[PATCH v1] usb: xhci: allow imod-interval to be configurable
From: Adam Wallis <hidden>
Date: 2017-11-28 17:11:46
Also in:
linux-devicetree, linux-mediatek
Subsystem:
open firmware and flattened device tree bindings, the rest, usb subsystem, usb xhci driver · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds, Greg Kroah-Hartman, Mathias Nyman
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.
Backwards compatibility is maintained for MTK_HOSTS through the quirk
bit, however, imod_interval should be pushed into device tree at a
future point and this quirk should be removed from xhci_plat_probe
Signed-off-by: Adam Wallis <redacted>
---
Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
drivers/usb/host/xhci-plat.c | 15 +++++++++++++++
drivers/usb/host/xhci.c | 7 ++-----
drivers/usb/host/xhci.h | 2 ++
4 files changed, 20 insertions(+), 5 deletions(-)
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index ae6e484..3998459 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: IMOD_INTERVAL in nano-seconds. Default is 40000 Example: usb at f0931000 {
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 09f164f..f7730c8 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c@@ -23,6 +23,7 @@ #include "xhci-plat.h" #include "xhci-mvebu.h" #include "xhci-rcar.h" +#include "xhci-mtk.h" static struct hc_driver __read_mostly xhci_plat_hc_driver;
@@ -269,6 +270,20 @@ 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 in nanoseconds */ + if (device_property_read_u32(sysdev, + "imod-interval", &xhci->imod_interval)) + xhci->imod_interval = 40000; + else if (xhci->quirks & XHCI_MTK_HOST) + /* + * The increment interval is 8 times as much as that defined in + * the xHCI spec on MTK's controller. This is added to provide + * backwards compatibility, however, this should be pushed into + * the device tree files at some point in the future and + * removed from xhci_plat_probe + */ + xhci->imod_interval = 5000; + 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..6a09311 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 |= (u16) (xhci->imod_interval / 250); + 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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