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SubjectRe: [PATCH v8 0/4] USB: pci-quirks: Add Raspberry Pi 4 quirk
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On Wed, 2020-05-13 at 12:17 +0100, Lorenzo Pieralisi wrote:
> On Tue, May 05, 2020 at 06:13:13PM +0200, Nicolas Saenz Julienne wrote:
> > On the Raspberry Pi 4, after a PCI reset, VL805's firmware may either be
> > loaded directly from an EEPROM or, if not present, by the SoC's
> > co-processor, VideoCore. This series adds support for the later.
> >
> > Note that there are a set of constraints we have to consider:
> > - We need to make sure the VideoCore firmware interface is up and
> > running before running the VL805 firmware load call.
> >
> > - There is no way to discern RPi4's VL805 chip from other platforms',
> > so we need the firmware load to happen *before* running
> > quirk_usb_handoff_xhci(). Failure to do so results in an unwarranted
> > 5 second wait while the fixup code polls xHC's non-existing state.
> >
> > By Florian's suggestion I've been spending some time exploring the device
> > link[1] API in order to see if that could save us from explicitly creating
> > probe dependencies between pcie-brcmstb and firmware/raspberrypi (patch #3).
> > Technically these dependencies could be inferred from DT. It turns out
> > Saravana
> > Kannan has been looking at this already. A new boot mechanism, activated
> > with
> > fw_devlink=on takes care of the device probe ordering on devices with
> > consumer/supplier relationships. For now this relationship is created based
> > on
> > the usage of generic DT properties, but has no support for vendor-specifc DT
> > properties, which we'd be forced to use in order to create a relationship
> > between our two devices since our setup is highly non generic. There will
> > probably be at some point support for such properties, and we will then be
> > able
> > to revisit some of this code.
> >
> > All this is based on the work by Tim Gover in RPi's downstream
> > kernel[2].
> >
> > [1] https://www.kernel.org/doc/html/v4.13/driver-api/device_link.html
> > [2]
> >
https://github.com/raspberrypi/linux/commit/9935b4c7e360b4494b4cb6e3ce797238a1ab78bd
> >
> > ---
> >
> > Changes since v7:
> > - Address Stefan's comments
> >
> > Changes since v6:
> > - Make rpi_firmware_init_vl805() more robust
> > - Rewrite comments and patch descriptions to be more accessible to non RPi
> > fluent people
> > - Removed Florian's Reviewed-by in patch #2 as function changed
> > substantially
> > - Tested with/witout u-boot
> >
> > Changes since v5:
> > - Fix issues reported by Kbuild test robot
> >
> > Changes since v4:
> > - Addressed Sergei's comments
> > - Fix potential warning in patch #2
> >
> > Changes since v3:
> > - Addressed Greg's comments
> >
> > There was no v2, my bad.
> >
> > Changes since v1:
> > - Addressed Floarians comments
> >
> > Nicolas Saenz Julienne (4):
> > soc: bcm2835: Add notify xHCI reset property
> > firmware: raspberrypi: Introduce vl805 init routine
> > PCI: brcmstb: Wait for Raspberry Pi's firmware when present
> > USB: pci-quirks: Add Raspberry Pi 4 quirk
> >
> > drivers/firmware/Kconfig | 3 +-
> > drivers/firmware/raspberrypi.c | 61 ++++++++++++++++++++++
> > drivers/pci/controller/pcie-brcmstb.c | 17 ++++++
> > drivers/usb/host/pci-quirks.c | 16 ++++++
> > include/soc/bcm2835/raspberrypi-firmware.h | 9 +++-
> > 5 files changed, 104 insertions(+), 2 deletions(-)
>
> Hi Nicolas,
>
> should I queue this series via the PCI tree ? Just let me know, most of
> the changes are not in the PCI tree, asking in order to
> minimize/simplify conflicts handling if possible.

Yes, I agree, it's better if you take the whole thing.

Thanks,
Nicolas

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