RE: Yosemite/440EP why are readl()/ioread32() setup to readlittle-endian?

quoted

quoted

readl() and ioread32() read the registers in little-endian format!

Correct. That's how it is implemented on all platforms. Think for
example of an pci device driver. Using these IO functions, the
driver will become platform independent, running without
modifications on little- and big-endian machines.

I just stumbled across the section in Rubini 3rd Ed that mislead
me into believing that the readl()/writel() were machine endianness
dependent, i.e., LE on x86, BE on PPC.

p453 of his book has a PCI DMA example, where he uses the
cpu_to_le32() macros inside calls writel().

However, since these functions are internally implemented to
perform LE operations, this example appears to be incorrect.

Would you agree?

No, I think it is correct.

On most architectures readl() and writel() assume you are
accessing MMIO on the PCI bus, which is little-endian.
So these macros convert between the endian-ness of the CPU
and the endian-ness of the PCI bus.

Clive