[PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Daniel Mack]

This patch makes the edma driver resume correctly after suspend. Tested
on an AM33xx platform with cyclic audio streams and omap_hsmmc.

All information can be reconstructed by already known runtime
information.

As we now use some functions that were previously only used from __init
context, annotations had to be dropped.

[nm@ti.com: added error handling for runtime + suspend_late/early_resume]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Daniel Mack <zonque@gmail.com>
Tested-by: Joel Fernandes <joelf@ti.com>
Acked-by: Joel Fernandes <joelf@ti.com>
---

v6:
  amended version from Nishanth Menon, adding error handling for runtime,
  and using suspend_late/early_resume.


 arch/arm/common/edma.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 91 insertions(+), 3 deletions(-)

diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
index 8e1a024..e2b9638 100644
--- a/arch/arm/common/edma.c
+++ b/arch/arm/common/edma.c
@@ -239,6 +239,8 @@ struct edma {
 	/* list of channels with no even trigger; terminated by "-1" */
 	const s8	*noevent;
 
+	struct edma_soc_info *info;
+
 	/* The edma_inuse bit for each PaRAM slot is clear unless the
 	 * channel is in use ... by ARM or DSP, for QDMA, or whatever.
 	 */
@@ -290,13 +292,13 @@ static void map_dmach_queue(unsigned ctlr, unsigned ch_no,
 			~(0x7 << bit), queue_no << bit);
 }
 
-static void __init map_queue_tc(unsigned ctlr, int queue_no, int tc_no)
+static void map_queue_tc(unsigned ctlr, int queue_no, int tc_no)
 {
 	int bit = queue_no * 4;
 	edma_modify(ctlr, EDMA_QUETCMAP, ~(0x7 << bit), ((tc_no & 0x7) << bit));
 }
 
-static void __init assign_priority_to_queue(unsigned ctlr, int queue_no,
+static void assign_priority_to_queue(unsigned ctlr, int queue_no,
 		int priority)
 {
 	int bit = queue_no * 4;
@@ -315,7 +317,7 @@ static void __init assign_priority_to_queue(unsigned ctlr, int queue_no,
  * included in that particular EDMA variant (Eg : dm646x)
  *
  */
-static void __init map_dmach_param(unsigned ctlr)
+static void map_dmach_param(unsigned ctlr)
 {
 	int i;
 	for (i = 0; i < EDMA_MAX_DMACH; i++)
@@ -1785,15 +1787,101 @@ static int edma_probe(struct platform_device *pdev)
 			edma_write_array2(j, EDMA_DRAE, i, 1, 0x0);
 			edma_write_array(j, EDMA_QRAE, i, 0x0);
 		}
+		edma_cc[j]->info = info[j];
 		arch_num_cc++;
 	}
 
 	return 0;
 }
 
+static int edma_pm_suspend(struct device *dev)
+{
+	int j, r;
+
+	r = pm_runtime_get_sync(dev);
+	if (IS_ERR_VALUE(r)) {
+		dev_err(dev, "%s: get_sync returned %d\n", __func__, r);
+		return r;
+	}
+
+	for (j = 0; j < arch_num_cc; j++) {
+		struct edma *ecc = edma_cc[j];
+
+		disable_irq(ecc->irq_res_start);
+		disable_irq(ecc->irq_res_end);
+	}
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int edma_pm_resume(struct device *dev)
+{
+	int i, j, r;
+
+	r = pm_runtime_get_sync(dev);
+	if (IS_ERR_VALUE(r)) {
+		dev_err(dev, "%s: get_sync returned %d\n", __func__, r);
+		return r;
+	}
+
+	for (j = 0; j < arch_num_cc; j++) {
+		struct edma *cc = edma_cc[j];
+
+		s8 (*queue_priority_mapping)[2];
+		s8 (*queue_tc_mapping)[2];
+
+		queue_tc_mapping = cc->info->queue_tc_mapping;
+		queue_priority_mapping = cc->info->queue_priority_mapping;
+
+		/* Event queue to TC mapping */
+		for (i = 0; queue_tc_mapping[i][0] != -1; i++)
+			map_queue_tc(j, queue_tc_mapping[i][0],
+					queue_tc_mapping[i][1]);
+
+		/* Event queue priority mapping */
+		for (i = 0; queue_priority_mapping[i][0] != -1; i++)
+			assign_priority_to_queue(j,
+						queue_priority_mapping[i][0],
+						queue_priority_mapping[i][1]);
+
+		/* Map the channel to param entry if channel mapping logic
+		 * exist
+		 */
+		if (edma_read(j, EDMA_CCCFG) & CHMAP_EXIST)
+			map_dmach_param(j);
+
+		for (i = 0; i < cc->num_channels; i++) {
+			if (test_bit(i, cc->edma_inuse)) {
+				/* ensure access through shadow region 0 */
+				edma_or_array2(j, EDMA_DRAE, 0, i >> 5,
+						BIT(i & 0x1f));
+
+				setup_dma_interrupt(i,
+						    cc->intr_data[i].callback,
+						    cc->intr_data[i].data);
+			}
+		}
+
+		enable_irq(cc->irq_res_start);
+		enable_irq(cc->irq_res_end);
+	}
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops edma_pm_ops = {
+	.suspend_late	= edma_pm_suspend,
+	.resume_early	= edma_pm_resume,
+};
+
 static struct platform_driver edma_driver = {
 	.driver = {
 		.name	= "edma",
+		.pm	= &edma_pm_ops,
 		.of_match_table = edma_of_ids,
 	},
 	.probe = edma_probe,
-- 
1.8.4.2

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Joel Fernandes]

On 11/17/2013 04:19 PM, Daniel Mack wrote:
> This patch makes the edma driver resume correctly after suspend. Tested
> on an AM33xx platform with cyclic audio streams and omap_hsmmc.
> 
> All information can be reconstructed by already known runtime
> information.
> 
> As we now use some functions that were previously only used from __init
> context, annotations had to be dropped.
> 
> [nm@ti.com: added error handling for runtime + suspend_late/early_resume]
> Signed-off-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Daniel Mack <zonque@gmail.com>
> Tested-by: Joel Fernandes <joelf@ti.com>
> Acked-by: Joel Fernandes <joelf@ti.com>

Hi Sekhar,

Can you consider pulling this patch? It has been tested and Acked. Thanks.

regards,

-Joel

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Sekhar Nori]

+ Kevin

On Monday 25 November 2013 11:04 PM, Joel Fernandes wrote:
> On 11/17/2013 04:19 PM, Daniel Mack wrote:
>> This patch makes the edma driver resume correctly after suspend. Tested
>> on an AM33xx platform with cyclic audio streams and omap_hsmmc.
>>
>> All information can be reconstructed by already known runtime
>> information.
>>
>> As we now use some functions that were previously only used from __init
>> context, annotations had to be dropped.
>>
>> [nm@ti.com: added error handling for runtime + suspend_late/early_resume]
>> Signed-off-by: Nishanth Menon <nm@ti.com>
>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>> Tested-by: Joel Fernandes <joelf@ti.com>
>> Acked-by: Joel Fernandes <joelf@ti.com>
> 
> Hi Sekhar,
> 
> Can you consider pulling this patch? It has been tested and Acked. Thanks.

Kevin had some inputs on previous version of this patch. Were you able
to make sure he is okay with this version being merged?

I have some comments for which I will send another e-mail.

Thanks,
Sekhar

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Daniel Mack]

On 11/27/2013 02:22 PM, Sekhar Nori wrote:
> + Kevin
> 
> On Monday 25 November 2013 11:04 PM, Joel Fernandes wrote:
>> On 11/17/2013 04:19 PM, Daniel Mack wrote:
>>> This patch makes the edma driver resume correctly after suspend. Tested
>>> on an AM33xx platform with cyclic audio streams and omap_hsmmc.
>>>
>>> All information can be reconstructed by already known runtime
>>> information.
>>>
>>> As we now use some functions that were previously only used from __init
>>> context, annotations had to be dropped.
>>>
>>> [nm@ti.com: added error handling for runtime + suspend_late/early_resume]
>>> Signed-off-by: Nishanth Menon <nm@ti.com>
>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>> Tested-by: Joel Fernandes <joelf@ti.com>
>>> Acked-by: Joel Fernandes <joelf@ti.com>
>>
>> Hi Sekhar,
>>
>> Can you consider pulling this patch? It has been tested and Acked. Thanks.
> 
> Kevin had some inputs on previous version of this patch. Were you able
> to make sure he is okay with this version being merged?

I had concerns about the feedback I got, and haven't got answers yet.

In particular, I'm not convinced that using runtime PM to suspend
channels would actually save any power during runtime, or have any other
benefit. But I might be wrong - maybe someone at TI could comment on that?


Thanks,
Daniel

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Sekhar Nori]

+ Kevin

On Monday 18 November 2013 03:49 AM, Daniel Mack wrote:
> This patch makes the edma driver resume correctly after suspend. Tested
> on an AM33xx platform with cyclic audio streams and omap_hsmmc.
> 
> All information can be reconstructed by already known runtime
> information.
> 
> As we now use some functions that were previously only used from __init
> context, annotations had to be dropped.
> 
> [nm@ti.com: added error handling for runtime + suspend_late/early_resume]
> Signed-off-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Daniel Mack <zonque@gmail.com>
> Tested-by: Joel Fernandes <joelf@ti.com>
> Acked-by: Joel Fernandes <joelf@ti.com>
> ---
> 
> v6:
>   amended version from Nishanth Menon, adding error handling for runtime,
>   and using suspend_late/early_resume.
> 
> 
>  arch/arm/common/edma.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 91 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
> index 8e1a024..e2b9638 100644
> --- a/arch/arm/common/edma.c
> +++ b/arch/arm/common/edma.c
> @@ -239,6 +239,8 @@ struct edma {
>  	/* list of channels with no even trigger; terminated by "-1" */
>  	const s8	*noevent;
>  
> +	struct edma_soc_info *info;
> +
>  	/* The edma_inuse bit for each PaRAM slot is clear unless the
>  	 * channel is in use ... by ARM or DSP, for QDMA, or whatever.
>  	 */
> @@ -290,13 +292,13 @@ static void map_dmach_queue(unsigned ctlr, unsigned ch_no,
>  			~(0x7 << bit), queue_no << bit);
>  }
>  
> -static void __init map_queue_tc(unsigned ctlr, int queue_no, int tc_no)
> +static void map_queue_tc(unsigned ctlr, int queue_no, int tc_no)
>  {
>  	int bit = queue_no * 4;
>  	edma_modify(ctlr, EDMA_QUETCMAP, ~(0x7 << bit), ((tc_no & 0x7) << bit));
>  }
>  
> -static void __init assign_priority_to_queue(unsigned ctlr, int queue_no,
> +static void assign_priority_to_queue(unsigned ctlr, int queue_no,
>  		int priority)
>  {
>  	int bit = queue_no * 4;
> @@ -315,7 +317,7 @@ static void __init assign_priority_to_queue(unsigned ctlr, int queue_no,
>   * included in that particular EDMA variant (Eg : dm646x)
>   *
>   */
> -static void __init map_dmach_param(unsigned ctlr)
> +static void map_dmach_param(unsigned ctlr)
>  {
>  	int i;
>  	for (i = 0; i < EDMA_MAX_DMACH; i++)
> @@ -1785,15 +1787,101 @@ static int edma_probe(struct platform_device *pdev)
>  			edma_write_array2(j, EDMA_DRAE, i, 1, 0x0);
>  			edma_write_array(j, EDMA_QRAE, i, 0x0);
>  		}
> +		edma_cc[j]->info = info[j];
>  		arch_num_cc++;
>  	}
>  
>  	return 0;
>  }
>  
> +static int edma_pm_suspend(struct device *dev)
> +{
> +	int j, r;
> +
> +	r = pm_runtime_get_sync(dev);
> +	if (IS_ERR_VALUE(r)) {

So IS_ERR_VALUE() is only for functions which may return a negative
number outside of MAX_ERRNO as a success indication.
pm_runtime_get_sync() does not appear to be one of them so just use"

if (r < 0) { .. }

> +		dev_err(dev, "%s: get_sync returned %d\n", __func__, r);
> +		return r;
> +	}
> +
> +	for (j = 0; j < arch_num_cc; j++) {
> +		struct edma *ecc = edma_cc[j];
> +
> +		disable_irq(ecc->irq_res_start);
> +		disable_irq(ecc->irq_res_end);
> +	}
> +
> +	pm_runtime_put_sync(dev);
> +
> +	return 0;
> +}
> +
> +static int edma_pm_resume(struct device *dev)
> +{
> +	int i, j, r;
> +
> +	r = pm_runtime_get_sync(dev);
> +	if (IS_ERR_VALUE(r)) {

Same here as above.

> +		dev_err(dev, "%s: get_sync returned %d\n", __func__, r);
> +		return r;
> +	}
> +
> +	for (j = 0; j < arch_num_cc; j++) {
> +		struct edma *cc = edma_cc[j];
> +
> +		s8 (*queue_priority_mapping)[2];
> +		s8 (*queue_tc_mapping)[2];
> +
> +		queue_tc_mapping = cc->info->queue_tc_mapping;
> +		queue_priority_mapping = cc->info->queue_priority_mapping;
> +
> +		/* Event queue to TC mapping */
> +		for (i = 0; queue_tc_mapping[i][0] != -1; i++)
> +			map_queue_tc(j, queue_tc_mapping[i][0],
> +					queue_tc_mapping[i][1]);
> +
> +		/* Event queue priority mapping */
> +		for (i = 0; queue_priority_mapping[i][0] != -1; i++)
> +			assign_priority_to_queue(j,
> +						queue_priority_mapping[i][0],
> +						queue_priority_mapping[i][1]);
> +
> +		/* Map the channel to param entry if channel mapping logic
> +		 * exist
> +		 */

Please follow the multi-line commenting style.

> +		if (edma_read(j, EDMA_CCCFG) & CHMAP_EXIST)
> +			map_dmach_param(j);
> +
> +		for (i = 0; i < cc->num_channels; i++) {
> +			if (test_bit(i, cc->edma_inuse)) {
> +				/* ensure access through shadow region 0 */
> +				edma_or_array2(j, EDMA_DRAE, 0, i >> 5,
> +						BIT(i & 0x1f));

There are some checkpatch checks that result from lines like this.
Please fix these as well.

CHECK: Alignment should match open parenthesis
#179: FILE: arch/arm/common/edma.c:1841:
+			map_queue_tc(j, queue_tc_mapping[i][0],
+					queue_tc_mapping[i][1]);

CHECK: Alignment should match open parenthesis
#184: FILE: arch/arm/common/edma.c:1846:
+			assign_priority_to_queue(j,
+						queue_priority_mapping[i][0],

CHECK: Alignment should match open parenthesis
#197: FILE: arch/arm/common/edma.c:1859:
+				edma_or_array2(j, EDMA_DRAE, 0, i >> 5,
+						BIT(i & 0x1f));

total: 0 errors, 0 warnings, 3 checks, 132 lines checked

Thanks,
Sekhar

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Daniel Mack]

Hi Sekhar,

On 11/27/2013 02:35 PM, Sekhar Nori wrote:
> On Monday 18 November 2013 03:49 AM, Daniel Mack wrote:

>> +static int edma_pm_suspend(struct device *dev)
>> +{
>> +	int j, r;
>> +
>> +	r = pm_runtime_get_sync(dev);
>> +	if (IS_ERR_VALUE(r)) {
> 
> So IS_ERR_VALUE() is only for functions which may return a negative
> number outside of MAX_ERRNO as a success indication.
> pm_runtime_get_sync() does not appear to be one of them so just use"
>
> if (r < 0) { .. }

That's true. Thanks for catching this, I'll fix it. However, grepping
through the tree, there are quite a lot places where the same mistake is
made.

>> +		/* Map the channel to param entry if channel mapping logic
>> +		 * exist
>> +		 */
> 
> Please follow the multi-line commenting style.

Can do. However, these lines in fact follow the style that is used
throughout the entire file ;)

> There are some checkpatch checks that result from lines like this.
> Please fix these as well.
> 
> CHECK: Alignment should match open parenthesis
> #179: FILE: arch/arm/common/edma.c:1841:
> +			map_queue_tc(j, queue_tc_mapping[i][0],
> +					queue_tc_mapping[i][1]);

If you say so, even though I disagree with checkpatch.pl here. The above
is actually more readable, right? :)


Thanks,
Daniel

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Sekhar Nori]

On Wednesday 27 November 2013 07:17 PM, Daniel Mack wrote:
> Hi Sekhar,
> 
> On 11/27/2013 02:35 PM, Sekhar Nori wrote:
>> On Monday 18 November 2013 03:49 AM, Daniel Mack wrote:
> 
>>> +static int edma_pm_suspend(struct device *dev)
>>> +{
>>> +	int j, r;
>>> +
>>> +	r = pm_runtime_get_sync(dev);
>>> +	if (IS_ERR_VALUE(r)) {
>>
>> So IS_ERR_VALUE() is only for functions which may return a negative
>> number outside of MAX_ERRNO as a success indication.
>> pm_runtime_get_sync() does not appear to be one of them so just use"
>>
>> if (r < 0) { .. }
> 
> That's true. Thanks for catching this, I'll fix it. However, grepping
> through the tree, there are quite a lot places where the same mistake is
> made.

Yes, this is a common fallacy. Russell cleaned up a bunch of these a
while back.

> 
>>> +		/* Map the channel to param entry if channel mapping logic
>>> +		 * exist
>>> +		 */
>>
>> Please follow the multi-line commenting style.
> 
> Can do. However, these lines in fact follow the style that is used
> throughout the entire file ;)

:) I did not compare the rest of the file, but hey the bar keep rising
all the time.

> 
>> There are some checkpatch checks that result from lines like this.
>> Please fix these as well.
>>
>> CHECK: Alignment should match open parenthesis
>> #179: FILE: arch/arm/common/edma.c:1841:
>> +			map_queue_tc(j, queue_tc_mapping[i][0],
>> +					queue_tc_mapping[i][1]);
> 
> If you say so, even though I disagree with checkpatch.pl here. The above
> is actually more readable, right? :)

In this particular case, I agree so I am okay if you keep it as is. The
rest of the two reports are valid though.

Thanks,
Sekhar

pm_runtime functions and IS_ERR_VALUE (was Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks)

[Nishanth Menon]

Change in subject line + wider forum

On 19:24-20131127, Sekhar Nori wrote:
> On Wednesday 27 November 2013 07:17 PM, Daniel Mack wrote:
> > On 11/27/2013 02:35 PM, Sekhar Nori wrote:
> >> On Monday 18 November 2013 03:49 AM, Daniel Mack wrote:
> >>> +static int edma_pm_suspend(struct device *dev)
> >>> +{
> >>> +	int j, r;
> >>> +
> >>> +	r = pm_runtime_get_sync(dev);
> >>> +	if (IS_ERR_VALUE(r)) {
> >>
> >> So IS_ERR_VALUE() is only for functions which may return a negative
> >> number outside of MAX_ERRNO as a success indication.
> >> pm_runtime_get_sync() does not appear to be one of them so just use"
> >>
> >> if (r < 0) { .. }
> > 
> > That's true. Thanks for catching this, I'll fix it. However, grepping
> > through the tree, there are quite a lot places where the same mistake is
> > made.
> 
> Yes, this is a common fallacy. Russell cleaned up a bunch of these a
> while back.

Thinking a little more on this front, to prevent recurrence and fixing
the ones we already have, how about something like the following
patch?

For example, on 3.13-rc1, with omap2plus_defconfig, I see the following:
http://pastebin.mozilla.org/3681911

-->8--
>From b7946d214fab72b2e18cd67eec01c377f1cddee8 Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@ti.com>
Date: Wed, 27 Nov 2013 17:01:20 -0600
Subject: [RFC PATCH] scripts: Coccinelle script for pm_runtime_* return checks
 with IS_ERR_VALUE

As indicated by Sekhar in [1], there seems to be a tendency to use
IS_ERR_VALUE to check the error result for pm_runtime_* functions which
make no sense considering commit c48cd65 (ARM: OMAP: use consistent
error checking) - the error values can either be < 0 for error OR
0, 1 in cases where we have success.

So, setup a coccinelle script to help identify the same.

[1] http://marc.info/?t=138472678100003&r=1&w=2

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Reported-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
---
 scripts/coccinelle/api/pm_runtime.cocci |  109 +++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 scripts/coccinelle/api/pm_runtime.cocci

diff --git a/scripts/coccinelle/api/pm_runtime.cocci b/scripts/coccinelle/api/pm_runtime.cocci
new file mode 100644
index 0000000..f01789e
--- /dev/null
+++ b/scripts/coccinelle/api/pm_runtime.cocci
@@ -0,0 +1,109 @@
+/// Make sure pm_runtime_* calls does not use unnecessary IS_ERR_VALUE
+//
+// Keywords: pm_runtime
+// Confidence: Medium
+// Copyright (C) 2013 Texas Instruments Incorporated - GPLv2.
+// URL: http://coccinelle.lip6.fr/
+// Options: --include-headers
+
+virtual patch
+virtual context
+virtual org
+virtual report
+
+//----------------------------------------------------------
+//  Detection
+//----------------------------------------------------------
+
+@runtime_bad_err_handle exists@
+expression ret;
+@@
+(
+ret = \(pm_runtime_idle\|
+	pm_runtime_suspend\|
+	pm_runtime_autosuspend\|
+	pm_runtime_resume\|
+	pm_request_idle\|
+	pm_request_resume\|
+	pm_request_autosuspend\|
+	pm_runtime_get\|
+	pm_runtime_get_sync\|
+	pm_runtime_put\|
+	pm_runtime_put_autosuspend\|
+	pm_runtime_put_sync\|
+	pm_runtime_put_sync_suspend\|
+	pm_runtime_put_sync_autosuspend\|
+	pm_runtime_set_active\|
+	pm_schedule_suspend\|
+	pm_runtime_barrier\|
+	pm_generic_runtime_suspend\|
+	pm_generic_runtime_resume\)(...);
+...
+IS_ERR_VALUE(ret)
+...
+)
+
+//----------------------------------------------------------
+//  For context mode
+//----------------------------------------------------------
+
+@depends on runtime_bad_err_handle && context@
+identifier pm_runtime_api;
+expression ret;
+@@
+(
+ret = pm_runtime_api(...);
+...
+* IS_ERR_VALUE(ret)
+...
+)
+
+//----------------------------------------------------------
+//  For patch mode
+//----------------------------------------------------------
+
+@depends on runtime_bad_err_handle && patch@
+identifier pm_runtime_api;
+expression ret;
+@@
+(
+ret = pm_runtime_api(...);
+...
+- IS_ERR_VALUE(ret)
++ ret < 0
+...
+)
+
+//----------------------------------------------------------
+//  For org and report mode
+//----------------------------------------------------------
+
+@r depends on runtime_bad_err_handle exists@
+position p1, p2;
+identifier pm_runtime_api;
+expression ret;
+@@
+(
+ret = pm_runtime_api@p1(...);
+...
+IS_ERR_VALUE@p2(ret)
+...
+)
+
+@script:python depends on org@
+p1 << r.p1;
+p2 << r.p2;
+pm_runtime_api << r.pm_runtime_api;
+@@
+
+cocci.print_main(pm_runtime_api,p1)
+cocci.print_secs("IS_ERR_VALUE",p2)
+
+@script:python depends on report@
+p1 << r.p1;
+p2 << r.p2;
+pm_runtime_api << r.pm_runtime_api;
+@@
+
+msg = "%s returns < 0 as error. Unecessary IS_ERR_VALUE at line %s" % (pm_runtime_api, p2[0].line)
+coccilib.report.print_report(p1[0],msg)
-- 
1.7.9.5

-- 
Regards,
Nishanth Menon

Re: pm_runtime functions and IS_ERR_VALUE (was Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks)

[Rafael J. Wysocki]

On Wednesday, November 27, 2013 05:15:41 PM Nishanth Menon wrote:
> Change in subject line + wider forum
> 
> On 19:24-20131127, Sekhar Nori wrote:
> > On Wednesday 27 November 2013 07:17 PM, Daniel Mack wrote:
> > > On 11/27/2013 02:35 PM, Sekhar Nori wrote:
> > >> On Monday 18 November 2013 03:49 AM, Daniel Mack wrote:
> > >>> +static int edma_pm_suspend(struct device *dev)
> > >>> +{
> > >>> +	int j, r;
> > >>> +
> > >>> +	r = pm_runtime_get_sync(dev);
> > >>> +	if (IS_ERR_VALUE(r)) {
> > >>
> > >> So IS_ERR_VALUE() is only for functions which may return a negative
> > >> number outside of MAX_ERRNO as a success indication.
> > >> pm_runtime_get_sync() does not appear to be one of them so just use"
> > >>
> > >> if (r < 0) { .. }
> > > 
> > > That's true. Thanks for catching this, I'll fix it. However, grepping
> > > through the tree, there are quite a lot places where the same mistake is
> > > made.
> > 
> > Yes, this is a common fallacy. Russell cleaned up a bunch of these a
> > while back.
> 
> Thinking a little more on this front, to prevent recurrence and fixing
> the ones we already have, how about something like the following
> patch?

Looks reasonable -  if the result survives the auto build testing. :-)

Thanks!

> For example, on 3.13-rc1, with omap2plus_defconfig, I see the following:
> http://pastebin.mozilla.org/3681911
> 
> -->8--
> From b7946d214fab72b2e18cd67eec01c377f1cddee8 Mon Sep 17 00:00:00 2001
> From: Nishanth Menon <nm@ti.com>
> Date: Wed, 27 Nov 2013 17:01:20 -0600
> Subject: [RFC PATCH] scripts: Coccinelle script for pm_runtime_* return checks
>  with IS_ERR_VALUE
> 
> As indicated by Sekhar in [1], there seems to be a tendency to use
> IS_ERR_VALUE to check the error result for pm_runtime_* functions which
> make no sense considering commit c48cd65 (ARM: OMAP: use consistent
> error checking) - the error values can either be < 0 for error OR
> 0, 1 in cases where we have success.
> 
> So, setup a coccinelle script to help identify the same.
> 
> [1] http://marc.info/?t=138472678100003&r=1&w=2
> 
> Cc: Russell King <rmk+kernel@arm.linux.org.uk>
> Reported-by: Sekhar Nori <nsekhar@ti.com>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> ---
>  scripts/coccinelle/api/pm_runtime.cocci |  109 +++++++++++++++++++++++++++++++
>  1 file changed, 109 insertions(+)
>  create mode 100644 scripts/coccinelle/api/pm_runtime.cocci
> 
> diff --git a/scripts/coccinelle/api/pm_runtime.cocci b/scripts/coccinelle/api/pm_runtime.cocci
> new file mode 100644
> index 0000000..f01789e
> --- /dev/null
> +++ b/scripts/coccinelle/api/pm_runtime.cocci
> @@ -0,0 +1,109 @@
> +/// Make sure pm_runtime_* calls does not use unnecessary IS_ERR_VALUE
> +//
> +// Keywords: pm_runtime
> +// Confidence: Medium
> +// Copyright (C) 2013 Texas Instruments Incorporated - GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Options: --include-headers
> +
> +virtual patch
> +virtual context
> +virtual org
> +virtual report
> +
> +//----------------------------------------------------------
> +//  Detection
> +//----------------------------------------------------------
> +
> +@runtime_bad_err_handle exists@
> +expression ret;
> +@@
> +(
> +ret = \(pm_runtime_idle\|
> +	pm_runtime_suspend\|
> +	pm_runtime_autosuspend\|
> +	pm_runtime_resume\|
> +	pm_request_idle\|
> +	pm_request_resume\|
> +	pm_request_autosuspend\|
> +	pm_runtime_get\|
> +	pm_runtime_get_sync\|
> +	pm_runtime_put\|
> +	pm_runtime_put_autosuspend\|
> +	pm_runtime_put_sync\|
> +	pm_runtime_put_sync_suspend\|
> +	pm_runtime_put_sync_autosuspend\|
> +	pm_runtime_set_active\|
> +	pm_schedule_suspend\|
> +	pm_runtime_barrier\|
> +	pm_generic_runtime_suspend\|
> +	pm_generic_runtime_resume\)(...);
> +...
> +IS_ERR_VALUE(ret)
> +...
> +)
> +
> +//----------------------------------------------------------
> +//  For context mode
> +//----------------------------------------------------------
> +
> +@depends on runtime_bad_err_handle && context@
> +identifier pm_runtime_api;
> +expression ret;
> +@@
> +(
> +ret = pm_runtime_api(...);
> +...
> +* IS_ERR_VALUE(ret)
> +...
> +)
> +
> +//----------------------------------------------------------
> +//  For patch mode
> +//----------------------------------------------------------
> +
> +@depends on runtime_bad_err_handle && patch@
> +identifier pm_runtime_api;
> +expression ret;
> +@@
> +(
> +ret = pm_runtime_api(...);
> +...
> +- IS_ERR_VALUE(ret)
> ++ ret < 0
> +...
> +)
> +
> +//----------------------------------------------------------
> +//  For org and report mode
> +//----------------------------------------------------------
> +
> +@r depends on runtime_bad_err_handle exists@
> +position p1, p2;
> +identifier pm_runtime_api;
> +expression ret;
> +@@
> +(
> +ret = pm_runtime_api@p1(...);
> +...
> +IS_ERR_VALUE@p2(ret)
> +...
> +)
> +
> +@script:python depends on org@
> +p1 << r.p1;
> +p2 << r.p2;
> +pm_runtime_api << r.pm_runtime_api;
> +@@
> +
> +cocci.print_main(pm_runtime_api,p1)
> +cocci.print_secs("IS_ERR_VALUE",p2)
> +
> +@script:python depends on report@
> +p1 << r.p1;
> +p2 << r.p2;
> +pm_runtime_api << r.pm_runtime_api;
> +@@
> +
> +msg = "%s returns < 0 as error. Unecessary IS_ERR_VALUE at line %s" % (pm_runtime_api, p2[0].line)
> +coccilib.report.print_report(p1[0],msg)
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [PATCH v6] ARM: omap: edma: add suspend suspend/resume hooks

[Kevin Hilman]

Daniel Mack <zonque@gmail.com> writes:

> On 11/27/2013 02:22 PM, Sekhar Nori wrote:
>> + Kevin
>> 
>> On Monday 25 November 2013 11:04 PM, Joel Fernandes wrote:
>>> On 11/17/2013 04:19 PM, Daniel Mack wrote:
>>>> This patch makes the edma driver resume correctly after suspend. Tested
>>>> on an AM33xx platform with cyclic audio streams and omap_hsmmc.
>>>>
>>>> All information can be reconstructed by already known runtime
>>>> information.
>>>>
>>>> As we now use some functions that were previously only used from __init
>>>> context, annotations had to be dropped.
>>>>
>>>> [nm@ti.com: added error handling for runtime + suspend_late/early_resume]
>>>> Signed-off-by: Nishanth Menon <nm@ti.com>
>>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>>> Tested-by: Joel Fernandes <joelf@ti.com>
>>>> Acked-by: Joel Fernandes <joelf@ti.com>
>>>
>>> Hi Sekhar,
>>>
>>> Can you consider pulling this patch? It has been tested and Acked. Thanks.
>> 
>> Kevin had some inputs on previous version of this patch. Were you able
>> to make sure he is okay with this version being merged?
>
> I had concerns about the feedback I got, and haven't got answers yet.
>
> In particular, I'm not convinced that using runtime PM to suspend
> channels would actually save any power during runtime, or have any other
> benefit. 

/me returning from a week off

The amount of power to be saved depends on the activity in the system.
If DMA is unused, at least the clocks could be gated allowing the
possibility of the enclosing power domain to be gated if other devices
are also clock gated, etc. etc.

However, my comments were not really about power saving, they were about
designing things in a way that are scalable and match the longer term
goals of converting drivers to be runtime PM centric.  For example, if
someone did want to add real runtime PM to this driver later, they would
need to rework much of this.  So my suggestion was to do runtime PM the
right way from the beginning.

That being said, I'm not the maintainer of this driver so don't get to
make the final call.  I will just say that from what I've seen here, I
don't think this is the right approach.

Kevin