On 12/2/2017 10:22 PM, Chunfeng Yun wrote:
> 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
Thanks, I definitely misunderstood his comments the first go around. I will make
the change.
>>
>> 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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>
--
Adam Wallis
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
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