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/platform_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 u32 value;
88 u32 mask;
89
90 if (smp2p->notified)
91 return;
92
93 smp2p->power_on = pm_runtime_get_if_active(dev: 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(state: 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(state: 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(ipa: 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(nh: &panic_notifier_list,
140 nb: &smp2p->panic_notifier);
141}
142
143static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
144{
145 atomic_notifier_chain_unregister(nh: &panic_notifier_list,
146 nb: &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 pm_runtime_mark_last_busy(dev);
175 (void)pm_runtime_put_autosuspend(dev);
176
177 return IRQ_HANDLED;
178}
179
180/* Initialize SMP2P interrupts */
181static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p,
182 struct platform_device *pdev,
183 const char *name, irq_handler_t handler)
184{
185 struct device *dev = &pdev->dev;
186 unsigned int irq;
187 int ret;
188
189 ret = platform_get_irq_byname(pdev, name);
190 if (ret <= 0)
191 return ret ? : -EINVAL;
192 irq = ret;
193
194 ret = request_threaded_irq(irq, NULL, thread_fn: handler, flags: 0, name, dev: 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->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
223ipa_smp2p_init(struct ipa *ipa, struct platform_device *pdev, bool modem_init)
224{
225 struct qcom_smem_state *enabled_state;
226 struct device *dev = &pdev->dev;
227 struct qcom_smem_state *valid_state;
228 struct ipa_smp2p *smp2p;
229 u32 enabled_bit;
230 u32 valid_bit;
231 int ret;
232
233 valid_state = qcom_smem_state_get(dev, con_id: "ipa-clock-enabled-valid",
234 bit: &valid_bit);
235 if (IS_ERR(ptr: valid_state))
236 return PTR_ERR(ptr: valid_state);
237 if (valid_bit >= 32) /* BITS_PER_U32 */
238 return -EINVAL;
239
240 enabled_state = qcom_smem_state_get(dev, con_id: "ipa-clock-enabled",
241 bit: &enabled_bit);
242 if (IS_ERR(ptr: enabled_state))
243 return PTR_ERR(ptr: enabled_state);
244 if (enabled_bit >= 32) /* BITS_PER_U32 */
245 return -EINVAL;
246
247 smp2p = kzalloc(size: sizeof(*smp2p), GFP_KERNEL);
248 if (!smp2p)
249 return -ENOMEM;
250
251 smp2p->ipa = ipa;
252
253 /* These fields are needed by the power query interrupt
254 * handler, so initialize them now.
255 */
256 mutex_init(&smp2p->mutex);
257 smp2p->valid_state = valid_state;
258 smp2p->valid_bit = valid_bit;
259 smp2p->enabled_state = enabled_state;
260 smp2p->enabled_bit = enabled_bit;
261
262 /* We have enough information saved to handle notifications */
263 ipa->smp2p = smp2p;
264
265 ret = ipa_smp2p_irq_init(smp2p, pdev, name: "ipa-clock-query",
266 handler: ipa_smp2p_modem_clk_query_isr);
267 if (ret < 0)
268 goto err_null_smp2p;
269 smp2p->clock_query_irq = ret;
270
271 ret = ipa_smp2p_panic_notifier_register(smp2p);
272 if (ret)
273 goto err_irq_exit;
274
275 if (modem_init) {
276 /* Result will be non-zero (negative for error) */
277 ret = ipa_smp2p_irq_init(smp2p, pdev, name: "ipa-setup-ready",
278 handler: ipa_smp2p_modem_setup_ready_isr);
279 if (ret < 0)
280 goto err_notifier_unregister;
281 smp2p->setup_ready_irq = ret;
282 }
283
284 return 0;
285
286err_notifier_unregister:
287 ipa_smp2p_panic_notifier_unregister(smp2p);
288err_irq_exit:
289 ipa_smp2p_irq_exit(smp2p, irq: smp2p->clock_query_irq);
290err_null_smp2p:
291 ipa->smp2p = NULL;
292 mutex_destroy(lock: &smp2p->mutex);
293 kfree(objp: smp2p);
294
295 return ret;
296}
297
298void ipa_smp2p_exit(struct ipa *ipa)
299{
300 struct ipa_smp2p *smp2p = ipa->smp2p;
301
302 if (smp2p->setup_ready_irq)
303 ipa_smp2p_irq_exit(smp2p, irq: smp2p->setup_ready_irq);
304 ipa_smp2p_panic_notifier_unregister(smp2p);
305 ipa_smp2p_irq_exit(smp2p, irq: smp2p->clock_query_irq);
306 /* We won't get notified any more; drop power reference (if any) */
307 ipa_smp2p_power_release(ipa);
308 ipa->smp2p = NULL;
309 mutex_destroy(lock: &smp2p->mutex);
310 kfree(objp: smp2p);
311}
312
313void ipa_smp2p_irq_disable_setup(struct ipa *ipa)
314{
315 struct ipa_smp2p *smp2p = ipa->smp2p;
316
317 if (!smp2p->setup_ready_irq)
318 return;
319
320 mutex_lock(&smp2p->mutex);
321
322 if (!smp2p->setup_disabled) {
323 disable_irq(irq: smp2p->setup_ready_irq);
324 smp2p->setup_disabled = true;
325 }
326
327 mutex_unlock(lock: &smp2p->mutex);
328}
329
330/* Reset state tracking whether we have notified the modem */
331void ipa_smp2p_notify_reset(struct ipa *ipa)
332{
333 struct ipa_smp2p *smp2p = ipa->smp2p;
334 u32 mask;
335
336 if (!smp2p->notified)
337 return;
338
339 ipa_smp2p_power_release(ipa);
340
341 /* Reset the power enabled valid flag */
342 mask = BIT(smp2p->valid_bit);
343 qcom_smem_state_update_bits(state: smp2p->valid_state, mask, value: 0);
344
345 /* Mark the power disabled for good measure... */
346 mask = BIT(smp2p->enabled_bit);
347 qcom_smem_state_update_bits(state: smp2p->enabled_state, mask, value: 0);
348
349 smp2p->notified = false;
350}
351

source code of linux/drivers/net/ipa/ipa_smp2p.c