[PATCH v3 6/7] clk: bcm281xx: add clock policy support
Alex Elder
elder at linaro.org
Tue Apr 1 19:04:54 PDT 2014
Add support for CCU policy engine control, and also for setting the
mask bits for bus clocks that require a policy change to get
activated. This includes adding validity checking framework for
CCUs, to validate the policy fields if defined.
Signed-off-by: Alex Elder <elder at linaro.org>
---
drivers/clk/bcm/clk-kona-setup.c | 92 ++++++++++++++++++++++
drivers/clk/bcm/clk-kona.c | 155 ++++++++++++++++++++++++++++++++++++++
drivers/clk/bcm/clk-kona.h | 71 +++++++++++++++++
3 files changed, 318 insertions(+)
diff --git a/drivers/clk/bcm/clk-kona-setup.c b/drivers/clk/bcm/clk-kona-setup.c
index 196922b..5a49deb 100644
--- a/drivers/clk/bcm/clk-kona-setup.c
+++ b/drivers/clk/bcm/clk-kona-setup.c
@@ -25,6 +25,31 @@ LIST_HEAD(ccu_list); /* The list of set up CCUs */
/* Validity checking */
+static bool ccu_data_offsets_valid(struct ccu_data *ccu)
+{
+ struct ccu_policy *ccu_policy = &ccu->policy;
+ u32 limit;
+
+ limit = ccu->range - sizeof(u32);
+ limit = round_down(limit, sizeof(u32));
+ if (ccu_policy_exists(ccu_policy)) {
+ if (ccu_policy->enable.offset > limit) {
+ pr_err("%s: bad policy enable offset for %s "
+ "(%u > %u)\n", __func__,
+ ccu->name, ccu_policy->enable.offset, limit);
+ return false;
+ }
+ if (ccu_policy->control.offset > limit) {
+ pr_err("%s: bad policy control offset for %s "
+ "(%u > %u)\n", __func__,
+ ccu->name, ccu_policy->control.offset, limit);
+ return false;
+ }
+ }
+
+ return true;
+}
+
static bool clk_requires_trigger(struct kona_clk *bcm_clk)
{
struct peri_clk_data *peri = bcm_clk->peri;
@@ -54,6 +79,7 @@ static bool clk_requires_trigger(struct kona_clk *bcm_clk)
static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
{
struct peri_clk_data *peri;
+ struct bcm_clk_policy *policy;
struct bcm_clk_gate *gate;
struct bcm_clk_div *div;
struct bcm_clk_sel *sel;
@@ -70,6 +96,15 @@ static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
limit = range - sizeof(u32);
limit = round_down(limit, sizeof(u32));
+ policy = &peri->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 = &peri->gate;
if (gate_exists(gate)) {
if (gate->offset > limit) {
@@ -167,6 +202,36 @@ static bool bitfield_valid(u32 shift, u32 width, const char *field_name,
return true;
}
+static bool
+ccu_policy_valid(struct ccu_policy *ccu_policy, const char *ccu_name)
+{
+ struct bcm_lvm_en *enable = &ccu_policy->enable;
+ struct bcm_policy_ctl *control;
+
+ if (!bit_posn_valid(enable->bit, "policy enable", ccu_name))
+ return false;
+
+ control = &ccu_policy->control;
+ if (!bit_posn_valid(control->go_bit, "policy control GO", ccu_name))
+ return false;
+
+ if (!bit_posn_valid(control->atl_bit, "policy control ATL", ccu_name))
+ return false;
+
+ if (!bit_posn_valid(control->ac_bit, "policy control AC", ccu_name))
+ return false;
+
+ return true;
+}
+
+static bool policy_valid(struct bcm_clk_policy *policy, const char *clock_name)
+{
+ if (!bit_posn_valid(policy->bit, "policy", clock_name))
+ return false;
+
+ return true;
+}
+
/*
* All gates, if defined, have a status bit, and for hardware-only
* gates, that's it. Gates that can be software controlled also
@@ -311,6 +376,7 @@ static bool
peri_clk_data_valid(struct kona_clk *bcm_clk)
{
struct peri_clk_data *peri;
+ struct bcm_clk_policy *policy;
struct bcm_clk_gate *gate;
struct bcm_clk_sel *sel;
struct bcm_clk_div *div;
@@ -330,6 +396,11 @@ peri_clk_data_valid(struct kona_clk *bcm_clk)
peri = bcm_clk->peri;
name = bcm_clk->init_data.name;
+
+ policy = &peri->policy;
+ if (policy_exists(policy) && !policy_valid(policy, name))
+ return false;
+
gate = &peri->gate;
if (gate_exists(gate) && !gate_valid(gate, "gate", name))
return false;
@@ -678,6 +749,21 @@ static void kona_ccu_teardown(struct ccu_data *ccu)
ccu->base = NULL;
}
+static bool ccu_data_valid(struct ccu_data *ccu)
+{
+ struct ccu_policy *ccu_policy;
+
+ if (!ccu_data_offsets_valid(ccu))
+ return false;
+
+ ccu_policy = &ccu->policy;
+ if (ccu_policy_exists(ccu_policy))
+ if (!ccu_policy_valid(ccu_policy, ccu->name))
+ return false;
+
+ return true;
+}
+
/*
* Set up a CCU. Call the provided ccu_clks_setup callback to
* initialize the array of clocks provided by the CCU.
@@ -717,6 +803,12 @@ void __init kona_dt_ccu_setup(struct ccu_data *ccu,
}
ccu->range = (u32)range;
+
+ if (!ccu_data_valid(ccu)) {
+ pr_err("%s: ccu data not valid for %s\n", __func__, node->name);
+ goto out_err;
+ }
+
ccu->base = ioremap(res.start, ccu->range);
if (!ccu->base) {
pr_err("%s: unable to map CCU registers for %s\n", __func__,
diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
index 5c0dc5b..bf9661c 100644
--- a/drivers/clk/bcm/clk-kona.c
+++ b/drivers/clk/bcm/clk-kona.c
@@ -16,6 +16,14 @@
#include <linux/delay.h>
+/*
+ * "Policies" affect the frequencies of bus clocks provided by a
+ * CCU. (I believe these polices are named "Deep Sleep", "Economy",
+ * "Normal", and "Turbo".) A lower policy number has lower power
+ * consumption, and policy 2 is the default.
+ */
+#define CCU_POLICY_COUNT 4
+
#define CCU_ACCESS_PASSWORD 0xA5A500
#define CLK_GATE_DELAY_LOOP 2000
@@ -213,6 +221,148 @@ __ccu_wait_bit(struct ccu_data *ccu, u32 reg_offset, u32 bit, bool want)
return false;
}
+/* Policy operations */
+
+static bool __ccu_policy_engine_start(struct ccu_data *ccu, bool sync)
+{
+ struct bcm_policy_ctl *control = &ccu->policy.control;
+ u32 offset;
+ u32 go_bit;
+ u32 mask;
+ bool ret;
+
+ /* If we don't need to control policy for this CCU, we're done. */
+ if (!policy_ctl_exists(control))
+ return true;
+
+ offset = control->offset;
+ go_bit = control->go_bit;
+
+ /* Ensure we're not busy before we start */
+ ret = __ccu_wait_bit(ccu, offset, go_bit, false);
+ if (!ret) {
+ pr_err("%s: ccu %s policy engine wouldn't go idle\n",
+ __func__, ccu->name);
+ return false;
+ }
+
+ /*
+ * If it's a synchronous request, we'll wait for the voltage
+ * and frequency of the active load to stabilize before
+ * returning. To do this we select the active load by
+ * setting the ATL bit.
+ *
+ * An asynchronous request instead ramps the voltage in the
+ * background, and when that process stabilizes, the target
+ * load is copied to the active load and the CCU frequency
+ * is switched. We do this by selecting the target load
+ * (ATL bit clear) and setting the request auto-copy (AC bit
+ * set).
+ *
+ * Note, we do NOT read-modify-write this register.
+ */
+ mask = (u32)1 << go_bit;
+ if (sync)
+ mask |= 1 << control->atl_bit;
+ else
+ mask |= 1 << control->ac_bit;
+ __ccu_write(ccu, offset, mask);
+
+ /* Wait for indication that operation is complete. */
+ ret = __ccu_wait_bit(ccu, offset, go_bit, false);
+ if (!ret)
+ pr_err("%s: ccu %s policy engine never started\n",
+ __func__, ccu->name);
+
+ return ret;
+}
+
+static bool __ccu_policy_engine_stop(struct ccu_data *ccu)
+{
+ struct bcm_lvm_en *enable = &ccu->policy.enable;
+ u32 offset;
+ u32 enable_bit;
+ bool ret;
+
+ /* If we don't need to control policy for this CCU, we're done. */
+ if (!policy_lvm_en_exists(enable))
+ return true;
+
+ /* Ensure we're not busy before we start */
+ offset = enable->offset;
+ enable_bit = enable->bit;
+ ret = __ccu_wait_bit(ccu, offset, enable_bit, false);
+ if (!ret) {
+ pr_err("%s: ccu %s policy engine already stopped\n",
+ __func__, ccu->name);
+ return false;
+ }
+
+ /* Now set the bit to stop the engine (NO read-modify-write) */
+ __ccu_write(ccu, offset, (u32)1 << enable_bit);
+
+ /* Wait for indication that it has stopped. */
+ ret = __ccu_wait_bit(ccu, offset, enable_bit, false);
+ if (!ret)
+ pr_err("%s: ccu %s policy engine never stopped\n",
+ __func__, ccu->name);
+
+ return ret;
+}
+
+/*
+ * A CCU has four operating conditions ("policies"), and some clocks
+ * can be disabled or enabled based on which policy is currently in
+ * effect. Such clocks have a bit in a "policy mask" register for
+ * each policy indicating whether the clock is enabled for that
+ * policy or not. The bit position for a clock is the same for all
+ * four registers, and the 32-bit registers are at consecutive
+ * addresses.
+ */
+static bool policy_init(struct ccu_data *ccu, struct bcm_clk_policy *policy)
+{
+ u32 offset;
+ u32 mask;
+ int i;
+ bool ret;
+
+ if (!policy_exists(policy))
+ return true;
+
+ /*
+ * We need to stop the CCU policy engine to allow update
+ * of our policy bits.
+ */
+ if (!__ccu_policy_engine_stop(ccu)) {
+ pr_err("%s: unable to stop CCU %s policy engine\n",
+ __func__, ccu->name);
+ return false;
+ }
+
+ /*
+ * For now, if a clock defines its policy bit we just mark
+ * it "enabled" for all four policies.
+ */
+ offset = policy->offset;
+ mask = (u32)1 << policy->bit;
+ for (i = 0; i < CCU_POLICY_COUNT; i++) {
+ u32 reg_val;
+
+ reg_val = __ccu_read(ccu, offset);
+ reg_val |= mask;
+ __ccu_write(ccu, offset, reg_val);
+ offset += sizeof(u32);
+ }
+
+ /* We're done updating; fire up the policy engine again. */
+ ret = __ccu_policy_engine_start(ccu, true);
+ if (!ret)
+ pr_err("%s: unable to restart CCU %s policy engine\n",
+ __func__, ccu->name);
+
+ return ret;
+}
+
/* Gate operations */
/* Determine whether a clock is gated. CCU lock must be held. */
@@ -970,6 +1120,11 @@ static bool __peri_clk_init(struct kona_clk *bcm_clk)
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;
diff --git a/drivers/clk/bcm/clk-kona.h b/drivers/clk/bcm/clk-kona.h
index fba2740..c390ca4 100644
--- a/drivers/clk/bcm/clk-kona.h
+++ b/drivers/clk/bcm/clk-kona.h
@@ -43,8 +43,14 @@
#define FLAG_FLIP(obj, type, flag) ((obj)->flags ^= FLAG(type, flag))
#define FLAG_TEST(obj, type, flag) (!!((obj)->flags & FLAG(type, flag)))
+/* CCU field state tests */
+
+#define ccu_policy_exists(ccu_policy) ((ccu_policy)->enable.offset != 0)
+
/* Clock field state tests */
+#define policy_exists(policy) ((policy)->offset != 0)
+
#define gate_exists(gate) FLAG_TEST(gate, GATE, EXISTS)
#define gate_is_enabled(gate) FLAG_TEST(gate, GATE, ENABLED)
#define gate_is_hw_controllable(gate) FLAG_TEST(gate, GATE, HW)
@@ -62,6 +68,9 @@
#define selector_exists(sel) ((sel)->width != 0)
#define trigger_exists(trig) FLAG_TEST(trig, TRIG, EXISTS)
+#define policy_lvm_en_exists(enable) ((enable)->offset != 0)
+#define policy_ctl_exists(control) ((control)->offset != 0)
+
/* Clock type, used to tell common block what it's part of */
enum bcm_clk_type {
bcm_clk_none, /* undefined clock type */
@@ -71,6 +80,27 @@ enum bcm_clk_type {
};
/*
+ * CCU policy control for clocks. Clocks can be enabled or disabled
+ * based on the CCU policy in effect. One bit in each policy mask
+ * register (one per CCU policy) represents whether the clock is
+ * enabled when that policy is effect or not. The CCU policy engine
+ * must be stopped to update these bits, and must be restarted again
+ * afterward.
+ */
+struct bcm_clk_policy {
+ u32 offset; /* first policy mask register offset */
+ u32 bit; /* bit used in all mask registers */
+};
+
+/* Policy initialization macro */
+
+#define POLICY(_offset, _bit) \
+ { \
+ .offset = (_offset), \
+ .bit = (_bit), \
+ }
+
+/*
* Gating control and status is managed by a 32-bit gate register.
*
* There are several types of gating available:
@@ -340,6 +370,7 @@ struct bcm_clk_trig {
}
struct peri_clk_data {
+ struct bcm_clk_policy policy;
struct bcm_clk_gate gate;
struct bcm_clk_trig pre_trig;
struct bcm_clk_div pre_div;
@@ -378,6 +409,45 @@ struct kona_clk {
#define LAST_KONA_CLK { .type = bcm_clk_none }
/*
+ * CCU policy control. To enable software update of the policy
+ * tables the CCU policy engine must be stopped by setting the
+ * software update enable bit (LVM_EN). After an update the engine
+ * is restarted using the GO bit and either the GO_ATL or GO_AC bit.
+ */
+struct bcm_lvm_en {
+ u32 offset; /* LVM_EN register offset */
+ u32 bit; /* POLICY_CONFIG_EN bit in register */
+};
+
+/* Policy enable initialization macro */
+#define CCU_LVM_EN(_offset, _bit) \
+ { \
+ .offset = (_offset), \
+ .bit = (_bit), \
+ }
+
+struct bcm_policy_ctl {
+ u32 offset; /* POLICY_CTL register offset */
+ u32 go_bit;
+ u32 atl_bit; /* GO, GO_ATL, and GO_AC bits */
+ u32 ac_bit;
+};
+
+/* Policy control initialization macro */
+#define CCU_POLICY_CTL(_offset, _go_bit, _ac_bit, _atl_bit) \
+ { \
+ .offset = (_offset), \
+ .go_bit = (_go_bit), \
+ .ac_bit = (_ac_bit), \
+ .atl_bit = (_atl_bit), \
+ }
+
+struct ccu_policy {
+ struct bcm_lvm_en enable;
+ struct bcm_policy_ctl control;
+};
+
+/*
* Each CCU defines a mapped area of memory containing registers
* used to manage clocks implemented by the CCU. Access to memory
* within the CCU's space is serialized by a spinlock. Before any
@@ -390,6 +460,7 @@ struct ccu_data {
void __iomem *base; /* base of mapped address space */
spinlock_t lock; /* serialization lock */
bool write_enabled; /* write access is currently enabled */
+ struct ccu_policy policy;
struct list_head links; /* for ccu_list */
struct device_node *node;
struct clk_onecell_data clk_data;
--
1.7.9.5
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