Linux 2.6.31.6
[linux/fpc-iii.git] / arch / mips / cavium-octeon / csrc-octeon.c
blob96110f217dcd6ac79d1aa7c8e644d2036a7d9113
1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
6 * Copyright (C) 2007 by Ralf Baechle
7 */
8 #include <linux/clocksource.h>
9 #include <linux/init.h>
11 #include <asm/time.h>
13 #include <asm/octeon/octeon.h>
14 #include <asm/octeon/cvmx-ipd-defs.h>
17 * Set the current core's cvmcount counter to the value of the
18 * IPD_CLK_COUNT. We do this on all cores as they are brought
19 * on-line. This allows for a read from a local cpu register to
20 * access a synchronized counter.
23 void octeon_init_cvmcount(void)
25 unsigned long flags;
26 unsigned loops = 2;
28 /* Clobber loops so GCC will not unroll the following while loop. */
29 asm("" : "+r" (loops));
31 local_irq_save(flags);
33 * Loop several times so we are executing from the cache,
34 * which should give more deterministic timing.
36 while (loops--)
37 write_c0_cvmcount(cvmx_read_csr(CVMX_IPD_CLK_COUNT));
38 local_irq_restore(flags);
41 static cycle_t octeon_cvmcount_read(struct clocksource *cs)
43 return read_c0_cvmcount();
46 static struct clocksource clocksource_mips = {
47 .name = "OCTEON_CVMCOUNT",
48 .read = octeon_cvmcount_read,
49 .mask = CLOCKSOURCE_MASK(64),
50 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
53 void __init plat_time_init(void)
55 clocksource_mips.rating = 300;
56 clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
57 clocksource_register(&clocksource_mips);