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clk: bcm: prerequisite and bus clock support

PATCH Superseded Alex Elder 1 participant 8 messages Jun 2, 2014

Subsystems (5)
Device tree bindings Common clk Broadcom BCM2711/BCM2835 Arm architecture Broadcom BCM281XX/BCM11XXX/BCM216XX Arm architecture +1 more subsystems

v5 of 6 Superseded Latest is v6 →

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Alex Elder

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#0 lore raw

v5 cover clk: bcm: prerequisite and bus clock support

Currently only peripheral clocks are supported for Broadcom platforms that use Kona style CCUs for clocking. This series adds support for bus clocks as well.

One motivation for doing this is that there exist peripheral clocks that cannot be configured without having first enabled a related bus clock. Adding bus clock support allows such peripheral clocks to be usable.

This also imposes a new requirement, however--that the bus clock be enabled *before* operating on the clock that depends on it. For this, we define the notion of a "prerequisite" clock. If a clock has a prerequisite specified, that prequisite clock will be prepared and enabled at the beginning of the dependent clock's ->prepare method. The prerequisite clock is similarly disabled and unprepared at the end of the dependent clock's ->unprepare method.

These patches are based on Mike Turquette's current "clk-next" branch.
9ec2749 clk: qcom: Return error pointers for unimplemented clocks

They are available here:
http://git.linaro.org/landing-teams/working/broadcom/kernel.git
Branch review/bcm-bus-clk-v5

-Alex

Version history:
v5 - All clocks get initialized the first time they are prepared.
- A per-clock flag now avoids doing initialization more than once.
- Prerequisite clocks get prepared and enabled in a dependent clock's prepare routine, *before* preparing the dependent.
- No longer require nestable CCU write enable requests.
- Dropped requirement that clock and prerequisite share CCU.
v4 - Remove boot-time initialization of clocks, opting instead to
do this work when needed, via clock ->prepare method.
- Prerequisite clocks are now prepared and enabled in a dependent clock's ->prepare method.
- Use __clk_lookup() to get the prerequisite clock pointer.
- ccu_write_enable() calls can now be nested
v3: - Deleted clk_lookup field from struct kona_clk.
- Now use term "initialized" rather than "enabled".
v2: - Added field "p" to the previously unnamed prereq union.

Alex Elder (7):
clk: kona: move some code
clk: kona: don't init clocks at startup time
clk: bcm281xx: add an initialized flag
clk: bcm281xx: implement prerequisite clocks
clk: bcm281xx: add bus clock support
clk: bcm281xx: define a bus clock
ARM: dts: add bus clock bsc3_apb for bcm281xx

 arch/arm/boot/dts/bcm11351.dtsi      |   3 +-
 drivers/clk/bcm/clk-bcm281xx.c       |  13 +-
 drivers/clk/bcm/clk-kona-setup.c     |  99 ++++++++++-
 drivers/clk/bcm/clk-kona.c           | 310 +++++++++++++++++++++++++----------
 drivers/clk/bcm/clk-kona.h           |  36 +++-
 include/dt-bindings/clock/bcm281xx.h |   3 +-
 6 files changed, 364 insertions(+), 100 deletions(-)
Signature · 1 line
1.9.1
author
#1 lore raw

PATCH v5 1/7 clk: kona: move some code

Move the definition of __peri_clk_init() up in "clk-kona.c", in preparation for the next patch (so it's defined before it's needed). Move kona_ccu_init() and __kona_clk_init() as well.

Done as a separate patch so doing so doesn't obscure other changes.

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-kona.c | 174 ++++++++++++++++++++++-----------------------
 1 file changed, 87 insertions(+), 87 deletions(-)
drivers/clk/bcm/clk-kona.c +87 -87
index 95af2e6..b643d35 100644
@@ -981,6 +981,93 @@ static int selector_write(struct ccu_data *ccu, struct bcm_clk_gate *gate,
 	return ret;
 }
 
+/* Put a peripheral clock into its initial state */
+static bool __peri_clk_init(struct kona_clk *bcm_clk)
+{
+	struct ccu_data *ccu = bcm_clk->ccu;
+	struct peri_clk_data *peri = bcm_clk->u.peri;
+	const char *name = bcm_clk->init_data.name;
+	struct bcm_clk_trig *trig;
+
+	BUG_ON(bcm_clk->type != bcm_clk_peri);
+
+	if (!policy_init(ccu, &peri->policy)) {
+		pr_err("%s: error initializing policy for %s\n",
+			__func__, name);
+		return false;
+	}
+	if (!gate_init(ccu, &peri->gate)) {
+		pr_err("%s: error initializing gate for %s\n", __func__, name);
+		return false;
+	}
+	if (!hyst_init(ccu, &peri->hyst)) {
+		pr_err("%s: error initializing hyst for %s\n", __func__, name);
+		return false;
+	}
+	if (!div_init(ccu, &peri->gate, &peri->div, &peri->trig)) {
+		pr_err("%s: error initializing divider for %s\n", __func__,
+			name);
+		return false;
+	}
+
+	/*
+	 * For the pre-divider and selector, the pre-trigger is used
+	 * if it's present, otherwise we just use the regular trigger.
+	 */
+	trig = trigger_exists(&peri->pre_trig) ? &peri->pre_trig
+					       : &peri->trig;
+
+	if (!div_init(ccu, &peri->gate, &peri->pre_div, trig)) {
+		pr_err("%s: error initializing pre-divider for %s\n", __func__,
+			name);
+		return false;
+	}
+
+	if (!sel_init(ccu, &peri->gate, &peri->sel, trig)) {
+		pr_err("%s: error initializing selector for %s\n", __func__,
+			name);
+		return false;
+	}
+
+	return true;
+}
+
+static bool __kona_clk_init(struct kona_clk *bcm_clk)
+{
+	switch (bcm_clk->type) {
+	case bcm_clk_peri:
+		return __peri_clk_init(bcm_clk);
+	default:
+		BUG();
+	}
+	return -EINVAL;
+}
+
+/* Set a CCU and all its clocks into their desired initial state */
+bool __init kona_ccu_init(struct ccu_data *ccu)
+{
+	unsigned long flags;
+	unsigned int which;
+	struct clk **clks = ccu->clk_data.clks;
+	bool success = true;
+
+	flags = ccu_lock(ccu);
+	__ccu_write_enable(ccu);
+
+	for (which = 0; which < ccu->clk_data.clk_num; which++) {
+		struct kona_clk *bcm_clk;
+
+		if (!clks[which])
+			continue;
+		bcm_clk = to_kona_clk(__clk_get_hw(clks[which]));
+		success &= __kona_clk_init(bcm_clk);
+	}
+
+	__ccu_write_disable(ccu);
+	ccu_unlock(ccu, flags);
+	return success;
+}
+
 /* Clock operations */
 
 static int kona_peri_clk_enable(struct clk_hw *hw)

@@ -1192,90 +1279,3 @@ struct clk_ops kona_peri_clk_ops = {
 	.get_parent = kona_peri_clk_get_parent,
 	.set_rate = kona_peri_clk_set_rate,
 };
-
-/* Put a peripheral clock into its initial state */
-static bool __peri_clk_init(struct kona_clk *bcm_clk)
-{
-	struct ccu_data *ccu = bcm_clk->ccu;
-	struct peri_clk_data *peri = bcm_clk->u.peri;
-	const char *name = bcm_clk->init_data.name;
-	struct bcm_clk_trig *trig;
-
-	BUG_ON(bcm_clk->type != bcm_clk_peri);
-
-	if (!policy_init(ccu, &peri->policy)) {
-		pr_err("%s: error initializing policy for %s\n",
-			__func__, name);
-		return false;
-	}
-	if (!gate_init(ccu, &peri->gate)) {
-		pr_err("%s: error initializing gate for %s\n", __func__, name);
-		return false;
-	}
-	if (!hyst_init(ccu, &peri->hyst)) {
-		pr_err("%s: error initializing hyst for %s\n", __func__, name);
-		return false;
-	}
-	if (!div_init(ccu, &peri->gate, &peri->div, &peri->trig)) {
-		pr_err("%s: error initializing divider for %s\n", __func__,
-			name);
-		return false;
-	}
-
-	/*
-	 * For the pre-divider and selector, the pre-trigger is used
-	 * if it's present, otherwise we just use the regular trigger.
-	 */
-	trig = trigger_exists(&peri->pre_trig) ? &peri->pre_trig
-					       : &peri->trig;
-
-	if (!div_init(ccu, &peri->gate, &peri->pre_div, trig)) {
-		pr_err("%s: error initializing pre-divider for %s\n", __func__,
-			name);
-		return false;
-	}
-
-	if (!sel_init(ccu, &peri->gate, &peri->sel, trig)) {
-		pr_err("%s: error initializing selector for %s\n", __func__,
-			name);
-		return false;
-	}
-
-	return true;
-}
-
-static bool __kona_clk_init(struct kona_clk *bcm_clk)
-{
-	switch (bcm_clk->type) {
-	case bcm_clk_peri:
-		return __peri_clk_init(bcm_clk);
-	default:
-		BUG();
-	}
-	return -EINVAL;
-}
-
-/* Set a CCU and all its clocks into their desired initial state */
-bool __init kona_ccu_init(struct ccu_data *ccu)
-{
-	unsigned long flags;
-	unsigned int which;
-	struct clk **clks = ccu->clk_data.clks;
-	bool success = true;
-
-	flags = ccu_lock(ccu);
-	__ccu_write_enable(ccu);
-
-	for (which = 0; which < ccu->clk_data.clk_num; which++) {
-		struct kona_clk *bcm_clk;
-
-		if (!clks[which])
-			continue;
-		bcm_clk = to_kona_clk(__clk_get_hw(clks[which]));
-		success &= __kona_clk_init(bcm_clk);
-	}
-
-	__ccu_write_disable(ccu);
-	ccu_unlock(ccu, flags);
-	return success;
-}
Signature · 1 line
1.9.1
author
#2 lore raw

PATCH v5 2/7 clk: kona: don't init clocks at startup time

In reply to Alex Elder

The last thing done for CCU setup is a call to kona_ccu_init(). This locks and enables write access on the CCU, then calls __kona_clk_init() for all of the clocks it provides. The purpose of this was to get or set the initial state of all the registers related to each clock.

There's no reason to do this though. The common clock framework assumes nothing about the state of the hardware, and if a driver requires its clock to be in a particular state it can set that state up itself.

Instead of initializing clocks at startup time, define a prepare method that performs that step when a clock is first needed.

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-kona-setup.c |  3 ---
 drivers/clk/bcm/clk-kona.c       | 49 +++++++++++++++++++---------------------
 drivers/clk/bcm/clk-kona.h       |  1 -
 3 files changed, 23 insertions(+), 30 deletions(-)
drivers/clk/bcm/clk-kona-setup.c +0 -3
index e5aeded..317f7dd 100644
@@ -867,9 +867,6 @@ void __init kona_dt_ccu_setup(struct ccu_data *ccu,
 		goto out_err;
 	}
 
-	if (!kona_ccu_init(ccu))
-		pr_err("Broadcom %s initialization had errors\n", node->name);
-
 	return;
 out_err:
 	kona_ccu_teardown(ccu);
drivers/clk/bcm/clk-kona.c +23 -26

72 lines not on this page · raw message

drivers/clk/bcm/clk-kona.h +0 -1
index 2537b30..4c7e796 100644
@@ -511,6 +511,5 @@ extern u64 scaled_div_build(struct bcm_clk_div *div, u32 div_value,
 extern struct clk *kona_clk_setup(struct kona_clk *bcm_clk);
 extern void __init kona_dt_ccu_setup(struct ccu_data *ccu,
 				struct device_node *node);
-extern bool __init kona_ccu_init(struct ccu_data *ccu);
 
 #endif /* _CLK_KONA_H */
Signature · 1 line
1.9.1
author
#3 lore raw

PATCH v5 3/7 clk: bcm281xx: add an initialized flag

In reply to Alex Elder

Add a flag that tracks whether a clock has already been initialized. Use it to avoid initializing a clock more than once.

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-kona.c | 12 ++++++++++++
 drivers/clk/bcm/clk-kona.h |  7 +++++++
 2 files changed, 19 insertions(+)
drivers/clk/bcm/clk-kona.c +12 -0
index cacbfd6..2e27924 100644
@@ -27,6 +27,9 @@
 #define CCU_ACCESS_PASSWORD      0xA5A500
 #define CLK_GATE_DELAY_LOOP      2000
 
+#define clk_is_initialized(_clk)	FLAG_TEST((_clk), KONA, INITIALIZED)
+#define clk_set_initialized(_clk)	FLAG_SET((_clk), KONA, INITIALIZED)
+
 /* Bitfield operations */
 
 /* Produces a mask of set bits covering a range of a 32-bit value */

@@ -1041,6 +1044,9 @@ static int kona_clk_prepare(struct clk_hw *hw)
 	unsigned long flags;
 	int ret = 0;
 
+	if (clk_is_initialized(bcm_clk))
+		return 0;
+
 	ccu = bcm_clk->ccu;
 	flags = ccu_lock(ccu);
 	__ccu_write_enable(ccu);

@@ -1057,11 +1063,17 @@ static int kona_clk_prepare(struct clk_hw *hw)
 	__ccu_write_disable(ccu);
 	ccu_unlock(ccu, flags);
 
+	if (!ret)
+		clk_set_initialized(bcm_clk);
+
 	return ret;
 }
 
 static void kona_clk_unprepare(struct clk_hw *hw)
 {
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+
+	WARN_ON(!clk_is_initialized(bcm_clk));
 	/* Nothing to do. */
 }
drivers/clk/bcm/clk-kona.h +7 -0
index 4c7e796..ea77ec1 100644
@@ -406,6 +406,7 @@ struct kona_clk {
 	struct clk_init_data init_data;	/* includes name of this clock */
 	struct ccu_data *ccu;	/* ccu this clock is associated with */
 	enum bcm_clk_type type;
+	u32 flags;		/* BCM_CLK_KONA_FLAGS_* below */
 	union {
 		void *data;
 		struct peri_clk_data *peri;

@@ -414,6 +415,12 @@ struct kona_clk {
 #define to_kona_clk(_hw) \
 	container_of(_hw, struct kona_clk, hw)
 
+/*
+ * Kona clock flags:
+ *   INITIALIZED	clock has been initialized already
+ */
+#define BCM_CLK_KONA_FLAGS_INITIALIZED	((u32)1 << 0)	/* Clock initialized */
+
 /* Initialization macro for an entry in a CCU's kona_clks[] array. */
 #define KONA_CLK(_ccu_name, _clk_name, _type)				\
 	{								\
Signature · 1 line
1.9.1
author
#4 lore raw

PATCH v5 4/7 clk: bcm281xx: implement prerequisite clocks

In reply to Alex Elder

Allow a clock to specify a "prerequisite" clock, identified by its name. The prerequisite clock must be prepared and enabled before a clock that depends on it is used. In order to simplify locking, we require a clock and its prerequisite to be associated with the same CCU. (We'll just trust--but not verify--that nobody defines a cycle of prerequisite clocks.)

Rework the KONA_CLK() macro, and define a new KONA_CLK_PREREQ() variant that allows a prerequisite clock to be specified.

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-kona.c | 70 ++++++++++++++++++++++++++++++++++++++++++++--
 drivers/clk/bcm/clk-kona.h | 20 +++++++++++--
 2 files changed, 85 insertions(+), 5 deletions(-)
drivers/clk/bcm/clk-kona.c +68 -2
index 2e27924..51b4edb 100644
@@ -1037,6 +1037,42 @@ static bool __peri_clk_init(struct kona_clk *bcm_clk)
 
 /* Clock operations */
 
+static int kona_prereq_prepare_enable(struct kona_clk *bcm_clk)
+{
+	const char *clk_name = bcm_clk->init_data.name;
+	const char *prereq_name = bcm_clk->prereq.name;
+	struct clk *prereq_clk = bcm_clk->prereq.clk;
+	int ret;
+
+	BUG_ON(!clk_name);
+
+	/* Look up the prerequisite clock if we haven't already */
+	if (!prereq_clk) {
+		prereq_clk = __clk_lookup(prereq_name);
+		if (WARN_ON_ONCE(!prereq_clk))
+			return -ENOENT;
+		bcm_clk->prereq.clk = prereq_clk;
+	}
+
+	/* Dependent clock already holds the prepare lock */
+	ret = __clk_prepare(prereq_clk);
+	if (ret) {
+		pr_err("%s: unable to prepare prereq clock %s for %s\n",
+			__func__, prereq_name, clk_name);
+		return ret;
+	}
+
+	ret = clk_enable(prereq_clk);
+	if (ret) {
+		__clk_unprepare(prereq_clk);
+		pr_err("%s: unable to enable prereq clock %s for %s\n",
+			__func__, prereq_name, clk_name);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int kona_clk_prepare(struct clk_hw *hw)
 {
 	struct kona_clk *bcm_clk = to_kona_clk(hw);

@@ -1044,6 +1080,13 @@ static int kona_clk_prepare(struct clk_hw *hw)
 	unsigned long flags;
 	int ret = 0;
 
+	/* Prepare the prerequisite clock first */
+	if (bcm_clk->prereq.name) {
+		ret = kona_prereq_prepare_enable(bcm_clk);
+		if (ret)
+			goto out;
+	}
+
 	if (clk_is_initialized(bcm_clk))
 		return 0;
 

@@ -1062,19 +1105,42 @@ static int kona_clk_prepare(struct clk_hw *hw)
 
 	__ccu_write_disable(ccu);
 	ccu_unlock(ccu, flags);
-
+out:
 	if (!ret)
 		clk_set_initialized(bcm_clk);
 
 	return ret;
 }
 
+/*
+ * Disable and unprepare a prerequisite clock, and drop our
+ * reference to it.
+ */
+static void kona_prereq_disable_unprepare(struct kona_clk *bcm_clk)
+{
+	struct clk *prereq_clk = bcm_clk->prereq.clk;
+
+	BUG_ON(!bcm_clk->prereq.name);
+	WARN_ON_ONCE(!prereq_clk);
+
+	clk_disable(prereq_clk);
+	__clk_unprepare(prereq_clk);
+}
+
 static void kona_clk_unprepare(struct clk_hw *hw)
 {
 	struct kona_clk *bcm_clk = to_kona_clk(hw);
 
 	WARN_ON(!clk_is_initialized(bcm_clk));
-	/* Nothing to do. */
+
+	/*
+	 * We don't do anything to unprepare Kona clocks themselves,
+	 * but if there's a prerequisite we'll need to unprepare it.
+	 */
+	if (!bcm_clk->prereq.name)
+		return;
+
+	kona_prereq_disable_unprepare(bcm_clk);
 }
 
 static int kona_peri_clk_enable(struct clk_hw *hw)
drivers/clk/bcm/clk-kona.h +17 -3
index ea77ec1..98b6fa1 100644
@@ -407,6 +407,10 @@ struct kona_clk {
 	struct ccu_data *ccu;	/* ccu this clock is associated with */
 	enum bcm_clk_type type;
 	u32 flags;		/* BCM_CLK_KONA_FLAGS_* below */
+	struct {
+		const char *name;
+		struct clk *clk;
+	} prereq;
 	union {
 		void *data;
 		struct peri_clk_data *peri;

@@ -422,16 +426,26 @@ struct kona_clk {
 #define BCM_CLK_KONA_FLAGS_INITIALIZED	((u32)1 << 0)	/* Clock initialized */
 
 /* Initialization macro for an entry in a CCU's kona_clks[] array. */
-#define KONA_CLK(_ccu_name, _clk_name, _type)				\
-	{								\
+#define ___KONA_CLK_COMMON(_ccu_name, _clk_name, _type)			\
 		.init_data	= {					\
 			.name = #_clk_name,				\
 			.ops = &kona_ ## _type ## _clk_ops,		\
 		},							\
 		.ccu		= &_ccu_name ## _ccu_data,		\
 		.type		= bcm_clk_ ## _type,			\
-		.u.data		= &_clk_name ## _data,			\
+		.u.data		= &_clk_name ## _data
+
+#define KONA_CLK_PREREQ(_ccu_name, _clk_name, _type, _prereq)		\
+	{								\
+		.prereq.name	= #_prereq,				\
+		___KONA_CLK_COMMON(_ccu_name, _clk_name, _type),	\
 	}
+
+#define KONA_CLK(_ccu_name, _clk_name, _type)				\
+	{								\
+		___KONA_CLK_COMMON(_ccu_name, _clk_name, _type),	\
+	}
+
 #define LAST_KONA_CLK	{ .type = bcm_clk_none }
 
 /*
Signature · 1 line
1.9.1
author
#5 lore raw

PATCH v5 5/7 clk: bcm281xx: add bus clock support

In reply to Alex Elder

Add bus clock support. A bus clock has a subset of the components present in a peripheral clock (again, all optional): a gate; CCU policy management bits; and if needed, bits to control hysteresis.

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-kona-setup.c | 96 ++++++++++++++++++++++++++++++++++++++--
 drivers/clk/bcm/clk-kona.c       | 61 +++++++++++++++++++++++++
 drivers/clk/bcm/clk-kona.h       |  8 ++++
 3 files changed, 162 insertions(+), 3 deletions(-)
drivers/clk/bcm/clk-kona-setup.c +93 -3
index 317f7dd..1dae591 100644
@@ -76,6 +76,56 @@ static bool clk_requires_trigger(struct kona_clk *bcm_clk)
 	return divider_exists(div) && !divider_is_fixed(div);
 }
 
+static bool bus_clk_data_offsets_valid(struct kona_clk *bcm_clk)
+{
+	struct bus_clk_data *bus;
+	struct bcm_clk_policy *policy;
+	struct bcm_clk_gate *gate;
+	struct bcm_clk_hyst *hyst;
+	const char *name;
+	u32 limit;
+
+	BUG_ON(bcm_clk->type != bcm_clk_bus);
+	bus = bcm_clk->u.bus;
+	name = bcm_clk->init_data.name;
+
+	limit = bcm_clk->ccu->range - sizeof(u32);
+	limit = round_down(limit, sizeof(u32));
+
+	policy = &bus->policy;
+	if (policy_exists(policy)) {
+		if (policy->offset > limit) {
+			pr_err("%s: bad policy offset for %s (%u > %u)\n",
+				__func__, name, policy->offset, limit);
+			return false;
+		}
+	}
+
+	gate = &bus->gate;
+	hyst = &bus->hyst;
+	if (gate_exists(gate)) {
+		if (gate->offset > limit) {
+			pr_err("%s: bad gate offset for %s (%u > %u)\n",
+				__func__, name, gate->offset, limit);
+			return false;
+		}
+		if (hyst_exists(hyst)) {
+			if (hyst->offset > limit) {
+				pr_err("%s: bad hysteresis offset for %s "
+					"(%u > %u)\n", __func__,
+					name, hyst->offset, limit);
+				return false;
+			}
+		}
+	} else if (hyst_exists(hyst)) {
+		pr_err("%s: hysteresis but no gate for %s\n", __func__, name);
+		return false;
+	}
+
+
+	return true;
+}
+
 static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
 {
 	struct peri_clk_data *peri;

@@ -86,15 +136,13 @@ static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
 	struct bcm_clk_sel *sel;
 	struct bcm_clk_trig *trig;
 	const char *name;
-	u32 range;
 	u32 limit;
 
 	BUG_ON(bcm_clk->type != bcm_clk_peri);
 	peri = bcm_clk->u.peri;
 	name = bcm_clk->init_data.name;
-	range = bcm_clk->ccu->range;
 
-	limit = range - sizeof(u32);
+	limit = bcm_clk->ccu->range - sizeof(u32);
 	limit = round_down(limit, sizeof(u32));
 
 	policy = &peri->policy;

@@ -397,6 +445,23 @@ static bool trig_valid(struct bcm_clk_trig *trig, const char *field_name,
 	return bit_posn_valid(trig->bit, field_name, clock_name);
 }
 
+/* Determine whether the set of bus clock registers are valid. */
+static bool
+bus_clk_data_valid(struct kona_clk *bcm_clk)
+{
+	struct bcm_clk_gate *gate;
+
+	BUG_ON(bcm_clk->type != bcm_clk_bus);
+	if (!bus_clk_data_offsets_valid(bcm_clk))
+		return false;
+
+	gate = &bcm_clk->u.bus->gate;
+	if (!gate_exists(gate))
+		return true;
+
+	return gate_valid(gate, "gate", bcm_clk->init_data.name);
+}
+
 /* Determine whether the set of peripheral clock registers are valid. */
 static bool
 peri_clk_data_valid(struct kona_clk *bcm_clk)

@@ -494,6 +559,10 @@ peri_clk_data_valid(struct kona_clk *bcm_clk)
 static bool kona_clk_valid(struct kona_clk *bcm_clk)
 {
 	switch (bcm_clk->type) {
+	case bcm_clk_bus:
+		if (!bus_clk_data_valid(bcm_clk))
+			return false;
+		break;
 	case bcm_clk_peri:
 		if (!peri_clk_data_valid(bcm_clk))
 			return false;

@@ -664,6 +733,20 @@ static void clk_sel_teardown(struct bcm_clk_sel *sel,
 	init_data->parent_names = NULL;
 }
 
+static void bus_clk_teardown(struct bus_clk_data *data,
+				struct clk_init_data *init_data)
+{
+	/* Nothing to do */
+}
+
+static int
+bus_clk_setup(struct bus_clk_data *data, struct clk_init_data *init_data)
+{
+	init_data->flags = CLK_IGNORE_UNUSED;
+
+	return 0;
+}
+
 static void peri_clk_teardown(struct peri_clk_data *data,
 				struct clk_init_data *init_data)
 {

@@ -687,6 +770,9 @@ peri_clk_setup(struct peri_clk_data *data, struct clk_init_data *init_data)
 static void bcm_clk_teardown(struct kona_clk *bcm_clk)
 {
 	switch (bcm_clk->type) {
+	case bcm_clk_bus:
+		bus_clk_teardown(bcm_clk->u.data, &bcm_clk->init_data);
+		break;
 	case bcm_clk_peri:
 		peri_clk_teardown(bcm_clk->u.data, &bcm_clk->init_data);
 		break;

@@ -722,6 +808,10 @@ struct clk *kona_clk_setup(struct kona_clk *bcm_clk)
 	struct clk *clk = NULL;
 
 	switch (bcm_clk->type) {
+	case bcm_clk_bus:
+		if (bus_clk_setup(bcm_clk->u.data, init_data))
+			return NULL;
+		break;
 	case bcm_clk_peri:
 		if (peri_clk_setup(bcm_clk->u.data, init_data))
 			return NULL;
drivers/clk/bcm/clk-kona.c +61 -0

79 lines not on this page · raw message

drivers/clk/bcm/clk-kona.h +8 -0
index 98b6fa1..46ea11f 100644
@@ -387,6 +387,12 @@ struct bcm_clk_trig {
 		.flags = FLAG(TRIG, EXISTS),				\
 	}
 
+struct bus_clk_data {
+	struct bcm_clk_policy policy;
+	struct bcm_clk_gate gate;
+	struct bcm_clk_hyst hyst;
+};
+
 struct peri_clk_data {
 	struct bcm_clk_policy policy;
 	struct bcm_clk_gate gate;

@@ -413,6 +419,7 @@ struct kona_clk {
 	} prereq;
 	union {
 		void *data;
+		struct bus_clk_data *bus;
 		struct peri_clk_data *peri;
 	} u;
 };

@@ -520,6 +527,7 @@ struct ccu_data {
 
 /* Exported globals */
 
+extern struct clk_ops kona_bus_clk_ops;
 extern struct clk_ops kona_peri_clk_ops;
 
 /* Externally visible functions */
Signature · 1 line
1.9.1
author
#6 lore raw

PATCH v5 6/7 clk: bcm281xx: define a bus clock

In reply to Alex Elder

Define the bus clock "bsc3_apb". This bus clock has to be managed using the CCU policy mechanism, so add the definitions required for that to the clock and its CCU.

This one bus clock in particular is defined because it is needed by peripheral clock "bsc3". Our boot loader does not properly activate "bsc3_apb", and as a result, "bsc3" isn't able to function properly. With "bsc3_apb" specified as a prerequisite clock for "bsc3", the latter works correctly.

For now only this one bus clock is defined, because it allows correct operation of "bsc3". Others can be added later as needed (and this patch serves to show how that's done).

Signed-off-by Alex Elder <[email protected]>
---
 drivers/clk/bcm/clk-bcm281xx.c       | 13 ++++++++++++-
 include/dt-bindings/clock/bcm281xx.h |  3 ++-
 2 files changed, 14 insertions(+), 2 deletions(-)
drivers/clk/bcm/clk-bcm281xx.c +12 -1
index 502a487..b937fc9 100644
@@ -309,8 +309,17 @@ static struct peri_clk_data pwm_data = {
 	.trig		= TRIGGER(0x0afc, 15),
 };
 
+static struct bus_clk_data bsc3_apb_data = {
+	.policy		= POLICY(0x0048, 4),
+	.gate		= HW_SW_GATE(0x0484, 16, 0, 1),
+};
+
 static struct ccu_data slave_ccu_data = {
 	BCM281XX_CCU_COMMON(slave, SLAVE),
+	.policy		= {
+		.enable		= CCU_LVM_EN(0x0034, 0),
+		.control	= CCU_POLICY_CTL(0x000c, 0, 1, 2),
+	},
 	.kona_clks	= {
 		[BCM281XX_SLAVE_CCU_UARTB] =
 			KONA_CLK(slave, uartb, peri),

@@ -329,9 +338,11 @@ static struct ccu_data slave_ccu_data = {
 		[BCM281XX_SLAVE_CCU_BSC2] =
 			KONA_CLK(slave, bsc2, peri),
 		[BCM281XX_SLAVE_CCU_BSC3] =
-			KONA_CLK(slave, bsc3, peri),
+			KONA_CLK_PREREQ(slave, bsc3, peri, bsc3_apb),
 		[BCM281XX_SLAVE_CCU_PWM] =
 			KONA_CLK(slave, pwm, peri),
+		[BCM281XX_SLAVE_CCU_BSC3_APB] =
+			KONA_CLK(slave, bsc3_apb, bus),
 		[BCM281XX_SLAVE_CCU_CLOCK_COUNT] = LAST_KONA_CLK,
 	},
 };
include/dt-bindings/clock/bcm281xx.h +2 -1
index a763460..99f4aad 100644
@@ -72,6 +72,7 @@
 #define BCM281XX_SLAVE_CCU_BSC2			7
 #define BCM281XX_SLAVE_CCU_BSC3			8
 #define BCM281XX_SLAVE_CCU_PWM			9
-#define BCM281XX_SLAVE_CCU_CLOCK_COUNT		10
+#define BCM281XX_SLAVE_CCU_BSC3_APB		10
+#define BCM281XX_SLAVE_CCU_CLOCK_COUNT		11
 
 #endif /* _CLOCK_BCM281XX_H */
Signature · 1 line
1.9.1
author
#7 lore raw

PATCH v5 7/7 ARM: dts: add bus clock bsc3_apb for bcm281xx

In reply to Alex Elder

Add the bus clock named "bsc3_apb" to the list of those provided by the slave CCU.

Signed-off-by Alex Elder <[email protected]>
---
 arch/arm/boot/dts/bcm11351.dtsi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm/boot/dts/bcm11351.dtsi +2 -1
index 64d069b..faff8af 100644
@@ -247,7 +247,8 @@
 					     "bsc1",
 					     "bsc2",
 					     "bsc3",
-					     "pwm";
+					     "pwm",
+					     "bsc3_apb";
 		};
 
 		ref_1m_clk: ref_1m {
Signature · 1 line
1.9.1