On Fri, Jan 31, 2014 at 04:37:47PM +0000, David Laight wrote:
> In order to get an ASMedia xhci controller to even detect a device
> being inserted I had to split the writeq() and readq().
> The following patch is sufficient on amd64.
I've reverted the commits that introduced the readq and writeq changes,
no need for this patch.
Sarah Sharp
> I've not yet tried to make the ax88179 card work.
>
> David
>
> [PATCH] xhci: Do not use 64bit accesses to the controller registers
>
> Some controllers (eg ASMedia) do not support 64 bit accesses to
> their internal registers even though they are 64bit capable.
>
> 32bit transfers in the correct order.
>
> Signed-off-by: David Laight <david.lai...@aculab.com>
> ---
> drivers/usb/host/xhci.h | 40 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index f8416639..ee893e6 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1614,6 +1616,44 @@ static inline struct usb_hcd *xhci_to_hcd(struct
> xhci_hcd *xhci)
> #define xhci_warn_ratelimited(xhci, fmt, args...) \
> dev_warn_ratelimited(xhci_to_hcd(xhci)->self.controller , fmt , ## args)
>
> +/*
> + * Registers should always be accessed with double word or quad word
> accesses.
> + *
> + * Some xHCI implementations may support 64-bit address pointers. Registers
> + * with 64-bit address pointers should be written to with dword accesses by
> + * writing the low dword first (ptr[0]), then the high dword (ptr[1]) second.
> + * xHCI implementations that do not support 64-bit address pointers will
> ignore
> + * the high dword, and write order is irrelevant.
> + *
> + * Some 64bit capable controllers (eg ASMedia) do not support 64bit accesses
> + * to their own registers.
> + */
> +static inline void xhci_write_64(const u64 val, __le64 __iomem *regs)
> +{
> + __u32 __iomem *ptr = (__u32 __iomem *) regs;
> + u32 val_lo = lower_32_bits(val);
> + u32 val_hi = upper_32_bits(val);
> +
> + writel(val_lo, ptr);
> + writel(val_hi, ptr + 1);
> +}
> +#define writeq writeq
> +#undef writeq
> +#define writeq(v, p) xhci_write_64(v, p)
> +
> +static inline u64 xhci_read_64(__le64 __iomem *regs)
> +{
> + __u32 __iomem *ptr = (__u32 __iomem *) regs;
> + u32 val_lo = readl(ptr);
> + u32 val_hi = readl(ptr + 1);
> +
> + return (u64)val_hi << 32 | val_lo;
> +}
> +#define readq readq
> +#undef readq
> +#define readq(p) xhci_read_64(p)
> +
> +
> static inline int xhci_link_trb_quirk(struct xhci_hcd *xhci)
> {
> return xhci->quirks & XHCI_LINK_TRB_QUIRK;
> --
> 1.8.1.2
>
>
>
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