On Wed, Jan 08, 2014 at 12:54:25PM +0100, Marc Kleine-Budde wrote: > On 01/08/2014 01:23 AM, Greg KH wrote: > > 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. > > It's an optimisation for the hot path, if kernel isn't build for a mx28 > the newly added if() is completely optimized out. The same argument > applies to the next patch. If the kernel isn't built for mx28 then the if statment goes away without the IS_ENABLED() call as well, due to the empty inline function, right? 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
