mpc5121_ads_cpld.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
  4 *
  5 * Author: John Rigby, <jrigby@freescale.com>
  6 *
  7 * Description:
  8 * MPC5121ADS CPLD irq handling
  9 */
 10
 11#undef DEBUG
 12
 13#include <linux/kernel.h>
 14#include <linux/interrupt.h>
 15#include <linux/irq.h>
 16#include <linux/io.h>
 17#include <linux/of_address.h>
 18#include <linux/of_irq.h>
 19
 20#include "mpc5121_ads.h"
 21
 22static struct device_node *cpld_pic_node;
 23static struct irq_domain *cpld_pic_host;
 24
 25/*
 26 * Bits to ignore in the misc_status register
 27 * 0x10 touch screen pendown is hard routed to irq1
 28 * 0x02 pci status is read from pci status register
 29 */
 30#define MISC_IGNORE 0x12
 31
 32/*
 33 * Nothing to ignore in pci status register
 34 */
 35#define PCI_IGNORE 0x00
 36
 37struct cpld_pic {
 38	u8 pci_mask;
 39	u8 pci_status;
 40	u8 route;
 41	u8 misc_mask;
 42	u8 misc_status;
 43	u8 misc_control;
 44};
 45
 46static struct cpld_pic __iomem *cpld_regs;
 47
 48static void __iomem *
 49irq_to_pic_mask(unsigned int irq)
 50{
 51	return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
 52}
 53
 54static unsigned int
 55irq_to_pic_bit(unsigned int irq)
 56{
 57	return 1 << (irq & 0x7);
 58}
 59
 60static void
 61cpld_mask_irq(struct irq_data *d)
 62{
 63	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
 64	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
 65
 66	out_8(pic_mask,
 67	      in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
 68}
 69
 70static void
 71cpld_unmask_irq(struct irq_data *d)
 72{
 73	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
 74	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
 75
 76	out_8(pic_mask,
 77	      in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
 78}
 79
 80static struct irq_chip cpld_pic = {
 81	.name = "CPLD PIC",
 82	.irq_mask = cpld_mask_irq,
 83	.irq_ack = cpld_mask_irq,
 84	.irq_unmask = cpld_unmask_irq,
 85};
 86
 87static unsigned int
 88cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
 89			    u8 __iomem *maskp)
 90{
 91	u8 status = in_8(statusp);
 92	u8 mask = in_8(maskp);
 93
 94	/* ignore don't cares and masked irqs */
 95	status |= (ignore | mask);
 96
 97	if (status == 0xff)
 98		return ~0;
 99
100	return ffz(status) + offset;
101}
102
103static void cpld_pic_cascade(struct irq_desc *desc)
104{
105	unsigned int hwirq;
106
107	hwirq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
108		&cpld_regs->pci_mask);
109	if (hwirq != ~0) {
110		generic_handle_domain_irq(cpld_pic_host, hwirq);
111		return;
112	}
113
114	hwirq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
115		&cpld_regs->misc_mask);
116	if (hwirq != ~0) {
117		generic_handle_domain_irq(cpld_pic_host, hwirq);
118		return;
119	}
120}
121
122static int
123cpld_pic_host_match(struct irq_domain *h, struct device_node *node,
124		    enum irq_domain_bus_token bus_token)
125{
126	return cpld_pic_node == node;
127}
128
129static int
130cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
131			     irq_hw_number_t hw)
132{
133	irq_set_status_flags(virq, IRQ_LEVEL);
134	irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
135	return 0;
136}
137
138static const struct irq_domain_ops cpld_pic_host_ops = {
139	.match = cpld_pic_host_match,
140	.map = cpld_pic_host_map,
141};
142
143void __init
144mpc5121_ads_cpld_map(void)
145{
146	struct device_node *np = NULL;
147
148	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
149	if (!np) {
150		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
151		return;
152	}
153
154	cpld_regs = of_iomap(np, 0);
155	of_node_put(np);
156}
157
158void __init
159mpc5121_ads_cpld_pic_init(void)
160{
161	unsigned int cascade_irq;
162	struct device_node *np = NULL;
163
164	pr_debug("cpld_ic_init\n");
165
166	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
167	if (!np) {
168		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
169		return;
170	}
171
172	if (!cpld_regs)
173		goto end;
174
175	cascade_irq = irq_of_parse_and_map(np, 0);
176	if (!cascade_irq)
177		goto end;
178
179	/*
180	 * statically route touch screen pendown through 1
181	 * and ignore it here
182	 * route all others through our cascade irq
183	 */
184	out_8(&cpld_regs->route, 0xfd);
185	out_8(&cpld_regs->pci_mask, 0xff);
186	/* unmask pci ints in misc mask */
187	out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
188
189	cpld_pic_node = of_node_get(np);
190
191	cpld_pic_host = irq_domain_create_linear(of_fwnode_handle(np), 16,
192						 &cpld_pic_host_ops, NULL);
193	if (!cpld_pic_host) {
194		printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
195		goto end;
196	}
197
198	irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
199end:
200	of_node_put(np);
201}