1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PQ2 ADS-style PCI interrupt controller
4 *
5 * Copyright 2007 Freescale Semiconductor, Inc.
6 * Author: Scott Wood <scottwood@freescale.com>
7 *
8 * Loosely based on mpc82xx ADS support by Vitaly Bordug <vbordug@ru.mvista.com>
9 * Copyright (c) 2006 MontaVista Software, Inc.
10 */
11
12#include <linux/init.h>
13#include <linux/spinlock.h>
14#include <linux/irq.h>
15#include <linux/types.h>
16#include <linux/slab.h>
17
18#include <asm/io.h>
19#include <asm/prom.h>
20#include <asm/cpm2.h>
21
22#include "pq2.h"
23
24static DEFINE_RAW_SPINLOCK(pci_pic_lock);
25
26struct pq2ads_pci_pic {
27	struct device_node *node;
28	struct irq_domain *host;
29
30	struct {
31		u32 stat;
32		u32 mask;
33	} __iomem *regs;
34};
35
36#define NUM_IRQS 32
37
38static void pq2ads_pci_mask_irq(struct irq_data *d)
39{
40	struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
41	int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
42
43	if (irq != -1) {
44		unsigned long flags;
45		raw_spin_lock_irqsave(&pci_pic_lock, flags);
46
47		setbits32(&priv->regs->mask, 1 << irq);
48		mb();
49
50		raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
51	}
52}
53
54static void pq2ads_pci_unmask_irq(struct irq_data *d)
55{
56	struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
57	int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
58
59	if (irq != -1) {
60		unsigned long flags;
61
62		raw_spin_lock_irqsave(&pci_pic_lock, flags);
63		clrbits32(&priv->regs->mask, 1 << irq);
64		raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
65	}
66}
67
68static struct irq_chip pq2ads_pci_ic = {
69	.name = "PQ2 ADS PCI",
70	.irq_mask = pq2ads_pci_mask_irq,
71	.irq_mask_ack = pq2ads_pci_mask_irq,
72	.irq_ack = pq2ads_pci_mask_irq,
73	.irq_unmask = pq2ads_pci_unmask_irq,
74	.irq_enable = pq2ads_pci_unmask_irq,
75	.irq_disable = pq2ads_pci_mask_irq
76};
77
78static void pq2ads_pci_irq_demux(struct irq_desc *desc)
79{
80	struct pq2ads_pci_pic *priv = irq_desc_get_handler_data(desc);
81	u32 stat, mask, pend;
82	int bit;
83
84	for (;;) {
85		stat = in_be32(&priv->regs->stat);
86		mask = in_be32(&priv->regs->mask);
87
88		pend = stat & ~mask;
89
90		if (!pend)
91			break;
92
93		for (bit = 0; pend != 0; ++bit, pend <<= 1) {
94			if (pend & 0x80000000) {
95				int virq = irq_linear_revmap(priv->host, bit);
96				generic_handle_irq(virq);
97			}
98		}
99	}
100}
101
102static int pci_pic_host_map(struct irq_domain *h, unsigned int virq,
103			    irq_hw_number_t hw)
104{
105	irq_set_status_flags(virq, IRQ_LEVEL);
106	irq_set_chip_data(virq, h->host_data);
107	irq_set_chip_and_handler(virq, &pq2ads_pci_ic, handle_level_irq);
108	return 0;
109}
110
111static const struct irq_domain_ops pci_pic_host_ops = {
112	.map = pci_pic_host_map,
113};
114
115int __init pq2ads_pci_init_irq(void)
116{
117	struct pq2ads_pci_pic *priv;
118	struct irq_domain *host;
119	struct device_node *np;
120	int ret = -ENODEV;
121	int irq;
122
123	np = of_find_compatible_node(NULL, NULL, "fsl,pq2ads-pci-pic");
124	if (!np) {
125		printk(KERN_ERR "No pci pic node in device tree.\n");
126		of_node_put(np);
127		goto out;
128	}
129
130	irq = irq_of_parse_and_map(np, 0);
131	if (!irq) {
132		printk(KERN_ERR "No interrupt in pci pic node.\n");
133		of_node_put(np);
134		goto out;
135	}
136
137	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
138	if (!priv) {
139		of_node_put(np);
140		ret = -ENOMEM;
141		goto out_unmap_irq;
142	}
143
144	/* PCI interrupt controller registers: status and mask */
145	priv->regs = of_iomap(np, 0);
146	if (!priv->regs) {
147		printk(KERN_ERR "Cannot map PCI PIC registers.\n");
148		goto out_free_kmalloc;
149	}
150
151	/* mask all PCI interrupts */
152	out_be32(&priv->regs->mask, ~0);
153	mb();
154
155	host = irq_domain_add_linear(np, NUM_IRQS, &pci_pic_host_ops, priv);
156	if (!host) {
157		ret = -ENOMEM;
158		goto out_unmap_regs;
159	}
160
161	priv->host = host;
162	irq_set_handler_data(irq, priv);
163	irq_set_chained_handler(irq, pq2ads_pci_irq_demux);
164
165	of_node_put(np);
166	return 0;
167
168out_unmap_regs:
169	iounmap(priv->regs);
170out_free_kmalloc:
171	kfree(priv);
172	of_node_put(np);
173out_unmap_irq:
174	irq_dispose_mapping(irq);
175out:
176	return ret;
177}
178