ipa_interrupt.c

  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, IRQ_SUSPEND_INFO);
 62		val = ioread32(ipa->reg_virt + reg_n_offset(reg, 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, IRQ_SUSPEND_CLR);
 69		iowrite32(val, ipa->reg_virt + reg_n_offset(reg, 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, 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, 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, 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, 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(ipa->interrupt->irq);
183}
184
185void ipa_interrupt_irq_enable(struct ipa *ipa)
186{
187	enable_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(interrupt->suspend_enabled, ipa->endpoint_count);
209	if (weight == 1 && !enable)
210		ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);
211
212	reg = ipa_reg(ipa, IRQ_SUSPEND_EN);
213	offset = reg_n_offset(reg, 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_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, 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, 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, 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(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, IPA_IRQ_EN);
270	iowrite32(0, ipa->reg_virt + reg_offset(reg));
271
272	ret = request_threaded_irq(irq, NULL, ipa_isr_thread, IRQF_ONESHOT,
273				   "ipa", 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, 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, false);
298err_free_irq:
299	free_irq(interrupt->irq, interrupt);
300err_free_bitmap:
301	bitmap_free(interrupt->suspend_enabled);
302err_kfree:
303	kfree(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, false);
318	free_irq(interrupt->irq, interrupt);
319	bitmap_free(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(irq ? : -EINVAL);
331
332	interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
333	if (!interrupt)
334		return ERR_PTR(-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(interrupt);
344}