/*
 * mtk-afe-platform-driver.c  --  Mediatek afe platform driver
 *
 * Copyright (c) 2016 MediaTek Inc.
 * Author: Garlic Tseng <garlic.tseng@mediatek.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 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <sound/soc.h>

#include "mtk-afe-platform-driver.h"
#include "mtk-base-afe.h"

static snd_pcm_uframes_t mtk_afe_pcm_pointer
			 (struct snd_pcm_substream *substream)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct mtk_base_afe *afe = snd_soc_platform_get_drvdata(rtd->platform);
	struct mtk_base_afe_memif *memif = &afe->memif[rtd->cpu_dai->id];
	const struct mtk_base_memif_data *memif_data = memif->data;
	struct regmap *regmap = afe->regmap;
	struct device *dev = afe->dev;
	int reg_ofs_base = memif_data->reg_ofs_base;
	int reg_ofs_cur = memif_data->reg_ofs_cur;
	unsigned int hw_ptr = 0, hw_base = 0;
	int ret, pcm_ptr_bytes;

	ret = regmap_read(regmap, reg_ofs_cur, &hw_ptr);
	if (ret || hw_ptr == 0) {
		dev_err(dev, "%s hw_ptr err\n", __func__);
		pcm_ptr_bytes = 0;
		goto POINTER_RETURN_FRAMES;
	}

	ret = regmap_read(regmap, reg_ofs_base, &hw_base);
	if (ret || hw_base == 0) {
		dev_err(dev, "%s hw_ptr err\n", __func__);
		pcm_ptr_bytes = 0;
		goto POINTER_RETURN_FRAMES;
	}

	pcm_ptr_bytes = hw_ptr - hw_base;

POINTER_RETURN_FRAMES:
	return bytes_to_frames(substream->runtime, pcm_ptr_bytes);
}

static const struct snd_pcm_ops mtk_afe_pcm_ops = {
	.ioctl = snd_pcm_lib_ioctl,
	.pointer = mtk_afe_pcm_pointer,
};

static int mtk_afe_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
	size_t size;
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	struct mtk_base_afe *afe = snd_soc_platform_get_drvdata(rtd->platform);

	size = afe->mtk_afe_hardware->buffer_bytes_max;
	return snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
						     card->dev, size, size);
}

static void mtk_afe_pcm_free(struct snd_pcm *pcm)
{
	snd_pcm_lib_preallocate_free_for_all(pcm);
}

const struct snd_soc_platform_driver mtk_afe_pcm_platform = {
	.ops = &mtk_afe_pcm_ops,
	.pcm_new = mtk_afe_pcm_new,
	.pcm_free = mtk_afe_pcm_free,
};
EXPORT_SYMBOL_GPL(mtk_afe_pcm_platform);

MODULE_DESCRIPTION("Mediatek simple platform driver");
MODULE_AUTHOR("Garlic Tseng <garlic.tseng@mediatek.com>");
MODULE_LICENSE("GPL v2");

option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<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/tools?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>testing</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>selftests</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>ftrace</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace/test.d?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>test.d</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace/test.d/kprobe?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>kprobe</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>kretprobe_args.tc</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/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?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/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc?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 'tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc')</div><table summary='diffstat' class='diffstat'>