Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1277 insertions, 0 deletions

diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
new file mode 100644
index 000000000..eee64b9e5
--- /dev/null
+++ b/drivers/clk/bcm/clk-kona.c
@@ -0,0 +1,1277 @@
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ * Copyright 2013 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "clk-kona.h"
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/clk.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
+
+/* Bitfield operations */
+
+/* Produces a mask of set bits covering a range of a 32-bit value */
+static inline u32 bitfield_mask(u32 shift, u32 width)
+{
+	return ((1 << width) - 1) << shift;
+}
+
+/* Extract the value of a bitfield found within a given register value */
+static inline u32 bitfield_extract(u32 reg_val, u32 shift, u32 width)
+{
+	return (reg_val & bitfield_mask(shift, width)) >> shift;
+}
+
+/* Replace the value of a bitfield found within a given register value */
+static inline u32 bitfield_replace(u32 reg_val, u32 shift, u32 width, u32 val)
+{
+	u32 mask = bitfield_mask(shift, width);
+
+	return (reg_val & ~mask) | (val << shift);
+}
+
+/* Divider and scaling helpers */
+
+/* Convert a divider into the scaled divisor value it represents. */
+static inline u64 scaled_div_value(struct bcm_clk_div *div, u32 reg_div)
+{
+	return (u64)reg_div + ((u64)1 << div->u.s.frac_width);
+}
+
+/*
+ * Build a scaled divider value as close as possible to the
+ * given whole part (div_value) and fractional part (expressed
+ * in billionths).
+ */
+u64 scaled_div_build(struct bcm_clk_div *div, u32 div_value, u32 billionths)
+{
+	u64 combined;
+
+	BUG_ON(!div_value);
+	BUG_ON(billionths >= BILLION);
+
+	combined = (u64)div_value * BILLION + billionths;
+	combined <<= div->u.s.frac_width;
+
+	return DIV_ROUND_CLOSEST_ULL(combined, BILLION);
+}
+
+/* The scaled minimum divisor representable by a divider */
+static inline u64
+scaled_div_min(struct bcm_clk_div *div)
+{
+	if (divider_is_fixed(div))
+		return (u64)div->u.fixed;
+
+	return scaled_div_value(div, 0);
+}
+
+/* The scaled maximum divisor representable by a divider */
+u64 scaled_div_max(struct bcm_clk_div *div)
+{
+	u32 reg_div;
+
+	if (divider_is_fixed(div))
+		return (u64)div->u.fixed;
+
+	reg_div = ((u32)1 << div->u.s.width) - 1;
+
+	return scaled_div_value(div, reg_div);
+}
+
+/*
+ * Convert a scaled divisor into its divider representation as
+ * stored in a divider register field.
+ */
+static inline u32
+divider(struct bcm_clk_div *div, u64 scaled_div)
+{
+	BUG_ON(scaled_div < scaled_div_min(div));
+	BUG_ON(scaled_div > scaled_div_max(div));
+
+	return (u32)(scaled_div - ((u64)1 << div->u.s.frac_width));
+}
+
+/* Return a rate scaled for use when dividing by a scaled divisor. */
+static inline u64
+scale_rate(struct bcm_clk_div *div, u32 rate)
+{
+	if (divider_is_fixed(div))
+		return (u64)rate;
+
+	return (u64)rate << div->u.s.frac_width;
+}
+
+/* CCU access */
+
+/* Read a 32-bit register value from a CCU's address space. */
+static inline u32 __ccu_read(struct ccu_data *ccu, u32 reg_offset)
+{
+	return readl(ccu->base + reg_offset);
+}
+
+/* Write a 32-bit register value into a CCU's address space. */
+static inline void
+__ccu_write(struct ccu_data *ccu, u32 reg_offset, u32 reg_val)
+{
+	writel(reg_val, ccu->base + reg_offset);
+}
+
+static inline unsigned long ccu_lock(struct ccu_data *ccu)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ccu->lock, flags);
+
+	return flags;
+}
+static inline void ccu_unlock(struct ccu_data *ccu, unsigned long flags)
+{
+	spin_unlock_irqrestore(&ccu->lock, flags);
+}
+
+/*
+ * Enable/disable write access to CCU protected registers.  The
+ * WR_ACCESS register for all CCUs is at offset 0.
+ */
+static inline void __ccu_write_enable(struct ccu_data *ccu)
+{
+	if (ccu->write_enabled) {
+		pr_err("%s: access already enabled for %s\n", __func__,
+			ccu->name);
+		return;
+	}
+	ccu->write_enabled = true;
+	__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD | 1);
+}
+
+static inline void __ccu_write_disable(struct ccu_data *ccu)
+{
+	if (!ccu->write_enabled) {
+		pr_err("%s: access wasn't enabled for %s\n", __func__,
+			ccu->name);
+		return;
+	}
+
+	__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD);
+	ccu->write_enabled = false;
+}
+
+/*
+ * Poll a register in a CCU's address space, returning when the
+ * specified bit in that register's value is set (or clear).  Delay
+ * a microsecond after each read of the register.  Returns true if
+ * successful, or false if we gave up trying.
+ *
+ * Caller must ensure the CCU lock is held.
+ */
+static inline bool
+__ccu_wait_bit(struct ccu_data *ccu, u32 reg_offset, u32 bit, bool want)
+{
+	unsigned int tries;
+	u32 bit_mask = 1 << bit;
+
+	for (tries = 0; tries < CLK_GATE_DELAY_LOOP; tries++) {
+		u32 val;
+		bool bit_val;
+
+		val = __ccu_read(ccu, reg_offset);
+		bit_val = (val & bit_mask) != 0;
+		if (bit_val == want)
+			return true;
+		udelay(1);
+	}
+	pr_warn("%s: %s/0x%04x bit %u was never %s\n", __func__,
+		ccu->name, reg_offset, bit, want ? "set" : "clear");
+
+	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.  */
+static bool
+__is_clk_gate_enabled(struct ccu_data *ccu, struct bcm_clk_gate *gate)
+{
+	u32 bit_mask;
+	u32 reg_val;
+
+	/* If there is no gate we can assume it's enabled. */
+	if (!gate_exists(gate))
+		return true;
+
+	bit_mask = 1 << gate->status_bit;
+	reg_val = __ccu_read(ccu, gate->offset);
+
+	return (reg_val & bit_mask) != 0;
+}
+
+/* Determine whether a clock is gated. */
+static bool
+is_clk_gate_enabled(struct ccu_data *ccu, struct bcm_clk_gate *gate)
+{
+	long flags;
+	bool ret;
+
+	/* Avoid taking the lock if we can */
+	if (!gate_exists(gate))
+		return true;
+
+	flags = ccu_lock(ccu);
+	ret = __is_clk_gate_enabled(ccu, gate);
+	ccu_unlock(ccu, flags);
+
+	return ret;
+}
+
+/*
+ * Commit our desired gate state to the hardware.
+ * Returns true if successful, false otherwise.
+ */
+static bool
+__gate_commit(struct ccu_data *ccu, struct bcm_clk_gate *gate)
+{
+	u32 reg_val;
+	u32 mask;
+	bool enabled = false;
+
+	BUG_ON(!gate_exists(gate));
+	if (!gate_is_sw_controllable(gate))
+		return true;		/* Nothing we can change */
+
+	reg_val = __ccu_read(ccu, gate->offset);
+
+	/* For a hardware/software gate, set which is in control */
+	if (gate_is_hw_controllable(gate)) {
+		mask = (u32)1 << gate->hw_sw_sel_bit;
+		if (gate_is_sw_managed(gate))
+			reg_val |= mask;
+		else
+			reg_val &= ~mask;
+	}
+
+	/*
+	 * If software is in control, enable or disable the gate.
+	 * If hardware is, clear the enabled bit for good measure.
+	 * If a software controlled gate can't be disabled, we're
+	 * required to write a 0 into the enable bit (but the gate
+	 * will be enabled).
+	 */
+	mask = (u32)1 << gate->en_bit;
+	if (gate_is_sw_managed(gate) && (enabled = gate_is_enabled(gate)) &&
+			!gate_is_no_disable(gate))
+		reg_val |= mask;
+	else
+		reg_val &= ~mask;
+
+	__ccu_write(ccu, gate->offset, reg_val);
+
+	/* For a hardware controlled gate, we're done */
+	if (!gate_is_sw_managed(gate))
+		return true;
+
+	/* Otherwise wait for the gate to be in desired state */
+	return __ccu_wait_bit(ccu, gate->offset, gate->status_bit, enabled);
+}
+
+/*
+ * Initialize a gate.  Our desired state (hardware/software select,
+ * and if software, its enable state) is committed to hardware
+ * without the usual checks to see if it's already set up that way.
+ * Returns true if successful, false otherwise.
+ */
+static bool gate_init(struct ccu_data *ccu, struct bcm_clk_gate *gate)
+{
+	if (!gate_exists(gate))
+		return true;
+	return __gate_commit(ccu, gate);
+}
+
+/*
+ * Set a gate to enabled or disabled state.  Does nothing if the
+ * gate is not currently under software control, or if it is already
+ * in the requested state.  Returns true if successful, false
+ * otherwise.  CCU lock must be held.
+ */
+static bool
+__clk_gate(struct ccu_data *ccu, struct bcm_clk_gate *gate, bool enable)
+{
+	bool ret;
+
+	if (!gate_exists(gate) || !gate_is_sw_managed(gate))
+		return true;	/* Nothing to do */
+
+	if (!enable && gate_is_no_disable(gate)) {
+		pr_warn("%s: invalid gate disable request (ignoring)\n",
+			__func__);
+		return true;
+	}
+
+	if (enable == gate_is_enabled(gate))
+		return true;	/* No change */
+
+	gate_flip_enabled(gate);
+	ret = __gate_commit(ccu, gate);
+	if (!ret)
+		gate_flip_enabled(gate);	/* Revert the change */
+
+	return ret;
+}
+
+/* Enable or disable a gate.  Returns 0 if successful, -EIO otherwise */
+static int clk_gate(struct ccu_data *ccu, const char *name,
+			struct bcm_clk_gate *gate, bool enable)
+{
+	unsigned long flags;
+	bool success;
+
+	/*
+	 * Avoid taking the lock if we can.  We quietly ignore
+	 * requests to change state that don't make sense.
+	 */
+	if (!gate_exists(gate) || !gate_is_sw_managed(gate))
+		return 0;
+	if (!enable && gate_is_no_disable(gate))
+		return 0;
+
+	flags = ccu_lock(ccu);
+	__ccu_write_enable(ccu);
+
+	success = __clk_gate(ccu, gate, enable);
+
+	__ccu_write_disable(ccu);
+	ccu_unlock(ccu, flags);
+
+	if (success)
+		return 0;
+
+	pr_err("%s: failed to %s gate for %s\n", __func__,
+		enable ? "enable" : "disable", name);
+
+	return -EIO;
+}
+
+/* Hysteresis operations */
+
+/*
+ * If a clock gate requires a turn-off delay it will have
+ * "hysteresis" register bits defined.  The first, if set, enables
+ * the delay; and if enabled, the second bit determines whether the
+ * delay is "low" or "high" (1 means high).  For now, if it's
+ * defined for a clock, we set it.
+ */
+static bool hyst_init(struct ccu_data *ccu, struct bcm_clk_hyst *hyst)
+{
+	u32 offset;
+	u32 reg_val;
+	u32 mask;
+
+	if (!hyst_exists(hyst))
+		return true;
+
+	offset = hyst->offset;
+	mask = (u32)1 << hyst->en_bit;
+	mask |= (u32)1 << hyst->val_bit;
+
+	reg_val = __ccu_read(ccu, offset);
+	reg_val |= mask;
+	__ccu_write(ccu, offset, reg_val);
+
+	return true;
+}
+
+/* Trigger operations */
+
+/*
+ * Caller must ensure CCU lock is held and access is enabled.
+ * Returns true if successful, false otherwise.
+ */
+static bool __clk_trigger(struct ccu_data *ccu, struct bcm_clk_trig *trig)
+{
+	/* Trigger the clock and wait for it to finish */
+	__ccu_write(ccu, trig->offset, 1 << trig->bit);
+
+	return __ccu_wait_bit(ccu, trig->offset, trig->bit, false);
+}
+
+/* Divider operations */
+
+/* Read a divider value and return the scaled divisor it represents. */
+static u64 divider_read_scaled(struct ccu_data *ccu, struct bcm_clk_div *div)
+{
+	unsigned long flags;
+	u32 reg_val;
+	u32 reg_div;
+
+	if (divider_is_fixed(div))
+		return (u64)div->u.fixed;
+
+	flags = ccu_lock(ccu);
+	reg_val = __ccu_read(ccu, div->u.s.offset);
+	ccu_unlock(ccu, flags);
+
+	/* Extract the full divider field from the register value */
+	reg_div = bitfield_extract(reg_val, div->u.s.shift, div->u.s.width);
+
+	/* Return the scaled divisor value it represents */
+	return scaled_div_value(div, reg_div);
+}
+
+/*
+ * Convert a divider's scaled divisor value into its recorded form
+ * and commit it into the hardware divider register.
+ *
+ * Returns 0 on success.  Returns -EINVAL for invalid arguments.
+ * Returns -ENXIO if gating failed, and -EIO if a trigger failed.
+ */
+static int __div_commit(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_div *div, struct bcm_clk_trig *trig)
+{
+	bool enabled;
+	u32 reg_div;
+	u32 reg_val;
+	int ret = 0;
+
+	BUG_ON(divider_is_fixed(div));
+
+	/*
+	 * If we're just initializing the divider, and no initial
+	 * state was defined in the device tree, we just find out
+	 * what its current value is rather than updating it.
+	 */
+	if (div->u.s.scaled_div == BAD_SCALED_DIV_VALUE) {
+		reg_val = __ccu_read(ccu, div->u.s.offset);
+		reg_div = bitfield_extract(reg_val, div->u.s.shift,
+						div->u.s.width);
+		div->u.s.scaled_div = scaled_div_value(div, reg_div);
+
+		return 0;
+	}
+
+	/* Convert the scaled divisor to the value we need to record */
+	reg_div = divider(div, div->u.s.scaled_div);
+
+	/* Clock needs to be enabled before changing the rate */
+	enabled = __is_clk_gate_enabled(ccu, gate);
+	if (!enabled && !__clk_gate(ccu, gate, true)) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	/* Replace the divider value and record the result */
+	reg_val = __ccu_read(ccu, div->u.s.offset);
+	reg_val = bitfield_replace(reg_val, div->u.s.shift, div->u.s.width,
+					reg_div);
+	__ccu_write(ccu, div->u.s.offset, reg_val);
+
+	/* If the trigger fails we still want to disable the gate */
+	if (!__clk_trigger(ccu, trig))
+		ret = -EIO;
+
+	/* Disable the clock again if it was disabled to begin with */
+	if (!enabled && !__clk_gate(ccu, gate, false))
+		ret = ret ? ret : -ENXIO;	/* return first error */
+out:
+	return ret;
+}
+
+/*
+ * Initialize a divider by committing our desired state to hardware
+ * without the usual checks to see if it's already set up that way.
+ * Returns true if successful, false otherwise.
+ */
+static bool div_init(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_div *div, struct bcm_clk_trig *trig)
+{
+	if (!divider_exists(div) || divider_is_fixed(div))
+		return true;
+	return !__div_commit(ccu, gate, div, trig);
+}
+
+static int divider_write(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_div *div, struct bcm_clk_trig *trig,
+			u64 scaled_div)
+{
+	unsigned long flags;
+	u64 previous;
+	int ret;
+
+	BUG_ON(divider_is_fixed(div));
+
+	previous = div->u.s.scaled_div;
+	if (previous == scaled_div)
+		return 0;	/* No change */
+
+	div->u.s.scaled_div = scaled_div;
+
+	flags = ccu_lock(ccu);
+	__ccu_write_enable(ccu);
+
+	ret = __div_commit(ccu, gate, div, trig);
+
+	__ccu_write_disable(ccu);
+	ccu_unlock(ccu, flags);
+
+	if (ret)
+		div->u.s.scaled_div = previous;		/* Revert the change */
+
+	return ret;
+
+}
+
+/* Common clock rate helpers */
+
+/*
+ * Implement the common clock framework recalc_rate method, taking
+ * into account a divider and an optional pre-divider.  The
+ * pre-divider register pointer may be NULL.
+ */
+static unsigned long clk_recalc_rate(struct ccu_data *ccu,
+			struct bcm_clk_div *div, struct bcm_clk_div *pre_div,
+			unsigned long parent_rate)
+{
+	u64 scaled_parent_rate;
+	u64 scaled_div;
+	u64 result;
+
+	if (!divider_exists(div))
+		return parent_rate;
+
+	if (parent_rate > (unsigned long)LONG_MAX)
+		return 0;	/* actually this would be a caller bug */
+
+	/*
+	 * If there is a pre-divider, divide the scaled parent rate
+	 * by the pre-divider value first.  In this case--to improve
+	 * accuracy--scale the parent rate by *both* the pre-divider
+	 * value and the divider before actually computing the
+	 * result of the pre-divider.
+	 *
+	 * If there's only one divider, just scale the parent rate.
+	 */
+	if (pre_div && divider_exists(pre_div)) {
+		u64 scaled_rate;
+
+		scaled_rate = scale_rate(pre_div, parent_rate);
+		scaled_rate = scale_rate(div, scaled_rate);
+		scaled_div = divider_read_scaled(ccu, pre_div);
+		scaled_parent_rate = DIV_ROUND_CLOSEST_ULL(scaled_rate,
+							scaled_div);
+	} else  {
+		scaled_parent_rate = scale_rate(div, parent_rate);
+	}
+
+	/*
+	 * Get the scaled divisor value, and divide the scaled
+	 * parent rate by that to determine this clock's resulting
+	 * rate.
+	 */
+	scaled_div = divider_read_scaled(ccu, div);
+	result = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate, scaled_div);
+
+	return (unsigned long)result;
+}
+
+/*
+ * Compute the output rate produced when a given parent rate is fed
+ * into two dividers.  The pre-divider can be NULL, and even if it's
+ * non-null it may be nonexistent.  It's also OK for the divider to
+ * be nonexistent, and in that case the pre-divider is also ignored.
+ *
+ * If scaled_div is non-null, it is used to return the scaled divisor
+ * value used by the (downstream) divider to produce that rate.
+ */
+static long round_rate(struct ccu_data *ccu, struct bcm_clk_div *div,
+				struct bcm_clk_div *pre_div,
+				unsigned long rate, unsigned long parent_rate,
+				u64 *scaled_div)
+{
+	u64 scaled_parent_rate;
+	u64 min_scaled_div;
+	u64 max_scaled_div;
+	u64 best_scaled_div;
+	u64 result;
+
+	BUG_ON(!divider_exists(div));
+	BUG_ON(!rate);
+	BUG_ON(parent_rate > (u64)LONG_MAX);
+
+	/*
+	 * If there is a pre-divider, divide the scaled parent rate
+	 * by the pre-divider value first.  In this case--to improve
+	 * accuracy--scale the parent rate by *both* the pre-divider
+	 * value and the divider before actually computing the
+	 * result of the pre-divider.
+	 *
+	 * If there's only one divider, just scale the parent rate.
+	 *
+	 * For simplicity we treat the pre-divider as fixed (for now).
+	 */
+	if (divider_exists(pre_div)) {
+		u64 scaled_rate;
+		u64 scaled_pre_div;
+
+		scaled_rate = scale_rate(pre_div, parent_rate);
+		scaled_rate = scale_rate(div, scaled_rate);
+		scaled_pre_div = divider_read_scaled(ccu, pre_div);
+		scaled_parent_rate = DIV_ROUND_CLOSEST_ULL(scaled_rate,
+							scaled_pre_div);
+	} else {
+		scaled_parent_rate = scale_rate(div, parent_rate);
+	}
+
+	/*
+	 * Compute the best possible divider and ensure it is in
+	 * range.  A fixed divider can't be changed, so just report
+	 * the best we can do.
+	 */
+	if (!divider_is_fixed(div)) {
+		best_scaled_div = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate,
+							rate);
+		min_scaled_div = scaled_div_min(div);
+		max_scaled_div = scaled_div_max(div);
+		if (best_scaled_div > max_scaled_div)
+			best_scaled_div = max_scaled_div;
+		else if (best_scaled_div < min_scaled_div)
+			best_scaled_div = min_scaled_div;
+	} else {
+		best_scaled_div = divider_read_scaled(ccu, div);
+	}
+
+	/* OK, figure out the resulting rate */
+	result = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate, best_scaled_div);
+
+	if (scaled_div)
+		*scaled_div = best_scaled_div;
+
+	return (long)result;
+}
+
+/* Common clock parent helpers */
+
+/*
+ * For a given parent selector (register field) value, find the
+ * index into a selector's parent_sel array that contains it.
+ * Returns the index, or BAD_CLK_INDEX if it's not found.
+ */
+static u8 parent_index(struct bcm_clk_sel *sel, u8 parent_sel)
+{
+	u8 i;
+
+	BUG_ON(sel->parent_count > (u32)U8_MAX);
+	for (i = 0; i < sel->parent_count; i++)
+		if (sel->parent_sel[i] == parent_sel)
+			return i;
+	return BAD_CLK_INDEX;
+}
+
+/*
+ * Fetch the current value of the selector, and translate that into
+ * its corresponding index in the parent array we registered with
+ * the clock framework.
+ *
+ * Returns parent array index that corresponds with the value found,
+ * or BAD_CLK_INDEX if the found value is out of range.
+ */
+static u8 selector_read_index(struct ccu_data *ccu, struct bcm_clk_sel *sel)
+{
+	unsigned long flags;
+	u32 reg_val;
+	u32 parent_sel;
+	u8 index;
+
+	/* If there's no selector, there's only one parent */
+	if (!selector_exists(sel))
+		return 0;
+
+	/* Get the value in the selector register */
+	flags = ccu_lock(ccu);
+	reg_val = __ccu_read(ccu, sel->offset);
+	ccu_unlock(ccu, flags);
+
+	parent_sel = bitfield_extract(reg_val, sel->shift, sel->width);
+
+	/* Look up that selector's parent array index and return it */
+	index = parent_index(sel, parent_sel);
+	if (index == BAD_CLK_INDEX)
+		pr_err("%s: out-of-range parent selector %u (%s 0x%04x)\n",
+			__func__, parent_sel, ccu->name, sel->offset);
+
+	return index;
+}
+
+/*
+ * Commit our desired selector value to the hardware.
+ *
+ * Returns 0 on success.  Returns -EINVAL for invalid arguments.
+ * Returns -ENXIO if gating failed, and -EIO if a trigger failed.
+ */
+static int
+__sel_commit(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_sel *sel, struct bcm_clk_trig *trig)
+{
+	u32 parent_sel;
+	u32 reg_val;
+	bool enabled;
+	int ret = 0;
+
+	BUG_ON(!selector_exists(sel));
+
+	/*
+	 * If we're just initializing the selector, and no initial
+	 * state was defined in the device tree, we just find out
+	 * what its current value is rather than updating it.
+	 */
+	if (sel->clk_index == BAD_CLK_INDEX) {
+		u8 index;
+
+		reg_val = __ccu_read(ccu, sel->offset);
+		parent_sel = bitfield_extract(reg_val, sel->shift, sel->width);
+		index = parent_index(sel, parent_sel);
+		if (index == BAD_CLK_INDEX)
+			return -EINVAL;
+		sel->clk_index = index;
+
+		return 0;
+	}
+
+	BUG_ON((u32)sel->clk_index >= sel->parent_count);
+	parent_sel = sel->parent_sel[sel->clk_index];
+
+	/* Clock needs to be enabled before changing the parent */
+	enabled = __is_clk_gate_enabled(ccu, gate);
+	if (!enabled && !__clk_gate(ccu, gate, true))
+		return -ENXIO;
+
+	/* Replace the selector value and record the result */
+	reg_val = __ccu_read(ccu, sel->offset);
+	reg_val = bitfield_replace(reg_val, sel->shift, sel->width, parent_sel);
+	__ccu_write(ccu, sel->offset, reg_val);
+
+	/* If the trigger fails we still want to disable the gate */
+	if (!__clk_trigger(ccu, trig))
+		ret = -EIO;
+
+	/* Disable the clock again if it was disabled to begin with */
+	if (!enabled && !__clk_gate(ccu, gate, false))
+		ret = ret ? ret : -ENXIO;	/* return first error */
+
+	return ret;
+}
+
+/*
+ * Initialize a selector by committing our desired state to hardware
+ * without the usual checks to see if it's already set up that way.
+ * Returns true if successful, false otherwise.
+ */
+static bool sel_init(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_sel *sel, struct bcm_clk_trig *trig)
+{
+	if (!selector_exists(sel))
+		return true;
+	return !__sel_commit(ccu, gate, sel, trig);
+}
+
+/*
+ * Write a new value into a selector register to switch to a
+ * different parent clock.  Returns 0 on success, or an error code
+ * (from __sel_commit()) otherwise.
+ */
+static int selector_write(struct ccu_data *ccu, struct bcm_clk_gate *gate,
+			struct bcm_clk_sel *sel, struct bcm_clk_trig *trig,
+			u8 index)
+{
+	unsigned long flags;
+	u8 previous;
+	int ret;
+
+	previous = sel->clk_index;
+	if (previous == index)
+		return 0;	/* No change */
+
+	sel->clk_index = index;
+
+	flags = ccu_lock(ccu);
+	__ccu_write_enable(ccu);
+
+	ret = __sel_commit(ccu, gate, sel, trig);
+
+	__ccu_write_disable(ccu);
+	ccu_unlock(ccu, flags);
+
+	if (ret)
+		sel->clk_index = previous;	/* Revert the change */
+
+	return ret;
+}
+
+/* Clock operations */
+
+static int kona_peri_clk_enable(struct clk_hw *hw)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate;
+
+	return clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, true);
+}
+
+static void kona_peri_clk_disable(struct clk_hw *hw)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate;
+
+	(void)clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, false);
+}
+
+static int kona_peri_clk_is_enabled(struct clk_hw *hw)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate;
+
+	return is_clk_gate_enabled(bcm_clk->ccu, gate) ? 1 : 0;
+}
+
+static unsigned long kona_peri_clk_recalc_rate(struct clk_hw *hw,
+			unsigned long parent_rate)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct peri_clk_data *data = bcm_clk->u.peri;
+
+	return clk_recalc_rate(bcm_clk->ccu, &data->div, &data->pre_div,
+				parent_rate);
+}
+
+static long kona_peri_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+			unsigned long *parent_rate)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct bcm_clk_div *div = &bcm_clk->u.peri->div;
+
+	if (!divider_exists(div))
+		return clk_hw_get_rate(hw);
+
+	/* Quietly avoid a zero rate */
+	return round_rate(bcm_clk->ccu, div, &bcm_clk->u.peri->pre_div,
+				rate ? rate : 1, *parent_rate, NULL);
+}
+
+static int kona_peri_clk_determine_rate(struct clk_hw *hw,
+					struct clk_rate_request *req)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct clk_hw *current_parent;
+	unsigned long parent_rate;
+	unsigned long best_delta;
+	unsigned long best_rate;
+	u32 parent_count;
+	long rate;
+	u32 which;
+
+	/*
+	 * If there is no other parent to choose, use the current one.
+	 * Note:  We don't honor (or use) CLK_SET_RATE_NO_REPARENT.
+	 */
+	WARN_ON_ONCE(bcm_clk->init_data.flags & CLK_SET_RATE_NO_REPARENT);
+	parent_count = (u32)bcm_clk->init_data.num_parents;
+	if (parent_count < 2) {
+		rate = kona_peri_clk_round_rate(hw, req->rate,
+						&req->best_parent_rate);
+		if (rate < 0)
+			return rate;
+
+		req->rate = rate;
+		return 0;
+	}
+
+	/* Unless we can do better, stick with current parent */
+	current_parent = clk_hw_get_parent(hw);
+	parent_rate = clk_hw_get_rate(current_parent);
+	best_rate = kona_peri_clk_round_rate(hw, req->rate, &parent_rate);
+	best_delta = abs(best_rate - req->rate);
+
+	/* Check whether any other parent clock can produce a better result */
+	for (which = 0; which < parent_count; which++) {
+		struct clk_hw *parent = clk_hw_get_parent_by_index(hw, which);
+		unsigned long delta;
+		unsigned long other_rate;
+
+		BUG_ON(!parent);
+		if (parent == current_parent)
+			continue;
+
+		/* We don't support CLK_SET_RATE_PARENT */
+		parent_rate = clk_hw_get_rate(parent);
+		other_rate = kona_peri_clk_round_rate(hw, req->rate,
+						      &parent_rate);
+		delta = abs(other_rate - req->rate);
+		if (delta < best_delta) {
+			best_delta = delta;
+			best_rate = other_rate;
+			req->best_parent_hw = parent;
+			req->best_parent_rate = parent_rate;
+		}
+	}
+
+	req->rate = best_rate;
+	return 0;
+}
+
+static int kona_peri_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct peri_clk_data *data = bcm_clk->u.peri;
+	struct bcm_clk_sel *sel = &data->sel;
+	struct bcm_clk_trig *trig;
+	int ret;
+
+	BUG_ON(index >= sel->parent_count);
+
+	/* If there's only one parent we don't require a selector */
+	if (!selector_exists(sel))
+		return 0;
+
+	/*
+	 * The regular trigger is used by default, but if there's a
+	 * pre-trigger we want to use that instead.
+	 */
+	trig = trigger_exists(&data->pre_trig) ? &data->pre_trig
+					       : &data->trig;
+
+	ret = selector_write(bcm_clk->ccu, &data->gate, sel, trig, index);
+	if (ret == -ENXIO) {
+		pr_err("%s: gating failure for %s\n", __func__,
+			bcm_clk->init_data.name);
+		ret = -EIO;	/* Don't proliferate weird errors */
+	} else if (ret == -EIO) {
+		pr_err("%s: %strigger failed for %s\n", __func__,
+			trig == &data->pre_trig ? "pre-" : "",
+			bcm_clk->init_data.name);
+	}
+
+	return ret;
+}
+
+static u8 kona_peri_clk_get_parent(struct clk_hw *hw)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct peri_clk_data *data = bcm_clk->u.peri;
+	u8 index;
+
+	index = selector_read_index(bcm_clk->ccu, &data->sel);
+
+	/* Not all callers would handle an out-of-range value gracefully */
+	return index == BAD_CLK_INDEX ? 0 : index;
+}
+
+static int kona_peri_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+			unsigned long parent_rate)
+{
+	struct kona_clk *bcm_clk = to_kona_clk(hw);
+	struct peri_clk_data *data = bcm_clk->u.peri;
+	struct bcm_clk_div *div = &data->div;
+	u64 scaled_div = 0;
+	int ret;
+
+	if (parent_rate > (unsigned long)LONG_MAX)
+		return -EINVAL;
+
+	if (rate == clk_hw_get_rate(hw))
+		return 0;
+
+	if (!divider_exists(div))
+		return rate == parent_rate ? 0 : -EINVAL;
+
+	/*
+	 * A fixed divider can't be changed.  (Nor can a fixed
+	 * pre-divider be, but for now we never actually try to
+	 * change that.)  Tolerate a request for a no-op change.
+	 */
+	if (divider_is_fixed(&data->div))
+		return rate == parent_rate ? 0 : -EINVAL;
+
+	/*
+	 * Get the scaled divisor value needed to achieve a clock
+	 * rate as close as possible to what was requested, given
+	 * the parent clock rate supplied.
+	 */
+	(void)round_rate(bcm_clk->ccu, div, &data->pre_div,
+				rate ? rate : 1, parent_rate, &scaled_div);
+
+	/*
+	 * We aren't updating any pre-divider at this point, so
+	 * we'll use the regular trigger.
+	 */
+	ret = divider_write(bcm_clk->ccu, &data->gate, &data->div,
+				&data->trig, scaled_div);
+	if (ret == -ENXIO) {
+		pr_err("%s: gating failure for %s\n", __func__,
+			bcm_clk->init_data.name);
+		ret = -EIO;	/* Don't proliferate weird errors */
+	} else if (ret == -EIO) {
+		pr_err("%s: trigger failed for %s\n", __func__,
+			bcm_clk->init_data.name);
+	}
+
+	return ret;
+}
+
+struct clk_ops kona_peri_clk_ops = {
+	.enable = kona_peri_clk_enable,
+	.disable = kona_peri_clk_disable,
+	.is_enabled = kona_peri_clk_is_enabled,
+	.recalc_rate = kona_peri_clk_recalc_rate,
+	.determine_rate = kona_peri_clk_determine_rate,
+	.set_parent = kona_peri_clk_set_parent,
+	.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 false;
+}
+
+/* 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 kona_clk *kona_clks = ccu->kona_clks;
+	bool success = true;
+
+	flags = ccu_lock(ccu);
+	__ccu_write_enable(ccu);
+
+	for (which = 0; which < ccu->clk_num; which++) {
+		struct kona_clk *bcm_clk = &kona_clks[which];
+
+		if (!bcm_clk->ccu)
+			continue;
+
+		success &= __kona_clk_init(bcm_clk);
+	}
+
+	__ccu_write_disable(ccu);
+	ccu_unlock(ccu, flags);
+	return success;
+}