1// SPDX-License-Identifier: GPL-2.0
2
3/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
4 * Copyright (C) 2018-2024 Linaro Ltd.
5 */
6
7/* DOC: IPA Interrupts
8 *
9 * The IPA has an interrupt line distinct from the interrupt used by the GSI
10 * code. Whereas GSI interrupts are generally related to channel events (like
11 * transfer completions), IPA interrupts are related to other events related
12 * to the IPA. Some of the IPA interrupts come from a microcontroller
13 * embedded in the IPA. Each IPA interrupt type can be both masked and
14 * acknowledged independent of the others.
15 *
16 * Two of the IPA interrupts are initiated by the microcontroller. A third
17 * can be generated to signal the need for a wakeup/resume when an IPA
18 * endpoint has been suspended. There are other IPA events, but at this
19 * time only these three are supported.
20 */
21
22#include <linux/interrupt.h>
23#include <linux/platform_device.h>
24#include <linux/pm_runtime.h>
25#include <linux/pm_wakeirq.h>
26#include <linux/types.h>
27
28#include "ipa.h"
29#include "ipa_endpoint.h"
30#include "ipa_interrupt.h"
31#include "ipa_power.h"
32#include "ipa_reg.h"
33#include "ipa_uc.h"
34
35/**
36 * struct ipa_interrupt - IPA interrupt information
37 * @ipa: IPA pointer
38 * @irq: Linux IRQ number used for IPA interrupts
39 * @enabled: Mask indicating which interrupts are enabled
40 * @suspend_enabled: Bitmap of endpoints with the SUSPEND interrupt enabled
41 */
42struct ipa_interrupt {
43 struct ipa *ipa;
44 u32 irq;
45 u32 enabled;
46 unsigned long *suspend_enabled;
47};
48
49/* Clear the suspend interrupt for all endpoints that signaled it */
50static void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
51{
52 struct ipa *ipa = interrupt->ipa;
53 u32 unit_count;
54 u32 unit;
55
56 unit_count = DIV_ROUND_UP(ipa->endpoint_count, 32);
57 for (unit = 0; unit < unit_count; unit++) {
58 const struct reg *reg;
59 u32 val;
60
61 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_INFO);
62 val = ioread32(ipa->reg_virt + reg_n_offset(reg, n: unit));
63
64 /* SUSPEND interrupt status isn't cleared on IPA version 3.0 */
65 if (!val || ipa->version == IPA_VERSION_3_0)
66 continue;
67
68 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_CLR);
69 iowrite32(val, ipa->reg_virt + reg_n_offset(reg, n: unit));
70 }
71}
72
73/* Process a particular interrupt type that has been received */
74static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
75{
76 struct ipa *ipa = interrupt->ipa;
77 const struct reg *reg;
78 u32 mask = BIT(irq_id);
79 u32 offset;
80
81 reg = ipa_reg(ipa, reg_id: IPA_IRQ_CLR);
82 offset = reg_offset(reg);
83
84 switch (irq_id) {
85 case IPA_IRQ_UC_0:
86 case IPA_IRQ_UC_1:
87 /* For microcontroller interrupts, clear the interrupt right
88 * away, "to avoid clearing unhandled interrupts."
89 */
90 iowrite32(mask, ipa->reg_virt + offset);
91 ipa_uc_interrupt_handler(ipa, irq_id);
92 break;
93
94 case IPA_IRQ_TX_SUSPEND:
95 /* Clearing the SUSPEND_TX interrupt also clears the
96 * register that tells us which suspended endpoint(s)
97 * caused the interrupt, so defer clearing until after
98 * the handler has been called.
99 */
100 ipa_interrupt_suspend_clear_all(interrupt);
101 fallthrough;
102
103 default: /* Silently ignore (and clear) any other condition */
104 iowrite32(mask, ipa->reg_virt + offset);
105 break;
106 }
107}
108
109/* IPA IRQ handler is threaded */
110static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
111{
112 struct ipa_interrupt *interrupt = dev_id;
113 struct ipa *ipa = interrupt->ipa;
114 u32 enabled = interrupt->enabled;
115 struct device *dev = ipa->dev;
116 const struct reg *reg;
117 u32 pending;
118 u32 offset;
119 u32 mask;
120 int ret;
121
122 ret = pm_runtime_get_sync(dev);
123 if (WARN_ON(ret < 0))
124 goto out_power_put;
125
126 /* The status register indicates which conditions are present,
127 * including conditions whose interrupt is not enabled. Handle
128 * only the enabled ones.
129 */
130 reg = ipa_reg(ipa, reg_id: IPA_IRQ_STTS);
131 offset = reg_offset(reg);
132 pending = ioread32(ipa->reg_virt + offset);
133 while ((mask = pending & enabled)) {
134 do {
135 u32 irq_id = __ffs(mask);
136
137 mask ^= BIT(irq_id);
138
139 ipa_interrupt_process(interrupt, irq_id);
140 } while (mask);
141 pending = ioread32(ipa->reg_virt + offset);
142 }
143
144 /* If any disabled interrupts are pending, clear them */
145 if (pending) {
146 dev_dbg(dev, "clearing disabled IPA interrupts 0x%08x\n",
147 pending);
148 reg = ipa_reg(ipa, reg_id: IPA_IRQ_CLR);
149 iowrite32(pending, ipa->reg_virt + reg_offset(reg));
150 }
151out_power_put:
152 (void)pm_runtime_put_autosuspend(dev);
153
154 return IRQ_HANDLED;
155}
156
157static void ipa_interrupt_enabled_update(struct ipa *ipa)
158{
159 const struct reg *reg = ipa_reg(ipa, reg_id: IPA_IRQ_EN);
160
161 iowrite32(ipa->interrupt->enabled, ipa->reg_virt + reg_offset(reg));
162}
163
164/* Enable an IPA interrupt type */
165void ipa_interrupt_enable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
166{
167 /* Update the IPA interrupt mask to enable it */
168 ipa->interrupt->enabled |= BIT(ipa_irq);
169 ipa_interrupt_enabled_update(ipa);
170}
171
172/* Disable an IPA interrupt type */
173void ipa_interrupt_disable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
174{
175 /* Update the IPA interrupt mask to disable it */
176 ipa->interrupt->enabled &= ~BIT(ipa_irq);
177 ipa_interrupt_enabled_update(ipa);
178}
179
180void ipa_interrupt_irq_disable(struct ipa *ipa)
181{
182 disable_irq(irq: ipa->interrupt->irq);
183}
184
185void ipa_interrupt_irq_enable(struct ipa *ipa)
186{
187 enable_irq(irq: ipa->interrupt->irq);
188}
189
190/* Common function used to enable/disable TX_SUSPEND for an endpoint */
191static void ipa_interrupt_suspend_control(struct ipa_interrupt *interrupt,
192 u32 endpoint_id, bool enable)
193{
194 struct ipa *ipa = interrupt->ipa;
195 u32 mask = BIT(endpoint_id % 32);
196 u32 unit = endpoint_id / 32;
197 const struct reg *reg;
198 unsigned long weight;
199 u32 offset;
200 u32 val;
201
202 WARN_ON(!test_bit(endpoint_id, ipa->available));
203
204 /* IPA version 3.0 does not support TX_SUSPEND interrupt control */
205 if (ipa->version == IPA_VERSION_3_0)
206 return;
207
208 weight = bitmap_weight(src: interrupt->suspend_enabled, nbits: ipa->endpoint_count);
209 if (weight == 1 && !enable)
210 ipa_interrupt_disable(ipa, ipa_irq: IPA_IRQ_TX_SUSPEND);
211
212 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_EN);
213 offset = reg_n_offset(reg, n: unit);
214 val = ioread32(ipa->reg_virt + offset);
215
216 if (enable)
217 val |= mask;
218 else
219 val &= ~mask;
220 __change_bit(endpoint_id, interrupt->suspend_enabled);
221
222 iowrite32(val, ipa->reg_virt + offset);
223
224 if (!weight && enable)
225 ipa_interrupt_enable(ipa, ipa_irq: IPA_IRQ_TX_SUSPEND);
226}
227
228/* Enable TX_SUSPEND for an endpoint */
229void
230ipa_interrupt_suspend_enable(struct ipa_interrupt *interrupt, u32 endpoint_id)
231{
232 ipa_interrupt_suspend_control(interrupt, endpoint_id, enable: true);
233}
234
235/* Disable TX_SUSPEND for an endpoint */
236void
237ipa_interrupt_suspend_disable(struct ipa_interrupt *interrupt, u32 endpoint_id)
238{
239 ipa_interrupt_suspend_control(interrupt, endpoint_id, enable: false);
240}
241
242/* Simulate arrival of an IPA TX_SUSPEND interrupt */
243void ipa_interrupt_simulate_suspend(struct ipa_interrupt *interrupt)
244{
245 ipa_interrupt_process(interrupt, irq_id: IPA_IRQ_TX_SUSPEND);
246}
247
248/* Configure the IPA interrupt framework */
249int ipa_interrupt_config(struct ipa *ipa)
250{
251 struct ipa_interrupt *interrupt = ipa->interrupt;
252 unsigned int irq = interrupt->irq;
253 struct device *dev = ipa->dev;
254 const struct reg *reg;
255 int ret;
256
257 interrupt->ipa = ipa;
258
259 /* Initially all IPA interrupt types are disabled */
260 interrupt->enabled = 0;
261 interrupt->suspend_enabled = bitmap_zalloc(nbits: ipa->endpoint_count,
262 GFP_KERNEL);
263 if (!interrupt->suspend_enabled) {
264 ret = -ENOMEM;
265 goto err_kfree;
266 }
267
268 /* Disable IPA interrupt types */
269 reg = ipa_reg(ipa, reg_id: IPA_IRQ_EN);
270 iowrite32(0, ipa->reg_virt + reg_offset(reg));
271
272 ret = request_threaded_irq(irq, NULL, thread_fn: ipa_isr_thread, IRQF_ONESHOT,
273 name: "ipa", dev: interrupt);
274 if (ret) {
275 dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
276 goto err_free_bitmap;
277 }
278
279 ret = device_init_wakeup(dev, enable: true);
280 if (ret) {
281 dev_err(dev, "error %d enabling wakeup\n", ret);
282 goto err_free_irq;
283 }
284
285 ret = dev_pm_set_wake_irq(dev, irq);
286 if (ret) {
287 dev_err(dev, "error %d registering \"ipa\" IRQ as wakeirq\n",
288 ret);
289 goto err_disable_wakeup;
290 }
291
292 ipa->interrupt = interrupt;
293
294 return 0;
295
296err_disable_wakeup:
297 (void)device_init_wakeup(dev, enable: false);
298err_free_irq:
299 free_irq(interrupt->irq, interrupt);
300err_free_bitmap:
301 bitmap_free(bitmap: interrupt->suspend_enabled);
302err_kfree:
303 kfree(objp: interrupt);
304
305 return ret;
306}
307
308/* Inverse of ipa_interrupt_config() */
309void ipa_interrupt_deconfig(struct ipa *ipa)
310{
311 struct ipa_interrupt *interrupt = ipa->interrupt;
312 struct device *dev = ipa->dev;
313
314 ipa->interrupt = NULL;
315
316 dev_pm_clear_wake_irq(dev);
317 (void)device_init_wakeup(dev, enable: false);
318 free_irq(interrupt->irq, interrupt);
319 bitmap_free(bitmap: interrupt->suspend_enabled);
320}
321
322/* Initialize the IPA interrupt structure */
323struct ipa_interrupt *ipa_interrupt_init(struct platform_device *pdev)
324{
325 struct ipa_interrupt *interrupt;
326 int irq;
327
328 irq = platform_get_irq_byname(pdev, "ipa");
329 if (irq <= 0)
330 return ERR_PTR(error: irq ? : -EINVAL);
331
332 interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
333 if (!interrupt)
334 return ERR_PTR(error: -ENOMEM);
335 interrupt->irq = irq;
336
337 return interrupt;
338}
339
340/* Inverse of ipa_interrupt_init() */
341void ipa_interrupt_exit(struct ipa_interrupt *interrupt)
342{
343 kfree(objp: interrupt);
344}
345

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