Commit | Line | Data |
---|---|---|
ef6c8445 HZ |
1 | /* |
2 | * linux/arch/arm/kernel/pj4-cp0.c | |
3 | * | |
4 | * PJ4 iWMMXt coprocessor context switching and handling | |
5 | * | |
6 | * Copyright (c) 2010 Marvell International Inc. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
ef6c8445 HZ |
13 | #include <linux/types.h> |
14 | #include <linux/kernel.h> | |
15 | #include <linux/signal.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/io.h> | |
19 | #include <asm/thread_notify.h> | |
20 | ||
21 | static int iwmmxt_do(struct notifier_block *self, unsigned long cmd, void *t) | |
22 | { | |
23 | struct thread_info *thread = t; | |
24 | ||
25 | switch (cmd) { | |
26 | case THREAD_NOTIFY_FLUSH: | |
27 | /* | |
28 | * flush_thread() zeroes thread->fpstate, so no need | |
29 | * to do anything here. | |
30 | * | |
31 | * FALLTHROUGH: Ensure we don't try to overwrite our newly | |
32 | * initialised state information on the first fault. | |
33 | */ | |
34 | ||
35 | case THREAD_NOTIFY_EXIT: | |
36 | iwmmxt_task_release(thread); | |
37 | break; | |
38 | ||
39 | case THREAD_NOTIFY_SWITCH: | |
40 | iwmmxt_task_switch(thread); | |
41 | break; | |
42 | } | |
43 | ||
44 | return NOTIFY_DONE; | |
45 | } | |
46 | ||
47 | static struct notifier_block iwmmxt_notifier_block = { | |
48 | .notifier_call = iwmmxt_do, | |
49 | }; | |
50 | ||
51 | ||
52 | static u32 __init pj4_cp_access_read(void) | |
53 | { | |
54 | u32 value; | |
55 | ||
56 | __asm__ __volatile__ ( | |
57 | "mrc p15, 0, %0, c1, c0, 2\n\t" | |
58 | : "=r" (value)); | |
59 | return value; | |
60 | } | |
61 | ||
62 | static void __init pj4_cp_access_write(u32 value) | |
63 | { | |
64 | u32 temp; | |
65 | ||
66 | __asm__ __volatile__ ( | |
67 | "mcr p15, 0, %1, c1, c0, 2\n\t" | |
68 | "mrc p15, 0, %0, c1, c0, 2\n\t" | |
69 | "mov %0, %0\n\t" | |
70 | "sub pc, pc, #4\n\t" | |
71 | : "=r" (temp) : "r" (value)); | |
72 | } | |
73 | ||
74 | ||
75 | /* | |
76 | * Disable CP0/CP1 on boot, and let call_fpe() and the iWMMXt lazy | |
77 | * switch code handle iWMMXt context switching. | |
78 | */ | |
79 | static int __init pj4_cp0_init(void) | |
80 | { | |
81 | u32 cp_access; | |
82 | ||
83 | cp_access = pj4_cp_access_read() & ~0xf; | |
84 | pj4_cp_access_write(cp_access); | |
85 | ||
86 | printk(KERN_INFO "PJ4 iWMMXt coprocessor enabled.\n"); | |
87 | elf_hwcap |= HWCAP_IWMMXT; | |
88 | thread_register_notifier(&iwmmxt_notifier_block); | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
93 | late_initcall(pj4_cp0_init); |