Commit Graph

2 Commits

Author SHA1 Message Date
Ben Dooks
e04a1de51c PCI: fu740: Force 2.5GT/s for initial device probe
commit a382c757ec5ef83137a86125f43a4c43dc2ab50b upstream.

The fu740 PCIe core does not probe any devices on the SiFive Unmatched
board without this fix (or having U-Boot explicitly start the PCIe via
either boot-script or user command). The fix is to start the link at
2.5GT/s speeds and once the link is up then change the maximum speed back
to the default.

The U-Boot driver claims to set the link-speed to 2.5GT/s to get the probe
to work (and U-Boot does print link up at 2.5GT/s) in the following code:
https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/pci/pcie_dw_sifive.c?id=v2022.01#L271

Link: https://lore.kernel.org/r/20220318152430.526320-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08 14:22:57 +02:00
Paul Walmsley
e7e21b3a33 PCI: fu740: Add SiFive FU740 PCIe host controller driver
Add driver for the SiFive FU740 PCIe host controller.
This controller is based on the DesignWare PCIe core.

Co-developed-by: Henry Styles <hes@sifive.com>
Co-developed-by: Erik Danie <erik.danie@sifive.com>
Co-developed-by: Greentime Hu <greentime.hu@sifive.com>
Link: https://lore.kernel.org/r/20210504105940.100004-6-greentime.hu@sifive.com
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Henry Styles <hes@sifive.com>
Signed-off-by: Erik Danie <erik.danie@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2021-05-04 14:58:22 +01:00