- 根目录:
- drivers
- clk
- bcm
- clk-kona.c
/*
* 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 clk **clks = ccu->clk_data.clks;
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_data.clk_num; which++) {
struct kona_clk *bcm_clk;
if (!clks[which])
continue;
bcm_clk = &kona_clks[which];
success &= __kona_clk_init(bcm_clk);
}
__ccu_write_disable(ccu);
ccu_unlock(ccu, flags);
return success;
}