Hi Geert Am 10.05.23 um 16:34 schrieb Geert Uytterhoeven:
Hi Thomas, On Wed, May 10, 2023 at 4:20 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:Am 10.05.23 um 14:34 schrieb Geert Uytterhoeven:On Wed, May 10, 2023 at 1:06 PM Thomas Zimmermann <tzimmermann@xxxxxxx> 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. v6: * fix fb_readq()/fb_writeq() on 64-bit mips (kernel test robot) v5: * include <linux/io.h> in <asm-generic/fb>; fix s390 build 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@xxxxxxx> Tested-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx> Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>--- a/arch/mips/include/asm/fb.h +++ b/arch/mips/include/asm/fb.h @@ -12,6 +12,28 @@ static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma, } #define fb_pgprotect fb_pgprotect +/* + * MIPS doesn't define __raw_ I/O macros, so the helpers + * in <asm-generic/fb.h> don't generate fb_readq() and + * fb_write(). We have to provide them here.MIPS does not include <asm-generic/io.h>, nor define its ownI know, that's why the TODO says to convert it to generic I/O.__raw_readq() and __raw_writeq()...It doesn't define those macros, but it generates function calls of the same names. Follow the macros at https://elixir.bootlin.com/linux/latest/source/arch/mips/include/asm/io.h#L357 It expands to a variety of helpers, including __raw_*().Thanks, I forgot MIPS is using these grep-unfriendly factories...+ * + * TODO: Convert MIPS to generic I/O. The helpers below can + * then be removed. + */ +#ifdef CONFIG_64BIT +static inline u64 fb_readq(const volatile void __iomem *addr) +{ + return __raw_readq(addr);... so how can this call work?On 64-bit builds, there's __raw_readq() and __raw_writeq(). At first, I tried to do the right thing and convert MIPS to work with <asm-generic/io.h>. But that created a ton of follow-up errors in other headers. So for now, it's better to handle this problem in asm/fb.h.So isn't just adding #define __raw_readq __raw_readq #define __raw_writeq __raw_writeq to arch/mips/include/asm/io.h sufficient to make <asm-generic/fb.h> do the right thing?
That works. I had a patch that adds all missing defines to MIPS' io.h. Then I went with the current fix, which is self-contained within fbdev. But I'd leave it to arch maintainers.
Best regards Thomas
Gr{oetje,eeting}s,
Geert
-- 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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