On 2023-05-11 14:35, Geert Uytterhoeven wrote:
Hi Arnd, CC Artur, who's working on HP Jornada 680.
Thanks for CC'ing me - I faced this exact issue while working on my (still not upstreamed) hd6446x PCMCIA controller driver. The PCMCIA subsystem uses `inb/outb`, which expect the `sh_io_port_base` to be set to something else than the default `-1`. At first I tried to set it to `0xa0000000`, so that all I/O goes through the fixed, non-cacheable P2 area. That however broke some other driver code (I had no time to debug which one). Eventually I ended up taking a suggestion from a MIPS PCMCIA driver [1] and simply substract the broken `sh_io_port_base` address from `HD64461_IOBASE`, as the base for `socket.io_offset`. This way all the PCMCIA `inb/outb` accesses are absolute, no matter what the `sh_io_port_base` is set to. This of course is a very ugly solution and we should instead fix the root cause of this mess. I will have a better look at this patch set and the problem at hand at a later date. Cheers, Artur[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pcmcia/db1xxx_ss.c?h=v6.4-rc1#n527
On Wed, May 10, 2023 at 5:55 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:On Wed, May 10, 2023, at 16:27, Thomas Zimmermann wrote: > Am 10.05.23 um 16:15 schrieb Arnd Bergmann: >> On Wed, May 10, 2023, at 16:03, kernel test robot wrote: >> I think that's a preexisting bug and I have no idea what the >> correct solution is. Looking for HD64461 shows it being used >> both with inw/outw and readw/writew, so there is no way to have >> the correct type. The sh __raw_readw() definition hides this bug, >> but that is a problem with arch/sh and it probably hides others >> as well. > > The constant HD64461_IOBASE is defined as integer at > > > https://elixir.bootlin.com/linux/latest/source/arch/sh/include/asm/hd64461.h#L17 > > but fb_readw() expects a volatile-void pointer. I guess we could add a > cast somewhere to silence the problem. In the current upstream code, > that appears to be done by sh's __raw_readw() internally: > > > https://elixir.bootlin.com/linux/latest/source/arch/sh/include/asm/io.h#L35 Sure, that would make it build again, but that still doesn't make the code correct, since it's completely unclear what base address the HD64461_IOBASE is relative to. The hp6xx platform code only passes itthrough inw()/outw(), which take an offset relative to sh_io_port_base,but that is not initialized on hp6xx. I tried to find in the history when it broke, apparently that was in 2007 commit 34a780a0afeb ("sh: hp6xx pata_platform support."), which removed the custom inw/outw implementations.See also commit 4aafae27d0ce73f8 ("sh: hd64461 tidying."), which claims they are no longer needed.Don't the I/O port macros just treat the port as an absolute base addresswhen sh_io_port_base isn't set? Gr{oetje,eeting}s, Geert
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