Hi

Am 12.05.23 um 13:16 schrieb David Laight:

From: Thomas Zimmermann

quoted

Sent: 12 May 2023 11:25

Cast I/O offsets to pointers to use them with I/O functions. The I/O
functions expect pointers of type 'volatile void __iomem *', but the
offsets are plain integers. Build warnings are

   ../drivers/video/fbdev/hitfb.c: In function 'hitfb_accel_wait':
   ../arch/x86/include/asm/hd64461.h:18:33: warning: passing argument 1 of 'fb_readw' makes pointer
from integer without a cast [-Wint-conversion]
    18 | #define HD64461_IO_OFFSET(x)    (HD64461_IOBASE + (x))
       |                                 ^~~~~~~~~~~~~~~~~~~~~~

...

quoted

    52 | static inline u16 fb_readw(const volatile void __iomem *addr)
       |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

This patch only fixes the build warnings. It's not clear if the I/O
offsets can legally be passed to the I/O helpers. It was apparently
broken in 2007 when custom inw()/outw() helpers got removed by
commit 34a780a0afeb ("sh: hp6xx pata_platform support."). Fixing the
driver would require setting the I/O base address.

Did you try changing the definition of HD64461_IOBASE to include
a (volatile void __iomem *) cast?

I thought about it, but didn't try it. I didn't want bend the meaning of 
OFFSET and IOBASE too much. They sound like integer constants to me.

A lot less churn...

I'm guessing that 'sh' deosn't have in/out instructions so this
is something that is always mapped at a fixed kernel virtual address?

No idea. I cannot try the driver and was only able to build it by 
hacking up something that makes COMPILE_TEST work.

The current patch seemed like the safest bet, even with the churn.

Best regards
Thomas

	David

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Thomas Zimmermann
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