summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/sysdev/ge/ge_pic.c
blob: 2bcb78bb3a15b4ea8043b78b892224d01ef2050f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
/*
 * Interrupt handling for GE FPGA based PIC
 *
 * Author: Martyn Welch <martyn.welch@ge.com>
 *
 * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2.  This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/irq.h>

#include "ge_pic.h"

#define DEBUG
#undef DEBUG

#ifdef DEBUG
#define DBG(fmt...) do { printk(KERN_DEBUG "gef_pic: " fmt); } while (0)
#else
#define DBG(fmt...) do { } while (0)
#endif

#define GEF_PIC_NUM_IRQS	32

/* Interrupt Controller Interface Registers */
#define GEF_PIC_INTR_STATUS	0x0000

#define GEF_PIC_INTR_MASK(cpu)	(0x0010 + (0x4 * cpu))
#define GEF_PIC_CPU0_INTR_MASK	GEF_PIC_INTR_MASK(0)
#define GEF_PIC_CPU1_INTR_MASK	GEF_PIC_INTR_MASK(1)

#define GEF_PIC_MCP_MASK(cpu)	(0x0018 + (0x4 * cpu))
#define GEF_PIC_CPU0_MCP_MASK	GEF_PIC_MCP_MASK(0)
#define GEF_PIC_CPU1_MCP_MASK	GEF_PIC_MCP_MASK(1)


static DEFINE_RAW_SPINLOCK(gef_pic_lock);

static void __iomem *gef_pic_irq_reg_base;
static struct irq_domain *gef_pic_irq_host;
static int gef_pic_cascade_irq;

/*
 * Interrupt Controller Handling
 *
 * The interrupt controller handles interrupts for most on board interrupts,
 * apart from PCI interrupts. For example on SBC610:
 *
 * 17:31 RO Reserved
 * 16    RO PCI Express Doorbell 3 Status
 * 15    RO PCI Express Doorbell 2 Status
 * 14    RO PCI Express Doorbell 1 Status
 * 13    RO PCI Express Doorbell 0 Status
 * 12    RO Real Time Clock Interrupt Status
 * 11    RO Temperature Interrupt Status
 * 10    RO Temperature Critical Interrupt Status
 * 9     RO Ethernet PHY1 Interrupt Status
 * 8     RO Ethernet PHY3 Interrupt Status
 * 7     RO PEX8548 Interrupt Status
 * 6     RO Reserved
 * 5     RO Watchdog 0 Interrupt Status
 * 4     RO Watchdog 1 Interrupt Status
 * 3     RO AXIS Message FIFO A Interrupt Status
 * 2     RO AXIS Message FIFO B Interrupt Status
 * 1     RO AXIS Message FIFO C Interrupt Status
 * 0     RO AXIS Message FIFO D Interrupt Status
 *
 * Interrupts can be forwarded to one of two output lines. Nothing
 * clever is done, so if the masks are incorrectly set, a single input
 * interrupt could generate interrupts on both output lines!
 *
 * The dual lines are there to allow the chained interrupts to be easily
 * passed into two different cores. We currently do not use this functionality
 * in this driver.
 *
 * Controller can also be configured to generate Machine checks (MCP), again on
 * two lines, to be attached to two different cores. It is suggested that these
 * should be masked out.
 */

void gef_pic_cascade(unsigned int irq, struct irq_desc *desc)
{
	struct irq_chip *chip = irq_desc_get_chip(desc);
	unsigned int cascade_irq;

	/*
	 * See if we actually have an interrupt, call generic handling code if
	 * we do.
	 */
	cascade_irq = gef_pic_get_irq();

	if (cascade_irq != NO_IRQ)
		generic_handle_irq(cascade_irq);

	chip->irq_eoi(&desc->irq_data);
}

static void gef_pic_mask(struct irq_data *d)
{
	unsigned long flags;
	unsigned int hwirq = irqd_to_hwirq(d);
	u32 mask;

	raw_spin_lock_irqsave(&gef_pic_lock, flags);
	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
	mask &= ~(1 << hwirq);
	out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
	raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
}

static void gef_pic_mask_ack(struct irq_data *d)
{
	/* Don't think we actually have to do anything to ack an interrupt,
	 * we just need to clear down the devices interrupt and it will go away
	 */
	gef_pic_mask(d);
}

static void gef_pic_unmask(struct irq_data *d)
{
	unsigned long flags;
	unsigned int hwirq = irqd_to_hwirq(d);
	u32 mask;

	raw_spin_lock_irqsave(&gef_pic_lock, flags);
	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
	mask |= (1 << hwirq);
	out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
	raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
}

static struct irq_chip gef_pic_chip = {
	.name		= "gefp",
	.irq_mask	= gef_pic_mask,
	.irq_mask_ack	= gef_pic_mask_ack,
	.irq_unmask	= gef_pic_unmask,
};


/* When an interrupt is being configured, this call allows some flexibilty
 * in deciding which irq_chip structure is used
 */
static int gef_pic_host_map(struct irq_domain *h, unsigned int virq,
			  irq_hw_number_t hwirq)
{
	/* All interrupts are LEVEL sensitive */
	irq_set_status_flags(virq, IRQ_LEVEL);
	irq_set_chip_and_handler(virq, &gef_pic_chip, handle_level_irq);

	return 0;
}

static int gef_pic_host_xlate(struct irq_domain *h, struct device_node *ct,
			    const u32 *intspec, unsigned int intsize,
			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
{

	*out_hwirq = intspec[0];
	if (intsize > 1)
		*out_flags = intspec[1];
	else
		*out_flags = IRQ_TYPE_LEVEL_HIGH;

	return 0;
}

static const struct irq_domain_ops gef_pic_host_ops = {
	.map	= gef_pic_host_map,
	.xlate	= gef_pic_host_xlate,
};


/*
 * Initialisation of PIC, this should be called in BSP
 */
void __init gef_pic_init(struct device_node *np)
{
	unsigned long flags;

	/* Map the devices registers into memory */
	gef_pic_irq_reg_base = of_iomap(np, 0);

	raw_spin_lock_irqsave(&gef_pic_lock, flags);

	/* Initialise everything as masked. */
	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_INTR_MASK, 0);
	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_INTR_MASK, 0);

	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_MCP_MASK, 0);
	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_MCP_MASK, 0);

	raw_spin_unlock_irqrestore(&gef_pic_lock, flags);

	/* Map controller */
	gef_pic_cascade_irq = irq_of_parse_and_map(np, 0);
	if (gef_pic_cascade_irq == NO_IRQ) {
		printk(KERN_ERR "SBC610: failed to map cascade interrupt");
		return;
	}

	/* Setup an irq_domain structure */
	gef_pic_irq_host = irq_domain_add_linear(np, GEF_PIC_NUM_IRQS,
					  &gef_pic_host_ops, NULL);
	if (gef_pic_irq_host == NULL)
		return;

	/* Chain with parent controller */
	irq_set_chained_handler(gef_pic_cascade_irq, gef_pic_cascade);
}

/*
 * This is called when we receive an interrupt with apparently comes from this
 * chip - check, returning the highest interrupt generated or return NO_IRQ
 */
unsigned int gef_pic_get_irq(void)
{
	u32 cause, mask, active;
	unsigned int virq = NO_IRQ;
	int hwirq;

	cause = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_STATUS);

	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));

	active = cause & mask;

	if (active) {
		for (hwirq = GEF_PIC_NUM_IRQS - 1; hwirq > -1; hwirq--) {
			if (active & (0x1 << hwirq))
				break;
		}
		virq = irq_linear_revmap(gef_pic_irq_host,
			(irq_hw_number_t)hwirq);
	}

	return virq;
}