On Fri, 2017-12-01 at 10:44 -0500, Adam Wallis wrote:
> The xHCI driver currently has the IMOD set to 160, which
> translates to an IMOD interval of 40,000ns (160 * 250)ns
>
> Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
> introduced a QUIRK for the MTK platform to adjust this interval to 20,
> which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
> due to the fact that the MTK controller IMOD interval is 8 times
> as much as defined in xHCI spec.
>
> Instead of adding more quirk bits for additional platforms, this patch
> introduces the ability for vendors to set the IMOD_INTERVAL as is
> optimal for their platform. By using device_property_read_u32() on
> "imod-interval", the IMOD INTERVAL can be specified in nano seconds. If
> no interval is specified, the default of 40,000ns (IMOD=160) will be
> used.
>
> No bounds checking has been implemented due to the fact that a vendor
> may have violated the spec and would need to specify a value outside of
> the max 8,000 IRQs/second limit specified in the xHCI spec.
>
> Signed-off-by: Adam Wallis <awallis@xxxxxxxxxxxxxx>
> ---
> changes from v2:
> * Added PCI default value [Mathias]
> * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
> * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
> * Updated bindings Documentation to use proper units [Rob Herring]
> * Added imod-interval description and example to MTK binding documentation
> changes from v1:
> * Removed device_property_read_u32() per suggestion from greg k-h
> * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast
>
> Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
> Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
> drivers/usb/host/xhci-mtk.c | 9 +++++++++
> drivers/usb/host/xhci-pci.c | 3 +++
> drivers/usb/host/xhci-plat.c | 4 ++++
> drivers/usb/host/xhci.c | 7 ++-----
> drivers/usb/host/xhci.h | 2 ++
> 7 files changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> index 3059596..45bbf18 100644
> --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> @@ -46,6 +46,7 @@ Optional properties:
> - pinctrl-names : a pinctrl state named "default" must be defined
> - pinctrl-0 : pin control group
> See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> + - imod-interval: Default interval is 5000ns
I think, as Rob suggested before, recommend to have a unit suffix
appended to the property name.
s/imod-interval/imod-interval-ns
>
> Example:
> usb30: usb@11270000 {
> @@ -66,6 +67,7 @@ usb30: usb@11270000 {
> usb3-lpm-capable;
> mediatek,syscon-wakeup = <&pericfg>;
> mediatek,wakeup-src = <1>;
> + imod-interval = <10000>;
> };
>
> 2nd: dual-role mode with xHCI driver
> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> index ae6e484..89b68f1 100644
> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> @@ -29,6 +29,7 @@ Optional properties:
> - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
> - usb3-lpm-capable: determines if platform is USB3 LPM capable
> - quirk-broken-port-ped: set if the controller has broken port disable mechanism
> + - imod-interval: Default interval is 40000ns
>
> Example:
> usb@f0931000 {
> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> index b62a1d2..278ea3b 100644
> --- a/drivers/usb/host/xhci-mtk.c
> +++ b/drivers/usb/host/xhci-mtk.c
> @@ -674,6 +674,15 @@ static int xhci_mtk_probe(struct platform_device *pdev)
>
> xhci = hcd_to_xhci(hcd);
> xhci->main_hcd = hcd;
> +
> + /*
> + * imod_interval is the interrupt modulation value in nanoseconds.
> + * The increment interval is 8 times as much as that defined in
> + * the xHCI spec on MTK's controller.
> + */
> + xhci->imod_interval = 5000;
> + device_property_read_u32(dev, "imod-interval", &xhci->imod_interval);
> +
> xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
> dev_name(dev), hcd);
> if (!xhci->shared_hcd) {
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 7ef1274..efbe57b 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -234,6 +234,9 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
> if (!xhci->sbrn)
> pci_read_config_byte(pdev, XHCI_SBRN_OFFSET, &xhci->sbrn);
>
> + /* imod_interval is the interrupt modulation value in nanoseconds. */
> + xhci->imod_interval = 40000;
> +
> retval = xhci_gen_setup(hcd, xhci_pci_quirks);
> if (retval)
> return retval;
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 09f164f..b78be87 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -269,6 +269,10 @@ static int xhci_plat_probe(struct platform_device *pdev)
> if (device_property_read_bool(&pdev->dev, "quirk-broken-port-ped"))
> xhci->quirks |= XHCI_BROKEN_PORT_PED;
>
> + /* imod_interval is the interrupt modulation value in nanoseconds. */
> + xhci->imod_interval = 40000;
> + device_property_read_u32(sysdev, "imod-interval", &xhci->imod_interval);
> +
> hcd->usb_phy = devm_usb_get_phy_by_phandle(sysdev, "usb-phy", 0);
> if (IS_ERR(hcd->usb_phy)) {
> ret = PTR_ERR(hcd->usb_phy);
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 2424d30..0b7755b 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -586,11 +586,8 @@ int xhci_run(struct usb_hcd *hcd)
> "// Set the interrupt modulation register");
> temp = readl(&xhci->ir_set->irq_control);
> temp &= ~ER_IRQ_INTERVAL_MASK;
> - /*
> - * the increment interval is 8 times as much as that defined
> - * in xHCI spec on MTK's controller
> - */
> - temp |= (u32) ((xhci->quirks & XHCI_MTK_HOST) ? 20 : 160);
> + temp |= (xhci->imod_interval / 250) & ER_IRQ_INTERVAL_MASK;
> +
> writel(temp, &xhci->ir_set->irq_control);
>
> /* Set the HCD state before we enable the irqs */
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index 99a014a..2a4177b 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1717,6 +1717,8 @@ struct xhci_hcd {
> u8 max_interrupters;
> u8 max_ports;
> u8 isoc_threshold;
> + /* imod_interval in ns (I * 250ns) */
> + u32 imod_interval;
> int event_ring_max;
> /* 4KB min, 128MB max */
> int page_size;
--
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