Hi Thomas,
On Thu, Apr 27, 2023 at 09:22:47AM +0200, Thomas Zimmermann wrote:
Hi Sam
Am 26.04.23 um 21:21 schrieb Sam Ravnborg:
Hi Thomas.
On Wed, Apr 26, 2023 at 03:04:15PM +0200, Thomas Zimmermann wrote:
Fbdev provides helpers for framebuffer I/O, such as fb_readl(),
fb_writel() or fb_memcpy_to_fb(). The implementation of each helper
depends on the architecture. It's still all located in fbdev's main
header file <linux/fb.h>. Move all of it into each archtecture's
<asm/fb.h>, with shared code in <asm-generic/fb.h>.
For once I think this cleanup is moving things in the wrong direction.
The fb_* helpers predates the generic io.h support and try to
add a generic layer for read read / write operations.
The right fix would be to migrate fb_* to use the io helpers
we have today - so we use the existing way to handle the architecture
specific details.
I looked through the existing versions of the fb_() I/O helpers. They can
apparently be implemented with the regular helpers of similar names.
I'm not sure, but even Sparc looks compatible. At least these sbus_
functions seem to be equivalent to the __raw_() I/O helpers of similar
names.
Do you still have that Sparc emulator?
I used qemu the last time I played with sparc and saved the instructions
somewhere how to redo it - but that would use to bohcs driver only I think.
I have saprc machines, but none of these are easy to get operational.
We can always ask on sparclinux to get some testing feedback.
From a quick look there seems to be some challenges but the current
helpers that re-do part of io.h is not the way forward and hiding them
in arch/include/asm/fb.h seems counter productive.
Which challenges did you see?
sparc was the main thing - but maybe I did not look close enough.
And then I tried to map the macros to some of the more highlevel ones
from io.h, but as Arnd says the __raw* is the way to go here.
Sam
