From ca148125e6134de334b61822539d220794d8da18 Mon Sep 17 00:00:00 2001 From: David Daney Date: Tue, 1 Jun 2010 13:18:15 -0700 Subject: MIPS: Octeon: Implement delays with cycle counter. Power throttling make deterministic delay loops impossible. Re-implement delays using the cycle counter. This also allows us to get rid of the code that calculates loops per jiffy. Signed-off-by: David Daney To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1317/ Signed-off-by: Ralf Baechle --- arch/mips/cavium-octeon/csrc-octeon.c | 55 +++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'arch/mips/cavium-octeon/csrc-octeon.c') diff --git a/arch/mips/cavium-octeon/csrc-octeon.c b/arch/mips/cavium-octeon/csrc-octeon.c index 36400d23ff59..b6847c8e0ddd 100644 --- a/arch/mips/cavium-octeon/csrc-octeon.c +++ b/arch/mips/cavium-octeon/csrc-octeon.c @@ -80,3 +80,58 @@ void __init plat_time_init(void) clocksource_set_clock(&clocksource_mips, mips_hpt_frequency); clocksource_register(&clocksource_mips); } + +static u64 octeon_udelay_factor; +static u64 octeon_ndelay_factor; + +void __init octeon_setup_delays(void) +{ + octeon_udelay_factor = octeon_get_clock_rate() / 1000000; + /* + * For __ndelay we divide by 2^16, so the factor is multiplied + * by the same amount. + */ + octeon_ndelay_factor = (octeon_udelay_factor * 0x10000ull) / 1000ull; + + preset_lpj = octeon_get_clock_rate() / HZ; +} + +void __udelay(unsigned long us) +{ + u64 cur, end, inc; + + cur = read_c0_cvmcount(); + + inc = us * octeon_udelay_factor; + end = cur + inc; + + while (end > cur) + cur = read_c0_cvmcount(); +} +EXPORT_SYMBOL(__udelay); + +void __ndelay(unsigned long ns) +{ + u64 cur, end, inc; + + cur = read_c0_cvmcount(); + + inc = ((ns * octeon_ndelay_factor) >> 16); + end = cur + inc; + + while (end > cur) + cur = read_c0_cvmcount(); +} +EXPORT_SYMBOL(__ndelay); + +void __delay(unsigned long loops) +{ + u64 cur, end; + + cur = read_c0_cvmcount(); + end = cur + loops; + + while (end > cur) + cur = read_c0_cvmcount(); +} +EXPORT_SYMBOL(__delay); -- cgit v1.2.1