Hi Felipe,
> Sent: Wednesday, March 09, 2016 8:00 PM
< snip >
> >> On xHCI controllers of R-Car Gen2 and Gen3, the AC64 bit (bit 0) of
> >> HCCPARAMS1 is set to 1. However, these SoCs don't support 64-bit address
> >> memory pointers. So, this driver should call dma_set_coherent_mask(dev,
> >> DMA_BIT_MASK(32)) in xhci_gen_setup(). Otherwise, the xHCI controller
> >> will be died after a usb device is connected if R-Car Gen2/3 run on above
> >> 4GB physical memory environment.
> >>
> >> This patch adds clearing the AC64 bit of xhci->hcc_params in the
> >> xhci_plat_quirks() to fix the issue.
> >>
> >> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>
> >> ---
> >> drivers/usb/host/xhci-plat.c | 13 +++++++++++++
> >> 1 file changed, 13 insertions(+)
> >>
> >> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> >> index d39d6bf..047fb6a 100644
> >> --- a/drivers/usb/host/xhci-plat.c
> >> +++ b/drivers/usb/host/xhci-plat.c
> >> @@ -39,12 +39,25 @@ static const struct xhci_driver_overrides
> >> xhci_plat_overrides __initconst = {
> >>
> >> static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
> >> {
> >> + struct usb_hcd *hcd = xhci_to_hcd(xhci);
> >> +
> >> /*
> >> * As of now platform drivers don't provide MSI support so we ensure
> >> * here that the generic code does not try to make a pci_dev from our
> >> * dev struct in order to setup MSI
> >> */
> >> xhci->quirks |= XHCI_PLAT;
> >> +
> >> + /*
> >> + * On R-Car Gen2 and Gen3, the AC64 bit (bit 0) of HCCPARAMS1 is set
> >> + * to 1. However, these SoCs don't support 64-bit address memory
> >> + * pointers. So, this driver clears the AC64 bit of xhci->hcc_params
> >> + * to call dma_set_coherent_mask(dev, DMA_BIT_MASK(32)) in
> >> + * xhci_gen_setup().
> >> + */
> >> + if (xhci_plat_type_is(hcd, XHCI_PLAT_TYPE_RENESAS_RCAR_GEN2) ||
> >> + xhci_plat_type_is(hcd, XHCI_PLAT_TYPE_RENESAS_RCAR_GEN3))
> >> + xhci->hcc_params &= ~BIT(0); /* clear HCC_64BIT_ADDR
> >> */
>
> Mathias, of course, has the final saying; but I feel that, just like any
> other quirk, this should be setting a flag in xhci->quirks and xhci core
> would clear hcc_params. The reason is that if we ever need this on some
> PCIe card, we won't have to shuffle code around.
Thank you for the comment. I agree with you.
So, I will make such a code and send v2 patch tomorrow.
Best regards,
Yoshihiro Shimoda
> --
> balbi
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