ipa_smp2p.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
  4 * Copyright (C) 2019-2024 Linaro Ltd.
  5 */
  6
  7#include <linux/interrupt.h>
  8#include <linux/notifier.h>
  9#include <linux/panic_notifier.h>
 10#include <linux/platform_device.h>
 11#include <linux/pm_runtime.h>
 12#include <linux/types.h>
 13
 14#include <linux/soc/qcom/smem_state.h>
 15
 16#include "ipa.h"
 17#include "ipa_smp2p.h"
 18#include "ipa_uc.h"
 19
 20/**
 21 * DOC: IPA SMP2P communication with the modem
 22 *
 23 * SMP2P is a primitive communication mechanism available between the AP and
 24 * the modem.  The IPA driver uses this for two purposes:  to enable the modem
 25 * to state that the GSI hardware is ready to use; and to communicate the
 26 * state of IPA power in the event of a crash.
 27 *
 28 * GSI needs to have early initialization completed before it can be used.
 29 * This initialization is done either by Trust Zone or by the modem.  In the
 30 * latter case, the modem uses an SMP2P interrupt to tell the AP IPA driver
 31 * when the GSI is ready to use.
 32 *
 33 * The modem is also able to inquire about the current state of IPA
 34 * power by trigging another SMP2P interrupt to the AP.  We communicate
 35 * whether power is enabled using two SMP2P state bits--one to indicate
 36 * the power state (on or off), and a second to indicate the power state
 37 * bit is valid.  The modem will poll the valid bit until it is set, and
 38 * at that time records whether the AP has IPA power enabled.
 39 *
 40 * Finally, if the AP kernel panics, we update the SMP2P state bits even if
 41 * we never receive an interrupt from the modem requesting this.
 42 */
 43
 44/**
 45 * struct ipa_smp2p - IPA SMP2P information
 46 * @ipa:		IPA pointer
 47 * @valid_state:	SMEM state indicating enabled state is valid
 48 * @enabled_state:	SMEM state to indicate power is enabled
 49 * @valid_bit:		Valid bit in 32-bit SMEM state mask
 50 * @enabled_bit:	Enabled bit in 32-bit SMEM state mask
 51 * @enabled_bit:	Enabled bit in 32-bit SMEM state mask
 52 * @clock_query_irq:	IPA interrupt triggered by modem for power query
 53 * @setup_ready_irq:	IPA interrupt triggered by modem to signal GSI ready
 54 * @power_on:		Whether IPA power is on
 55 * @notified:		Whether modem has been notified of power state
 56 * @setup_disabled:	Whether setup ready interrupt handler is disabled
 57 * @mutex:		Mutex protecting ready-interrupt/shutdown interlock
 58 * @panic_notifier:	Panic notifier structure
 59*/
 60struct ipa_smp2p {
 61	struct ipa *ipa;
 62	struct qcom_smem_state *valid_state;
 63	struct qcom_smem_state *enabled_state;
 64	u32 valid_bit;
 65	u32 enabled_bit;
 66	u32 clock_query_irq;
 67	u32 setup_ready_irq;
 68	bool power_on;
 69	bool notified;
 70	bool setup_disabled;
 71	struct mutex mutex;
 72	struct notifier_block panic_notifier;
 73};
 74
 75/**
 76 * ipa_smp2p_notify() - use SMP2P to tell modem about IPA power state
 77 * @smp2p:	SMP2P information
 78 *
 79 * This is called either when the modem has requested it (by triggering
 80 * the modem power query IPA interrupt) or whenever the AP is shutting down
 81 * (via a panic notifier).  It sets the two SMP2P state bits--one saying
 82 * whether the IPA power is on, and the other indicating the first bit
 83 * is valid.
 84 */
 85static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
 86{
 87	u32 value;
 88	u32 mask;
 89
 90	if (smp2p->notified)
 91		return;
 92
 93	smp2p->power_on = pm_runtime_get_if_active(smp2p->ipa->dev) > 0;
 94
 95	/* Signal whether the IPA power is enabled */
 96	mask = BIT(smp2p->enabled_bit);
 97	value = smp2p->power_on ? mask : 0;
 98	qcom_smem_state_update_bits(smp2p->enabled_state, mask, value);
 99
100	/* Now indicate that the enabled flag is valid */
101	mask = BIT(smp2p->valid_bit);
102	value = mask;
103	qcom_smem_state_update_bits(smp2p->valid_state, mask, value);
104
105	smp2p->notified = true;
106}
107
108/* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */
109static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id)
110{
111	struct ipa_smp2p *smp2p = dev_id;
112
113	ipa_smp2p_notify(smp2p);
114
115	return IRQ_HANDLED;
116}
117
118static int ipa_smp2p_panic_notifier(struct notifier_block *nb,
119				    unsigned long action, void *data)
120{
121	struct ipa_smp2p *smp2p;
122
123	smp2p = container_of(nb, struct ipa_smp2p, panic_notifier);
124
125	ipa_smp2p_notify(smp2p);
126
127	if (smp2p->power_on)
128		ipa_uc_panic_notifier(smp2p->ipa);
129
130	return NOTIFY_DONE;
131}
132
133static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
134{
135	/* IPA panic handler needs to run before modem shuts down */
136	smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
137	smp2p->panic_notifier.priority = INT_MAX;	/* Do it early */
138
139	return atomic_notifier_chain_register(&panic_notifier_list,
140					      &smp2p->panic_notifier);
141}
142
143static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
144{
145	atomic_notifier_chain_unregister(&panic_notifier_list,
146					 &smp2p->panic_notifier);
147}
148
149/* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */
150static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
151{
152	struct ipa_smp2p *smp2p = dev_id;
153	struct ipa *ipa = smp2p->ipa;
154	struct device *dev;
155	int ret;
156
157	/* Ignore any (spurious) interrupts received after the first */
158	if (ipa->setup_complete)
159		return IRQ_HANDLED;
160
161	/* Power needs to be active for setup */
162	dev = ipa->dev;
163	ret = pm_runtime_get_sync(dev);
164	if (ret < 0) {
165		dev_err(dev, "error %d getting power for setup\n", ret);
166		goto out_power_put;
167	}
168
169	/* An error here won't cause driver shutdown, so warn if one occurs */
170	ret = ipa_setup(ipa);
171	WARN(ret != 0, "error %d from ipa_setup()\n", ret);
172
173out_power_put:
174	(void)pm_runtime_put_autosuspend(dev);
175
176	return IRQ_HANDLED;
177}
178
179/* Initialize SMP2P interrupts */
180static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p,
181			      struct platform_device *pdev,
182			      const char *name, irq_handler_t handler)
183{
184	struct device *dev = &pdev->dev;
185	unsigned int irq;
186	int ret;
187
188	ret = platform_get_irq_byname(pdev, name);
189	if (ret <= 0)
190		return ret ? : -EINVAL;
191	irq = ret;
192
193	ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p);
194	if (ret) {
195		dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name);
196		return ret;
197	}
198
199	return irq;
200}
201
202static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq)
203{
204	free_irq(irq, smp2p);
205}
206
207/* Drop the power reference if it was taken in ipa_smp2p_notify() */
208static void ipa_smp2p_power_release(struct ipa *ipa)
209{
210	struct device *dev = ipa->dev;
211
212	if (!ipa->smp2p->power_on)
213		return;
214
215	(void)pm_runtime_put_autosuspend(dev);
216	ipa->smp2p->power_on = false;
217}
218
219/* Initialize the IPA SMP2P subsystem */
220int
221ipa_smp2p_init(struct ipa *ipa, struct platform_device *pdev, bool modem_init)
222{
223	struct qcom_smem_state *enabled_state;
224	struct device *dev = &pdev->dev;
225	struct qcom_smem_state *valid_state;
226	struct ipa_smp2p *smp2p;
227	u32 enabled_bit;
228	u32 valid_bit;
229	int ret;
230
231	valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid",
232					  &valid_bit);
233	if (IS_ERR(valid_state))
234		return PTR_ERR(valid_state);
235	if (valid_bit >= 32)		/* BITS_PER_U32 */
236		return -EINVAL;
237
238	enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
239					    &enabled_bit);
240	if (IS_ERR(enabled_state))
241		return PTR_ERR(enabled_state);
242	if (enabled_bit >= 32)		/* BITS_PER_U32 */
243		return -EINVAL;
244
245	smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL);
246	if (!smp2p)
247		return -ENOMEM;
248
249	smp2p->ipa = ipa;
250
251	/* These fields are needed by the power query interrupt
252	 * handler, so initialize them now.
253	 */
254	mutex_init(&smp2p->mutex);
255	smp2p->valid_state = valid_state;
256	smp2p->valid_bit = valid_bit;
257	smp2p->enabled_state = enabled_state;
258	smp2p->enabled_bit = enabled_bit;
259
260	/* We have enough information saved to handle notifications */
261	ipa->smp2p = smp2p;
262
263	ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-clock-query",
264				 ipa_smp2p_modem_clk_query_isr);
265	if (ret < 0)
266		goto err_null_smp2p;
267	smp2p->clock_query_irq = ret;
268
269	ret = ipa_smp2p_panic_notifier_register(smp2p);
270	if (ret)
271		goto err_irq_exit;
272
273	if (modem_init) {
274		/* Result will be non-zero (negative for error) */
275		ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-setup-ready",
276					 ipa_smp2p_modem_setup_ready_isr);
277		if (ret < 0)
278			goto err_notifier_unregister;
279		smp2p->setup_ready_irq = ret;
280	}
281
282	return 0;
283
284err_notifier_unregister:
285	ipa_smp2p_panic_notifier_unregister(smp2p);
286err_irq_exit:
287	ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
288err_null_smp2p:
289	ipa->smp2p = NULL;
290	mutex_destroy(&smp2p->mutex);
291	kfree(smp2p);
292
293	return ret;
294}
295
296void ipa_smp2p_exit(struct ipa *ipa)
297{
298	struct ipa_smp2p *smp2p = ipa->smp2p;
299
300	if (smp2p->setup_ready_irq)
301		ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
302	ipa_smp2p_panic_notifier_unregister(smp2p);
303	ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
304	/* We won't get notified any more; drop power reference (if any) */
305	ipa_smp2p_power_release(ipa);
306	ipa->smp2p = NULL;
307	mutex_destroy(&smp2p->mutex);
308	kfree(smp2p);
309}
310
311void ipa_smp2p_irq_disable_setup(struct ipa *ipa)
312{
313	struct ipa_smp2p *smp2p = ipa->smp2p;
314
315	if (!smp2p->setup_ready_irq)
316		return;
317
318	mutex_lock(&smp2p->mutex);
319
320	if (!smp2p->setup_disabled) {
321		disable_irq(smp2p->setup_ready_irq);
322		smp2p->setup_disabled = true;
323	}
324
325	mutex_unlock(&smp2p->mutex);
326}
327
328/* Reset state tracking whether we have notified the modem */
329void ipa_smp2p_notify_reset(struct ipa *ipa)
330{
331	struct ipa_smp2p *smp2p = ipa->smp2p;
332	u32 mask;
333
334	if (!smp2p->notified)
335		return;
336
337	ipa_smp2p_power_release(ipa);
338
339	/* Reset the power enabled valid flag */
340	mask = BIT(smp2p->valid_bit);
341	qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
342
343	/* Mark the power disabled for good measure... */
344	mask = BIT(smp2p->enabled_bit);
345	qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
346
347	smp2p->notified = false;
348}