usb: xhci: allow imod-interval to be configurable

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-ns", 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.

Tested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
index 30595964876a941a2cf6b0c08a06dacc18fdee2d..9ff560298498d767e5dd7bd0a3dca6c7a4fadfe6 100644 (file)
--- 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-ns: default interrupt moderation interval is 5000ns
 
 Example:
 usb30: usb@11270000 {
@@ -66,6 +67,7 @@ usb30: usb@11270000 {
        usb3-lpm-capable;
        mediatek,syscon-wakeup = <&pericfg>;
        mediatek,wakeup-src = <1>;
+       imod-interval-ns = <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 a53107132cc393bc79c2cef9eaafc8598240bf97..e2ea59bbca93f1cd0ec107bd3d6ff3cc175a7043 100644 (file)
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -31,6 +31,7 @@ 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-ns: default interrupt moderation interval is 5000ns
 
 Example:
        usb@f0931000 {

diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index b62a1d23244b29c92bab7b8182e025033e6cb0e1..1cb2a8ba2de5da5309ddd1a8969e55d1e102faea 100644 (file)
--- 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 moderation 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-ns", &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 7ef1274ef7f7f245a03e539982da07f6242343b1..4bcddd424a07a781a1c6518898de41b0e511ca4e 100644 (file)
--- 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 moderation 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 09f164f8cf8c9bad438655a28469efd0fe842199..6f038306c14d6c244dc9a7305adce185ee3aaecc 100644 (file)
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -269,6 +269,11 @@ 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 moderation value in nanoseconds. */
+       xhci->imod_interval = 40000;
+       device_property_read_u32(sysdev, "imod-interval-ns",
+                                &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 060e5b446902b675b2cc2acd269fd5aabd75363b..05104bd2b611ec7ce9d3762ab408fd973e663394 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -583,11 +583,7 @@ 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 7c8781758cea2f9a6fd19ad2e6709c12b264818d..96099a245c69eecdd84feae2c3924ac7e9ca0a84 100644 (file)
--- 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;