1 /*
2 * Carsten Langgaard, carstenl@mips.com
3 * Copyright (C) 2000, 2001, 2004 MIPS Technologies, Inc.
4 * Copyright (C) 2001 Ralf Baechle
5 * Portions copyright (C) 2009 Cisco Systems, Inc.
6 *
7 * This program is free software; you can distribute it and/or modify it
8 * under the terms of the GNU General Public License (Version 2) as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
19 *
20 * Routines for generic manipulation of the interrupts found on the PowerTV
21 * platform.
22 *
23 * The interrupt controller is located in the South Bridge a PIIX4 device
24 * with two internal 82C95 interrupt controllers.
25 */
26 #include <linux/init.h>
27 #include <linux/irq.h>
28 #include <linux/sched.h>
29 #include <linux/interrupt.h>
30 #include <linux/kernel_stat.h>
31 #include <linux/kernel.h>
32 #include <linux/random.h>
33
34 #include <asm/irq_cpu.h>
35 #include <linux/io.h>
36 #include <asm/irq_regs.h>
37 #include <asm/mips-boards/generic.h>
38
39 #include <asm/mach-powertv/asic_regs.h>
40
41 static DEFINE_RAW_SPINLOCK(asic_irq_lock);
42
get_int(void)43 static inline int get_int(void)
44 {
45 unsigned long flags;
46 int irq;
47
48 raw_spin_lock_irqsave(&asic_irq_lock, flags);
49
50 irq = (asic_read(int_int_scan) >> 4) - 1;
51
52 if (irq == 0 || irq >= NR_IRQS)
53 irq = -1;
54
55 raw_spin_unlock_irqrestore(&asic_irq_lock, flags);
56
57 return irq;
58 }
59
asic_irqdispatch(void)60 static void asic_irqdispatch(void)
61 {
62 int irq;
63
64 irq = get_int();
65 if (irq < 0)
66 return; /* interrupt has already been cleared */
67
68 do_IRQ(irq);
69 }
70
clz(unsigned long x)71 static inline int clz(unsigned long x)
72 {
73 __asm__(
74 " .set push \n"
75 " .set mips32 \n"
76 " clz %0, %1 \n"
77 " .set pop \n"
78 : "=r" (x)
79 : "r" (x));
80
81 return x;
82 }
83
84 /*
85 * Version of ffs that only looks at bits 12..15.
86 */
irq_ffs(unsigned int pending)87 static inline unsigned int irq_ffs(unsigned int pending)
88 {
89 return fls(pending) - 1 + CAUSEB_IP;
90 }
91
92 /*
93 * TODO: check how it works under EIC mode.
94 */
plat_irq_dispatch(void)95 asmlinkage void plat_irq_dispatch(void)
96 {
97 unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
98 int irq;
99
100 irq = irq_ffs(pending);
101
102 if (irq == CAUSEF_IP3)
103 asic_irqdispatch();
104 else if (irq >= 0)
105 do_IRQ(irq);
106 else
107 spurious_interrupt();
108 }
109
arch_init_irq(void)110 void __init arch_init_irq(void)
111 {
112 int i;
113
114 asic_irq_init();
115
116 /*
117 * Initialize interrupt exception vectors.
118 */
119 if (cpu_has_veic || cpu_has_vint) {
120 int nvec = cpu_has_veic ? 64 : 8;
121 for (i = 0; i < nvec; i++)
122 set_vi_handler(i, asic_irqdispatch);
123 }
124 }
125