blk: rq_data_dir() should not return a boolean
[cris-mirror.git] / arch / arm / kernel / thumbee.c
blob8ff8dbfbe9fbef5f7898c65419f3e1a60f2667cc
1 /*
2 * arch/arm/kernel/thumbee.c
4 * Copyright (C) 2008 ARM Limited
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/kernel.h>
21 #include <linux/init.h>
23 #include <asm/cputype.h>
24 #include <asm/system_info.h>
25 #include <asm/thread_notify.h>
28 * Access to the ThumbEE Handler Base register
30 static inline unsigned long teehbr_read(void)
32 unsigned long v;
33 asm("mrc p14, 6, %0, c1, c0, 0\n" : "=r" (v));
34 return v;
37 static inline void teehbr_write(unsigned long v)
39 asm("mcr p14, 6, %0, c1, c0, 0\n" : : "r" (v));
42 static int thumbee_notifier(struct notifier_block *self, unsigned long cmd, void *t)
44 struct thread_info *thread = t;
46 switch (cmd) {
47 case THREAD_NOTIFY_FLUSH:
48 teehbr_write(0);
49 break;
50 case THREAD_NOTIFY_SWITCH:
51 current_thread_info()->thumbee_state = teehbr_read();
52 teehbr_write(thread->thumbee_state);
53 break;
56 return NOTIFY_DONE;
59 static struct notifier_block thumbee_notifier_block = {
60 .notifier_call = thumbee_notifier,
63 static int __init thumbee_init(void)
65 unsigned long pfr0;
66 unsigned int cpu_arch = cpu_architecture();
68 if (cpu_arch < CPU_ARCH_ARMv7)
69 return 0;
71 pfr0 = read_cpuid_ext(CPUID_EXT_PFR0);
72 if ((pfr0 & 0x0000f000) != 0x00001000)
73 return 0;
75 pr_info("ThumbEE CPU extension supported.\n");
76 elf_hwcap |= HWCAP_THUMBEE;
77 thread_register_notifier(&thumbee_notifier_block);
79 return 0;
82 late_initcall(thumbee_init);