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, IRQ_SUSPEND_INFO);
 60		val = ioread32(ipa->reg_virt + reg_n_offset(reg, 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, IRQ_SUSPEND_CLR);
 67		iowrite32(val, ipa->reg_virt + reg_n_offset(reg, 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, 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, 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, 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, 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(ipa->interrupt->irq);
182}
183
184void ipa_interrupt_irq_enable(struct ipa *ipa)
185{
186	enable_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, IRQ_SUSPEND_EN);
207	offset = reg_n_offset(reg, 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, 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, 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, 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, IPA_IRQ_EN);
251	iowrite32(0, ipa->reg_virt + reg_offset(reg));
252
253	ret = request_threaded_irq(irq, NULL, ipa_isr_thread, IRQF_ONESHOT,
254				   "ipa", 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(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(irq ? : -EINVAL);
303	}
304
305	interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
306	if (!interrupt)
307		return ERR_PTR(-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(interrupt);
317}