linux/drivers/net/ipa/ipa_clock.c
Alex Elder 4c7ccfcd09 net: ipa: use dev_err_probe() in ipa_clock.c
When initializing the IPA core clock and interconnects, it's
possible we'll get an EPROBE_DEFER error.  This isn't really an
error, it's just means we need to be re-probed later.

Use dev_err_probe() to report the error rather than dev_err().
This avoids polluting the log with these "error" messages.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-12 16:54:17 -08:00

332 lines
8.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
* Copyright (C) 2018-2021 Linaro Ltd.
*/
#include <linux/refcount.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/interconnect.h>
#include "ipa.h"
#include "ipa_clock.h"
#include "ipa_modem.h"
#include "ipa_data.h"
/**
* DOC: IPA Clocking
*
* The "IPA Clock" manages both the IPA core clock and the interconnects
* (buses) the IPA depends on as a single logical entity. A reference count
* is incremented by "get" operations and decremented by "put" operations.
* Transitions of that count from 0 to 1 result in the clock and interconnects
* being enabled, and transitions of the count from 1 to 0 cause them to be
* disabled. We currently operate the core clock at a fixed clock rate, and
* all buses at a fixed average and peak bandwidth. As more advanced IPA
* features are enabled, we can make better use of clock and bus scaling.
*
* An IPA clock reference must be held for any access to IPA hardware.
*/
/**
* struct ipa_interconnect - IPA interconnect information
* @path: Interconnect path
* @average_bandwidth: Average interconnect bandwidth (KB/second)
* @peak_bandwidth: Peak interconnect bandwidth (KB/second)
*/
struct ipa_interconnect {
struct icc_path *path;
u32 average_bandwidth;
u32 peak_bandwidth;
};
/**
* struct ipa_clock - IPA clocking information
* @count: Clocking reference count
* @mutex: Protects clock enable/disable
* @core: IPA core clock
* @interconnect_count: Number of elements in interconnect[]
* @interconnect: Interconnect array
*/
struct ipa_clock {
refcount_t count;
struct mutex mutex; /* protects clock enable/disable */
struct clk *core;
u32 interconnect_count;
struct ipa_interconnect *interconnect;
};
static int ipa_interconnect_init_one(struct device *dev,
struct ipa_interconnect *interconnect,
const struct ipa_interconnect_data *data)
{
struct icc_path *path;
path = of_icc_get(dev, data->name);
if (IS_ERR(path)) {
int ret = PTR_ERR(path);
dev_err_probe(dev, ret, "error getting %s interconnect\n",
data->name);
return ret;
}
interconnect->path = path;
interconnect->average_bandwidth = data->average_bandwidth;
interconnect->peak_bandwidth = data->peak_bandwidth;
return 0;
}
static void ipa_interconnect_exit_one(struct ipa_interconnect *interconnect)
{
icc_put(interconnect->path);
memset(interconnect, 0, sizeof(*interconnect));
}
/* Initialize interconnects required for IPA operation */
static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev,
const struct ipa_interconnect_data *data)
{
struct ipa_interconnect *interconnect;
u32 count;
int ret;
count = clock->interconnect_count;
interconnect = kcalloc(count, sizeof(*interconnect), GFP_KERNEL);
if (!interconnect)
return -ENOMEM;
clock->interconnect = interconnect;
while (count--) {
ret = ipa_interconnect_init_one(dev, interconnect, data++);
if (ret)
goto out_unwind;
interconnect++;
}
return 0;
out_unwind:
while (interconnect-- > clock->interconnect)
ipa_interconnect_exit_one(interconnect);
kfree(clock->interconnect);
clock->interconnect = NULL;
return ret;
}
/* Inverse of ipa_interconnect_init() */
static void ipa_interconnect_exit(struct ipa_clock *clock)
{
struct ipa_interconnect *interconnect;
interconnect = clock->interconnect + clock->interconnect_count;
while (interconnect-- > clock->interconnect)
ipa_interconnect_exit_one(interconnect);
kfree(clock->interconnect);
clock->interconnect = NULL;
}
/* Currently we only use one bandwidth level, so just "enable" interconnects */
static int ipa_interconnect_enable(struct ipa *ipa)
{
struct ipa_interconnect *interconnect;
struct ipa_clock *clock = ipa->clock;
int ret;
u32 i;
interconnect = clock->interconnect;
for (i = 0; i < clock->interconnect_count; i++) {
ret = icc_set_bw(interconnect->path,
interconnect->average_bandwidth,
interconnect->peak_bandwidth);
if (ret)
goto out_unwind;
interconnect++;
}
return 0;
out_unwind:
while (interconnect-- > clock->interconnect)
(void)icc_set_bw(interconnect->path, 0, 0);
return ret;
}
/* To disable an interconnect, we just its bandwidth to 0 */
static void ipa_interconnect_disable(struct ipa *ipa)
{
struct ipa_interconnect *interconnect;
struct ipa_clock *clock = ipa->clock;
int result = 0;
u32 count;
int ret;
count = clock->interconnect_count;
interconnect = clock->interconnect + count;
while (count--) {
interconnect--;
ret = icc_set_bw(interconnect->path, 0, 0);
if (ret && !result)
result = ret;
}
if (result)
dev_err(&ipa->pdev->dev,
"error %d disabling IPA interconnects\n", ret);
}
/* Turn on IPA clocks, including interconnects */
static int ipa_clock_enable(struct ipa *ipa)
{
int ret;
ret = ipa_interconnect_enable(ipa);
if (ret)
return ret;
ret = clk_prepare_enable(ipa->clock->core);
if (ret)
ipa_interconnect_disable(ipa);
return ret;
}
/* Inverse of ipa_clock_enable() */
static void ipa_clock_disable(struct ipa *ipa)
{
clk_disable_unprepare(ipa->clock->core);
ipa_interconnect_disable(ipa);
}
/* Get an IPA clock reference, but only if the reference count is
* already non-zero. Returns true if the additional reference was
* added successfully, or false otherwise.
*/
bool ipa_clock_get_additional(struct ipa *ipa)
{
return refcount_inc_not_zero(&ipa->clock->count);
}
/* Get an IPA clock reference. If the reference count is non-zero, it is
* incremented and return is immediate. Otherwise it is checked again
* under protection of the mutex, and if appropriate the IPA clock
* is enabled.
*
* Incrementing the reference count is intentionally deferred until
* after the clock is running and endpoints are resumed.
*/
void ipa_clock_get(struct ipa *ipa)
{
struct ipa_clock *clock = ipa->clock;
int ret;
/* If the clock is running, just bump the reference count */
if (ipa_clock_get_additional(ipa))
return;
/* Otherwise get the mutex and check again */
mutex_lock(&clock->mutex);
/* A reference might have been added before we got the mutex. */
if (ipa_clock_get_additional(ipa))
goto out_mutex_unlock;
ret = ipa_clock_enable(ipa);
if (ret) {
dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret);
goto out_mutex_unlock;
}
refcount_set(&clock->count, 1);
out_mutex_unlock:
mutex_unlock(&clock->mutex);
}
/* Attempt to remove an IPA clock reference. If this represents the
* last reference, disable the IPA clock under protection of the mutex.
*/
void ipa_clock_put(struct ipa *ipa)
{
struct ipa_clock *clock = ipa->clock;
/* If this is not the last reference there's nothing more to do */
if (!refcount_dec_and_mutex_lock(&clock->count, &clock->mutex))
return;
ipa_clock_disable(ipa);
mutex_unlock(&clock->mutex);
}
/* Return the current IPA core clock rate */
u32 ipa_clock_rate(struct ipa *ipa)
{
return ipa->clock ? (u32)clk_get_rate(ipa->clock->core) : 0;
}
/* Initialize IPA clocking */
struct ipa_clock *
ipa_clock_init(struct device *dev, const struct ipa_clock_data *data)
{
struct ipa_clock *clock;
struct clk *clk;
int ret;
clk = clk_get(dev, "core");
if (IS_ERR(clk)) {
dev_err_probe(dev, PTR_ERR(clk), "error getting core clock\n");
return ERR_CAST(clk);
}
ret = clk_set_rate(clk, data->core_clock_rate);
if (ret) {
dev_err(dev, "error %d setting core clock rate to %u\n",
ret, data->core_clock_rate);
goto err_clk_put;
}
clock = kzalloc(sizeof(*clock), GFP_KERNEL);
if (!clock) {
ret = -ENOMEM;
goto err_clk_put;
}
clock->core = clk;
clock->interconnect_count = data->interconnect_count;
ret = ipa_interconnect_init(clock, dev, data->interconnect_data);
if (ret)
goto err_kfree;
mutex_init(&clock->mutex);
refcount_set(&clock->count, 0);
return clock;
err_kfree:
kfree(clock);
err_clk_put:
clk_put(clk);
return ERR_PTR(ret);
}
/* Inverse of ipa_clock_init() */
void ipa_clock_exit(struct ipa_clock *clock)
{
struct clk *clk = clock->core;
WARN_ON(refcount_read(&clock->count) != 0);
mutex_destroy(&clock->mutex);
ipa_interconnect_exit(clock);
kfree(clock);
clk_put(clk);
}