Hi Sylwester, On Wed, Apr 22, 2020 at 12:51 AM Sylwester Nawrocki <[email protected]> wrote: > > This patch adds a Kconfig option which allows accessing 64-bit xHCI > IO registers only with 2 double word accesses rather than using > a single quad word access. There might be HW configurations where > single quad word access doesn't work, even though the CPU is 64-bit. > That seems to be the case on rpi4 board with Broadcom BCM2711 SoC, > where the VL805 USB xHCI hub is connected to the PCIe controller > behind the SCB bridge. > > Signed-off-by: Sylwester Nawrocki <[email protected]> > --- > So far I couldn't come up with anything better to make the xHCI host > controller working on the rpi4 board. For some reason dereferencing > a 64-bit pointer to access 64-bit registers doesn't work there, > might be a limitation of the PCIe bridge behind the SCB. In Linux > always 2 double word accesses are used.
If Linux always uses 2 double word accesses, let's simply do the same in U-Boot by removing the readq/writeq. > --- > drivers/usb/host/Kconfig | 7 +++++++ > include/usb/xhci.h | 4 ++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > Regards, Bin
