On Thu, Mar 4, 2021 at 11:40 PM Hector Martin [off-list ref] wrote:

ARM64 currently defaults to posted MMIO (nGnRnE), but some devices
require the use of non-posted MMIO (nGnRE). Introduce a new ioremap()
variant to handle this case. ioremap_np() is aliased to ioremap() by
default on arches that do not implement this variant.

Hmm... But isn't it basically a requirement to those device drivers to
use readX()/writeX() instead of readX_relaxed() / writeX_relaxed()?

...

 #define IORESOURCE_MEM_32BIT           (3<<3)
 #define IORESOURCE_MEM_SHADOWABLE      (1<<5)  /* dup: IORESOURCE_SHADOWABLE */
 #define IORESOURCE_MEM_EXPANSIONROM    (1<<6)
+#define IORESOURCE_MEM_NONPOSTED       (1<<7)

Not sure it's the right location (in a bit field) for this flag.

-- 
With Best Regards,
Andy Shevchenko