1// SPDX-License-Identifier: GPL-2.0
  2
  3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
  4 * Copyright (C) 2019-2022 Linaro Ltd.
  5 */
  6
  7#include <linux/types.h>
  8#include <linux/device.h>
  9#include <linux/interrupt.h>
 10#include <linux/notifier.h>
 11#include <linux/panic_notifier.h>
 12#include <linux/pm_runtime.h>
 13#include <linux/soc/qcom/smem.h>
 14#include <linux/soc/qcom/smem_state.h>
 15
 16#include "ipa_smp2p.h"
 17#include "ipa.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	struct device *dev;
 88	u32 value;
 89	u32 mask;
 90
 91	if (smp2p->notified)
 92		return;
 93
 94	dev = &smp2p->ipa->pdev->dev;
 95	smp2p->power_on = pm_runtime_get_if_active(dev, true) > 0;
 96
 97	/* Signal whether the IPA power is enabled */
 98	mask = BIT(smp2p->enabled_bit);
 99	value = smp2p->power_on ? mask : 0;
100	qcom_smem_state_update_bits(smp2p->enabled_state, mask, value);
101
102	/* Now indicate that the enabled flag is valid */
103	mask = BIT(smp2p->valid_bit);
104	value = mask;
105	qcom_smem_state_update_bits(smp2p->valid_state, mask, value);
106
107	smp2p->notified = true;
108}
109
110/* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */
111static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id)
112{
113	struct ipa_smp2p *smp2p = dev_id;
114
115	ipa_smp2p_notify(smp2p);
116
117	return IRQ_HANDLED;
118}
119
120static int ipa_smp2p_panic_notifier(struct notifier_block *nb,
121				    unsigned long action, void *data)
122{
123	struct ipa_smp2p *smp2p;
124
125	smp2p = container_of(nb, struct ipa_smp2p, panic_notifier);
126
127	ipa_smp2p_notify(smp2p);
128
129	if (smp2p->power_on)
130		ipa_uc_panic_notifier(smp2p->ipa);
131
132	return NOTIFY_DONE;
133}
134
135static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
136{
137	/* IPA panic handler needs to run before modem shuts down */
138	smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
139	smp2p->panic_notifier.priority = INT_MAX;	/* Do it early */
140
141	return atomic_notifier_chain_register(&panic_notifier_list,
142					      &smp2p->panic_notifier);
143}
144
145static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
146{
147	atomic_notifier_chain_unregister(&panic_notifier_list,
148					 &smp2p->panic_notifier);
149}
150
151/* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */
152static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
153{
154	struct ipa_smp2p *smp2p = dev_id;
155	struct device *dev;
156	int ret;
157
158	/* Ignore any (spurious) interrupts received after the first */
159	if (smp2p->ipa->setup_complete)
160		return IRQ_HANDLED;
161
162	/* Power needs to be active for setup */
163	dev = &smp2p->ipa->pdev->dev;
164	ret = pm_runtime_get_sync(dev);
165	if (ret < 0) {
166		dev_err(dev, "error %d getting power for setup\n", ret);
167		goto out_power_put;
168	}
169
170	/* An error here won't cause driver shutdown, so warn if one occurs */
171	ret = ipa_setup(smp2p->ipa);
172	WARN(ret != 0, "error %d from ipa_setup()\n", ret);
173
174out_power_put:
175	pm_runtime_mark_last_busy(dev);
176	(void)pm_runtime_put_autosuspend(dev);
177
178	return IRQ_HANDLED;
179}
180
181/* Initialize SMP2P interrupts */
182static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p, const char *name,
183			      irq_handler_t handler)
184{
185	struct device *dev = &smp2p->ipa->pdev->dev;
186	unsigned int irq;
187	int ret;
188
189	ret = platform_get_irq_byname(smp2p->ipa->pdev, name);
190	if (ret <= 0)
191		return ret ? : -EINVAL;
192	irq = ret;
193
194	ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p);
195	if (ret) {
196		dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name);
197		return ret;
198	}
199
200	return irq;
201}
202
203static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq)
204{
205	free_irq(irq, smp2p);
206}
207
208/* Drop the power reference if it was taken in ipa_smp2p_notify() */
209static void ipa_smp2p_power_release(struct ipa *ipa)
210{
211	struct device *dev = &ipa->pdev->dev;
212
213	if (!ipa->smp2p->power_on)
214		return;
215
216	pm_runtime_mark_last_busy(dev);
217	(void)pm_runtime_put_autosuspend(dev);
218	ipa->smp2p->power_on = false;
219}
220
221/* Initialize the IPA SMP2P subsystem */
222int ipa_smp2p_init(struct ipa *ipa, bool modem_init)
223{
224	struct qcom_smem_state *enabled_state;
225	struct device *dev = &ipa->pdev->dev;
226	struct qcom_smem_state *valid_state;
227	struct ipa_smp2p *smp2p;
228	u32 enabled_bit;
229	u32 valid_bit;
230	int ret;
231
232	valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid",
233					  &valid_bit);
234	if (IS_ERR(valid_state))
235		return PTR_ERR(valid_state);
236	if (valid_bit >= 32)		/* BITS_PER_U32 */
237		return -EINVAL;
238
239	enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
240					    &enabled_bit);
241	if (IS_ERR(enabled_state))
242		return PTR_ERR(enabled_state);
243	if (enabled_bit >= 32)		/* BITS_PER_U32 */
244		return -EINVAL;
245
246	smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL);
247	if (!smp2p)
248		return -ENOMEM;
249
250	smp2p->ipa = ipa;
251
252	/* These fields are needed by the power query interrupt
253	 * handler, so initialize them now.
254	 */
255	mutex_init(&smp2p->mutex);
256	smp2p->valid_state = valid_state;
257	smp2p->valid_bit = valid_bit;
258	smp2p->enabled_state = enabled_state;
259	smp2p->enabled_bit = enabled_bit;
260
261	/* We have enough information saved to handle notifications */
262	ipa->smp2p = smp2p;
263
264	ret = ipa_smp2p_irq_init(smp2p, "ipa-clock-query",
265				 ipa_smp2p_modem_clk_query_isr);
266	if (ret < 0)
267		goto err_null_smp2p;
268	smp2p->clock_query_irq = ret;
269
270	ret = ipa_smp2p_panic_notifier_register(smp2p);
271	if (ret)
272		goto err_irq_exit;
273
274	if (modem_init) {
275		/* Result will be non-zero (negative for error) */
276		ret = ipa_smp2p_irq_init(smp2p, "ipa-setup-ready",
277					 ipa_smp2p_modem_setup_ready_isr);
278		if (ret < 0)
279			goto err_notifier_unregister;
280		smp2p->setup_ready_irq = ret;
281	}
282
283	return 0;
284
285err_notifier_unregister:
286	ipa_smp2p_panic_notifier_unregister(smp2p);
287err_irq_exit:
288	ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
289err_null_smp2p:
290	ipa->smp2p = NULL;
291	mutex_destroy(&smp2p->mutex);
292	kfree(smp2p);
293
294	return ret;
295}
296
297void ipa_smp2p_exit(struct ipa *ipa)
298{
299	struct ipa_smp2p *smp2p = ipa->smp2p;
300
301	if (smp2p->setup_ready_irq)
302		ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
303	ipa_smp2p_panic_notifier_unregister(smp2p);
304	ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
305	/* We won't get notified any more; drop power reference (if any) */
306	ipa_smp2p_power_release(ipa);
307	ipa->smp2p = NULL;
308	mutex_destroy(&smp2p->mutex);
309	kfree(smp2p);
310}
311
312void ipa_smp2p_irq_disable_setup(struct ipa *ipa)
313{
314	struct ipa_smp2p *smp2p = ipa->smp2p;
315
316	if (!smp2p->setup_ready_irq)
317		return;
318
319	mutex_lock(&smp2p->mutex);
320
321	if (!smp2p->setup_disabled) {
322		disable_irq(smp2p->setup_ready_irq);
323		smp2p->setup_disabled = true;
324	}
325
326	mutex_unlock(&smp2p->mutex);
327}
328
329/* Reset state tracking whether we have notified the modem */
330void ipa_smp2p_notify_reset(struct ipa *ipa)
331{
332	struct ipa_smp2p *smp2p = ipa->smp2p;
333	u32 mask;
334
335	if (!smp2p->notified)
336		return;
337
338	ipa_smp2p_power_release(ipa);
339
340	/* Reset the power enabled valid flag */
341	mask = BIT(smp2p->valid_bit);
342	qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
343
344	/* Mark the power disabled for good measure... */
345	mask = BIT(smp2p->enabled_bit);
346	qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
347
348	smp2p->notified = false;
349}