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Commit cf1d53c2 authored by Devdutt Patnaik's avatar Devdutt Patnaik Committed by Mayank Rana
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usb: xhci-plat: Add support to modify imod from sysfs 



xhci allows interrupts to be moderated at 250ns interval;
provide an sysfs interface to modify interrupt rate from
userspace to understand throughput variation by changing imod.

Usage:
Below command will moderate interrupts at 1ms or (4000 * 250ns)
interval.
echo 4000 > /sys/devices/8a00000.ssusb/8a00000.dwc3/xhci-hcd.0.auto/
config_imod

Change-Id: I455d5a0f9a0314e86f711efd35315002b20f5343
Signed-off-by: default avatarDevdutt Patnaik <dpatnaik@codeaurora.org>
Signed-off-by: default avatarMayank Rana <mrana@codeaurora.org>
parent 6862ebda

drivers/usb/host/xhci-plat.c

+59 −0
Original line number Diff line number Diff line
@@ -136,6 +136,59 @@ static const struct of_device_id usb_xhci_of_match[] = { 
MODULE_DEVICE_TABLE(of, usb_xhci_of_match);

#endif



static ssize_t config_imod_store(struct device *pdev,

		struct device_attribute *attr, const char *buff, size_t size)

{

	struct usb_hcd *hcd = dev_get_drvdata(pdev);

	struct xhci_hcd *xhci;

	u32 temp;

	u32 imod;

	unsigned long flags;



	if (kstrtouint(buff, 10, &imod) != 1)

		return 0;



	imod &= ER_IRQ_INTERVAL_MASK;

	xhci = hcd_to_xhci(hcd);



	if (xhci->shared_hcd->state == HC_STATE_SUSPENDED

		&& hcd->state == HC_STATE_SUSPENDED)

		return -EACCES;



	spin_lock_irqsave(&xhci->lock, flags);

	temp = readl_relaxed(&xhci->ir_set->irq_control);

	temp &= ~ER_IRQ_INTERVAL_MASK;

	temp |= imod;

	writel_relaxed(temp, &xhci->ir_set->irq_control);

	spin_unlock_irqrestore(&xhci->lock, flags);



	return size;

}



static ssize_t config_imod_show(struct device *pdev,

		struct device_attribute *attr, char *buff)

{

	struct usb_hcd *hcd = dev_get_drvdata(pdev);

	struct xhci_hcd *xhci;

	u32 temp;

	unsigned long flags;



	xhci = hcd_to_xhci(hcd);



	if (xhci->shared_hcd->state == HC_STATE_SUSPENDED

		&& hcd->state == HC_STATE_SUSPENDED)

		return -EACCES;



	spin_lock_irqsave(&xhci->lock, flags);

	temp = readl_relaxed(&xhci->ir_set->irq_control) &

			ER_IRQ_INTERVAL_MASK;

	spin_unlock_irqrestore(&xhci->lock, flags);



	return snprintf(buff, PAGE_SIZE, "%08u\n", temp);

}



static DEVICE_ATTR(config_imod, 0644, config_imod_show, config_imod_store);



static int xhci_plat_probe(struct platform_device *pdev)

{

	const struct of_device_id *match;
@@ -278,6 +331,11 @@ static int xhci_plat_probe(struct platform_device *pdev) 
	if (ret)

		goto dealloc_usb2_hcd;



	ret = device_create_file(&pdev->dev, &dev_attr_config_imod);

	if (ret)

		dev_err(&pdev->dev, "%s: unable to create imod sysfs entry\n",

					__func__);



	pm_runtime_mark_last_busy(&pdev->dev);

	pm_runtime_put_autosuspend(&pdev->dev);
@@ -312,6 +370,7 @@ static int xhci_plat_remove(struct platform_device *dev) 
	pm_runtime_disable(&dev->dev);

	xhci->xhc_state |= XHCI_STATE_REMOVING;



	device_remove_file(&dev->dev, &dev_attr_config_imod);

	usb_remove_hcd(xhci->shared_hcd);

	usb_phy_shutdown(hcd->usb_phy);