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.c...@freescale.com> Acked-by: Alan Stern <st...@rowland.harvard.edu> Signed-off-by: Marc Kleine-Budde <m...@pengutronix.de> --- 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 e8f41c5..4a320ab 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 } -- 1.7.8 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
