Orange Pi5 kernel

// 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);
}