xref: /openbmc/linux/drivers/net/ipa/ipa_interrupt.c (revision 0a32395f)
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/types.h>
23 #include <linux/interrupt.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/pm_wakeirq.h>
26 
27 #include "ipa.h"
28 #include "ipa_reg.h"
29 #include "ipa_endpoint.h"
30 #include "ipa_power.h"
31 #include "ipa_uc.h"
32 #include "ipa_interrupt.h"
33 
34 /**
35  * struct ipa_interrupt - IPA interrupt information
36  * @ipa:		IPA pointer
37  * @irq:		Linux IRQ number used for IPA interrupts
38  * @enabled:		Mask indicating which interrupts are enabled
39  */
40 struct ipa_interrupt {
41 	struct ipa *ipa;
42 	u32 irq;
43 	u32 enabled;
44 };
45 
46 /* Process a particular interrupt type that has been received */
ipa_interrupt_process(struct ipa_interrupt * interrupt,u32 irq_id)47 static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
48 {
49 	struct ipa *ipa = interrupt->ipa;
50 	const struct reg *reg;
51 	u32 mask = BIT(irq_id);
52 	u32 offset;
53 
54 	reg = ipa_reg(ipa, IPA_IRQ_CLR);
55 	offset = reg_offset(reg);
56 
57 	switch (irq_id) {
58 	case IPA_IRQ_UC_0:
59 	case IPA_IRQ_UC_1:
60 		/* For microcontroller interrupts, clear the interrupt right
61 		 * away, "to avoid clearing unhandled interrupts."
62 		 */
63 		iowrite32(mask, ipa->reg_virt + offset);
64 		ipa_uc_interrupt_handler(ipa, irq_id);
65 		break;
66 
67 	case IPA_IRQ_TX_SUSPEND:
68 		/* Clearing the SUSPEND_TX interrupt also clears the
69 		 * register that tells us which suspended endpoint(s)
70 		 * caused the interrupt, so defer clearing until after
71 		 * the handler has been called.
72 		 */
73 		ipa_power_suspend_handler(ipa, irq_id);
74 		fallthrough;
75 
76 	default:	/* Silently ignore (and clear) any other condition */
77 		iowrite32(mask, ipa->reg_virt + offset);
78 		break;
79 	}
80 }
81 
82 /* IPA IRQ handler is threaded */
ipa_isr_thread(int irq,void * dev_id)83 static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
84 {
85 	struct ipa_interrupt *interrupt = dev_id;
86 	struct ipa *ipa = interrupt->ipa;
87 	u32 enabled = interrupt->enabled;
88 	const struct reg *reg;
89 	struct device *dev;
90 	u32 pending;
91 	u32 offset;
92 	u32 mask;
93 	int ret;
94 
95 	dev = &ipa->pdev->dev;
96 	ret = pm_runtime_get_sync(dev);
97 	if (WARN_ON(ret < 0))
98 		goto out_power_put;
99 
100 	/* The status register indicates which conditions are present,
101 	 * including conditions whose interrupt is not enabled.  Handle
102 	 * only the enabled ones.
103 	 */
104 	reg = ipa_reg(ipa, IPA_IRQ_STTS);
105 	offset = reg_offset(reg);
106 	pending = ioread32(ipa->reg_virt + offset);
107 	while ((mask = pending & enabled)) {
108 		do {
109 			u32 irq_id = __ffs(mask);
110 
111 			mask ^= BIT(irq_id);
112 
113 			ipa_interrupt_process(interrupt, irq_id);
114 		} while (mask);
115 		pending = ioread32(ipa->reg_virt + offset);
116 	}
117 
118 	/* If any disabled interrupts are pending, clear them */
119 	if (pending) {
120 		dev_dbg(dev, "clearing disabled IPA interrupts 0x%08x\n",
121 			pending);
122 		reg = ipa_reg(ipa, IPA_IRQ_CLR);
123 		iowrite32(pending, ipa->reg_virt + reg_offset(reg));
124 	}
125 out_power_put:
126 	pm_runtime_mark_last_busy(dev);
127 	(void)pm_runtime_put_autosuspend(dev);
128 
129 	return IRQ_HANDLED;
130 }
131 
ipa_interrupt_enabled_update(struct ipa * ipa)132 static void ipa_interrupt_enabled_update(struct ipa *ipa)
133 {
134 	const struct reg *reg = ipa_reg(ipa, IPA_IRQ_EN);
135 
136 	iowrite32(ipa->interrupt->enabled, ipa->reg_virt + reg_offset(reg));
137 }
138 
139 /* Enable an IPA interrupt type */
ipa_interrupt_enable(struct ipa * ipa,enum ipa_irq_id ipa_irq)140 void ipa_interrupt_enable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
141 {
142 	/* Update the IPA interrupt mask to enable it */
143 	ipa->interrupt->enabled |= BIT(ipa_irq);
144 	ipa_interrupt_enabled_update(ipa);
145 }
146 
147 /* Disable an IPA interrupt type */
ipa_interrupt_disable(struct ipa * ipa,enum ipa_irq_id ipa_irq)148 void ipa_interrupt_disable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
149 {
150 	/* Update the IPA interrupt mask to disable it */
151 	ipa->interrupt->enabled &= ~BIT(ipa_irq);
152 	ipa_interrupt_enabled_update(ipa);
153 }
154 
ipa_interrupt_irq_disable(struct ipa * ipa)155 void ipa_interrupt_irq_disable(struct ipa *ipa)
156 {
157 	disable_irq(ipa->interrupt->irq);
158 }
159 
ipa_interrupt_irq_enable(struct ipa * ipa)160 void ipa_interrupt_irq_enable(struct ipa *ipa)
161 {
162 	enable_irq(ipa->interrupt->irq);
163 }
164 
165 /* Common function used to enable/disable TX_SUSPEND for an endpoint */
ipa_interrupt_suspend_control(struct ipa_interrupt * interrupt,u32 endpoint_id,bool enable)166 static void ipa_interrupt_suspend_control(struct ipa_interrupt *interrupt,
167 					  u32 endpoint_id, bool enable)
168 {
169 	struct ipa *ipa = interrupt->ipa;
170 	u32 mask = BIT(endpoint_id % 32);
171 	u32 unit = endpoint_id / 32;
172 	const struct reg *reg;
173 	u32 offset;
174 	u32 val;
175 
176 	WARN_ON(!test_bit(endpoint_id, ipa->available));
177 
178 	/* IPA version 3.0 does not support TX_SUSPEND interrupt control */
179 	if (ipa->version == IPA_VERSION_3_0)
180 		return;
181 
182 	reg = ipa_reg(ipa, IRQ_SUSPEND_EN);
183 	offset = reg_n_offset(reg, unit);
184 	val = ioread32(ipa->reg_virt + offset);
185 
186 	if (enable)
187 		val |= mask;
188 	else
189 		val &= ~mask;
190 
191 	iowrite32(val, ipa->reg_virt + offset);
192 }
193 
194 /* Enable TX_SUSPEND for an endpoint */
195 void
ipa_interrupt_suspend_enable(struct ipa_interrupt * interrupt,u32 endpoint_id)196 ipa_interrupt_suspend_enable(struct ipa_interrupt *interrupt, u32 endpoint_id)
197 {
198 	ipa_interrupt_suspend_control(interrupt, endpoint_id, true);
199 }
200 
201 /* Disable TX_SUSPEND for an endpoint */
202 void
ipa_interrupt_suspend_disable(struct ipa_interrupt * interrupt,u32 endpoint_id)203 ipa_interrupt_suspend_disable(struct ipa_interrupt *interrupt, u32 endpoint_id)
204 {
205 	ipa_interrupt_suspend_control(interrupt, endpoint_id, false);
206 }
207 
208 /* Clear the suspend interrupt for all endpoints that signaled it */
ipa_interrupt_suspend_clear_all(struct ipa_interrupt * interrupt)209 void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
210 {
211 	struct ipa *ipa = interrupt->ipa;
212 	u32 unit_count;
213 	u32 unit;
214 
215 	unit_count = DIV_ROUND_UP(ipa->endpoint_count, 32);
216 	for (unit = 0; unit < unit_count; unit++) {
217 		const struct reg *reg;
218 		u32 val;
219 
220 		reg = ipa_reg(ipa, IRQ_SUSPEND_INFO);
221 		val = ioread32(ipa->reg_virt + reg_n_offset(reg, unit));
222 
223 		/* SUSPEND interrupt status isn't cleared on IPA version 3.0 */
224 		if (ipa->version == IPA_VERSION_3_0)
225 			continue;
226 
227 		reg = ipa_reg(ipa, IRQ_SUSPEND_CLR);
228 		iowrite32(val, ipa->reg_virt + reg_n_offset(reg, unit));
229 	}
230 }
231 
232 /* Simulate arrival of an IPA TX_SUSPEND interrupt */
ipa_interrupt_simulate_suspend(struct ipa_interrupt * interrupt)233 void ipa_interrupt_simulate_suspend(struct ipa_interrupt *interrupt)
234 {
235 	ipa_interrupt_process(interrupt, IPA_IRQ_TX_SUSPEND);
236 }
237 
238 /* Configure the IPA interrupt framework */
ipa_interrupt_config(struct ipa * ipa)239 struct ipa_interrupt *ipa_interrupt_config(struct ipa *ipa)
240 {
241 	struct device *dev = &ipa->pdev->dev;
242 	struct ipa_interrupt *interrupt;
243 	const struct reg *reg;
244 	unsigned int irq;
245 	int ret;
246 
247 	ret = platform_get_irq_byname(ipa->pdev, "ipa");
248 	if (ret <= 0) {
249 		dev_err(dev, "DT error %d getting \"ipa\" IRQ property\n",
250 			ret);
251 		return ERR_PTR(ret ? : -EINVAL);
252 	}
253 	irq = ret;
254 
255 	interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
256 	if (!interrupt)
257 		return ERR_PTR(-ENOMEM);
258 	interrupt->ipa = ipa;
259 	interrupt->irq = irq;
260 
261 	/* Start with all IPA interrupts disabled */
262 	reg = ipa_reg(ipa, IPA_IRQ_EN);
263 	iowrite32(0, ipa->reg_virt + reg_offset(reg));
264 
265 	ret = request_threaded_irq(irq, NULL, ipa_isr_thread, IRQF_ONESHOT,
266 				   "ipa", interrupt);
267 	if (ret) {
268 		dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
269 		goto err_kfree;
270 	}
271 
272 	ret = dev_pm_set_wake_irq(dev, irq);
273 	if (ret) {
274 		dev_err(dev, "error %d registering \"ipa\" IRQ as wakeirq\n", ret);
275 		goto err_free_irq;
276 	}
277 
278 	return interrupt;
279 
280 err_free_irq:
281 	free_irq(interrupt->irq, interrupt);
282 err_kfree:
283 	kfree(interrupt);
284 
285 	return ERR_PTR(ret);
286 }
287 
288 /* Inverse of ipa_interrupt_config() */
ipa_interrupt_deconfig(struct ipa_interrupt * interrupt)289 void ipa_interrupt_deconfig(struct ipa_interrupt *interrupt)
290 {
291 	struct device *dev = &interrupt->ipa->pdev->dev;
292 
293 	dev_pm_clear_wake_irq(dev);
294 	free_irq(interrupt->irq, interrupt);
295 	kfree(interrupt);
296 }
297