/*
 * linux/driver/usb/host/ehci-w90x900.c
 *
 * Copyright (c) 2008 Nuvoton technology corporation.
 *
 * Wan ZongShun <mcuos.com@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation;version 2 of the License.
 *
 */

#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>

#include "ehci.h"

/* enable phy0 and phy1 for w90p910 */
#define	ENPHY		(0x01<<8)
#define PHY0_CTR	(0xA4)
#define PHY1_CTR	(0xA8)

#define DRIVER_DESC "EHCI w90x900 driver"

static const char hcd_name[] = "ehci-w90x900 ";

static struct hc_driver __read_mostly ehci_w90x900_hc_driver;

static int ehci_w90x900_probe(struct platform_device *pdev)
{
	struct usb_hcd *hcd;
	struct ehci_hcd *ehci;
	struct resource *res;
	int retval = 0, irq;
	unsigned long val;

	hcd = usb_create_hcd(&ehci_w90x900_hc_driver,
			&pdev->dev, "w90x900 EHCI");
	if (!hcd) {
		retval = -ENOMEM;
		goto err1;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	hcd->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(hcd->regs)) {
		retval = PTR_ERR(hcd->regs);
		goto err2;
	}
	hcd->rsrc_start = res->start;
	hcd->rsrc_len = resource_size(res);

	ehci = hcd_to_ehci(hcd);
	ehci->caps = hcd->regs;
	ehci->regs = hcd->regs +
		HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));

	/* enable PHY 0,1,the regs only apply to w90p910
	 *  0xA4,0xA8 were offsets of PHY0 and PHY1 controller of
	 *  w90p910 IC relative to ehci->regs.
	 */
	val = __raw_readl(ehci->regs+PHY0_CTR);
	val |= ENPHY;
	__raw_writel(val, ehci->regs+PHY0_CTR);

	val = __raw_readl(ehci->regs+PHY1_CTR);
	val |= ENPHY;
	__raw_writel(val, ehci->regs+PHY1_CTR);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		retval = irq;
		goto err2;
	}

	retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
	if (retval != 0)
		goto err2;

	device_wakeup_enable(hcd->self.controller);
	return retval;
err2:
	usb_put_hcd(hcd);
err1:
	return retval;
}

static int ehci_w90x900_remove(struct platform_device *pdev)
{
	struct usb_hcd *hcd = platform_get_drvdata(pdev);

	usb_remove_hcd(hcd);
	usb_put_hcd(hcd);

	return 0;
}

static struct platform_driver ehci_hcd_w90x900_driver = {
	.probe  = ehci_w90x900_probe,
	.remove = ehci_w90x900_remove,
	.driver = {
		.name = "w90x900-ehci",
	},
};

static int __init ehci_w90X900_init(void)
{
	if (usb_disabled())
		return -ENODEV;

	pr_info("%s: " DRIVER_DESC "\n", hcd_name);

	ehci_init_driver(&ehci_w90x900_hc_driver, NULL);
	return platform_driver_register(&ehci_hcd_w90x900_driver);
}
module_init(ehci_w90X900_init);

static void __exit ehci_w90X900_cleanup(void)
{
	platform_driver_unregister(&ehci_hcd_w90x900_driver);
}
module_exit(ehci_w90X900_cleanup);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
MODULE_ALIAS("platform:w90p910-ehci");
MODULE_LICENSE("GPL v2");
.git/commit/include/dt-bindings?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>dt-bindings</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>reset</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>qcom,gcc-mdm9615.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='39cb2c9a316e77f6dfba96c543e55b6672d5a37e'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include/dt-bindings/reset/qcom,gcc-mdm9615.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/reset/qcom,gcc-mdm9615.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'include/dt-bindings/reset/qcom,gcc-mdm9615.h')</div><table summary='diffstat' class='diffstat'>