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Message-ID: <20141022224614.GD4250@dtor-ws>
Date: Wed, 22 Oct 2014 15:46:14 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Grygorii Strashko <grygorii.strashko@...com>
Cc: ssantosh@...nel.org, "Rafael J. Wysocki" <rjw@...ysocki.net>,
khilman@...aro.org, Geert Uytterhoeven <geert+renesas@...der.be>,
linux-pm@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
grant.likely@...retlab.ca, ulf.hansson@...aro.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH v2 1/3] PM / clock_ops: Add pm_clk_add_clk()
On Wed, Oct 22, 2014 at 02:16:31PM -0700, Dmitry Torokhov wrote:
> On Wed, Oct 22, 2014 at 01:14:09PM -0700, Dmitry Torokhov wrote:
> > On Wed, Oct 22, 2014 at 10:02:41PM +0300, Grygorii Strashko wrote:
> > > On 10/22/2014 08:38 PM, Dmitry Torokhov wrote:
> > > >On Mon, Oct 20, 2014 at 03:56:02PM +0300, Grygorii Strashko wrote:
> > > >>From: Geert Uytterhoeven <geert+renesas@...der.be>
> > > >>
> > > >>The existing pm_clk_add() allows to pass a clock by con_id. However,
> > > >>when referring to a specific clock from DT, no con_id is available.
> > > >>
> > > >>Add pm_clk_add_clk(), which allows to specify the struct clk * directly.
> > > >>
> > > >>Reviewed-by: Kevin Hilman <khilman@...aro.org>
> > > >>Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> > > >>Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
> > > >>---
> > > >>
> > > >> Pay attantion pls, that there is another series of patches
> > > >> which have been posted already and which depends from this patch
> > > >> "[PATCH v4 0/3] ARM: rk3288 : Add PM Domain support"
> > > >> https://lkml.org/lkml/2014/10/20/105
> > > >>
> > > >> drivers/base/power/clock_ops.c | 41 +++++++++++++++++++++++++++++++----------
> > > >> include/linux/pm_clock.h | 8 ++++++++
> > > >> 2 files changed, 39 insertions(+), 10 deletions(-)
> > > >>
> > > >>diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
> > > >>index 7836930..f14b767 100644
> > > >>--- a/drivers/base/power/clock_ops.c
> > > >>+++ b/drivers/base/power/clock_ops.c
> > > >>@@ -53,7 +53,8 @@ static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
> > > >> */
> > > >> static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
> > > >> {
> > > >>- ce->clk = clk_get(dev, ce->con_id);
> > > >>+ if (!ce->clk)
> > > >>+ ce->clk = clk_get(dev, ce->con_id);
> > > >> if (IS_ERR(ce->clk)) {
> > > >> ce->status = PCE_STATUS_ERROR;
> > > >> } else {
> > > >>@@ -63,15 +64,8 @@ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
> > > >> }
> > > >> }
> > > >>
> > > >>-/**
> > > >>- * pm_clk_add - Start using a device clock for power management.
> > > >>- * @dev: Device whose clock is going to be used for power management.
> > > >>- * @con_id: Connection ID of the clock.
> > > >>- *
> > > >>- * Add the clock represented by @con_id to the list of clocks used for
> > > >>- * the power management of @dev.
> > > >>- */
> > > >>-int pm_clk_add(struct device *dev, const char *con_id)
> > > >>+static int __pm_clk_add(struct device *dev, const char *con_id,
> > > >>+ struct clk *clk)
> > > >> {
> > > >> struct pm_subsys_data *psd = dev_to_psd(dev);
> > > >> struct pm_clock_entry *ce;
> > > >>@@ -93,6 +87,8 @@ int pm_clk_add(struct device *dev, const char *con_id)
> > > >> kfree(ce);
> > > >> return -ENOMEM;
> > > >> }
> > > >>+ } else {
> > > >>+ ce->clk = clk;
>
> Shouldn't this be
>
> ce->clk = __clk_get(clk);
>
> to account for clk_put() in __pm_clk_remove()?
>
> > > >> }
> > > >>
> > > >> pm_clk_acquire(dev, ce);
> > > >>@@ -104,6 +100,31 @@ int pm_clk_add(struct device *dev, const char *con_id)
> > > >> }
> > > >>
> > > >> /**
> > > >>+ * pm_clk_add - Start using a device clock for power management.
> > > >>+ * @dev: Device whose clock is going to be used for power management.
> > > >>+ * @con_id: Connection ID of the clock.
> > > >>+ *
> > > >>+ * Add the clock represented by @con_id to the list of clocks used for
> > > >>+ * the power management of @dev.
> > > >>+ */
> > > >>+int pm_clk_add(struct device *dev, const char *con_id)
> > > >>+{
> > > >>+ return __pm_clk_add(dev, con_id, NULL);
> > > >
> > > >Bikeshedding: why do we need __pm_clk_add() and not simply have
> > > >"canonical" pm_clk_add_clk() and then do:
> > > >
> > > >int pm_clk_add(struct device *dev, const char *con_id)
> > > >{
> > > > struct clk *clk;
> > > >
> > > > clk = clk_get(dev, con_id);
> > > > ...
> > > > return pm_clk_add_clk(dev, clk);
> > > >}
> > >
> > > Hm. I did fast look at code and:
> > > 1) agree - there is a lot of thing which can be optimized ;)
> > > 2) in my strong opinion, this patch is the fastest and simplest
> > > way to introduce new API (take a look on pm_clock_entry->con_id
> > > management code) and It is exactly what we need as of now.
> >
> > Yeah, I guess. We are lucky we do not crash when we are tryign to print
> > NULL strings (see pm_clk_acquire).
> >
> > BTW, what is the point of doing pm_clk_add(dev, NULL)? We add clock
> > entry with status PCE_STATUS_ERROR and then have to handle it
> > everywhere? Can we just return -EINVAL if someone triies to pass NULL
> > ass con_id?
>
> Umm, no, ignore me here, I misread clk_get(dev, NULL) - it won't return
> error. Still, do why do we need to keep clock entry if clk_get() fails
> for some reason?
OK, so what if we do something like the patch below?
Thanks.
--
Dmitry
PM / clock_ops: Add pm_clk_remove_clk()
Implement pm_clk_remove_clk() that complements the new pm_clk_add_clk().
Fix reference counting, rework the code to avoid storing invalid clocks,
clean up the code.
Signed-off-by: Dmitry Torokhov <dtor@...omium.org>
---
drivers/base/power/clock_ops.c | 169 ++++++++++++++++++++---------------------
1 file changed, 81 insertions(+), 88 deletions(-)
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index f14b767..840e133 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c
@@ -12,21 +12,21 @@
#include <linux/pm.h>
#include <linux/pm_clock.h>
#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
#include <linux/slab.h>
#include <linux/err.h>
#ifdef CONFIG_PM
enum pce_status {
- PCE_STATUS_NONE = 0,
- PCE_STATUS_ACQUIRED,
+ PCE_STATUS_ACQUIRED = 0,
+ PCE_STATUS_PREPARED,
PCE_STATUS_ENABLED,
- PCE_STATUS_ERROR,
};
struct pm_clock_entry {
struct list_head node;
- char *con_id;
struct clk *clk;
enum pce_status status;
};
@@ -47,25 +47,13 @@ static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
}
/**
- * pm_clk_acquire - Acquire a device clock.
- * @dev: Device whose clock is to be acquired.
- * @ce: PM clock entry corresponding to the clock.
+ * pm_clk_add_clk - Start using a device clock for power management.
+ * @dev: Device whose clock is going to be used for power management.
+ * @clk: Clock pointer
+ *
+ * Add the clock to the list of clocks used for the power management of @dev.
*/
-static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
-{
- if (!ce->clk)
- ce->clk = clk_get(dev, ce->con_id);
- if (IS_ERR(ce->clk)) {
- ce->status = PCE_STATUS_ERROR;
- } else {
- clk_prepare(ce->clk);
- ce->status = PCE_STATUS_ACQUIRED;
- dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
- }
-}
-
-static int __pm_clk_add(struct device *dev, const char *con_id,
- struct clk *clk)
+int pm_clk_add_clk(struct device *dev, struct clk *clk)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
@@ -79,23 +67,19 @@ static int __pm_clk_add(struct device *dev, const char *con_id,
return -ENOMEM;
}
- if (con_id) {
- ce->con_id = kstrdup(con_id, GFP_KERNEL);
- if (!ce->con_id) {
- dev_err(dev,
- "Not enough memory for clock connection ID.\n");
- kfree(ce);
- return -ENOMEM;
- }
- } else {
- ce->clk = clk;
- }
+ __clk_get(clk);
- pm_clk_acquire(dev, ce);
+ clk_prepare(clk);
+
+ ce->status = PCE_STATUS_PREPARED;
+ ce->clk = clk;
spin_lock_irq(&psd->lock);
list_add_tail(&ce->node, &psd->clock_list);
spin_unlock_irq(&psd->lock);
+
+ dev_dbg(dev, "Clock %s managed by runtime PM.\n", __clk_get_name(clk));
+
return 0;
}
@@ -109,19 +93,23 @@ static int __pm_clk_add(struct device *dev, const char *con_id,
*/
int pm_clk_add(struct device *dev, const char *con_id)
{
- return __pm_clk_add(dev, con_id, NULL);
-}
+ struct clk *clk;
+ int retval;
-/**
- * pm_clk_add_clk - Start using a device clock for power management.
- * @dev: Device whose clock is going to be used for power management.
- * @clk: Clock pointer
- *
- * Add the clock to the list of clocks used for the power management of @dev.
- */
-int pm_clk_add_clk(struct device *dev, struct clk *clk)
-{
- return __pm_clk_add(dev, NULL, clk);
+ clk = clk_get(dev, con_id);
+ if (IS_ERR(clk)) {
+ retval = PTR_ERR(clk);
+ dev_err(dev, "Failed to locate lock (con_id %s): %d\n",
+ con_id, retval);
+ return retval;
+ }
+
+ retval = pm_clk_add_clk(dev, clk);
+
+ /* pm_clk_add_clk takes its own reference to clk */
+ clk_put(clk);
+
+ return retval;
}
/**
@@ -133,32 +121,30 @@ static void __pm_clk_remove(struct pm_clock_entry *ce)
if (!ce)
return;
- if (ce->status < PCE_STATUS_ERROR) {
- if (ce->status == PCE_STATUS_ENABLED)
- clk_disable(ce->clk);
+ if (ce->status == PCE_STATUS_ENABLED)
+ clk_disable(ce->clk);
- if (ce->status >= PCE_STATUS_ACQUIRED) {
- clk_unprepare(ce->clk);
- clk_put(ce->clk);
- }
+ if (ce->status >= PCE_STATUS_ACQUIRED) {
+ clk_unprepare(ce->clk);
+ clk_put(ce->clk);
}
- kfree(ce->con_id);
kfree(ce);
}
/**
* pm_clk_remove - Stop using a device clock for power management.
* @dev: Device whose clock should not be used for PM any more.
- * @con_id: Connection ID of the clock.
+ * @clk: Clock pointer
*
- * Remove the clock represented by @con_id from the list of clocks used for
- * the power management of @dev.
+ * Remove the clock from the list of clocks used for the power
+ * management of @dev.
*/
-void pm_clk_remove(struct device *dev, const char *con_id)
+
+void pm_clk_remove_clk(struct device *dev, struct clk *clk)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
- struct pm_clock_entry *ce;
+ struct pm_clock_entry *ce, *matching_ce = NULL;
if (!psd)
return;
@@ -166,22 +152,35 @@ void pm_clk_remove(struct device *dev, const char *con_id)
spin_lock_irq(&psd->lock);
list_for_each_entry(ce, &psd->clock_list, node) {
- if (!con_id && !ce->con_id)
- goto remove;
- else if (!con_id || !ce->con_id)
- continue;
- else if (!strcmp(con_id, ce->con_id))
- goto remove;
+ if (ce->clk == clk) {
+ matching_ce = ce;
+ list_del(&ce->node);
+ break;
+ }
}
spin_unlock_irq(&psd->lock);
- return;
- remove:
- list_del(&ce->node);
- spin_unlock_irq(&psd->lock);
+ __pm_clk_remove(matching_ce);
+}
+
+/**
+ * pm_clk_remove - Stop using a device clock for power management.
+ * @dev: Device whose clock should not be used for PM any more.
+ * @con_id: Connection ID of the clock.
+ *
+ * Remove the clock represented by @con_id from the list of clocks used for
+ * the power management of @dev.
+ */
+void pm_clk_remove(struct device *dev, const char *con_id)
+{
+ struct clk *clk;
- __pm_clk_remove(ce);
+ clk = clk_get(dev, con_id);
+ if (!IS_ERR(clk)) {
+ pm_clk_remove_clk(dev, clk);
+ clk_put(clk);
+ }
}
/**
@@ -266,10 +265,9 @@ int pm_clk_suspend(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry_reverse(ce, &psd->clock_list, node) {
- if (ce->status < PCE_STATUS_ERROR) {
- if (ce->status == PCE_STATUS_ENABLED)
- clk_disable(ce->clk);
- ce->status = PCE_STATUS_ACQUIRED;
+ if (ce->status == PCE_STATUS_ENABLED) {
+ clk_disable(ce->clk);
+ ce->status = PCE_STATUS_PREPARED;
}
}
@@ -297,11 +295,9 @@ int pm_clk_resume(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry(ce, &psd->clock_list, node) {
- if (ce->status < PCE_STATUS_ERROR) {
- ret = __pm_clk_enable(dev, ce->clk);
- if (!ret)
- ce->status = PCE_STATUS_ENABLED;
- }
+ ret = __pm_clk_enable(dev, ce->clk);
+ if (!ret)
+ ce->status = PCE_STATUS_ENABLED;
}
spin_unlock_irqrestore(&psd->lock, flags);
@@ -390,10 +386,9 @@ int pm_clk_suspend(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry_reverse(ce, &psd->clock_list, node) {
- if (ce->status < PCE_STATUS_ERROR) {
- if (ce->status == PCE_STATUS_ENABLED)
- clk_disable(ce->clk);
- ce->status = PCE_STATUS_ACQUIRED;
+ if (ce->status == PCE_STATUS_ENABLED) {
+ clk_disable(ce->clk);
+ ce->status = PCE_STATUS_PREPARED;
}
}
@@ -422,11 +417,9 @@ int pm_clk_resume(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry(ce, &psd->clock_list, node) {
- if (ce->status < PCE_STATUS_ERROR) {
- ret = __pm_clk_enable(dev, ce->clk);
- if (!ret)
- ce->status = PCE_STATUS_ENABLED;
- }
+ ret = __pm_clk_enable(dev, ce->clk);
+ if (!ret)
+ ce->status = PCE_STATUS_ENABLED;
}
spin_unlock_irqrestore(&psd->lock, flags);
--
2.1.0.rc2.206.gedb03e5
:
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