From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Mon, 11 Mar 2013 21:26:35 -0500 Subject: [PATCH 1/3] ARM: sched_clock: allow changing to higher frequency counter In-Reply-To: <1363055197-17296-1-git-send-email-robherring2@gmail.com> References: <1363055197-17296-1-git-send-email-robherring2@gmail.com> Message-ID: <1363055197-17296-2-git-send-email-robherring2@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Rob Herring Allow multiple calls to setup_sched_clock and switch to the new counter if it is higher frequency. Signed-off-by: Rob Herring --- arch/arm/kernel/sched_clock.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c index bd6f56b..040168e 100644 --- a/arch/arm/kernel/sched_clock.c +++ b/arch/arm/kernel/sched_clock.c @@ -20,6 +20,7 @@ struct clock_data { u64 epoch_ns; u32 epoch_cyc; u32 epoch_cyc_copy; + unsigned long rate; u32 mult; u32 shift; bool suspended; @@ -113,11 +114,14 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate) u64 res, wrap; char r_unit; + if (cd.rate > rate) + return; + BUG_ON(bits > 32); WARN_ON(!irqs_disabled()); - WARN_ON(read_sched_clock != jiffy_sched_clock_read); read_sched_clock = read; sched_clock_mask = (1 << bits) - 1; + cd.rate = rate; /* calculate the mult/shift to convert counter ticks to ns. */ clocks_calc_mult_shift(&cd.mult, &cd.shift, rate, NSEC_PER_SEC, 0); -- 1.7.10.4