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- Drop redundant '-gpios' from DT GPIO lookup (Ben Dooks)
- Force 2.5GT/s for initial device probe to workaround enumeration issue on
SiFive Unmatched board (Ben Dooks)
* pci/host/fu740:
PCI: fu740: Force 2.5GT/s for initial device probe
PCI: fu740: Drop redundant '-gpios' from DT GPIO lookup
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fu740_pcie_host_init() assigned "ret", but never used the value. Drop it.
Found by Krzysztof using cppcheck:
$ cppcheck --enable=all --force
unreadVariable drivers/pci/controller/dwc/pcie-fu740.c:227 Variable 'ret' is assigned a value that is never used.
Reported-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20220313192933.434746-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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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>
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The calls to devm_gpiod_get_optional() have the -gpios at the end of the
name but the GPIO core code is already adding the suffix during the lookup.
This means the PCIe driver is not finding the necessary reset or power
lines to allow initialisation of the PCIe.
Drop the redundant '-gpios' when we look up GPIOs from the DT.
This bug has not been noticed because if U-Boot has setup the GPIO lines
for the hardware when it does the PCIe initialisation (either by booting
from PCIe or user command to access PCIe) then the PCIe will work in Linux.
The U-Boot as supplied by SiFive does not by default initialise any PCIe
component.
Link: https://lore.kernel.org/r/20220221210347.1335004-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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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>
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