1/*
2 * Copyright (C) 2014-2015 Toradex AG
3 * Author: Stefan Agner <stefan@agner.ch>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 *
10 * IRQ chip driver for MSCM interrupt router available on Vybrid SoC's.
11 * The interrupt router is between the CPU's interrupt controller and the
12 * peripheral. The router allows to route the peripheral interrupts to
13 * one of the two available CPU's on Vybrid VF6xx SoC's (Cortex-A5 or
14 * Cortex-M4). The router will be configured transparently on a IRQ
15 * request.
16 *
17 * o All peripheral interrupts of the Vybrid SoC can be routed to
18 *   CPU 0, CPU 1 or both. The routing is useful for dual-core
19 *   variants of Vybrid SoC such as VF6xx. This driver routes the
20 *   requested interrupt to the CPU currently running on.
21 *
22 * o It is required to setup the interrupt router even on single-core
23 *   variants of Vybrid.
24 */
25
26#include <linux/cpu_pm.h>
27#include <linux/io.h>
28#include <linux/irq.h>
29#include <linux/irqdomain.h>
30#include <linux/mfd/syscon.h>
31#include <dt-bindings/interrupt-controller/arm-gic.h>
32#include <linux/of.h>
33#include <linux/of_address.h>
34#include <linux/slab.h>
35#include <linux/regmap.h>
36
37#include "irqchip.h"
38
39#define MSCM_CPxNUM		0x4
40
41#define MSCM_IRSPRC(n)		(0x80 + 2 * (n))
42#define MSCM_IRSPRC_CPEN_MASK	0x3
43
44#define MSCM_IRSPRC_NUM		112
45
46struct vf610_mscm_ir_chip_data {
47	void __iomem *mscm_ir_base;
48	u16 cpu_mask;
49	u16 saved_irsprc[MSCM_IRSPRC_NUM];
50};
51
52static struct vf610_mscm_ir_chip_data *mscm_ir_data;
53
54static inline void vf610_mscm_ir_save(struct vf610_mscm_ir_chip_data *data)
55{
56	int i;
57
58	for (i = 0; i < MSCM_IRSPRC_NUM; i++)
59		data->saved_irsprc[i] = readw_relaxed(data->mscm_ir_base + MSCM_IRSPRC(i));
60}
61
62static inline void vf610_mscm_ir_restore(struct vf610_mscm_ir_chip_data *data)
63{
64	int i;
65
66	for (i = 0; i < MSCM_IRSPRC_NUM; i++)
67		writew_relaxed(data->saved_irsprc[i], data->mscm_ir_base + MSCM_IRSPRC(i));
68}
69
70static int vf610_mscm_ir_notifier(struct notifier_block *self,
71				  unsigned long cmd, void *v)
72{
73	switch (cmd) {
74	case CPU_CLUSTER_PM_ENTER:
75		vf610_mscm_ir_save(mscm_ir_data);
76		break;
77	case CPU_CLUSTER_PM_ENTER_FAILED:
78	case CPU_CLUSTER_PM_EXIT:
79		vf610_mscm_ir_restore(mscm_ir_data);
80		break;
81	}
82
83	return NOTIFY_OK;
84}
85
86static struct notifier_block mscm_ir_notifier_block = {
87	.notifier_call = vf610_mscm_ir_notifier,
88};
89
90static void vf610_mscm_ir_enable(struct irq_data *data)
91{
92	irq_hw_number_t hwirq = data->hwirq;
93	struct vf610_mscm_ir_chip_data *chip_data = data->chip_data;
94	u16 irsprc;
95
96	irsprc = readw_relaxed(chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
97	irsprc &= MSCM_IRSPRC_CPEN_MASK;
98
99	WARN_ON(irsprc & ~chip_data->cpu_mask);
100
101	writew_relaxed(chip_data->cpu_mask,
102		       chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
103
104	irq_chip_unmask_parent(data);
105}
106
107static void vf610_mscm_ir_disable(struct irq_data *data)
108{
109	irq_hw_number_t hwirq = data->hwirq;
110	struct vf610_mscm_ir_chip_data *chip_data = data->chip_data;
111
112	writew_relaxed(0x0, chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
113
114	irq_chip_mask_parent(data);
115}
116
117static struct irq_chip vf610_mscm_ir_irq_chip = {
118	.name			= "mscm-ir",
119	.irq_mask		= irq_chip_mask_parent,
120	.irq_unmask		= irq_chip_unmask_parent,
121	.irq_eoi		= irq_chip_eoi_parent,
122	.irq_enable		= vf610_mscm_ir_enable,
123	.irq_disable		= vf610_mscm_ir_disable,
124	.irq_retrigger		= irq_chip_retrigger_hierarchy,
125	.irq_set_affinity	= irq_chip_set_affinity_parent,
126};
127
128static int vf610_mscm_ir_domain_alloc(struct irq_domain *domain, unsigned int virq,
129				      unsigned int nr_irqs, void *arg)
130{
131	int i;
132	irq_hw_number_t hwirq;
133	struct of_phandle_args *irq_data = arg;
134	struct of_phandle_args gic_data;
135
136	if (irq_data->args_count != 2)
137		return -EINVAL;
138
139	hwirq = irq_data->args[0];
140	for (i = 0; i < nr_irqs; i++)
141		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
142					      &vf610_mscm_ir_irq_chip,
143					      domain->host_data);
144
145	gic_data.np = domain->parent->of_node;
146	gic_data.args_count = 3;
147	gic_data.args[0] = GIC_SPI;
148	gic_data.args[1] = irq_data->args[0];
149	gic_data.args[2] = irq_data->args[1];
150	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_data);
151}
152
153static const struct irq_domain_ops mscm_irq_domain_ops = {
154	.xlate = irq_domain_xlate_twocell,
155	.alloc = vf610_mscm_ir_domain_alloc,
156	.free = irq_domain_free_irqs_common,
157};
158
159static int __init vf610_mscm_ir_of_init(struct device_node *node,
160			       struct device_node *parent)
161{
162	struct irq_domain *domain, *domain_parent;
163	struct regmap *mscm_cp_regmap;
164	int ret, cpuid;
165
166	domain_parent = irq_find_host(parent);
167	if (!domain_parent) {
168		pr_err("vf610_mscm_ir: interrupt-parent not found\n");
169		return -EINVAL;
170	}
171
172	mscm_ir_data = kzalloc(sizeof(*mscm_ir_data), GFP_KERNEL);
173	if (!mscm_ir_data)
174		return -ENOMEM;
175
176	mscm_ir_data->mscm_ir_base = of_io_request_and_map(node, 0, "mscm-ir");
177
178	if (!mscm_ir_data->mscm_ir_base) {
179		pr_err("vf610_mscm_ir: unable to map mscm register\n");
180		ret = -ENOMEM;
181		goto out_free;
182	}
183
184	mscm_cp_regmap = syscon_regmap_lookup_by_phandle(node, "fsl,cpucfg");
185	if (IS_ERR(mscm_cp_regmap)) {
186		ret = PTR_ERR(mscm_cp_regmap);
187		pr_err("vf610_mscm_ir: regmap lookup for cpucfg failed\n");
188		goto out_unmap;
189	}
190
191	regmap_read(mscm_cp_regmap, MSCM_CPxNUM, &cpuid);
192	mscm_ir_data->cpu_mask = 0x1 << cpuid;
193
194	domain = irq_domain_add_hierarchy(domain_parent, 0,
195					  MSCM_IRSPRC_NUM, node,
196					  &mscm_irq_domain_ops, mscm_ir_data);
197	if (!domain) {
198		ret = -ENOMEM;
199		goto out_unmap;
200	}
201
202	cpu_pm_register_notifier(&mscm_ir_notifier_block);
203
204	return 0;
205
206out_unmap:
207	iounmap(mscm_ir_data->mscm_ir_base);
208out_free:
209	kfree(mscm_ir_data);
210	return ret;
211}
212IRQCHIP_DECLARE(vf610_mscm_ir, "fsl,vf610-mscm-ir", vf610_mscm_ir_of_init);
213