tree a7c80d5c1d7c2580f76f38ca709d254893164136
parent d62e9bf5dd4c0298465dd70b78b5532ea6708d63
author Thomas Petazzoni <thomas.petazzoni@free-electrons.com> 1512400145 +0100
committer Rich Felker <dalias@libc.org> 1523576877 -0400

arch/sh: pcie-sh7786: adjust PCI MEM and IO regions

The current definition of the PCIe IO and MEM resources for SH7786
doesn't match what the datasheet says. For example, for PCIe0
0xfe100000 is advertised by the datasheet as a PCI IO region, while
0xfd000000 is advertised as a PCI MEM region. The code currently
inverts the two.

The SH4A_PCIEPARL and SH4A_PCIEPTCTLR registers allow to define the
base address and role of the different regions (including whether it's
a MEM or IO region). However, practical experience on a SH7786 shows
that if 0xfe100000 is used for LEL and 0xfd000000 for IO, a PCIe
device using two MEM BARs cannot be accessed at all. Simply using
0xfe100000 for IO and 0xfd000000 for MEM makes the PCIe device
accessible.

It is very likely that this was never seen because there are two other
PCI MEM region listed in the resources. However, for different
reasons, none of the two other MEM regions are usable on the specific
SH7786 platform the problem was encountered. Therefore, the last MEM
region at 0xfe100000 was used to place the BARs, making the device
non-functional.

This commit therefore adjusts those PCI MEM and IO resources
definitions so that they match what the datasheet says. They have only
been tested with PCIe 0.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Rich Felker <dalias@libc.org>