Hi,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> writes:
> [ text/plain ]
> Hi Mathias,
>
> Would you review this patch?
> This patch could be applied into the latest usb.git / usb-next branch.
>
> Best regards,
> Yoshihiro Shimoda
>
>> -----Original Message-----
>> From: Yoshihiro Shimoda
>> Sent: Tuesday, February 16, 2016 12:26 PM
>> To: mathias.nyman@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-usb@xxxxxxxxxxxxxxx; linux-renesas-soc@xxxxxxxxxxxxxxx; Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>> Subject: [PATCH] usb: host: xhci-plat: fix cannot work if R-Car Gen2/3 run on above 4GB phys
>>
>> 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.uh@xxxxxxxxxxx>
>> ---
>> 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.
--
balbi
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