From: Alan Stern <stern@rowland.harvard.edu>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: gregkh@linuxfoundation.org, <linux@prisktech.co.nz>,
<linux-usb@vger.kernel.org>, <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH v3] usb: host: ehci-platform: add a quirk to avoid stuck
Date: Fri, 24 Jan 2020 10:18:23 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.2001241012160.1610-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <1579840923-10709-1-git-send-email-yoshihiro.shimoda.uh@renesas.com>
On Fri, 24 Jan 2020, Yoshihiro Shimoda wrote:
> Since EHCI/OHCI controllers on R-Car Gen3 SoCs are possible to
> be getting stuck very rarely after a full/low usb device was
> disconnected. To detect/recover from such a situation, the controllers
> require a special way which poll the EHCI PORTSC register and changes
> the OHCI functional state.
>
> So, this patch adds a polling timer into the ehci-platform driver,
> and if the ehci driver detects the issue by the EHCI PORTSC register,
> the ehci driver removes a companion device (= the OHCI controller)
> to change the OHCI functional state to USB Reset once. And then,
> the ehci driver adds the companion device again.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
All good, except for one thing at the end...
> diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h
> index a15ce99..0ebfa74 100644
> --- a/include/linux/usb/ehci_def.h
> +++ b/include/linux/usb/ehci_def.h
> @@ -150,6 +150,7 @@ struct ehci_regs {
> #define PORT_LED_MASK (3<<14)
> #define PORT_OWNER (1<<13) /* true: companion hc owns this port */
> #define PORT_POWER (1<<12) /* true: has power (see PPC) */
> +#define PORT_LS_MASK (3<<10) /* USB 1.1 device */
The comment should say: /* Link status (SE0, K, or J) */
> #define PORT_USB11(x) (((x)&(3<<10)) == (1<<10)) /* USB 1.1 device */
> /* 11:10 for detecting lowspeed devices (reset vs release ownership) */
You can remove this comment now. Since there is an actual macro for
bits 11:10, we don't need a separate comment saying what they are.
Alan Stern
> /* 9 reserved */
next prev parent reply other threads:[~2020-01-24 15:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 4:42 [PATCH v3] usb: host: ehci-platform: add a quirk to avoid stuck Yoshihiro Shimoda
2020-01-24 15:18 ` Alan Stern [this message]
2020-01-27 8:08 ` Yoshihiro Shimoda
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