| Message ID | 20200910025154.20848-1-chris.packham@alliedtelesis.co.nz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | usb: host: ehci-platform: Add workaround for brcm, xgs-iproc-ehci | expand |
On Thu, Sep 10, 2020 at 02:51:53PM +1200, Chris Packham wrote: > The ehci controller found in some Broadcom switches with integrated SoCs > has an issue which causes a soft lockup with large transfers like you > see when running ext4 on USB3 flash drive. > > Port the fix from the Broadcom XLDK to increase the OUT_THRESHOLD to > avoid the problem. > > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> > --- > > I don't have much data on what this change does. I can say it is needed to > avoid a soft lockup when using a USB3 Flash drive formatted has ext4 (USB2 + > ext4 is OK, USB3 + fat is OK). I presume the affected combination ends up using > larger transfers triggering the problem. > > The equivalent change in the Broadcom XLDK is > > if (IS_ENABLED(CONFIG_USB_EHCI_XGS_IPROC)) > ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, > &ehci->regs->reserved4[6]); > > This is problematic because it would unconditionally apply to all ehci > controllers whenever CONFIG_USB_EHCI_XGS_IPROC is enabled (also reserved4 only > goes to 6 so technically it's indexing off the end of the array). > > I wasn't sure if I should add a new property or somehow detect the affected > host controller. I settled on using of_device_is_compatible() as that seemed > the simplest thing to do. Reasonable. > drivers/usb/host/ehci-platform.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c > index 006c4f6188a5..0d2de8faa3c1 100644 > --- a/drivers/usb/host/ehci-platform.c > +++ b/drivers/usb/host/ehci-platform.c > @@ -53,6 +53,9 @@ struct ehci_platform_priv { > > static const char hcd_name[] = "ehci-platform"; > > +#define bcm_iproc_insnreg01 hostpc > +#define BCM_USB_FIFO_THRESHOLD 0x00800040 Minor nit: Since hostpc is nominally an array, IMO it would be a little clearer to define bcm_iproc_insnreg01 as hostpc[0] and then do the ehci_writel to &ehci->regs->bcm_iproc_insnreg01. That makes it look more like an ordinary structure member. Also IMO, it's better to put the #define's before the structure definitions. > + > static int ehci_platform_reset(struct usb_hcd *hcd) > { > struct platform_device *pdev = to_platform_device(hcd->self.controller); > @@ -358,6 +361,9 @@ static int ehci_platform_probe(struct platform_device *dev) > > device_wakeup_enable(hcd->self.controller); > device_enable_async_suspend(hcd->self.controller); > + if (of_device_is_compatible(dev->dev.of_node, "brcm,xgs-iproc-ehci")) > + ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, > + ehci->regs->bcm_iproc_insnreg01); In theory, this should go before the usb_add_hcd() call because afterward the controller is active. But you can't put it before ehci->regs has been assigned, which happens in ehci_setup(). Probably the best place is at the end of ehci_platform_reset(). Alan Stern > platform_set_drvdata(dev, hcd); > > if (priv->quirk_poll) > -- > 2.28.0 >
diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c index 006c4f6188a5..0d2de8faa3c1 100644 --- a/drivers/usb/host/ehci-platform.c +++ b/drivers/usb/host/ehci-platform.c @@ -53,6 +53,9 @@ struct ehci_platform_priv { static const char hcd_name[] = "ehci-platform"; +#define bcm_iproc_insnreg01 hostpc +#define BCM_USB_FIFO_THRESHOLD 0x00800040 + static int ehci_platform_reset(struct usb_hcd *hcd) { struct platform_device *pdev = to_platform_device(hcd->self.controller); @@ -358,6 +361,9 @@ static int ehci_platform_probe(struct platform_device *dev) device_wakeup_enable(hcd->self.controller); device_enable_async_suspend(hcd->self.controller); + if (of_device_is_compatible(dev->dev.of_node, "brcm,xgs-iproc-ehci")) + ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, + ehci->regs->bcm_iproc_insnreg01); platform_set_drvdata(dev, hcd); if (priv->quirk_poll)
The ehci controller found in some Broadcom switches with integrated SoCs has an issue which causes a soft lockup with large transfers like you see when running ext4 on USB3 flash drive. Port the fix from the Broadcom XLDK to increase the OUT_THRESHOLD to avoid the problem. Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> --- I don't have much data on what this change does. I can say it is needed to avoid a soft lockup when using a USB3 Flash drive formatted has ext4 (USB2 + ext4 is OK, USB3 + fat is OK). I presume the affected combination ends up using larger transfers triggering the problem. The equivalent change in the Broadcom XLDK is if (IS_ENABLED(CONFIG_USB_EHCI_XGS_IPROC)) ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, &ehci->regs->reserved4[6]); This is problematic because it would unconditionally apply to all ehci controllers whenever CONFIG_USB_EHCI_XGS_IPROC is enabled (also reserved4 only goes to 6 so technically it's indexing off the end of the array). I wasn't sure if I should add a new property or somehow detect the affected host controller. I settled on using of_device_is_compatible() as that seemed the simplest thing to do. drivers/usb/host/ehci-platform.c | 6 ++++++ 1 file changed, 6 insertions(+)