1// SPDX-License-Identifier: GPL-2.0
2
3/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
4 * Copyright (C) 2018-2022 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/platform_device.h>
23#include <linux/types.h>
24#include <linux/interrupt.h>
25#include <linux/pm_runtime.h>
26#include <linux/pm_wakeirq.h>
27
28#include "ipa.h"
29#include "ipa_reg.h"
30#include "ipa_endpoint.h"
31#include "ipa_power.h"
32#include "ipa_uc.h"
33#include "ipa_interrupt.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 */
41struct ipa_interrupt {
42 struct ipa *ipa;
43 u32 irq;
44 u32 enabled;
45};
46
47/* Clear the suspend interrupt for all endpoints that signaled it */
48static void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
49{
50 struct ipa *ipa = interrupt->ipa;
51 u32 unit_count;
52 u32 unit;
53
54 unit_count = DIV_ROUND_UP(ipa->endpoint_count, 32);
55 for (unit = 0; unit < unit_count; unit++) {
56 const struct reg *reg;
57 u32 val;
58
59 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_INFO);
60 val = ioread32(ipa->reg_virt + reg_n_offset(reg, n: unit));
61
62 /* SUSPEND interrupt status isn't cleared on IPA version 3.0 */
63 if (!val || ipa->version == IPA_VERSION_3_0)
64 continue;
65
66 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_CLR);
67 iowrite32(val, ipa->reg_virt + reg_n_offset(reg, n: unit));
68 }
69}
70
71/* Process a particular interrupt type that has been received */
72static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
73{
74 struct ipa *ipa = interrupt->ipa;
75 const struct reg *reg;
76 u32 mask = BIT(irq_id);
77 u32 offset;
78
79 reg = ipa_reg(ipa, reg_id: IPA_IRQ_CLR);
80 offset = reg_offset(reg);
81
82 switch (irq_id) {
83 case IPA_IRQ_UC_0:
84 case IPA_IRQ_UC_1:
85 /* For microcontroller interrupts, clear the interrupt right
86 * away, "to avoid clearing unhandled interrupts."
87 */
88 iowrite32(mask, ipa->reg_virt + offset);
89 ipa_uc_interrupt_handler(ipa, irq_id);
90 break;
91
92 case IPA_IRQ_TX_SUSPEND:
93 /* Clearing the SUSPEND_TX interrupt also clears the
94 * register that tells us which suspended endpoint(s)
95 * caused the interrupt, so defer clearing until after
96 * the handler has been called.
97 */
98 ipa_interrupt_suspend_clear_all(interrupt);
99 fallthrough;
100
101 default: /* Silently ignore (and clear) any other condition */
102 iowrite32(mask, ipa->reg_virt + offset);
103 break;
104 }
105}
106
107/* IPA IRQ handler is threaded */
108static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
109{
110 struct ipa_interrupt *interrupt = dev_id;
111 struct ipa *ipa = interrupt->ipa;
112 u32 enabled = interrupt->enabled;
113 struct device *dev = ipa->dev;
114 const struct reg *reg;
115 u32 pending;
116 u32 offset;
117 u32 mask;
118 int ret;
119
120 ret = pm_runtime_get_sync(dev);
121 if (WARN_ON(ret < 0))
122 goto out_power_put;
123
124 /* The status register indicates which conditions are present,
125 * including conditions whose interrupt is not enabled. Handle
126 * only the enabled ones.
127 */
128 reg = ipa_reg(ipa, reg_id: IPA_IRQ_STTS);
129 offset = reg_offset(reg);
130 pending = ioread32(ipa->reg_virt + offset);
131 while ((mask = pending & enabled)) {
132 do {
133 u32 irq_id = __ffs(mask);
134
135 mask ^= BIT(irq_id);
136
137 ipa_interrupt_process(interrupt, irq_id);
138 } while (mask);
139 pending = ioread32(ipa->reg_virt + offset);
140 }
141
142 /* If any disabled interrupts are pending, clear them */
143 if (pending) {
144 dev_dbg(dev, "clearing disabled IPA interrupts 0x%08x\n",
145 pending);
146 reg = ipa_reg(ipa, reg_id: IPA_IRQ_CLR);
147 iowrite32(pending, ipa->reg_virt + reg_offset(reg));
148 }
149out_power_put:
150 pm_runtime_mark_last_busy(dev);
151 (void)pm_runtime_put_autosuspend(dev);
152
153 return IRQ_HANDLED;
154}
155
156static void ipa_interrupt_enabled_update(struct ipa *ipa)
157{
158 const struct reg *reg = ipa_reg(ipa, reg_id: IPA_IRQ_EN);
159
160 iowrite32(ipa->interrupt->enabled, ipa->reg_virt + reg_offset(reg));
161}
162
163/* Enable an IPA interrupt type */
164void ipa_interrupt_enable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
165{
166 /* Update the IPA interrupt mask to enable it */
167 ipa->interrupt->enabled |= BIT(ipa_irq);
168 ipa_interrupt_enabled_update(ipa);
169}
170
171/* Disable an IPA interrupt type */
172void ipa_interrupt_disable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
173{
174 /* Update the IPA interrupt mask to disable it */
175 ipa->interrupt->enabled &= ~BIT(ipa_irq);
176 ipa_interrupt_enabled_update(ipa);
177}
178
179void ipa_interrupt_irq_disable(struct ipa *ipa)
180{
181 disable_irq(irq: ipa->interrupt->irq);
182}
183
184void ipa_interrupt_irq_enable(struct ipa *ipa)
185{
186 enable_irq(irq: ipa->interrupt->irq);
187}
188
189/* Common function used to enable/disable TX_SUSPEND for an endpoint */
190static void ipa_interrupt_suspend_control(struct ipa_interrupt *interrupt,
191 u32 endpoint_id, bool enable)
192{
193 struct ipa *ipa = interrupt->ipa;
194 u32 mask = BIT(endpoint_id % 32);
195 u32 unit = endpoint_id / 32;
196 const struct reg *reg;
197 u32 offset;
198 u32 val;
199
200 WARN_ON(!test_bit(endpoint_id, ipa->available));
201
202 /* IPA version 3.0 does not support TX_SUSPEND interrupt control */
203 if (ipa->version == IPA_VERSION_3_0)
204 return;
205
206 reg = ipa_reg(ipa, reg_id: IRQ_SUSPEND_EN);
207 offset = reg_n_offset(reg, n: unit);
208 val = ioread32(ipa->reg_virt + offset);
209
210 if (enable)
211 val |= mask;
212 else
213 val &= ~mask;
214
215 iowrite32(val, ipa->reg_virt + offset);
216}
217
218/* Enable TX_SUSPEND for an endpoint */
219void
220ipa_interrupt_suspend_enable(struct ipa_interrupt *interrupt, u32 endpoint_id)
221{
222 ipa_interrupt_suspend_control(interrupt, endpoint_id, enable: true);
223}
224
225/* Disable TX_SUSPEND for an endpoint */
226void
227ipa_interrupt_suspend_disable(struct ipa_interrupt *interrupt, u32 endpoint_id)
228{
229 ipa_interrupt_suspend_control(interrupt, endpoint_id, enable: false);
230}
231
232/* Simulate arrival of an IPA TX_SUSPEND interrupt */
233void ipa_interrupt_simulate_suspend(struct ipa_interrupt *interrupt)
234{
235 ipa_interrupt_process(interrupt, irq_id: IPA_IRQ_TX_SUSPEND);
236}
237
238/* Configure the IPA interrupt framework */
239int ipa_interrupt_config(struct ipa *ipa)
240{
241 struct ipa_interrupt *interrupt = ipa->interrupt;
242 unsigned int irq = interrupt->irq;
243 struct device *dev = ipa->dev;
244 const struct reg *reg;
245 int ret;
246
247 interrupt->ipa = ipa;
248
249 /* Disable all IPA interrupt types */
250 reg = ipa_reg(ipa, reg_id: IPA_IRQ_EN);
251 iowrite32(0, ipa->reg_virt + reg_offset(reg));
252
253 ret = request_threaded_irq(irq, NULL, thread_fn: ipa_isr_thread, IRQF_ONESHOT,
254 name: "ipa", dev: interrupt);
255 if (ret) {
256 dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
257 goto err_kfree;
258 }
259
260 ret = dev_pm_set_wake_irq(dev, irq);
261 if (ret) {
262 dev_err(dev, "error %d registering \"ipa\" IRQ as wakeirq\n",
263 ret);
264 goto err_free_irq;
265 }
266
267 ipa->interrupt = interrupt;
268
269 return 0;
270
271err_free_irq:
272 free_irq(interrupt->irq, interrupt);
273err_kfree:
274 kfree(objp: interrupt);
275
276 return ret;
277}
278
279/* Inverse of ipa_interrupt_config() */
280void ipa_interrupt_deconfig(struct ipa *ipa)
281{
282 struct ipa_interrupt *interrupt = ipa->interrupt;
283 struct device *dev = ipa->dev;
284
285 ipa->interrupt = NULL;
286
287 dev_pm_clear_wake_irq(dev);
288 free_irq(interrupt->irq, interrupt);
289}
290
291/* Initialize the IPA interrupt structure */
292struct ipa_interrupt *ipa_interrupt_init(struct platform_device *pdev)
293{
294 struct device *dev = &pdev->dev;
295 struct ipa_interrupt *interrupt;
296 int irq;
297
298 irq = platform_get_irq_byname(pdev, "ipa");
299 if (irq <= 0) {
300 dev_err(dev, "DT error %d getting \"ipa\" IRQ property\n", irq);
301
302 return ERR_PTR(error: irq ? : -EINVAL);
303 }
304
305 interrupt = kzalloc(size: sizeof(*interrupt), GFP_KERNEL);
306 if (!interrupt)
307 return ERR_PTR(error: -ENOMEM);
308 interrupt->irq = irq;
309
310 return interrupt;
311}
312
313/* Inverse of ipa_interrupt_init() */
314void ipa_interrupt_exit(struct ipa_interrupt *interrupt)
315{
316 kfree(objp: interrupt);
317}
318

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