cxl: Abstract the differences between the PSL and XSL

[Michael Ellerman]

On Mon, 2016-23-05 at 17:39:18 UTC, Ian Munsie wrote:
> From: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
> 
> The XSL (Translation Service Layer) is a stripped down version of the
> PSL (Power Service Layer) used in some cards such as the Mellanox CX4.
> 
> Like the PSL, it implements the CAIA architecture, but has a number of
> differences, mostly in it's implementation dependent registers. This
> adds an ops structure to abstract these differences to bring initial
> support for XSL CAPI devices.
> 
> The XSL does not implement the optional architected SERR register,
> however while it treats it as a reserved register and should work with
> no special treatment, attempting to access it will cause the XSL_FEC
> (First Error Capture) register to be filled out, preventing it from
> capturing any subsequent errors. Therefore, this patch also prevents the
> kernel from trying to set up the SERR register so that the FEC register
> may still be useful, and to save one interrupt.
> 
> The XSL also uses a special DMA cxl mode, which uses a slightly
> different init sequence for the CAPP and PHB. The kernel support for
> this will be in a future patch once the corresponding support has been
> merged into skiboot.
> 
> Co-authored-by: Ian Munsie <imunsie at au1.ibm.com>
> Signed-off-by: Ian Munsie <imunsie at au1.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/6d382616ac2283ed65c7a6a52d

cheers