>> +    memcpy((void __force *)to, from, n);
>> +}
>> +#define fb_memcpy_tofb fb_memcpy_tofb
>> +
>> +static inline void fb_memset(volatile void __iomem *addr, int c, 
>> size_t n)
>> +{
>> +    memset((void __force *)addr, c, n);
>> +}
>> +#define fb_memset fb_memset
>> +
>>   #include <asm-generic/fb.h>
>>   #endif /* _ASM_FB_H_ */
>> diff --git a/arch/loongarch/include/asm/fb.h 
>> b/arch/loongarch/include/asm/fb.h
>> index ff82f20685c8..c6fc7ef374a4 100644
>> --- a/arch/loongarch/include/asm/fb.h
>> +++ b/arch/loongarch/include/asm/fb.h
>> @@ -5,6 +5,27 @@
>>   #ifndef _ASM_FB_H_
>>   #define _ASM_FB_H_
>> +#include <linux/compiler.h>
>> +#include <linux/string.h>
>> +
>> +static inline void fb_memcpy_fromfb(void *to, const volatile void 
>> __iomem *from, size_t n)
>> +{
>> +    memcpy(to, (void __force *)from, n);
>> +}
>> +#define fb_memcpy_fromfb fb_memcpy_fromfb
>> +
>> +static inline void fb_memcpy_tofb(volatile void __iomem *to, const 
>> void *from, size_t n)
>> +{
>> +    memcpy((void __force *)to, from, n);
>> +}
>> +#define fb_memcpy_tofb fb_memcpy_tofb
>> +
>> +static inline void fb_memset(volatile void __iomem *addr, int c, 
>> size_t n)
>> +{
>> +    memset((void __force *)addr, c, n);
>> +}
>> +#define fb_memset fb_memset
>> +
>>   #include <asm-generic/fb.h>
> 
> Here works as the past, but  why bother cast it to (void __force *) ?
> 
> why not use __memcpy_fromio, __memcpy_toio and __memset_io directly?
> 
> I modify it this patch as following, it still works.
> 
> 
> 
>   static inline void fb_memcpy_fromio(void *to, const volatile void 
> __iomem *from, size_t n)
>   {
> -       memcpy(to, (void __force *)from, n);
> +       __memcpy_fromio(to, from, n);
>   }
>   #define fb_memcpy_fromio fb_memcpy_fromio
> 
>   static inline void fb_memcpy_toio(volatile void __iomem *to, const 
> void *from, size_t n)
>   {
> -       memcpy((void __force *)to, from, n);
> +       __memcpy_toio(to, from, n);
>   }
>   #define fb_memcpy_toio fb_memcpy_toio
> 
>   static inline void fb_memset_io(volatile void __iomem *addr, int c, 
> size_t n)
>   {
> -       memset((void __force *)addr, c, n);
> +       __memset_io(addr, c, n);
>   }
>   #define fb_memset fb_memset_io
> 
>>   #endif /* _ASM_FB_H_ */
>> diff --git a/arch/sparc/include/asm/fb.h b/arch/sparc/include/asm/fb.h
>> index 689ee5c60054..077da91aeba1 100644
>> --- a/arch/sparc/include/asm/fb.h
>> +++ b/arch/sparc/include/asm/fb.h
>> @@ -2,6 +2,8 @@
>>   #ifndef _SPARC_FB_H_
>>   #define _SPARC_FB_H_
>> +#include <linux/io.h>
>> +
>>   struct fb_info;
>>   struct file;
>>   struct vm_area_struct;
>> @@ -16,6 +18,24 @@ static inline void fb_pgprotect(struct file *file, 
>> struct vm_area_struct *vma,
>>   int fb_is_primary_device(struct fb_info *info);
>>   #define fb_is_primary_device fb_is_primary_device
>> +static inline void fb_memcpy_fromfb(void *to, const volatile void 
>> __iomem *from, size_t n)
>> +{
>> +    sbus_memcpy_fromio(to, from, n);
>> +}
>> +#define fb_memcpy_fromfb fb_memcpy_fromfb
>> +
>> +static inline void fb_memcpy_tofb(volatile void __iomem *to, const 
>> void *from, size_t n)
>> +{
>> +    sbus_memcpy_toio(to, from, n);
>> +}
>> +#define fb_memcpy_tofb fb_memcpy_tofb
>> +
>> +static inline void fb_memset(volatile void __iomem *addr, int c, 
>> size_t n)
>> +{
>> +    sbus_memset_io(addr, c, n);
>> +}
>> +#define fb_memset fb_memset
>> +
>>   #include <asm-generic/fb.h>
>>   #endif /* _SPARC_FB_H_ */
>> diff --git a/include/asm-generic/fb.h b/include/asm-generic/fb.h
>> index c8af99f5a535..6ef624b3ce12 100644
>> --- a/include/asm-generic/fb.h
>> +++ b/include/asm-generic/fb.h
>> @@ -30,4 +30,105 @@ static inline int fb_is_primary_device(struct 
>> fb_info *info)
>>   }
>>   #endif
>> +/*
>> + * I/O helpers for the framebuffer. Prefer these functions over their
>> + * regular counterparts. The regular I/O functions provide in-order
>> + * access and swap bytes to/from little-endian ordering. Neither is
>> + * required for framebuffers. Instead, the helpers read and write
>> + * raw framebuffer data. Independent operations can be reordered for
>> + * improved performance.
>> + */
>> +
>> +#ifndef fb_readb
>> +static inline u8 fb_readb(const volatile void __iomem *addr)
>> +{
>> +    return __raw_readb(addr);
>> +}
>> +#define fb_readb fb_readb
>> +#endif
>> +
>> +#ifndef fb_readw
>> +static inline u16 fb_readw(const volatile void __iomem *addr)
>> +{
>> +    return __raw_readw(addr);
>> +}
>> +#define fb_readw fb_readw
>> +#endif
>> +
>> +#ifndef fb_readl
>> +static inline u32 fb_readl(const volatile void __iomem *addr)
>> +{
>> +    return __raw_readl(addr);
>> +}
>> +#define fb_readl fb_readl
>> +#endif
>> +
>> +#ifndef fb_readq
>> +#if defined(__raw_readq)
>> +static inline u64 fb_readq(const volatile void __iomem *addr)
>> +{
>> +    return __raw_readq(addr);
>> +}
>> +#define fb_readq fb_readq
>> +#endif
>> +#endif
>> +
>> +#ifndef fb_writeb
>> +static inline void fb_writeb(u8 b, volatile void __iomem *addr)
>> +{
>> +    __raw_writeb(b, addr);
>> +}
>> +#define fb_writeb fb_writeb
>> +#endif
>> +
>> +#ifndef fb_writew
>> +static inline void fb_writew(u16 b, volatile void __iomem *addr)
>> +{
>> +    __raw_writew(b, addr);
>> +}
>> +#define fb_writew fb_writew
>> +#endif
>> +
>> +#ifndef fb_writel
>> +static inline void fb_writel(u32 b, volatile void __iomem *addr)
>> +{
>> +    __raw_writel(b, addr);
>> +}
>> +#define fb_writel fb_writel
>> +#endif
>> +
>> +#ifndef fb_writeq
>> +#if defined(__raw_writeq)
>> +static inline void fb_writeq(u64 b, volatile void __iomem *addr)
>> +{
>> +    __raw_writeq(b, addr);
>> +}
>> +#define fb_writeq fb_writeq
>> +#endif
>> +#endif
>> +
>> +#ifndef fb_memcpy_fromfb
>> +static inline void fb_memcpy_fromfb(void *to, const volatile void 
>> __iomem *from, size_t n)
>> +{
>> +    memcpy_fromio(to, from, n);
>> +}
>> +#define fb_memcpy_fromfb fb_memcpy_fromfb
>> +#endif
>> +
>> +#ifndef fb_memcpy_tofb
>> +static inline void fb_memcpy_tofb(volatile void __iomem *to, const 
>> void *from, size_t n)
>> +{
>> +    memcpy_toio(to, from, n);
>> +}
>> +#define fb_memcpy_tofb fb_memcpy_tofb
>> +#endif
>> +
>> +#ifndef fb_memset
>> +static inline void fb_memset(volatile void __iomem *addr, int c, 
>> size_t n)
>> +{
>> +    memset_io(addr, c, n);
>> +}
>> +#define fb_memset fb_memset
>> +#endif
>> +
>>   #endif /* __ASM_GENERIC_FB_H_ */
>> diff --git a/include/linux/fb.h b/include/linux/fb.h
>> index c0f97160ebbf..eb7e52940c60 100644
>> --- a/include/linux/fb.h
>> +++ b/include/linux/fb.h
>> @@ -17,7 +17,6 @@
>>   #include <linux/slab.h>
>>   #include <asm/fb.h>
>> -#include <asm/io.h>
>>   struct vm_area_struct;
>>   struct fb_info;
>> @@ -513,58 +512,6 @@ struct fb_info {
>>    */
>>   #define STUPID_ACCELF_TEXT_SHIT
>> -// This will go away
>> -#if defined(__sparc__)
>> -
>> -/* We map all of our framebuffers such that big-endian accesses
>> - * are what we want, so the following is sufficient.
>> - */
>> -
>> -// This will go away
>> -#define fb_readb sbus_readb
>> -#define fb_readw sbus_readw
>> -#define fb_readl sbus_readl
>> -#define fb_readq sbus_readq
>> -#define fb_writeb sbus_writeb
>> -#define fb_writew sbus_writew
>> -#define fb_writel sbus_writel
>> -#define fb_writeq sbus_writeq
>> -#define fb_memset sbus_memset_io
>> -#define fb_memcpy_fromfb sbus_memcpy_fromio
>> -#define fb_memcpy_tofb sbus_memcpy_toio
>> -
>> -#elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) 
>> ||    \
>> -    defined(__hppa__) || defined(__sh__) || defined(__powerpc__) ||    \
>> -    defined(__arm__) || defined(__aarch64__) || defined(__mips__)
>> -
>> -#define fb_readb __raw_readb
>> -#define fb_readw __raw_readw
>> -#define fb_readl __raw_readl
>> -#define fb_readq __raw_readq
>> -#define fb_writeb __raw_writeb
>> -#define fb_writew __raw_writew
>> -#define fb_writel __raw_writel
>> -#define fb_writeq __raw_writeq
>> -#define fb_memset memset_io
>> -#define fb_memcpy_fromfb memcpy_fromio
>> -#define fb_memcpy_tofb memcpy_toio
>> -
>> -#else
>> -
>> -#define fb_readb(addr) (*(volatile u8 *) (addr))
>> -#define fb_readw(addr) (*(volatile u16 *) (addr))
>> -#define fb_readl(addr) (*(volatile u32 *) (addr))
>> -#define fb_readq(addr) (*(volatile u64 *) (addr))
>> -#define fb_writeb(b,addr) (*(volatile u8 *) (addr) = (b))
>> -#define fb_writew(b,addr) (*(volatile u16 *) (addr) = (b))
>> -#define fb_writel(b,addr) (*(volatile u32 *) (addr) = (b))
>> -#define fb_writeq(b,addr) (*(volatile u64 *) (addr) = (b))
>> -#define fb_memset memset
>> -#define fb_memcpy_fromfb memcpy
>> -#define fb_memcpy_tofb memcpy
>> -
>> -#endif
>> -
>>   #define FB_LEFT_POS(p, bpp)          (fb_be_math(p) ? (32 - (bpp)) : 0)
>>   #define FB_SHIFT_HIGH(p, val, bits)  (fb_be_math(p) ? (val) >> 
>> (bits) : \
>>                                 (val) << (bits))

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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