[v3,2/4] clk: core: link consumer with clock driver
diff mbox series

Message ID 20181204192440.12125-3-miquel.raynal@bootlin.com
State New
Headers show
Series
  • Add device links to clocks
Related show

Commit Message

Miquel Raynal Dec. 4, 2018, 7:24 p.m. UTC
One major concern when, for instance, suspending/resuming a platform
is to never access registers before the underlying clock has been
resumed, otherwise most of the time the kernel will just crash. One
solution is to use syscore operations when registering clock drivers
suspend/resume callbacks. One problem of using syscore_ops is that the
suspend/resume scheduling will depend on the order of the
registrations, which brings (unacceptable) randomness in the process.

A feature called device links has been introduced to handle such
situation. It creates dependencies between consumers and providers,
enforcing e.g. the suspend/resume order when needed. Such feature is
already in use for regulators.

Add device links support in the clock subsystem by creating/deleting
the links at get/put time.

Example of a boot (ESPRESSObin, A3700 SoC) with devices linked to clocks:

marvell-armada-3700-tbg-clock d0013200.tbg: Linked as a consumer to d0013800.pinctrl:xtal-clk
marvell-armada-3700-tbg-clock d0013200.tbg: Dropping the link to d0013800.pinctrl:xtal-clk
marvell-armada-3700-tbg-clock d0013200.tbg: Linked as a consumer to d0013800.pinctrl:xtal-clk
marvell-armada-3700-periph-clock d0013000.nb-periph-clk: Linked as a consumer to d0013200.tbg
marvell-armada-3700-periph-clock d0013000.nb-periph-clk: Linked as a consumer to d0013800.pinctrl:xtal-clk
marvell-armada-3700-periph-clock d0018000.sb-periph-clk: Linked as a consumer to d0013200.tbg
mvneta d0030000.ethernet: Linked as a consumer to d0018000.sb-periph-clk
xhci-hcd d0058000.usb: Linked as a consumer to d0018000.sb-periph-clk
xenon-sdhci d00d0000.sdhci: Linked as a consumer to d0013000.nb-periph-clk
xenon-sdhci d00d0000.sdhci: Dropping the link to d0013000.nb-periph-clk
mvebu-uart d0012000.serial: Linked as a consumer to d0013800.pinctrl:xtal-clk
advk-pcie d0070000.pcie: Linked as a consumer to d0018000.sb-periph-clk
xenon-sdhci d00d0000.sdhci: Linked as a consumer to d0013000.nb-periph-clk
xenon-sdhci d00d0000.sdhci: Linked as a consumer to regulator.1
cpu cpu0: Linked as a consumer to d0013000.nb-periph-clk
cpu cpu0: Dropping the link to d0013000.nb-periph-clk
cpu cpu0: Linked as a consumer to d0013000.nb-periph-clk

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/clk/clk.c            | 53 ++++++++++++++++++++++++++++++++++--
 drivers/clk/clkdev.c         | 16 +++++++++--
 include/linux/clk-provider.h |  2 ++
 3 files changed, 66 insertions(+), 5 deletions(-)

Comments

Stephen Boyd Dec. 11, 2018, 5:12 p.m. UTC | #1
Sorry, I'm not reviewing the whole patch right now, just this one little
bit because I'm also working in the same area.

Quoting Miquel Raynal (2018-12-04 11:24:38)
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 60c51871b04b..721d6b55b2fa 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -781,6 +781,8 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
>  const char *__clk_get_name(const struct clk *clk);
>  const char *clk_hw_get_name(const struct clk_hw *hw);
>  struct clk_hw *__clk_get_hw(struct clk *clk);
> +void clk_link_consumer(struct device *consumer, struct clk *clk);
> +void clk_unlink_consumer(struct clk *clk);

We shouldn't need to add these functions as far as I can tell. That's
because __clk_get() has become an internal API between clkdev.c and
clk.c that does nothing now on implementations that aren't the CCF. We
can even change this API to take a clk_hw pointer instead of a clk
pointer.

I'd rather see us plumb a struct device and clk_hw structure down into
__clk_get() and fold it all into __clk_create_clk, possibly even
renaming __clk_create_clk to clk_hw_create_clk(). That way we can get
the calling device and clk_hw pointer in one call in the clk framework,
along with the device name and connection name, and then generate the
struct clk right there. This can simplify some code and make it easier
to extend this to associate calling devices with the clk consumer
somehow.

Here's the diff. With this, you should be able to add and remove device
links in clk_hw_create_clk() when dev != NULL.

----8<----

 drivers/clk/clk.c    | 57 +++++++++++++++++++++++-----------------------------
 drivers/clk/clk.h    | 12 +++++------
 drivers/clk/clkdev.c | 43 ++++++++++++++++++++-------------------
 3 files changed, 53 insertions(+), 59 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index af011974d4ec..684f9a4b7d65 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3202,10 +3202,11 @@ static int __clk_core_init(struct clk_core *core)
 	return ret;
 }
 
-struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
-			     const char *con_id)
+struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
+			      const char *dev_id, const char *con_id)
 {
 	struct clk *clk;
+	struct clk_core *core;
 
 	/* This is to allow this function to be chained to others */
 	if (IS_ERR_OR_NULL(hw))
@@ -3215,15 +3216,23 @@ struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
 	if (!clk)
 		return ERR_PTR(-ENOMEM);
 
-	clk->core = hw->core;
+	core = hw->core;
+	clk->core = core;
 	clk->dev_id = dev_id;
 	clk->con_id = kstrdup_const(con_id, GFP_KERNEL);
 	clk->max_rate = ULONG_MAX;
 
 	clk_prepare_lock();
-	hlist_add_head(&clk->clks_node, &hw->core->clks);
+	hlist_add_head(&clk->clks_node, &core->clks);
 	clk_prepare_unlock();
 
+	if (!try_module_get(core->owner)) {
+		kfree(clk);
+		return ERR_PTR(-ENOENT);
+	}
+
+	kref_get(&core->ref);
+
 	return clk;
 }
 
@@ -3313,7 +3322,11 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 
 	INIT_HLIST_HEAD(&core->clks);
 
-	hw->clk = __clk_create_clk(hw, NULL, NULL);
+	/*
+	 * Pass NULL here for device because we eventually plan
+	 * to get rid of this clk created here
+	 */
+	hw->clk = clk_hw_create_clk(NULL, hw, NULL, NULL);
 	if (IS_ERR(hw->clk)) {
 		ret = PTR_ERR(hw->clk);
 		goto fail_parents;
@@ -3594,18 +3607,6 @@ EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);
 /*
  * clkdev helpers
  */
-int __clk_get(struct clk *clk)
-{
-	struct clk_core *core = !clk ? NULL : clk->core;
-
-	if (core) {
-		if (!try_module_get(core->owner))
-			return 0;
-
-		kref_get(&core->ref);
-	}
-	return 1;
-}
 
 /* keep in sync with __clk_free_clk */
 void __clk_put(struct clk *clk)
@@ -3976,12 +3977,12 @@ __of_clk_get_hw_from_provider(struct of_clk_provider *provider,
 	return __clk_get_hw(clk);
 }
 
-struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
+struct clk *__of_clk_get_from_provider(struct device *dev,
+				       struct of_phandle_args *clkspec,
 				       const char *dev_id, const char *con_id)
 {
 	struct of_clk_provider *provider;
-	struct clk *clk = ERR_PTR(-EPROBE_DEFER);
-	struct clk_hw *hw;
+	struct clk_hw *hw = ERR_PTR(-EPROBE_DEFER);
 
 	if (!clkspec)
 		return ERR_PTR(-EINVAL);
@@ -3991,21 +3992,13 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 	list_for_each_entry(provider, &of_clk_providers, link) {
 		if (provider->node == clkspec->np) {
 			hw = __of_clk_get_hw_from_provider(provider, clkspec);
-			clk = __clk_create_clk(hw, dev_id, con_id);
-		}
-
-		if (!IS_ERR(clk)) {
-			if (!__clk_get(clk)) {
-				__clk_free_clk(clk);
-				clk = ERR_PTR(-ENOENT);
-			}
-
-			break;
+			if (!IS_ERR(hw))
+				break;
 		}
 	}
 	mutex_unlock(&of_clk_mutex);
 
-	return clk;
+	return clk_hw_create_clk(dev, hw, dev_id, con_id);
 }
 
 /**
@@ -4018,7 +4011,7 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
  */
 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 {
-	return __of_clk_get_from_provider(clkspec, NULL, __func__);
+	return __of_clk_get_from_provider(NULL, clkspec, NULL, __func__);
 }
 EXPORT_SYMBOL_GPL(of_clk_get_from_provider);
 
diff --git a/drivers/clk/clk.h b/drivers/clk/clk.h
index 70c0ba6336c1..a0d4aa0fcfcd 100644
--- a/drivers/clk/clk.h
+++ b/drivers/clk/clk.h
@@ -12,20 +12,21 @@
 struct clk_hw;
 
 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
-struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
+struct clk *__of_clk_get_from_provider(struct device *dev,
+				       struct of_phandle_args *clkspec,
 				       const char *dev_id, const char *con_id);
 #endif
 
 #ifdef CONFIG_COMMON_CLK
-struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
-			     const char *con_id);
+struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
+			      const char *dev_id, const char *con_id);
 void __clk_free_clk(struct clk *clk);
-int __clk_get(struct clk *clk);
 void __clk_put(struct clk *clk);
 #else
 /* All these casts to avoid ifdefs in clkdev... */
 static inline struct clk *
-__clk_create_clk(struct clk_hw *hw, const char *dev_id, const char *con_id)
+clk_hw_create_clk(struct device *dev, struct clk_hw *hw, const char *dev_id,
+		  const char *con_id)
 {
 	return (struct clk *)hw;
 }
@@ -34,7 +35,6 @@ static struct clk_hw *__clk_get_hw(struct clk *clk)
 {
 	return (struct clk_hw *)clk;
 }
-static inline int __clk_get(struct clk *clk) { return 1; }
 static inline void __clk_put(struct clk *clk) { }
 
 #endif
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 9ab3db8b3988..08cf01c168fb 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -28,8 +28,9 @@ static LIST_HEAD(clocks);
 static DEFINE_MUTEX(clocks_mutex);
 
 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
-static struct clk *__of_clk_get(struct device_node *np, int index,
-			       const char *dev_id, const char *con_id)
+static struct clk *__of_clk_get(struct device *dev, struct device_node *np,
+				int index, const char *dev_id,
+				const char *con_id)
 {
 	struct of_phandle_args clkspec;
 	struct clk *clk;
@@ -40,7 +41,7 @@ static struct clk *__of_clk_get(struct device_node *np, int index,
 	if (rc)
 		return ERR_PTR(rc);
 
-	clk = __of_clk_get_from_provider(&clkspec, dev_id, con_id);
+	clk = __of_clk_get_from_provider(dev, &clkspec, dev_id, con_id);
 	of_node_put(clkspec.np);
 
 	return clk;
@@ -48,13 +49,13 @@ static struct clk *__of_clk_get(struct device_node *np, int index,
 
 struct clk *of_clk_get(struct device_node *np, int index)
 {
-	return __of_clk_get(np, index, np->full_name, NULL);
+	return __of_clk_get(NULL, np, index, np->full_name, NULL);
 }
 EXPORT_SYMBOL(of_clk_get);
 
-static struct clk *__of_clk_get_by_name(struct device_node *np,
-					const char *dev_id,
-					const char *name)
+static struct clk *__of_clk_get_by_name(struct device *dev,
+					struct device_node *np,
+					const char *dev_id, const char *name)
 {
 	struct clk *clk = ERR_PTR(-ENOENT);
 
@@ -69,7 +70,7 @@ static struct clk *__of_clk_get_by_name(struct device_node *np,
 		 */
 		if (name)
 			index = of_property_match_string(np, "clock-names", name);
-		clk = __of_clk_get(np, index, dev_id, name);
+		clk = __of_clk_get(dev, np, index, dev_id, name);
 		if (!IS_ERR(clk)) {
 			break;
 		} else if (name && index >= 0) {
@@ -106,13 +107,14 @@ struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
 	if (!np)
 		return ERR_PTR(-ENOENT);
 
-	return __of_clk_get_by_name(np, np->full_name, name);
+	return __of_clk_get_by_name(NULL, np, np->full_name, name);
 }
 EXPORT_SYMBOL(of_clk_get_by_name);
 
 #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
 
-static struct clk *__of_clk_get_by_name(struct device_node *np,
+static struct clk *__of_clk_get_by_name(struct device *dev,
+					struct device_node *np,
 					const char *dev_id,
 					const char *name)
 {
@@ -163,7 +165,8 @@ static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
 	return cl;
 }
 
-struct clk *clk_get_sys(const char *dev_id, const char *con_id)
+static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
+				 const char *con_id)
 {
 	struct clk_lookup *cl;
 	struct clk *clk = NULL;
@@ -174,21 +177,19 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 	if (!cl)
 		goto out;
 
-	clk = __clk_create_clk(cl->clk_hw, dev_id, con_id);
+	clk = clk_hw_create_clk(dev, cl->clk_hw, dev_id, con_id);
 	if (IS_ERR(clk))
-		goto out;
-
-	if (!__clk_get(clk)) {
-		__clk_free_clk(clk);
 		cl = NULL;
-		goto out;
-	}
-
 out:
 	mutex_unlock(&clocks_mutex);
 
 	return cl ? clk : ERR_PTR(-ENOENT);
 }
+
+struct clk *clk_get_sys(const char *dev_id, const char *con_id)
+{
+	return __clk_get_sys(NULL, dev_id, con_id);
+}
 EXPORT_SYMBOL(clk_get_sys);
 
 struct clk *clk_get(struct device *dev, const char *con_id)
@@ -197,12 +198,12 @@ struct clk *clk_get(struct device *dev, const char *con_id)
 	struct clk *clk;
 
 	if (dev && dev->of_node) {
-		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
+		clk = __of_clk_get_by_name(dev, dev->of_node, dev_id, con_id);
 		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
 			return clk;
 	}
 
-	return clk_get_sys(dev_id, con_id);
+	return __clk_get_sys(dev, dev_id, con_id);
 }
 EXPORT_SYMBOL(clk_get);
Miquel Raynal Dec. 17, 2018, 2:24 p.m. UTC | #2
Hi Stephen,

Stephen Boyd <sboyd@kernel.org> wrote on Tue, 11 Dec 2018 09:12:55
-0800:

> Sorry, I'm not reviewing the whole patch right now, just this one little
> bit because I'm also working in the same area.
> 
> Quoting Miquel Raynal (2018-12-04 11:24:38)
> > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> > index 60c51871b04b..721d6b55b2fa 100644
> > --- a/include/linux/clk-provider.h
> > +++ b/include/linux/clk-provider.h
> > @@ -781,6 +781,8 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
> >  const char *__clk_get_name(const struct clk *clk);
> >  const char *clk_hw_get_name(const struct clk_hw *hw);
> >  struct clk_hw *__clk_get_hw(struct clk *clk);
> > +void clk_link_consumer(struct device *consumer, struct clk *clk);
> > +void clk_unlink_consumer(struct clk *clk);  
> 
> We shouldn't need to add these functions as far as I can tell. That's
> because __clk_get() has become an internal API between clkdev.c and
> clk.c that does nothing now on implementations that aren't the CCF. We
> can even change this API to take a clk_hw pointer instead of a clk
> pointer.
> 
> I'd rather see us plumb a struct device and clk_hw structure down into
> __clk_get() and fold it all into __clk_create_clk, possibly even
> renaming __clk_create_clk to clk_hw_create_clk(). That way we can get
> the calling device and clk_hw pointer in one call in the clk framework,
> along with the device name and connection name, and then generate the
> struct clk right there. This can simplify some code and make it easier
> to extend this to associate calling devices with the clk consumer
> somehow.
> 
> Here's the diff. With this, you should be able to add and remove device
> links in clk_hw_create_clk() when dev != NULL.

Thanks for the pointers, if you think we should modify the API then
it's fine by me, I will integrate your diff and try to propose
something in sync with your comments this week.

Thanks,
Miquèl
Miquel Raynal Jan. 4, 2019, 3:54 p.m. UTC | #3
Hi Stephen,

Stephen Boyd <sboyd@kernel.org> wrote on Tue, 11 Dec 2018 09:12:55
-0800:

> Sorry, I'm not reviewing the whole patch right now, just this one little
> bit because I'm also working in the same area.
> 
> Quoting Miquel Raynal (2018-12-04 11:24:38)
> > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> > index 60c51871b04b..721d6b55b2fa 100644
> > --- a/include/linux/clk-provider.h
> > +++ b/include/linux/clk-provider.h
> > @@ -781,6 +781,8 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
> >  const char *__clk_get_name(const struct clk *clk);
> >  const char *clk_hw_get_name(const struct clk_hw *hw);
> >  struct clk_hw *__clk_get_hw(struct clk *clk);
> > +void clk_link_consumer(struct device *consumer, struct clk *clk);
> > +void clk_unlink_consumer(struct clk *clk);  
> 
> We shouldn't need to add these functions as far as I can tell. That's
> because __clk_get() has become an internal API between clkdev.c and
> clk.c that does nothing now on implementations that aren't the CCF. We
> can even change this API to take a clk_hw pointer instead of a clk
> pointer.
> 
> I'd rather see us plumb a struct device and clk_hw structure down into
> __clk_get() and fold it all into __clk_create_clk, possibly even
> renaming __clk_create_clk to clk_hw_create_clk(). That way we can get
> the calling device and clk_hw pointer in one call in the clk framework,
> along with the device name and connection name, and then generate the
> struct clk right there. This can simplify some code and make it easier
> to extend this to associate calling devices with the clk consumer
> somehow.
> 
> Here's the diff. With this, you should be able to add and remove device
> links in clk_hw_create_clk() when dev != NULL.

Thanks for the help; I updated my work on top of yours, it looks ok but
I need to run some more tests.

However I had to tweak a parameter in one of your recent changes, you
used '-1' as index in __of_clock_get() while it is not a valid value
(returning an error). As in the __of_clk_get_by_name() function you
removed index was just set to 0 at the top of the function, I think the
below fix is valid.


Thanks,
Miquèl


---

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index ba4d1e06732d..f2f4f2afd28c 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -163,7 +163,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
        struct clk_hw *hw;
 
        if (dev && dev->of_node) {
-               hw = of_clk_get_hw(dev->of_node, -1, con_id);
+               hw = of_clk_get_hw(dev->of_node, 0, con_id);
                if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER)
                        return clk_hw_create_clk(dev, hw, dev_id, con_id);
        }
Stephen Boyd Jan. 25, 2019, 9:28 p.m. UTC | #4
Quoting Miquel Raynal (2019-01-04 07:54:06)
> Hi Stephen,
> 
> Stephen Boyd <sboyd@kernel.org> wrote on Tue, 11 Dec 2018 09:12:55
> -0800:
> 
> > Sorry, I'm not reviewing the whole patch right now, just this one little
> > bit because I'm also working in the same area.
> > 
> > Quoting Miquel Raynal (2018-12-04 11:24:38)
> > > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> > > index 60c51871b04b..721d6b55b2fa 100644
> > > --- a/include/linux/clk-provider.h
> > > +++ b/include/linux/clk-provider.h
> > > @@ -781,6 +781,8 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
> > >  const char *__clk_get_name(const struct clk *clk);
> > >  const char *clk_hw_get_name(const struct clk_hw *hw);
> > >  struct clk_hw *__clk_get_hw(struct clk *clk);
> > > +void clk_link_consumer(struct device *consumer, struct clk *clk);
> > > +void clk_unlink_consumer(struct clk *clk);  
> > 
> > We shouldn't need to add these functions as far as I can tell. That's
> > because __clk_get() has become an internal API between clkdev.c and
> > clk.c that does nothing now on implementations that aren't the CCF. We
> > can even change this API to take a clk_hw pointer instead of a clk
> > pointer.
> > 
> > I'd rather see us plumb a struct device and clk_hw structure down into
> > __clk_get() and fold it all into __clk_create_clk, possibly even
> > renaming __clk_create_clk to clk_hw_create_clk(). That way we can get
> > the calling device and clk_hw pointer in one call in the clk framework,
> > along with the device name and connection name, and then generate the
> > struct clk right there. This can simplify some code and make it easier
> > to extend this to associate calling devices with the clk consumer
> > somehow.
> > 
> > Here's the diff. With this, you should be able to add and remove device
> > links in clk_hw_create_clk() when dev != NULL.
> 
> Thanks for the help; I updated my work on top of yours, it looks ok but
> I need to run some more tests.
> 
> However I had to tweak a parameter in one of your recent changes, you
> used '-1' as index in __of_clock_get() while it is not a valid value
> (returning an error). As in the __of_clk_get_by_name() function you
> removed index was just set to 0 at the top of the function, I think the
> below fix is valid.

Thanks. Makes sense so I folded it in.
Miquel Raynal Jan. 28, 2019, 10:06 a.m. UTC | #5
Hi Stephen,

Stephen Boyd <sboyd@kernel.org> wrote on Fri, 25 Jan 2019 13:28:28
-0800:

> Quoting Miquel Raynal (2019-01-04 07:54:06)
> > Hi Stephen,
> > 
> > Stephen Boyd <sboyd@kernel.org> wrote on Tue, 11 Dec 2018 09:12:55
> > -0800:
> >   
> > > Sorry, I'm not reviewing the whole patch right now, just this one little
> > > bit because I'm also working in the same area.
> > > 
> > > Quoting Miquel Raynal (2018-12-04 11:24:38)  
> > > > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> > > > index 60c51871b04b..721d6b55b2fa 100644
> > > > --- a/include/linux/clk-provider.h
> > > > +++ b/include/linux/clk-provider.h
> > > > @@ -781,6 +781,8 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
> > > >  const char *__clk_get_name(const struct clk *clk);
> > > >  const char *clk_hw_get_name(const struct clk_hw *hw);
> > > >  struct clk_hw *__clk_get_hw(struct clk *clk);
> > > > +void clk_link_consumer(struct device *consumer, struct clk *clk);
> > > > +void clk_unlink_consumer(struct clk *clk);    
> > > 
> > > We shouldn't need to add these functions as far as I can tell. That's
> > > because __clk_get() has become an internal API between clkdev.c and
> > > clk.c that does nothing now on implementations that aren't the CCF. We
> > > can even change this API to take a clk_hw pointer instead of a clk
> > > pointer.
> > > 
> > > I'd rather see us plumb a struct device and clk_hw structure down into
> > > __clk_get() and fold it all into __clk_create_clk, possibly even
> > > renaming __clk_create_clk to clk_hw_create_clk(). That way we can get
> > > the calling device and clk_hw pointer in one call in the clk framework,
> > > along with the device name and connection name, and then generate the
> > > struct clk right there. This can simplify some code and make it easier
> > > to extend this to associate calling devices with the clk consumer
> > > somehow.
> > > 
> > > Here's the diff. With this, you should be able to add and remove device
> > > links in clk_hw_create_clk() when dev != NULL.  
> > 
> > Thanks for the help; I updated my work on top of yours, it looks ok but
> > I need to run some more tests.
> > 
> > However I had to tweak a parameter in one of your recent changes, you
> > used '-1' as index in __of_clock_get() while it is not a valid value
> > (returning an error). As in the __of_clk_get_by_name() function you
> > removed index was just set to 0 at the top of the function, I think the
> > below fix is valid.  
> 
> Thanks. Makes sense so I folded it in.

Great!

Can you update me with the status of this series? Is it going in for 5.1?

Lorenzo, the PCI maintainer, is waiting for this series to enter before
accepting another series depending on it; so please do not hesitate to
keep me updated.


Thanks,
Miquèl

Patch
diff mbox series

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b799347c5fd6..0cc887b43f66 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -77,6 +77,7 @@  struct clk_core {
 	struct hlist_node	debug_node;
 #endif
 	struct kref		ref;
+	struct device_link	*parent_clk_link;
 };
 
 #define CREATE_TRACE_POINTS
@@ -90,6 +91,7 @@  struct clk {
 	unsigned long max_rate;
 	unsigned int exclusive_count;
 	struct hlist_node clks_node;
+	struct device_link *consumer_link;
 };
 
 /***           runtime pm          ***/
@@ -274,6 +276,37 @@  struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(clk_hw_get_parent);
 
+void clk_link_consumer(struct device *consumer, struct clk *clk)
+{
+	if (consumer && clk)
+		clk->consumer_link = device_link_add(consumer, clk->core->dev,
+						     DL_FLAG_STATELESS);
+}
+EXPORT_SYMBOL_GPL(clk_link_consumer);
+
+void clk_unlink_consumer(struct clk *clk)
+{
+	if (clk && clk->consumer_link)
+		device_link_del(clk->consumer_link);
+}
+EXPORT_SYMBOL_GPL(clk_unlink_consumer);
+
+static void clk_link_hierarchy(struct clk_core *consumer,
+			       struct clk_core *provider)
+{
+	if (consumer && provider)
+		consumer->parent_clk_link = device_link_add(consumer->dev,
+							    provider->dev,
+							    DL_FLAG_STATELESS);
+}
+
+static void clk_unlink_hierarchy(struct clk_core *consumer,
+				 struct clk_core *provider)
+{
+	if (consumer && provider && consumer->parent_clk_link)
+		device_link_del(consumer->parent_clk_link);
+}
+
 static struct clk_core *__clk_lookup_subtree(const char *name,
 					     struct clk_core *core)
 {
@@ -1542,6 +1575,9 @@  static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
 
 	hlist_del(&core->child_node);
 
+	if (core->parent)
+		clk_unlink_hierarchy(core, core->parent);
+
 	if (new_parent) {
 		bool becomes_orphan = new_parent->orphan;
 
@@ -1553,6 +1589,8 @@  static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
 
 		if (was_orphan != becomes_orphan)
 			clk_core_update_orphan_status(core, becomes_orphan);
+
+		clk_link_hierarchy(core, new_parent);
 	} else {
 		hlist_add_head(&core->child_node, &clk_orphan_list);
 		if (!was_orphan)
@@ -2244,12 +2282,16 @@  EXPORT_SYMBOL_GPL(clk_get_parent);
 
 static struct clk_core *__clk_init_parent(struct clk_core *core)
 {
+	struct clk_core *parent;
 	u8 index = 0;
 
 	if (core->num_parents > 1 && core->ops->get_parent)
 		index = core->ops->get_parent(core->hw);
 
-	return clk_core_get_parent_by_index(core, index);
+	parent = clk_core_get_parent_by_index(core, index);
+	clk_link_hierarchy(core, parent);
+
+	return parent;
 }
 
 static void clk_core_reparent(struct clk_core *core,
@@ -3437,11 +3479,18 @@  void clk_unregister(struct clk *clk)
 	clk->core->ops = &clk_nodrv_ops;
 	clk_enable_unlock(flags);
 
+	clk_unlink_hierarchy(clk->core, clk->core->parent);
+
 	if (!hlist_empty(&clk->core->children)) {
 		struct clk_core *child;
 		struct hlist_node *t;
 
-		/* Reparent all children to the orphan list. */
+		/*
+		 * Reparent all children to the orphan list.
+		 *
+		 * No need to unlink the child clock manually, this will be
+		 * handled by clk_reparent().
+		 */
 		hlist_for_each_entry_safe(child, t, &clk->core->children,
 					  child_node)
 			clk_core_set_parent_nolock(child, NULL);
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 9ab3db8b3988..8c6e087437bf 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -112,6 +112,9 @@  EXPORT_SYMBOL(of_clk_get_by_name);
 
 #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
 
+void clk_link_consumer(struct device *consumer, struct clk *clk) {}
+void clk_unlink_consumer(struct clk *clk) {}
+
 static struct clk *__of_clk_get_by_name(struct device_node *np,
 					const char *dev_id,
 					const char *name)
@@ -194,20 +197,27 @@  EXPORT_SYMBOL(clk_get_sys);
 struct clk *clk_get(struct device *dev, const char *con_id)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;
-	struct clk *clk;
+	struct clk *clk = NULL;
 
 	if (dev && dev->of_node) {
 		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
-		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
+		if (PTR_ERR(clk) == -EPROBE_DEFER)
 			return clk;
 	}
 
-	return clk_get_sys(dev_id, con_id);
+	if (IS_ERR_OR_NULL(clk))
+		clk = clk_get_sys(dev_id, con_id);
+
+	if (!IS_ERR(clk))
+		clk_link_consumer(dev, clk);
+
+	return clk;
 }
 EXPORT_SYMBOL(clk_get);
 
 void clk_put(struct clk *clk)
 {
+	clk_unlink_consumer(clk);
 	__clk_put(clk);
 }
 EXPORT_SYMBOL(clk_put);
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 60c51871b04b..721d6b55b2fa 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -781,6 +781,8 @@  void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
 const char *__clk_get_name(const struct clk *clk);
 const char *clk_hw_get_name(const struct clk_hw *hw);
 struct clk_hw *__clk_get_hw(struct clk *clk);
+void clk_link_consumer(struct device *consumer, struct clk *clk);
+void clk_unlink_consumer(struct clk *clk);
 unsigned int clk_hw_get_num_parents(const struct clk_hw *hw);
 struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw);
 struct clk_hw *clk_hw_get_parent_by_index(const struct clk_hw *hw,