Hi Arnd Am 06.09.23 um 21:53 schrieb Arnd Bergmann:
On Wed, Sep 6, 2023, at 10:35, Thomas Zimmermann wrote:Rename the fbdev mmap helper fb_pgprotect() to fb_pgprot_device(). The helper sets VMA page-access flags for framebuffers in device I/O memory. The new name follows pgprot_device(), which does the same for arbitrary devices. Also clean up the helper's parameters and return value. Instead of the VMA instance, pass the individial parameters separately: existing page-access flags, the VMAs start and end addresses and the offset in the underlying device memory rsp file. Return the new page-access flags. These changes align fb_pgprot_device() closer with pgprot_device. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>This makes sense as a cleanup, but I'm not sure the new naming is helpful. The 'pgprot_device' permissions are based on Arm's memory attributes, which have slightly different behavior for "device", "uncached" and "writecombine" mappings. I think simply calling this one pgprot_fb() or fb_pgprot() would be less confusing, since depending on the architecture it appears to give either uncached or writecombine mappings but not "device" on the architectures where this is different.
I see. Thanks for the info. I like pgprot_fb() maybe pgprot_framebuffer(). I'll update the patchset.
One thing I've been wondering is whether I should attempt to integrate the helpers in <asm/fb.h> in the regular asm headers. So the pgprot code would go into pgtable.h, the I/O functions would go into io.h. The I/O functions could then be called readb_fb(), writel_fb(), memcpy_tofb() and so on. Would you prefer that or rather not?
Best regards Thomas
Arnd
-- 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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