This patch exports a in-kernel 'library' API which can be called by
other drivers to help interacting with an IBM XSL on a POWER9 system.
The XSL (Translation Service Layer) is a stripped down version of the
PSL (Power Service Layer) used in some cards such as the Mellanox CX5.
Like the PSL, it implements the CAIA architecture, but has a number
of differences, mostly in it's implementation dependent registers.
The XSL also uses a special DMA cxl mode, which uses a slightly
different init sequence for the CAPP and PHB.
Signed-off-by: Andrew Donnellan <email@example.com>
Signed-off-by: Christophe Lombard <firstname.lastname@example.org>
Acked-by: Frederic Barrat <email@example.com>
Signed-off-by: Michael Ellerman <firstname.lastname@example.org>