[PATCH v4] usb: xhci: allow imod-interval to be configurable

On 05.12.2017 04:54, Adam Wallis wrote:

On 12/4/2017 9:15 PM, Chunfeng Yun wrote:

quoted

On Mon, 2017-12-04 at 09:27 -0500, Adam Wallis wrote:

quoted

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>
Signed-off-by: Adam Wallis <redacted>
---
changes from v3:
   * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
   * Changed "modulation" to "moderation" throughout patch [Mathias]
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                                | 5 +++++
  drivers/usb/host/xhci.c                                     | 7 ++-----
  drivers/usb/host/xhci.h                                     | 2 ++
  7 files changed, 24 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..9ff5602 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-ns: default interrupt moderation interval is 5000ns
  
  Example:
  usb30: usb at 11270000 {

@@ -66,6 +67,7 @@ usb30: usb at 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 ae6e484..969908d 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-ns: default interrupt moderation interval is 5000ns
  
  Example:
  	usb at f0931000 {

diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index b62a1d2..1cb2a8b 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 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 7ef1274..4bcddd4 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 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 09f164f..6f03830 100644
--- 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 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");

s/modulation/moderation

Mathias said there was no need to change the existing modulation strings - only
the ones that I had added.

Baolu is working on a cleanup patch that removes debug messages that became
useless with debugfs and proper tracing support, including this line.

Less conflicts to resolve for me if we don't change this.

quoted

quoted

  	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;
+

No need a blank line

If this patch goes through another version, I will remove this line

If Rob Acks this version I'll apply it and remove that blank line.

-Mathias