/arch/powerpc/platforms/512x/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 <asm/prom.h>
 18
 19static struct device_node *cpld_pic_node;
 20static struct irq_domain *cpld_pic_host;
 21
 22/*
 23 * Bits to ignore in the misc_status register
 24 * 0x10 touch screen pendown is hard routed to irq1
 25 * 0x02 pci status is read from pci status register
 26 */
 27#define MISC_IGNORE 0x12
 28
 29/*
 30 * Nothing to ignore in pci status register
 31 */
 32#define PCI_IGNORE 0x00
 33
 34struct cpld_pic {
 35	u8 pci_mask;
 36	u8 pci_status;
 37	u8 route;
 38	u8 misc_mask;
 39	u8 misc_status;
 40	u8 misc_control;
 41};
 42
 43static struct cpld_pic __iomem *cpld_regs;
 44
 45static void __iomem *
 46irq_to_pic_mask(unsigned int irq)
 47{
 48	return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
 49}
 50
 51static unsigned int
 52irq_to_pic_bit(unsigned int irq)
 53{
 54	return 1 << (irq & 0x7);
 55}
 56
 57static void
 58cpld_mask_irq(struct irq_data *d)
 59{
 60	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
 61	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
 62
 63	out_8(pic_mask,
 64	      in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
 65}
 66
 67static void
 68cpld_unmask_irq(struct irq_data *d)
 69{
 70	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
 71	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
 72
 73	out_8(pic_mask,
 74	      in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
 75}
 76
 77static struct irq_chip cpld_pic = {
 78	.name = "CPLD PIC",
 79	.irq_mask = cpld_mask_irq,
 80	.irq_ack = cpld_mask_irq,
 81	.irq_unmask = cpld_unmask_irq,
 82};
 83
 84static int
 85cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
 86			    u8 __iomem *maskp)
 87{
 88	int cpld_irq;
 89	u8 status = in_8(statusp);
 90	u8 mask = in_8(maskp);
 91
 92	/* ignore don't cares and masked irqs */
 93	status |= (ignore | mask);
 94
 95	if (status == 0xff)
 96		return 0;
 97
 98	cpld_irq = ffz(status) + offset;
 99
100	return irq_linear_revmap(cpld_pic_host, cpld_irq);
101}
102
103static void cpld_pic_cascade(struct irq_desc *desc)
104{
105	unsigned int irq;
106
107	irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
108		&cpld_regs->pci_mask);
109	if (irq) {
110		generic_handle_irq(irq);
111		return;
112	}
113
114	irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
115		&cpld_regs->misc_mask);
116	if (irq) {
117		generic_handle_irq(irq);
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_add_linear(np, 16, &cpld_pic_host_ops, NULL);
192	if (!cpld_pic_host) {
193		printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
194		goto end;
195	}
196
197	irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
198end:
199	of_node_put(np);
200}