Re: [PATCH 14/23] memory: ti-emif-pm: Fix cast to iomem pointer

Krzysztof Kozlowski
2020-07-23T09:02:38Z

On Thu, Jul 23, 2020 at 10:48:19AM +0200, Arnd Bergmann wrote:
> On Thu, Jul 23, 2020 at 9:39 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> > Cast pointer to iomem memory properly to fix sparse warning:
> >
> > drivers/memory/ti-emif-pm.c:251:38: warning: incorrect type in argument 1 (different address spaces)
> > drivers/memory/ti-emif-pm.c:251:38: expected void const volatile [noderef] __iomem *addr
> > drivers/memory/ti-emif-pm.c:251:38: got void *
> >
> > Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> > ---
> > drivers/memory/ti-emif-pm.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/memory/ti-emif-pm.c b/drivers/memory/ti-emif-pm.c
> > index 9c90f815ad3a..6c747c1e98cb 100644
> > --- a/drivers/memory/ti-emif-pm.c
> > +++ b/drivers/memory/ti-emif-pm.c
> > @@ -248,7 +248,7 @@ MODULE_DEVICE_TABLE(of, ti_emif_of_match);
> > static int ti_emif_resume(struct device *dev)
> > {
> > unsigned long tmp =
> > - __raw_readl((void *)emif_instance->ti_emif_sram_virt);
> > + __raw_readl((void __iomem *)emif_instance->ti_emif_sram_virt);
> >
>
> Maybe this shouldn't even be __raw_readl(), but instead READ_ONCE()?

Won't readl() be enough? Indeed it looks problematic.

>
> The other accesses in this file don't use MMIO wrappers either but just treat
> it as a pointer. The effect would be the same though.

I think all the reads and writes are with readl() and writel().

Best regards,
Krzysztof