blob: a2c0fde0581994c18d928c6daf1e64b126a27023 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
* Copyright (C) 2018-2020 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"
/**
* 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.
*/
#define IPA_CORE_CLOCK_RATE (75UL * 1000 * 1000) /* Hz */
/* Interconnect path bandwidths (each times 1000 bytes per second) */
#define IPA_MEMORY_AVG (80 * 1000) /* 80 MBps */
#define IPA_MEMORY_PEAK (600 * 1000)
#define IPA_IMEM_AVG (80 * 1000)
#define IPA_IMEM_PEAK (350 * 1000)
#define IPA_CONFIG_AVG (40 * 1000)
#define IPA_CONFIG_PEAK (40 * 1000)
/**
* struct ipa_clock - IPA clocking information
* @count: Clocking reference count
* @mutex: Protects clock enable/disable
* @core: IPA core clock
* @memory_path: Memory interconnect
* @imem_path: Internal memory interconnect
* @config_path: Configuration space interconnect
*/
struct ipa_clock {
refcount_t count;
struct mutex mutex; /* protects clock enable/disable */
struct clk *core;
struct icc_path *memory_path;
struct icc_path *imem_path;
struct icc_path *config_path;
};
static struct icc_path *
ipa_interconnect_init_one(struct device *dev, const char *name)
{
struct icc_path *path;
path = of_icc_get(dev, name);
if (IS_ERR(path))
dev_err(dev, "error %ld getting %s interconnect\n",
PTR_ERR(path), name);
return path;
}
/* Initialize interconnects required for IPA operation */
static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev)
{
struct icc_path *path;
path = ipa_interconnect_init_one(dev, "memory");
if (IS_ERR(path))
goto err_return;
clock->memory_path = path;
path = ipa_interconnect_init_one(dev, "imem");
if (IS_ERR(path))
goto err_memory_path_put;
clock->imem_path = path;
path = ipa_interconnect_init_one(dev, "config");
if (IS_ERR(path))
goto err_imem_path_put;
clock->config_path = path;
return 0;
err_imem_path_put:
icc_put(clock->imem_path);
err_memory_path_put:
icc_put(clock->memory_path);
err_return:
return PTR_ERR(path);
}
/* Inverse of ipa_interconnect_init() */
static void ipa_interconnect_exit(struct ipa_clock *clock)
{
icc_put(clock->config_path);
icc_put(clock->imem_path);
icc_put(clock->memory_path);
}
/* Currently we only use one bandwidth level, so just "enable" interconnects */
static int ipa_interconnect_enable(struct ipa *ipa)
{
struct ipa_clock *clock = ipa->clock;
int ret;
ret = icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
if (ret)
return ret;
ret = icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
if (ret)
goto err_memory_path_disable;
ret = icc_set_bw(clock->config_path, IPA_CONFIG_AVG, IPA_CONFIG_PEAK);
if (ret)
goto err_imem_path_disable;
return 0;
err_imem_path_disable:
(void)icc_set_bw(clock->imem_path, 0, 0);
err_memory_path_disable:
(void)icc_set_bw(clock->memory_path, 0, 0);
return ret;
}
/* To disable an interconnect, we just its bandwidth to 0 */
static int ipa_interconnect_disable(struct ipa *ipa)
{
struct ipa_clock *clock = ipa->clock;
int ret;
ret = icc_set_bw(clock->memory_path, 0, 0);
if (ret)
return ret;
ret = icc_set_bw(clock->imem_path, 0, 0);
if (ret)
goto err_memory_path_reenable;
ret = icc_set_bw(clock->config_path, 0, 0);
if (ret)
goto err_imem_path_reenable;
return 0;
err_imem_path_reenable:
(void)icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
err_memory_path_reenable:
(void)icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
return 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);
(void)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)
{
struct ipa_clock *clock;
struct clk *clk;
int ret;
clk = clk_get(dev, "core");
if (IS_ERR(clk)) {
dev_err(dev, "error %ld getting core clock\n", PTR_ERR(clk));
return ERR_CAST(clk);
}
ret = clk_set_rate(clk, IPA_CORE_CLOCK_RATE);
if (ret) {
dev_err(dev, "error %d setting core clock rate to %lu\n",
ret, IPA_CORE_CLOCK_RATE);
goto err_clk_put;
}
clock = kzalloc(sizeof(*clock), GFP_KERNEL);
if (!clock) {
ret = -ENOMEM;
goto err_clk_put;
}
clock->core = clk;
ret = ipa_interconnect_init(clock, dev);
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);
}