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 */
60 struct 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 */
ipa_smp2p_notify(struct ipa_smp2p * smp2p)85 static 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 */
ipa_smp2p_modem_clk_query_isr(int irq,void * dev_id)109 static 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
ipa_smp2p_panic_notifier(struct notifier_block * nb,unsigned long action,void * data)118 static 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
ipa_smp2p_panic_notifier_register(struct ipa_smp2p * smp2p)133 static 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
ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p * smp2p)143 static 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 */
ipa_smp2p_modem_setup_ready_isr(int irq,void * dev_id)150 static 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
173 out_power_put:
174 (void)pm_runtime_put_autosuspend(dev);
175
176 return IRQ_HANDLED;
177 }
178
179 /* Initialize SMP2P interrupts */
ipa_smp2p_irq_init(struct ipa_smp2p * smp2p,struct platform_device * pdev,const char * name,irq_handler_t handler)180 static 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
ipa_smp2p_irq_exit(struct ipa_smp2p * smp2p,u32 irq)202 static 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() */
ipa_smp2p_power_release(struct ipa * ipa)208 static 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 */
220 int
ipa_smp2p_init(struct ipa * ipa,struct platform_device * pdev,bool modem_init)221 ipa_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 ret = -EINVAL;
237 goto err_valid_state_put;
238 }
239
240 enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
241 &enabled_bit);
242 if (IS_ERR(enabled_state)) {
243 ret = PTR_ERR(enabled_state);
244 goto err_valid_state_put;
245 }
246 if (enabled_bit >= 32) { /* BITS_PER_U32 */
247 ret = -EINVAL;
248 goto err_enabled_state_put;
249 }
250
251 smp2p = kzalloc_obj(*smp2p);
252 if (!smp2p) {
253 ret = -ENOMEM;
254 goto err_enabled_state_put;
255 }
256
257 smp2p->ipa = ipa;
258
259 /* These fields are needed by the power query interrupt
260 * handler, so initialize them now.
261 */
262 mutex_init(&smp2p->mutex);
263 smp2p->valid_state = valid_state;
264 smp2p->valid_bit = valid_bit;
265 smp2p->enabled_state = enabled_state;
266 smp2p->enabled_bit = enabled_bit;
267
268 /* We have enough information saved to handle notifications */
269 ipa->smp2p = smp2p;
270
271 ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-clock-query",
272 ipa_smp2p_modem_clk_query_isr);
273 if (ret < 0)
274 goto err_null_smp2p;
275 smp2p->clock_query_irq = ret;
276
277 ret = ipa_smp2p_panic_notifier_register(smp2p);
278 if (ret)
279 goto err_irq_exit;
280
281 if (modem_init) {
282 /* Result will be non-zero (negative for error) */
283 ret = ipa_smp2p_irq_init(smp2p, pdev, "ipa-setup-ready",
284 ipa_smp2p_modem_setup_ready_isr);
285 if (ret < 0)
286 goto err_notifier_unregister;
287 smp2p->setup_ready_irq = ret;
288 }
289
290 return 0;
291
292 err_notifier_unregister:
293 ipa_smp2p_panic_notifier_unregister(smp2p);
294 err_irq_exit:
295 ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
296 err_null_smp2p:
297 ipa->smp2p = NULL;
298 mutex_destroy(&smp2p->mutex);
299 kfree(smp2p);
300 err_enabled_state_put:
301 qcom_smem_state_put(enabled_state);
302 err_valid_state_put:
303 qcom_smem_state_put(valid_state);
304
305 return ret;
306 }
307
ipa_smp2p_exit(struct ipa * ipa)308 void ipa_smp2p_exit(struct ipa *ipa)
309 {
310 struct ipa_smp2p *smp2p = ipa->smp2p;
311
312 if (smp2p->setup_ready_irq)
313 ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
314 ipa_smp2p_panic_notifier_unregister(smp2p);
315 ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
316 /* We won't get notified any more; drop power reference (if any) */
317 ipa_smp2p_power_release(ipa);
318 ipa->smp2p = NULL;
319 mutex_destroy(&smp2p->mutex);
320 qcom_smem_state_put(smp2p->enabled_state);
321 qcom_smem_state_put(smp2p->valid_state);
322 kfree(smp2p);
323 }
324
ipa_smp2p_irq_disable_setup(struct ipa * ipa)325 void ipa_smp2p_irq_disable_setup(struct ipa *ipa)
326 {
327 struct ipa_smp2p *smp2p = ipa->smp2p;
328
329 if (!smp2p->setup_ready_irq)
330 return;
331
332 mutex_lock(&smp2p->mutex);
333
334 if (!smp2p->setup_disabled) {
335 disable_irq(smp2p->setup_ready_irq);
336 smp2p->setup_disabled = true;
337 }
338
339 mutex_unlock(&smp2p->mutex);
340 }
341
342 /* Reset state tracking whether we have notified the modem */
ipa_smp2p_notify_reset(struct ipa * ipa)343 void ipa_smp2p_notify_reset(struct ipa *ipa)
344 {
345 struct ipa_smp2p *smp2p = ipa->smp2p;
346 u32 mask;
347
348 if (!smp2p->notified)
349 return;
350
351 ipa_smp2p_power_release(ipa);
352
353 /* Reset the power enabled valid flag */
354 mask = BIT(smp2p->valid_bit);
355 qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
356
357 /* Mark the power disabled for good measure... */
358 mask = BIT(smp2p->enabled_bit);
359 qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
360
361 smp2p->notified = false;
362 }
363