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
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");
