On Fri, 31 Jul 2015, Nikhil Badola wrote:
> Incoming packets in high speed are randomly corrupted by h/w
> resulting in multiple errors. This workaround makes FS as
> default mode in all affected socs by disabling HS chirp
> signalling.This errata does not affect FS and LS mode.
>
> Forces all HS devices to connect in FS mode for all socs
> affected by this erratum:
> P3041 and P2041 rev 1.0 and 1.1
> P5020 and P5010 rev 1.0 and 2.0
> P5040, P1010 and T4240 rev 1.0
Ooh, that's a really bad bug. People will be pretty annoyed that they
can't use high speed connections.
> --- a/drivers/usb/host/ehci-hub.c
> +++ b/drivers/usb/host/ehci-hub.c
> @@ -1222,6 +1222,13 @@ int ehci_hub_control(
> ehci->reset_done [wIndex] = jiffies
> + msecs_to_jiffies (50);
> }
> +
> + /* Force full-speed connect for FSL high-speed erratum;
> + * disable HS Chirp by setting PFSC bit
> + */
> + if (ehci_has_fsl_hs_errata(ehci))
> + temp |= (1 << PORTSC_FSL_PFSC);
> +
This hunk was added in the wrong place. It should come before the
closing '}' above, not after. That's because you don't want to force a
full-speed connection if the device is already using low speed.
> --- a/drivers/usb/host/ehci.h
> +++ b/drivers/usb/host/ehci.h
> @@ -215,6 +215,7 @@ struct ehci_hcd { /* one per controller */
> /* SILICON QUIRKS */
> unsigned no_selective_suspend:1;
> unsigned has_fsl_port_bug:1; /* FreeScale */
> + unsigned has_fsl_hs_errata:1; /* Freescale HS quirk */
> unsigned big_endian_mmio:1;
> unsigned big_endian_desc:1;
> unsigned big_endian_capbase:1;
> @@ -675,6 +676,17 @@ ehci_port_speed(struct ehci_hcd *ehci, unsigned int
> portsc)
> #define ehci_port_speed(ehci, portsc) USB_PORT_STAT_HIGH_SPEED
> #endif
>
> +#define PORTSC_FSL_PFSC 24 /* Port Force Full-Speed Connect */
> +
> +#if defined(CONFIG_PPC_85xx)
> +/* Some Freescale processors have an erratum (USB A-005275) in which
> + * incoming packets get corrupted in HS mode
> + */
> +#define ehci_has_fsl_hs_errata(e) ((e)->has_fsl_hs_errata)
> +#else
> +#define ehci_has_fsl_hs_errata(e) (0)
> +#endif
> +
> /*-------------------------------------------------------------------------*/
I would prefer it if you add your new hunk after this /*-----...---*/
dividing line (that is, next to the ehci_has_fsl_portno_bug() code)
instead of before the dividing line.
Otherwise this looks okay.
Alan Stern
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
