/*
 * Generic implementation of 64-bit atomics using spinlocks,
 * useful on processors that don't have 64-bit atomic instructions.
 *
 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.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; either version
 * 2 of the License, or (at your option) any later version.
 */
#ifndef _ASM_GENERIC_ATOMIC64_H
#define _ASM_GENERIC_ATOMIC64_H

typedef struct {
	long long counter;
} atomic64_t;

#define ATOMIC64_INIT(i)	{ (i) }

extern long long atomic64_read(const atomic64_t *v);
extern void	 atomic64_set(atomic64_t *v, long long i);

#define ATOMIC64_OP(op)							\
extern void	 atomic64_##op(long long a, atomic64_t *v);

#define ATOMIC64_OP_RETURN(op)						\
extern long long atomic64_##op##_return(long long a, atomic64_t *v);

#define ATOMIC64_FETCH_OP(op)						\
extern long long atomic64_fetch_##op(long long a, atomic64_t *v);

#define ATOMIC64_OPS(op)	ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)

ATOMIC64_OPS(add)
ATOMIC64_OPS(sub)

#undef ATOMIC64_OPS
#define ATOMIC64_OPS(op)	ATOMIC64_OP(op) ATOMIC64_FETCH_OP(op)

ATOMIC64_OPS(and)
ATOMIC64_OPS(or)
ATOMIC64_OPS(xor)

#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP

extern long long atomic64_dec_if_positive(atomic64_t *v);
extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
extern long long atomic64_xchg(atomic64_t *v, long long new);
extern int	 atomic64_add_unless(atomic64_t *v, long long a, long long u);

#define atomic64_add_negative(a, v)	(atomic64_add_return((a), (v)) < 0)
#define atomic64_inc(v)			atomic64_add(1LL, (v))
#define atomic64_inc_return(v)		atomic64_add_return(1LL, (v))
#define atomic64_inc_and_test(v) 	(atomic64_inc_return(v) == 0)
#define atomic64_sub_and_test(a, v)	(atomic64_sub_return((a), (v)) == 0)
#define atomic64_dec(v)			atomic64_sub(1LL, (v))
#define atomic64_dec_return(v)		atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v)	(atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) 	atomic64_add_unless((v), 1LL, 0LL)

#endif  /*  _ASM_GENERIC_ATOMIC64_H  */
<td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/net/bluetooth'>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>bluetooth</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'/><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>Tony Lindgren &lt;tony@atomide.com&gt;</td><td class='right'>2017-01-19 08:49:07 -0800</td></tr>
<tr><th>committer</th><td>Vinod Koul &lt;vinod.koul@intel.com&gt;</td><td class='right'>2017-01-25 11:29:11 +0530</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/bluetooth?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>139fc7e29f97d6bb6c4dca2a97be2dc3f824bd51</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/bluetooth?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>net/bluetooth</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth?h=nds-private-remove&amp;id=49def1853334396f948dcb4cedb9347abb318df5'>49def1853334396f948dcb4cedb9347abb318df5</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bluetooth?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b&amp;id2=49def1853334396f948dcb4cedb9347abb318df5'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: cppi41: Fix runtime PM timeouts with USB mass storage</div><div class='commit-msg'>Commit fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
added runtime PM support for cppi41, but had corner case issues. Some of
the issues were fixed with commit 098de42ad670 ("dmaengine: cppi41: Fix
unpaired pm runtime when only a USB hub is connected"). That fix however
caused a new regression where we can get error -115 messages with USB on
BeagleBone when connecting a USB mass storage device to a hub.

This is because when connecting a USB mass storage device to a hub, the
initial DMA transfers can take over 200ms to complete and cppi41
autosuspend delay times out.

To fix the issue, we want to implement refcounting for chan_busy array
that contains the active dma transfers. Increasing the autosuspend delay
won't help as that the delay could be potentially seconds, and it's best
to let the USB subsystem to deal with the timeouts on errors.

The earlier attempt for runtime PM was buggy as the pm_runtime_get/put()
calls could get unpaired easily as they did not follow the state of
the chan_busy array as described in commit 098de42ad670 ("dmaengine:
cppi41: Fix unpaired pm runtime when only a USB hub is connected".

Let's fix the issue by adding pm_runtime_get() to where a new transfer
is added to the chan_busy array, and calls to pm_runtime_put() where
chan_busy array entry is cleared. This prevents any autosuspend timeouts
from happening while dma transfers are active.

Fixes: 098de42ad670 ("dmaengine: cppi41: Fix unpaired pm runtime when
only a USB hub is connected")
Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
Cc: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: Bin Liu &lt;b-liu@ti.com&gt;
Cc: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Cc: Kevin Hilman &lt;khilman@baylibre.com&gt;
Cc: Patrick Titiano &lt;ptitiano@baylibre.com&gt;
Cc: Sergei Shtylyov &lt;sergei.shtylyov@cogentembedded.com&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Tested-by: Bin Liu &lt;b-liu@ti.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>Diffstat</a> (limited to 'net/bluetooth')</div><table summary='diffstat' class='diffstat'>