/*
 * ARConnect IP Support (Multi core enabler: Cross core IPI, RTC ...)
 *
 * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef __SOC_ARC_MCIP_H
#define __SOC_ARC_MCIP_H

#include <soc/arc/aux.h>

#define ARC_REG_MCIP_BCR	0x0d0
#define ARC_REG_MCIP_CMD	0x600
#define ARC_REG_MCIP_WDATA	0x601
#define ARC_REG_MCIP_READBACK	0x602

struct mcip_cmd {
#ifdef CONFIG_CPU_BIG_ENDIAN
	unsigned int pad:8, param:16, cmd:8;
#else
	unsigned int cmd:8, param:16, pad:8;
#endif

#define CMD_INTRPT_GENERATE_IRQ		0x01
#define CMD_INTRPT_GENERATE_ACK		0x02
#define CMD_INTRPT_READ_STATUS		0x03
#define CMD_INTRPT_CHECK_SOURCE		0x04

/* Semaphore Commands */
#define CMD_SEMA_CLAIM_AND_READ		0x11
#define CMD_SEMA_RELEASE		0x12

#define CMD_DEBUG_SET_MASK		0x34
#define CMD_DEBUG_SET_SELECT		0x36

#define CMD_GFRC_READ_LO		0x42
#define CMD_GFRC_READ_HI		0x43

#define CMD_IDU_ENABLE			0x71
#define CMD_IDU_DISABLE			0x72
#define CMD_IDU_SET_MODE		0x74
#define CMD_IDU_SET_DEST		0x76
#define CMD_IDU_SET_MASK		0x7C

#define IDU_M_TRIG_LEVEL		0x0
#define IDU_M_TRIG_EDGE			0x1

#define IDU_M_DISTRI_RR			0x0
#define IDU_M_DISTRI_DEST		0x2
};

struct mcip_bcr {
#ifdef CONFIG_CPU_BIG_ENDIAN
		unsigned int pad4:6, pw_dom:1, pad3:1,
			     idu:1, pad2:1, num_cores:6,
			     pad:1,  gfrc:1, dbg:1, pw:1,
			     msg:1, sem:1, ipi:1, slv:1,
			     ver:8;
#else
		unsigned int ver:8,
			     slv:1, ipi:1, sem:1, msg:1,
			     pw:1, dbg:1, gfrc:1, pad:1,
			     num_cores:6, pad2:1, idu:1,
			     pad3:1, pw_dom:1, pad4:6;
#endif
};

/*
 * MCIP programming model
 *
 * - Simple commands write {cmd:8,param:16} to MCIP_CMD aux reg
 *   (param could be irq, common_irq, core_id ...)
 * - More involved commands setup MCIP_WDATA with cmd specific data
 *   before invoking the simple command
 */
static inline void __mcip_cmd(unsigned int cmd, unsigned int param)
{
	struct mcip_cmd buf;

	buf.pad = 0;
	buf.cmd = cmd;
	buf.param = param;

	WRITE_AUX(ARC_REG_MCIP_CMD, buf);
}

/*
 * Setup additional data for a cmd
 * Callers need to lock to ensure atomicity
 */
static inline void __mcip_cmd_data(unsigned int cmd, unsigned int param,
				   unsigned int data)
{
	write_aux_reg(ARC_REG_MCIP_WDATA, data);

	__mcip_cmd(cmd, param);
}

#endif
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/net?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/net/llc_c_st.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>llc_c_st.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/net/llc_c_st.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/net/llc_c_st.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/net/llc_c_st.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include/net/llc_c_st.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/llc_c_st.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/net/llc_c_st.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/net/llc_c_st.h')</div><table summary='diffstat' class='diffstat'>