[PATCH V2 1/4] ARM64 LPC: Indirect ISA port IO introduced

On Wednesday, September 7, 2016 9:33:50 PM CEST Zhichang Yuan wrote:

+#ifdef CONFIG_ARM64_INDIRECT_PIO
+
+typedef u64 (*inhook)(void *devobj, unsigned long ptaddr, void *inbuf,
+                               size_t dlen, unsigned int count);
+typedef void (*outhook)(void *devobj, unsigned long ptaddr,
+                               const void *outbuf, size_t dlen,
+                               unsigned int count);
+
+struct extio_ops {
+       inhook  pfin;
+       outhook pfout;
+       void *devpara;
+};
+
+extern struct extio_ops *arm64_simops __refdata;
+
+/*Up to now, only applied to Hip06 LPC. Define as static here.*/
+static inline void arm64_set_simops(struct extio_ops *ops)
+{
+       if (ops)
+               WRITE_ONCE(arm64_simops, ops);
+}
+
+
+#define BUILDIO(bw, type)                                              \
+static inline type in##bw(unsigned long addr)                          \
+{                                                                      \
+       if (addr >= PCIBIOS_MIN_IO)                                     \
+               return read##bw(PCI_IOBASE + addr);                     \
+       return (arm64_simops && arm64_simops->pfin) ?                   \
+               arm64_simops->pfin(arm64_simops->devpara, addr, NULL,   \
+                                       sizeof(type), 1) : -1;          \
+}                                                      \

Hmm, the way this is done, enabling CONFIG_ARM64_INDIRECT_PIO at
compile time means that only the dynamically registered PIO support
is possible for I/O port ranges 0-0xfff.

I think the runtime check should better test if simops was defined
first and fall back to normal PIO otherwise, in order to allow
LPC implementations on a PCI-LPC bridge.

How about allowing an I/O port range to be defined along with
the operations and check against that?

u8 intb(unsigned long port)
{
	if (arm64_simops &&
	    (port >= arm64_simops->min) && 
	    (port <= arm64_simops->max))
		return arm64_simops->pfin(arm64_simops, port, 1);
	else
		return readb(PCI_IOBASE + addr);
}

The other advantage of that is that you can dynamically register
a translation for the LPC port range into the Linux I/O port range
like PCI hosts do.

We may also want to move the inb/outb definitions into a .c file
as they are getting rather big.

	Arnd