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1 /*
2  * arch/sh/mach-cayman/irq.c - SH-5 Cayman Interrupt Support
3  *
4  * This file handles the board specific parts of the Cayman interrupt system
5  *
6  * Copyright (C) 2002 Stuart Menefy
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License.  See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12 #include <linux/io.h>
13 #include <linux/irq.h>
14 #include <linux/interrupt.h>
15 #include <linux/signal.h>
16 #include <cpu/irq.h>
17 #include <asm/page.h>
18 
19 /* Setup for the SMSC FDC37C935 / LAN91C100FD */
20 #define SMSC_IRQ         IRQ_IRL1
21 
22 /* Setup for PCI Bus 2, which transmits interrupts via the EPLD */
23 #define PCI2_IRQ         IRQ_IRL3
24 
25 unsigned long epld_virt;
26 
27 #define EPLD_BASE        0x04002000
28 #define EPLD_STATUS_BASE (epld_virt + 0x10)
29 #define EPLD_MASK_BASE   (epld_virt + 0x20)
30 
31 /* Note the SMSC SuperIO chip and SMSC LAN chip interrupts are all muxed onto
32    the same SH-5 interrupt */
33 
cayman_interrupt_smsc(int irq,void * dev_id)34 static irqreturn_t cayman_interrupt_smsc(int irq, void *dev_id)
35 {
36         printk(KERN_INFO "CAYMAN: spurious SMSC interrupt\n");
37 	return IRQ_NONE;
38 }
39 
cayman_interrupt_pci2(int irq,void * dev_id)40 static irqreturn_t cayman_interrupt_pci2(int irq, void *dev_id)
41 {
42         printk(KERN_INFO "CAYMAN: spurious PCI interrupt, IRQ %d\n", irq);
43 	return IRQ_NONE;
44 }
45 
46 static struct irqaction cayman_action_smsc = {
47 	.name		= "Cayman SMSC Mux",
48 	.handler	= cayman_interrupt_smsc,
49 };
50 
51 static struct irqaction cayman_action_pci2 = {
52 	.name		= "Cayman PCI2 Mux",
53 	.handler	= cayman_interrupt_pci2,
54 };
55 
enable_cayman_irq(struct irq_data * data)56 static void enable_cayman_irq(struct irq_data *data)
57 {
58 	unsigned int irq = data->irq;
59 	unsigned long flags;
60 	unsigned long mask;
61 	unsigned int reg;
62 	unsigned char bit;
63 
64 	irq -= START_EXT_IRQS;
65 	reg = EPLD_MASK_BASE + ((irq / 8) << 2);
66 	bit = 1<<(irq % 8);
67 	local_irq_save(flags);
68 	mask = __raw_readl(reg);
69 	mask |= bit;
70 	__raw_writel(mask, reg);
71 	local_irq_restore(flags);
72 }
73 
disable_cayman_irq(struct irq_data * data)74 static void disable_cayman_irq(struct irq_data *data)
75 {
76 	unsigned int irq = data->irq;
77 	unsigned long flags;
78 	unsigned long mask;
79 	unsigned int reg;
80 	unsigned char bit;
81 
82 	irq -= START_EXT_IRQS;
83 	reg = EPLD_MASK_BASE + ((irq / 8) << 2);
84 	bit = 1<<(irq % 8);
85 	local_irq_save(flags);
86 	mask = __raw_readl(reg);
87 	mask &= ~bit;
88 	__raw_writel(mask, reg);
89 	local_irq_restore(flags);
90 }
91 
92 struct irq_chip cayman_irq_type = {
93 	.name		= "Cayman-IRQ",
94 	.irq_unmask	= enable_cayman_irq,
95 	.irq_mask	= disable_cayman_irq,
96 };
97 
cayman_irq_demux(int evt)98 int cayman_irq_demux(int evt)
99 {
100 	int irq = intc_evt_to_irq[evt];
101 
102 	if (irq == SMSC_IRQ) {
103 		unsigned long status;
104 		int i;
105 
106 		status = __raw_readl(EPLD_STATUS_BASE) &
107 			 __raw_readl(EPLD_MASK_BASE) & 0xff;
108 		if (status == 0) {
109 			irq = -1;
110 		} else {
111 			for (i=0; i<8; i++) {
112 				if (status & (1<<i))
113 					break;
114 			}
115 			irq = START_EXT_IRQS + i;
116 		}
117 	}
118 
119 	if (irq == PCI2_IRQ) {
120 		unsigned long status;
121 		int i;
122 
123 		status = __raw_readl(EPLD_STATUS_BASE + 3 * sizeof(u32)) &
124 			 __raw_readl(EPLD_MASK_BASE + 3 * sizeof(u32)) & 0xff;
125 		if (status == 0) {
126 			irq = -1;
127 		} else {
128 			for (i=0; i<8; i++) {
129 				if (status & (1<<i))
130 					break;
131 			}
132 			irq = START_EXT_IRQS + (3 * 8) + i;
133 		}
134 	}
135 
136 	return irq;
137 }
138 
init_cayman_irq(void)139 void init_cayman_irq(void)
140 {
141 	int i;
142 
143 	epld_virt = (unsigned long)ioremap_nocache(EPLD_BASE, 1024);
144 	if (!epld_virt) {
145 		printk(KERN_ERR "Cayman IRQ: Unable to remap EPLD\n");
146 		return;
147 	}
148 
149 	for (i = 0; i < NR_EXT_IRQS; i++) {
150 		irq_set_chip_and_handler(START_EXT_IRQS + i,
151 					 &cayman_irq_type, handle_level_irq);
152 	}
153 
154 	/* Setup the SMSC interrupt */
155 	setup_irq(SMSC_IRQ, &cayman_action_smsc);
156 	setup_irq(PCI2_IRQ, &cayman_action_pci2);
157 }
158