1// SPDX-License-Identifier: GPL-2.0
  2
  3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
  4 * Copyright (C) 2018-2020 Linaro Ltd.
  5 */
  6
  7#include <linux/atomic.h>
  8#include <linux/mutex.h>
  9#include <linux/clk.h>
 10#include <linux/device.h>
 11#include <linux/interconnect.h>
 12
 13#include "ipa.h"
 14#include "ipa_clock.h"
 15#include "ipa_modem.h"
 16
 17/**
 18 * DOC: IPA Clocking
 19 *
 20 * The "IPA Clock" manages both the IPA core clock and the interconnects
 21 * (buses) the IPA depends on as a single logical entity.  A reference count
 22 * is incremented by "get" operations and decremented by "put" operations.
 23 * Transitions of that count from 0 to 1 result in the clock and interconnects
 24 * being enabled, and transitions of the count from 1 to 0 cause them to be
 25 * disabled.  We currently operate the core clock at a fixed clock rate, and
 26 * all buses at a fixed average and peak bandwidth.  As more advanced IPA
 27 * features are enabled, we can make better use of clock and bus scaling.
 28 *
 29 * An IPA clock reference must be held for any access to IPA hardware.
 30 */
 31
 32#define	IPA_CORE_CLOCK_RATE		(75UL * 1000 * 1000)	/* Hz */
 33
 34/* Interconnect path bandwidths (each times 1000 bytes per second) */
 35#define IPA_MEMORY_AVG			(80 * 1000)	/* 80 MBps */
 36#define IPA_MEMORY_PEAK			(600 * 1000)
 37
 38#define IPA_IMEM_AVG			(80 * 1000)
 39#define IPA_IMEM_PEAK			(350 * 1000)
 40
 41#define IPA_CONFIG_AVG			(40 * 1000)
 42#define IPA_CONFIG_PEAK			(40 * 1000)
 43
 44/**
 45 * struct ipa_clock - IPA clocking information
 46 * @count:		Clocking reference count
 47 * @mutex:		Protects clock enable/disable
 48 * @core:		IPA core clock
 49 * @memory_path:	Memory interconnect
 50 * @imem_path:		Internal memory interconnect
 51 * @config_path:	Configuration space interconnect
 52 */
 53struct ipa_clock {
 54	atomic_t count;
 55	struct mutex mutex; /* protects clock enable/disable */
 56	struct clk *core;
 57	struct icc_path *memory_path;
 58	struct icc_path *imem_path;
 59	struct icc_path *config_path;
 60};
 61
 62static struct icc_path *
 63ipa_interconnect_init_one(struct device *dev, const char *name)
 64{
 65	struct icc_path *path;
 66
 67	path = of_icc_get(dev, name);
 68	if (IS_ERR(path))
 69		dev_err(dev, "error %ld getting %s interconnect\n",
 70			PTR_ERR(path), name);
 71
 72	return path;
 73}
 74
 75/* Initialize interconnects required for IPA operation */
 76static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev)
 77{
 78	struct icc_path *path;
 79
 80	path = ipa_interconnect_init_one(dev, "memory");
 81	if (IS_ERR(path))
 82		goto err_return;
 83	clock->memory_path = path;
 84
 85	path = ipa_interconnect_init_one(dev, "imem");
 86	if (IS_ERR(path))
 87		goto err_memory_path_put;
 88	clock->imem_path = path;
 89
 90	path = ipa_interconnect_init_one(dev, "config");
 91	if (IS_ERR(path))
 92		goto err_imem_path_put;
 93	clock->config_path = path;
 94
 95	return 0;
 96
 97err_imem_path_put:
 98	icc_put(clock->imem_path);
 99err_memory_path_put:
100	icc_put(clock->memory_path);
101err_return:
102	return PTR_ERR(path);
103}
104
105/* Inverse of ipa_interconnect_init() */
106static void ipa_interconnect_exit(struct ipa_clock *clock)
107{
108	icc_put(clock->config_path);
109	icc_put(clock->imem_path);
110	icc_put(clock->memory_path);
111}
112
113/* Currently we only use one bandwidth level, so just "enable" interconnects */
114static int ipa_interconnect_enable(struct ipa *ipa)
115{
116	struct ipa_clock *clock = ipa->clock;
117	int ret;
118
119	ret = icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
120	if (ret)
121		return ret;
122
123	ret = icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
124	if (ret)
125		goto err_memory_path_disable;
126
127	ret = icc_set_bw(clock->config_path, IPA_CONFIG_AVG, IPA_CONFIG_PEAK);
128	if (ret)
129		goto err_imem_path_disable;
130
131	return 0;
132
133err_imem_path_disable:
134	(void)icc_set_bw(clock->imem_path, 0, 0);
135err_memory_path_disable:
136	(void)icc_set_bw(clock->memory_path, 0, 0);
137
138	return ret;
139}
140
141/* To disable an interconnect, we just its bandwidth to 0 */
142static int ipa_interconnect_disable(struct ipa *ipa)
143{
144	struct ipa_clock *clock = ipa->clock;
145	int ret;
146
147	ret = icc_set_bw(clock->memory_path, 0, 0);
148	if (ret)
149		return ret;
150
151	ret = icc_set_bw(clock->imem_path, 0, 0);
152	if (ret)
153		goto err_memory_path_reenable;
154
155	ret = icc_set_bw(clock->config_path, 0, 0);
156	if (ret)
157		goto err_imem_path_reenable;
158
159	return 0;
160
161err_imem_path_reenable:
162	(void)icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
163err_memory_path_reenable:
164	(void)icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
165
166	return ret;
167}
168
169/* Turn on IPA clocks, including interconnects */
170static int ipa_clock_enable(struct ipa *ipa)
171{
172	int ret;
173
174	ret = ipa_interconnect_enable(ipa);
175	if (ret)
176		return ret;
177
178	ret = clk_prepare_enable(ipa->clock->core);
179	if (ret)
180		ipa_interconnect_disable(ipa);
181
182	return ret;
183}
184
185/* Inverse of ipa_clock_enable() */
186static void ipa_clock_disable(struct ipa *ipa)
187{
188	clk_disable_unprepare(ipa->clock->core);
189	(void)ipa_interconnect_disable(ipa);
190}
191
192/* Get an IPA clock reference, but only if the reference count is
193 * already non-zero.  Returns true if the additional reference was
194 * added successfully, or false otherwise.
195 */
196bool ipa_clock_get_additional(struct ipa *ipa)
197{
198	return !!atomic_inc_not_zero(&ipa->clock->count);
199}
200
201/* Get an IPA clock reference.  If the reference count is non-zero, it is
202 * incremented and return is immediate.  Otherwise it is checked again
203 * under protection of the mutex, and if appropriate the clock (and
204 * interconnects) are enabled suspended endpoints (if any) are resumed
205 * before returning.
206 *
207 * Incrementing the reference count is intentionally deferred until
208 * after the clock is running and endpoints are resumed.
209 */
210void ipa_clock_get(struct ipa *ipa)
211{
212	struct ipa_clock *clock = ipa->clock;
213	int ret;
214
215	/* If the clock is running, just bump the reference count */
216	if (ipa_clock_get_additional(ipa))
217		return;
218
219	/* Otherwise get the mutex and check again */
220	mutex_lock(&clock->mutex);
221
222	/* A reference might have been added before we got the mutex. */
223	if (ipa_clock_get_additional(ipa))
224		goto out_mutex_unlock;
225
226	ret = ipa_clock_enable(ipa);
227	if (ret) {
228		dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret);
229		goto out_mutex_unlock;
230	}
231
232	ipa_endpoint_resume(ipa);
233
234	atomic_inc(&clock->count);
235
236out_mutex_unlock:
237	mutex_unlock(&clock->mutex);
238}
239
240/* Attempt to remove an IPA clock reference.  If this represents the last
241 * reference, suspend endpoints and disable the clock (and interconnects)
242 * under protection of a mutex.
243 */
244void ipa_clock_put(struct ipa *ipa)
245{
246	struct ipa_clock *clock = ipa->clock;
247
248	/* If this is not the last reference there's nothing more to do */
249	if (!atomic_dec_and_mutex_lock(&clock->count, &clock->mutex))
250		return;
251
252	ipa_endpoint_suspend(ipa);
253
254	ipa_clock_disable(ipa);
255
256	mutex_unlock(&clock->mutex);
257}
258
259/* Return the current IPA core clock rate */
260u32 ipa_clock_rate(struct ipa *ipa)
261{
262	return ipa->clock ? (u32)clk_get_rate(ipa->clock->core) : 0;
263}
264
265/* Initialize IPA clocking */
266struct ipa_clock *ipa_clock_init(struct device *dev)
267{
268	struct ipa_clock *clock;
269	struct clk *clk;
270	int ret;
271
272	clk = clk_get(dev, "core");
273	if (IS_ERR(clk)) {
274		dev_err(dev, "error %ld getting core clock\n", PTR_ERR(clk));
275		return ERR_CAST(clk);
276	}
277
278	ret = clk_set_rate(clk, IPA_CORE_CLOCK_RATE);
279	if (ret) {
280		dev_err(dev, "error %d setting core clock rate to %lu\n",
281			ret, IPA_CORE_CLOCK_RATE);
282		goto err_clk_put;
283	}
284
285	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
286	if (!clock) {
287		ret = -ENOMEM;
288		goto err_clk_put;
289	}
290	clock->core = clk;
291
292	ret = ipa_interconnect_init(clock, dev);
293	if (ret)
294		goto err_kfree;
295
296	mutex_init(&clock->mutex);
297	atomic_set(&clock->count, 0);
298
299	return clock;
300
301err_kfree:
302	kfree(clock);
303err_clk_put:
304	clk_put(clk);
305
306	return ERR_PTR(ret);
307}
308
309/* Inverse of ipa_clock_init() */
310void ipa_clock_exit(struct ipa_clock *clock)
311{
312	struct clk *clk = clock->core;
313
314	WARN_ON(atomic_read(&clock->count) != 0);
315	mutex_destroy(&clock->mutex);
316	ipa_interconnect_exit(clock);
317	kfree(clock);
318	clk_put(clk);
319}