| Message ID | 20200913215926.29880-1-chris.packham@alliedtelesis.co.nz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] usb: host: ehci-platform: Add workaround for brcm, xgs-iproc-ehci | expand |
On Mon, Sep 14, 2020 at 09:59:26AM +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. > > Changes in v2: > - move workaround to ehci_platform_reset > - cosmetic changes suggested by Alan > > drivers/usb/host/ehci-platform.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c > index 006c4f6188a5..9804ffa9e67f 100644 > --- a/drivers/usb/host/ehci-platform.c > +++ b/drivers/usb/host/ehci-platform.c > @@ -42,6 +42,9 @@ > #define EHCI_MAX_CLKS 4 > #define hcd_to_ehci_priv(h) ((struct ehci_platform_priv *)hcd_to_ehci(h)->priv) > > +#define BCM_USB_FIFO_THRESHOLD 0x00800040 > +#define bcm_iproc_insnreg01 hostpc[0] > + > struct ehci_platform_priv { > struct clk *clks[EHCI_MAX_CLKS]; > struct reset_control *rsts; > @@ -75,6 +78,11 @@ static int ehci_platform_reset(struct usb_hcd *hcd) > > if (pdata->no_io_watchdog) > ehci->need_io_watchdog = 0; > + > + if (of_device_is_compatible(pdev->dev.of_node, "brcm,xgs-iproc-ehci")) > + ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, > + &ehci->regs->bcm_iproc_insnreg01); > + > return 0; > } Acked-by: Alan Stern <stern@rowland.harvard.edu>
diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c index 006c4f6188a5..9804ffa9e67f 100644 --- a/drivers/usb/host/ehci-platform.c +++ b/drivers/usb/host/ehci-platform.c @@ -42,6 +42,9 @@ #define EHCI_MAX_CLKS 4 #define hcd_to_ehci_priv(h) ((struct ehci_platform_priv *)hcd_to_ehci(h)->priv) +#define BCM_USB_FIFO_THRESHOLD 0x00800040 +#define bcm_iproc_insnreg01 hostpc[0] + struct ehci_platform_priv { struct clk *clks[EHCI_MAX_CLKS]; struct reset_control *rsts; @@ -75,6 +78,11 @@ static int ehci_platform_reset(struct usb_hcd *hcd) if (pdata->no_io_watchdog) ehci->need_io_watchdog = 0; + + if (of_device_is_compatible(pdev->dev.of_node, "brcm,xgs-iproc-ehci")) + ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD, + &ehci->regs->bcm_iproc_insnreg01); + return 0; }
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. Changes in v2: - move workaround to ehci_platform_reset - cosmetic changes suggested by Alan drivers/usb/host/ehci-platform.c | 8 ++++++++ 1 file changed, 8 insertions(+)