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    Subject[PATCH 4.19 163/206] usb: host: ehci-platform: add a quirk to avoid stuck
    Date
    From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

    [ Upstream commit cc7eac1e4afdd151085be4d0341a155760388653 ]

    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>
    Acked-by: Alan Stern <stern@rowland.harvard.edu>
    Link: https://lore.kernel.org/r/1580114262-25029-1-git-send-email-yoshihiro.shimoda.uh@renesas.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/usb/host/ehci-platform.c | 127 +++++++++++++++++++++++++++++++
    include/linux/usb/ehci_def.h | 2 +-
    2 files changed, 128 insertions(+), 1 deletion(-)

    diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
    index 4c306fb6b0699..8a45362155c5a 100644
    --- a/drivers/usb/host/ehci-platform.c
    +++ b/drivers/usb/host/ehci-platform.c
    @@ -29,6 +29,8 @@
    #include <linux/of.h>
    #include <linux/platform_device.h>
    #include <linux/reset.h>
    +#include <linux/sys_soc.h>
    +#include <linux/timer.h>
    #include <linux/usb.h>
    #include <linux/usb/hcd.h>
    #include <linux/usb/ehci_pdriver.h>
    @@ -44,6 +46,9 @@ struct ehci_platform_priv {
    struct clk *clks[EHCI_MAX_CLKS];
    struct reset_control *rsts;
    bool reset_on_resume;
    + bool quirk_poll;
    + struct timer_list poll_timer;
    + struct delayed_work poll_work;
    };

    static const char hcd_name[] = "ehci-platform";
    @@ -118,6 +123,111 @@ static struct usb_ehci_pdata ehci_platform_defaults = {
    .power_off = ehci_platform_power_off,
    };

    +/**
    + * quirk_poll_check_port_status - Poll port_status if the device sticks
    + * @ehci: the ehci hcd pointer
    + *
    + * 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 such a situation, the controllers require a special way which poll
    + * the EHCI PORTSC register.
    + *
    + * Return: true if the controller's port_status indicated getting stuck
    + */
    +static bool quirk_poll_check_port_status(struct ehci_hcd *ehci)
    +{
    + u32 port_status = ehci_readl(ehci, &ehci->regs->port_status[0]);
    +
    + if (!(port_status & PORT_OWNER) &&
    + (port_status & PORT_POWER) &&
    + !(port_status & PORT_CONNECT) &&
    + (port_status & PORT_LS_MASK))
    + return true;
    +
    + return false;
    +}
    +
    +/**
    + * quirk_poll_rebind_companion - rebind comanion device to recover
    + * @ehci: the ehci hcd pointer
    + *
    + * 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
    + * recover from such a situation, the controllers require changing the OHCI
    + * functional state.
    + */
    +static void quirk_poll_rebind_companion(struct ehci_hcd *ehci)
    +{
    + struct device *companion_dev;
    + struct usb_hcd *hcd = ehci_to_hcd(ehci);
    +
    + companion_dev = usb_of_get_companion_dev(hcd->self.controller);
    + if (!companion_dev)
    + return;
    +
    + device_release_driver(companion_dev);
    + if (device_attach(companion_dev) < 0)
    + ehci_err(ehci, "%s: failed\n", __func__);
    +
    + put_device(companion_dev);
    +}
    +
    +static void quirk_poll_work(struct work_struct *work)
    +{
    + struct ehci_platform_priv *priv =
    + container_of(to_delayed_work(work), struct ehci_platform_priv,
    + poll_work);
    + struct ehci_hcd *ehci = container_of((void *)priv, struct ehci_hcd,
    + priv);
    +
    + /* check the status twice to reduce misdetection rate */
    + if (!quirk_poll_check_port_status(ehci))
    + return;
    + udelay(10);
    + if (!quirk_poll_check_port_status(ehci))
    + return;
    +
    + ehci_dbg(ehci, "%s: detected getting stuck. rebind now!\n", __func__);
    + quirk_poll_rebind_companion(ehci);
    +}
    +
    +static void quirk_poll_timer(struct timer_list *t)
    +{
    + struct ehci_platform_priv *priv = from_timer(priv, t, poll_timer);
    + struct ehci_hcd *ehci = container_of((void *)priv, struct ehci_hcd,
    + priv);
    +
    + if (quirk_poll_check_port_status(ehci)) {
    + /*
    + * Now scheduling the work for testing the port more. Note that
    + * updating the status is possible to be delayed when
    + * reconnection. So, this uses delayed work with 5 ms delay
    + * to avoid misdetection.
    + */
    + schedule_delayed_work(&priv->poll_work, msecs_to_jiffies(5));
    + }
    +
    + mod_timer(&priv->poll_timer, jiffies + HZ);
    +}
    +
    +static void quirk_poll_init(struct ehci_platform_priv *priv)
    +{
    + INIT_DELAYED_WORK(&priv->poll_work, quirk_poll_work);
    + timer_setup(&priv->poll_timer, quirk_poll_timer, 0);
    + mod_timer(&priv->poll_timer, jiffies + HZ);
    +}
    +
    +static void quirk_poll_end(struct ehci_platform_priv *priv)
    +{
    + del_timer_sync(&priv->poll_timer);
    + cancel_delayed_work(&priv->poll_work);
    +}
    +
    +static const struct soc_device_attribute quirk_poll_match[] = {
    + { .family = "R-Car Gen3" },
    + { /* sentinel*/ }
    +};
    +
    static int ehci_platform_probe(struct platform_device *dev)
    {
    struct usb_hcd *hcd;
    @@ -178,6 +288,9 @@ static int ehci_platform_probe(struct platform_device *dev)
    "has-transaction-translator"))
    hcd->has_tt = 1;

    + if (soc_device_match(quirk_poll_match))
    + priv->quirk_poll = true;
    +
    for (clk = 0; clk < EHCI_MAX_CLKS; clk++) {
    priv->clks[clk] = of_clk_get(dev->dev.of_node, clk);
    if (IS_ERR(priv->clks[clk])) {
    @@ -249,6 +362,9 @@ static int ehci_platform_probe(struct platform_device *dev)
    device_enable_async_suspend(hcd->self.controller);
    platform_set_drvdata(dev, hcd);

    + if (priv->quirk_poll)
    + quirk_poll_init(priv);
    +
    return err;

    err_power:
    @@ -275,6 +391,9 @@ static int ehci_platform_remove(struct platform_device *dev)
    struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
    int clk;

    + if (priv->quirk_poll)
    + quirk_poll_end(priv);
    +
    usb_remove_hcd(hcd);

    if (pdata->power_off)
    @@ -299,9 +418,13 @@ static int ehci_platform_suspend(struct device *dev)
    struct usb_hcd *hcd = dev_get_drvdata(dev);
    struct usb_ehci_pdata *pdata = dev_get_platdata(dev);
    struct platform_device *pdev = to_platform_device(dev);
    + struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
    bool do_wakeup = device_may_wakeup(dev);
    int ret;

    + if (priv->quirk_poll)
    + quirk_poll_end(priv);
    +
    ret = ehci_suspend(hcd, do_wakeup);
    if (ret)
    return ret;
    @@ -333,6 +456,10 @@ static int ehci_platform_resume(struct device *dev)
    }

    ehci_resume(hcd, priv->reset_on_resume);
    +
    + if (priv->quirk_poll)
    + quirk_poll_init(priv);
    +
    return 0;
    }
    #endif /* CONFIG_PM_SLEEP */
    diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h
    index a15ce99dfc2d6..78e0063555575 100644
    --- a/include/linux/usb/ehci_def.h
    +++ b/include/linux/usb/ehci_def.h
    @@ -151,7 +151,7 @@ struct ehci_regs {
    #define PORT_OWNER (1<<13) /* true: companion hc owns this port */
    #define PORT_POWER (1<<12) /* true: has power (see PPC) */
    #define PORT_USB11(x) (((x)&(3<<10)) == (1<<10)) /* USB 1.1 device */
    -/* 11:10 for detecting lowspeed devices (reset vs release ownership) */
    +#define PORT_LS_MASK (3<<10) /* Link status (SE0, K or J */
    /* 9 reserved */
    #define PORT_LPM (1<<9) /* LPM transaction */
    #define PORT_RESET (1<<8) /* reset port */
    --
    2.25.1


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