Hi Corey

Many Thanks for your comments

[...]

quoted

  #define IO_SPACE_LIMIT 0xffff
  #endif

+#include <linux/logic_pio.h>

This whole thing would be a lot simpler if you had:

#ifdef CONFIG_INDIRECT_PIO
#define inb logic_inb
#define outb logic outb
.
.
#endif /* CONFIG_INDIRECT_PIO */

and let the "ifndef XXX" below handle not enabling the standard code.
You could even put that in logic_pio.h to avoid polluting io.h.

Agreed. I'll move it into "logic_pio.h"

You might have to add "#ifndef inb", etc. above, but I still think it
would
be better.

Yes agreed also on adding the "#ifndef ***" around each function re-definition
in logic_pio.h

This will be fixed in v11

I'm not sure if this wouldn't be better done in arm64/include/asm/io.h,
though.
A specific machine may want to only do this in ranges, for instance.

No I don?t think so...this io functions re-0definition has nothing to do
with ARM architecture and I think it is better to keep everything in
logic_pio.h including the file from "include/asm-generic/io.h"

Cheers
Gab

-corey

[...]

quoted

--- a/lib/Kconfig
+++ b/lib/Kconfig

@@ -59,6 +59,32 @@ config ARCH_USE_CMPXCHG_LOCKREF
  config ARCH_HAS_FAST_MULTIPLIER
  	bool

+config LOGIC_PIO
+	bool "Generic logical I/O management"
+	def_bool y if PCI && !X86 && !IA64 && !POWERPC
+	help
+	  For some architectures, there are no IO space. To support the
+	  accesses to legacy I/O devices on those architectures, kernel
+	  implemented the memory mapped I/O mechanism based on bridge bus
+	  supports. But for some buses which do not support MMIO, the
+	  peripherals there should be accessed with device-specific way.
+	  To abstract those different I/O accesses into unified I/O

accessors,

quoted

+	  this option provide a generic I/O space management way after

mapping

quoted

+	  the device I/O to system logical/fake I/O and help to hide all

the

quoted

+	  hardware detail.
+
+config INDIRECT_PIO
+	bool "Access I/O in non-MMIO mode" if LOGIC_PIO
+	help
+	  On some platforms where no separate I/O space exist, there are

I/O

quoted

+	  hosts which can not be accessed in MMIO mode. Based on

LOGIC_PIO

quoted

+	  mechanism, the host-local I/O resource can be mapped into

system

quoted

+	  logic PIO space shared with MMIO hosts, such as PCI/PCIE, then

system

quoted

+	  can access the I/O devices with the mapped logic PIO through

I/O

quoted

+	  accessors.
+	  This way has a little I/O performance cost. Please make sure

your

quoted

+	  devices really need this configure item enabled.
+

If this is always available on the hisilicon chips, I think you would
want to just always
enable this on those chips.

In patch 6/9 we have 

+config HISILICON_LPC
+	bool "Support for ISA I/O space on Hisilicon Hip0X"
+	depends on (ARM64 && (ARCH_HISI || COMPILE_TEST))
+	select LOGIC_PIO
+	select INDIRECT_PIO

So the LPC host controller driver is selecting INDIRECT_PIO...

-corey

Cheers
Gab