1// SPDX-License-Identifier: GPL-2.0
  2
  3/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
  4 * Copyright (C) 2018-2020 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
 25#include "ipa.h"
 26#include "ipa_clock.h"
 27#include "ipa_reg.h"
 28#include "ipa_endpoint.h"
 29#include "ipa_interrupt.h"
 30
 31/**
 32 * struct ipa_interrupt - IPA interrupt information
 33 * @ipa:		IPA pointer
 34 * @irq:		Linux IRQ number used for IPA interrupts
 35 * @enabled:		Mask indicating which interrupts are enabled
 36 * @handler:		Array of handlers indexed by IPA interrupt ID
 37 */
 38struct ipa_interrupt {
 39	struct ipa *ipa;
 40	u32 irq;
 41	u32 enabled;
 42	ipa_irq_handler_t handler[IPA_IRQ_COUNT];
 43};
 44
 45/* Returns true if the interrupt type is associated with the microcontroller */
 46static bool ipa_interrupt_uc(struct ipa_interrupt *interrupt, u32 irq_id)
 47{
 48	return irq_id == IPA_IRQ_UC_0 || irq_id == IPA_IRQ_UC_1;
 49}
 50
 51/* Process a particular interrupt type that has been received */
 52static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
 53{
 54	bool uc_irq = ipa_interrupt_uc(interrupt, irq_id);
 55	struct ipa *ipa = interrupt->ipa;
 56	u32 mask = BIT(irq_id);
 57	u32 offset;
 58
 59	/* For microcontroller interrupts, clear the interrupt right away,
 60	 * "to avoid clearing unhandled interrupts."
 61	 */
 62	offset = ipa_reg_irq_clr_offset(ipa->version);
 63	if (uc_irq)
 64		iowrite32(mask, ipa->reg_virt + offset);
 65
 66	if (irq_id < IPA_IRQ_COUNT && interrupt->handler[irq_id])
 67		interrupt->handler[irq_id](interrupt->ipa, irq_id);
 68
 69	/* Clearing the SUSPEND_TX interrupt also clears the register
 70	 * that tells us which suspended endpoint(s) caused the interrupt,
 71	 * so defer clearing until after the handler has been called.
 72	 */
 73	if (!uc_irq)
 74		iowrite32(mask, ipa->reg_virt + offset);
 75}
 76
 77/* Process all IPA interrupt types that have been signaled */
 78static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 79{
 80	struct ipa *ipa = interrupt->ipa;
 81	u32 enabled = interrupt->enabled;
 82	u32 offset;
 83	u32 mask;
 84
 85	/* The status register indicates which conditions are present,
 86	 * including conditions whose interrupt is not enabled.  Handle
 87	 * only the enabled ones.
 88	 */
 89	offset = ipa_reg_irq_stts_offset(ipa->version);
 90	mask = ioread32(ipa->reg_virt + offset);
 91	while ((mask &= enabled)) {
 92		do {
 93			u32 irq_id = __ffs(mask);
 94
 95			mask ^= BIT(irq_id);
 96
 97			ipa_interrupt_process(interrupt, irq_id);
 98		} while (mask);
 99		mask = ioread32(ipa->reg_virt + offset);
100	}
101}
102
103/* Threaded part of the IPA IRQ handler */
104static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
105{
106	struct ipa_interrupt *interrupt = dev_id;
107
108	ipa_clock_get(interrupt->ipa);
109
110	ipa_interrupt_process_all(interrupt);
111
112	ipa_clock_put(interrupt->ipa);
113
114	return IRQ_HANDLED;
115}
116
117/* Hard part (i.e., "real" IRQ handler) of the IRQ handler */
118static irqreturn_t ipa_isr(int irq, void *dev_id)
119{
120	struct ipa_interrupt *interrupt = dev_id;
121	struct ipa *ipa = interrupt->ipa;
122	u32 offset;
123	u32 mask;
124
125	offset = ipa_reg_irq_stts_offset(ipa->version);
126	mask = ioread32(ipa->reg_virt + offset);
127	if (mask & interrupt->enabled)
128		return IRQ_WAKE_THREAD;
129
130	/* Nothing in the mask was supposed to cause an interrupt */
131	offset = ipa_reg_irq_clr_offset(ipa->version);
132	iowrite32(mask, ipa->reg_virt + offset);
133
134	dev_err(&ipa->pdev->dev, "%s: unexpected interrupt, mask 0x%08x\n",
135		__func__, mask);
136
137	return IRQ_HANDLED;
138}
139
140/* Common function used to enable/disable TX_SUSPEND for an endpoint */
141static void ipa_interrupt_suspend_control(struct ipa_interrupt *interrupt,
142					  u32 endpoint_id, bool enable)
143{
144	struct ipa *ipa = interrupt->ipa;
145	u32 mask = BIT(endpoint_id);
146	u32 offset;
147	u32 val;
148
149	/* assert(mask & ipa->available); */
150
151	/* IPA version 3.0 does not support TX_SUSPEND interrupt control */
152	if (ipa->version == IPA_VERSION_3_0)
153		return;
154
155	offset = ipa_reg_irq_suspend_en_offset(ipa->version);
156	val = ioread32(ipa->reg_virt + offset);
157	if (enable)
158		val |= mask;
159	else
160		val &= ~mask;
161	iowrite32(val, ipa->reg_virt + offset);
162}
163
164/* Enable TX_SUSPEND for an endpoint */
165void
166ipa_interrupt_suspend_enable(struct ipa_interrupt *interrupt, u32 endpoint_id)
167{
168	ipa_interrupt_suspend_control(interrupt, endpoint_id, true);
169}
170
171/* Disable TX_SUSPEND for an endpoint */
172void
173ipa_interrupt_suspend_disable(struct ipa_interrupt *interrupt, u32 endpoint_id)
174{
175	ipa_interrupt_suspend_control(interrupt, endpoint_id, false);
176}
177
178/* Clear the suspend interrupt for all endpoints that signaled it */
179void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
180{
181	struct ipa *ipa = interrupt->ipa;
182	u32 offset;
183	u32 val;
184
185	offset = ipa_reg_irq_suspend_info_offset(ipa->version);
186	val = ioread32(ipa->reg_virt + offset);
187
188	/* SUSPEND interrupt status isn't cleared on IPA version 3.0 */
189	if (ipa->version == IPA_VERSION_3_0)
190		return;
191
192	offset = ipa_reg_irq_suspend_clr_offset(ipa->version);
193	iowrite32(val, ipa->reg_virt + offset);
194}
195
196/* Simulate arrival of an IPA TX_SUSPEND interrupt */
197void ipa_interrupt_simulate_suspend(struct ipa_interrupt *interrupt)
198{
199	ipa_interrupt_process(interrupt, IPA_IRQ_TX_SUSPEND);
200}
201
202/* Add a handler for an IPA interrupt */
203void ipa_interrupt_add(struct ipa_interrupt *interrupt,
204		       enum ipa_irq_id ipa_irq, ipa_irq_handler_t handler)
205{
206	struct ipa *ipa = interrupt->ipa;
207	u32 offset;
208
209	/* assert(ipa_irq < IPA_IRQ_COUNT); */
210	interrupt->handler[ipa_irq] = handler;
211
212	/* Update the IPA interrupt mask to enable it */
213	interrupt->enabled |= BIT(ipa_irq);
214	offset = ipa_reg_irq_en_offset(ipa->version);
215	iowrite32(interrupt->enabled, ipa->reg_virt + offset);
216}
217
218/* Remove the handler for an IPA interrupt type */
219void
220ipa_interrupt_remove(struct ipa_interrupt *interrupt, enum ipa_irq_id ipa_irq)
221{
222	struct ipa *ipa = interrupt->ipa;
223	u32 offset;
224
225	/* assert(ipa_irq < IPA_IRQ_COUNT); */
226	/* Update the IPA interrupt mask to disable it */
227	interrupt->enabled &= ~BIT(ipa_irq);
228	offset = ipa_reg_irq_en_offset(ipa->version);
229	iowrite32(interrupt->enabled, ipa->reg_virt + offset);
230
231	interrupt->handler[ipa_irq] = NULL;
232}
233
234/* Set up the IPA interrupt framework */
235struct ipa_interrupt *ipa_interrupt_setup(struct ipa *ipa)
236{
237	struct device *dev = &ipa->pdev->dev;
238	struct ipa_interrupt *interrupt;
239	unsigned int irq;
240	u32 offset;
241	int ret;
242
243	ret = platform_get_irq_byname(ipa->pdev, "ipa");
244	if (ret <= 0) {
245		dev_err(dev, "DT error %d getting \"ipa\" IRQ property\n",
246			ret);
247		return ERR_PTR(ret ? : -EINVAL);
248	}
249	irq = ret;
250
251	interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
252	if (!interrupt)
253		return ERR_PTR(-ENOMEM);
254	interrupt->ipa = ipa;
255	interrupt->irq = irq;
256
257	/* Start with all IPA interrupts disabled */
258	offset = ipa_reg_irq_en_offset(ipa->version);
259	iowrite32(0, ipa->reg_virt + offset);
260
261	ret = request_threaded_irq(irq, ipa_isr, ipa_isr_thread, IRQF_ONESHOT,
262				   "ipa", interrupt);
263	if (ret) {
264		dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
265		goto err_kfree;
266	}
267
268	ret = enable_irq_wake(irq);
269	if (ret) {
270		dev_err(dev, "error %d enabling wakeup for \"ipa\" IRQ\n", ret);
271		goto err_free_irq;
272	}
273
274	return interrupt;
275
276err_free_irq:
277	free_irq(interrupt->irq, interrupt);
278err_kfree:
279	kfree(interrupt);
280
281	return ERR_PTR(ret);
282}
283
284/* Tear down the IPA interrupt framework */
285void ipa_interrupt_teardown(struct ipa_interrupt *interrupt)
286{
287	struct device *dev = &interrupt->ipa->pdev->dev;
288	int ret;
289
290	ret = disable_irq_wake(interrupt->irq);
291	if (ret)
292		dev_err(dev, "error %d disabling \"ipa\" IRQ wakeup\n", ret);
293	free_irq(interrupt->irq, interrupt);
294	kfree(interrupt);
295}