On Mon, Jan 06, 2014 at 10:10:41AM +0800, Peter Chen wrote: > According to Freescale imx28 Errata, "ENGR119653 USB: ARM to USB > register error issue", All USB register write operations must > use the ARM SWP instruction. So, we implement a special ehci_write > for imx28. > > Discussion for it at below: > http://marc.info/?l=linux-usb&m=137996395529294&w=2 > > Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx> > Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Tested-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > --- > drivers/usb/host/ehci.h | 18 +++++++++++++++++- > 1 files changed, 17 insertions(+), 1 deletions(-) > > diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h > index c35a6e2b..e26099b 100644 > --- a/drivers/usb/host/ehci.h > +++ b/drivers/usb/host/ehci.h > @@ -225,6 +225,7 @@ struct ehci_hcd { /* one per controller */ > unsigned has_synopsys_hc_bug:1; /* Synopsys HC */ > unsigned frame_index_bug:1; /* MosChip (AKA NetMos) */ > unsigned need_oc_pp_cycle:1; /* MPC834X port power */ > + unsigned imx28_write_fix:1; /* For Freescale i.MX28 */ > > /* required for usb32 quirk */ > #define OHCI_CTRL_HCFS (3 << 6) > @@ -728,6 +729,18 @@ static inline unsigned int ehci_readl(const struct ehci_hcd *ehci, > #endif > } > > +#ifdef CONFIG_SOC_IMX28 > +static inline void imx28_ehci_writel(const unsigned int val, > + volatile __u32 __iomem *addr) > +{ > + __asm__ ("swp %0, %0, [%1]" : : "r"(val), "r"(addr)); > +} > +#else > +static inline void imx28_ehci_writel(const unsigned int val, > + volatile __u32 __iomem *addr) > +{ > +} > +#endif > static inline void ehci_writel(const struct ehci_hcd *ehci, > const unsigned int val, __u32 __iomem *regs) > { > @@ -736,7 +749,10 @@ static inline void ehci_writel(const struct ehci_hcd *ehci, > writel_be(val, regs) : > writel(val, regs); > #else > - writel(val, regs); > + if (IS_ENABLED(CONFIG_SOC_IMX28) && ehci->imx28_write_fix) > + imx28_ehci_writel(val, regs); > + else > + writel(val, regs); > #endif This IS_ENABLED() isn't needed at all, so please remove it. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
