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MIPS: Octeon: Scale Octeon2 clocks in octeon_init_cvmcount()

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The per-CPU clocks are synchronized from IPD_CLK_COUNT, on cn63XX it must
be scaled by the clock frequency ratio.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Patchwork: http://patchwork.linux-mips.org/patch/1667/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2010-10-07 16:03:47 -07:00 committed by Ralf Baechle
parent f92a6b0875
commit 54954a6d6b
1 changed files with 31 additions and 3 deletions
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34
arch/mips/cavium-octeon/csrc-octeon.c
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@ -4,14 +4,18 @@
* for more details.
*
* Copyright (C) 2007 by Ralf Baechle
* Copyright (C) 2009, 2010 Cavium Networks, Inc.
*/
#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <asm/cpu-info.h>
#include <asm/time.h>
#include <asm/octeon/octeon.h>
#include <asm/octeon/cvmx-ipd-defs.h>
#include <asm/octeon/cvmx-mio-defs.h>
/*
* Set the current core's cvmcount counter to the value of the
@ -19,11 +23,23 @@
* on-line. This allows for a read from a local cpu register to
* access a synchronized counter.
*
* On CPU_CAVIUM_OCTEON2 the IPD_CLK_COUNT is scaled by rdiv/sdiv.
*/
void octeon_init_cvmcount(void)
{
unsigned long flags;
unsigned loops = 2;
u64 f = 0;
u64 rdiv = 0;
u64 sdiv = 0;
if (current_cpu_type() == CPU_CAVIUM_OCTEON2) {
union cvmx_mio_rst_boot rst_boot;
rst_boot.u64 = cvmx_read_csr(CVMX_MIO_RST_BOOT);
rdiv = rst_boot.s.c_mul; /* CPU clock */
sdiv = rst_boot.s.pnr_mul; /* I/O clock */
f = (0x8000000000000000ull / sdiv) * 2;
}
/* Clobber loops so GCC will not unroll the following while loop. */
asm("" : "+r" (loops));
@ -33,8 +49,20 @@ void octeon_init_cvmcount(void)
* Loop several times so we are executing from the cache,
* which should give more deterministic timing.
*/
while (loops--)
write_c0_cvmcount(cvmx_read_csr(CVMX_IPD_CLK_COUNT));
while (loops--) {
u64 ipd_clk_count = cvmx_read_csr(CVMX_IPD_CLK_COUNT);
if (rdiv != 0) {
ipd_clk_count *= rdiv;
if (f != 0) {
asm("dmultu\t%[cnt],%[f]\n\t"
"mfhi\t%[cnt]"
: [cnt] "+r" (ipd_clk_count),
[f] "=r" (f)
: : "hi", "lo");
}
}
write_c0_cvmcount(ipd_clk_count);
}
local_irq_restore(flags);
}
@ -77,7 +105,7 @@ unsigned long long notrace sched_clock(void)
void __init plat_time_init(void)
{
clocksource_mips.rating = 300;
clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
clocksource_set_clock(&clocksource_mips, octeon_get_clock_rate());
clocksource_register(&clocksource_mips);
}