On Fri, Jun 14, 2019 at 4:52 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
On Mon, Apr 29, 2019 at 2:40 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
On Mon, Apr 29, 2019 at 10:19 AM Geert Uytterhoeven
This looks correct to me, but there are two points that stick out to me:
- why do you only do this for mmio and not for pio?
Because no one had a need for it? ;-)
Now seriously, m68k only has MMIO, no PIO. Any PIO, if used, is for ISA or
PCMCIA I/O accesses, which are little endian.
I suppose the majority of PIO operations are single-byte only,
so endianess doesn't apply at all ;-). You are certainly right
that big-endian PIO access has close to zero uses in the
kernel (I could not find any either).
If you don't have ISA or PCMCIA devices, then using the
trivial readl/writel based wrappers is clearly the easiest way.
If you do have PIO based devices, then defining pio_read16be
etc would save a few bytes in lib/iomap.c.
- why do you even use the generic_iomap wrappers rather than
the trivial asm-generic versions of those functions?
Looking at git history, that was done to fix some link errors, which no
longer seem to happen with the more mature asm-generic infrastructure we
have now.
So probably we can drop the selection of GENERIC_IOMAP and inclusion
of <asm-generic/iomap.h>, after fixing a few compiler warnings like:
include/asm-generic/io.h: In function ‘ioread8_rep’
arch/m68k/include/asm/io_mm.h:371:44: warning: passing argument 1
of ‘raw_insb’ discard ‘const’ qualifier from pointer target type
[-Wdiscarded-qualifiers]
#define readsb(port, buf, nr) raw_insb((port), (u8 *)(buf), (nr))
arch/m68k/include/asm/raw_io.h:101:50: note: expected ‘volatile u8
*’ {aka ‘volatile unsigned char *’} but argument is of type ‘const
volatile void *’
static inline void raw_insb(volatile u8 __iomem *port, u8 *buf,
unsigned int len)
Those should just be missing 'volatile' and 'const' modifiers
on the arguments.
Arnd
