From ca148125e6134de334b61822539d220794d8da18 Mon Sep 17 00:00:00 2001 From: David Daney Date: Tue, 1 Jun 2010 13:18:15 -0700 Subject: [PATCH] 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 +++++++++++++++++++ arch/mips/cavium-octeon/setup.c | 4 +- .../cpu-feature-overrides.h | 11 ---- arch/mips/include/asm/octeon/octeon.h | 1 + 4 files changed, 58 insertions(+), 13 deletions(-) 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); diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c index 8c81a5c5bbab..7216fbd5d79d 100644 --- a/arch/mips/cavium-octeon/setup.c +++ b/arch/mips/cavium-octeon/setup.c @@ -594,13 +594,13 @@ void __init prom_init(void) * the filesystem. Also specify the calibration delay * to avoid calculating it every time. */ - strcat(arcs_cmdline, " rw root=1f00" - " lpj=60176 slram=root,0x40000000,+1073741824"); + strcat(arcs_cmdline, " rw root=1f00 slram=root,0x40000000,+1073741824"); } mips_hpt_frequency = octeon_get_clock_rate(); octeon_init_cvmcount(); + octeon_setup_delays(); _machine_restart = octeon_restart; _machine_halt = octeon_halt; diff --git a/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h b/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h index 2a7ea90fee2a..b952fc7215e2 100644 --- a/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h +++ b/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h @@ -61,22 +61,11 @@ #define kernel_uses_smartmips_rixi (cpu_data[0].cputype == CPU_CAVIUM_OCTEON_PLUS) -#define ARCH_HAS_READ_CURRENT_TIMER 1 #define ARCH_HAS_IRQ_PER_CPU 1 #define ARCH_HAS_SPINLOCK_PREFETCH 1 #define spin_lock_prefetch(x) prefetch(x) #define PREFETCH_STRIDE 128 -static inline int read_current_timer(unsigned long *result) -{ - asm volatile ("rdhwr %0,$31\n" -#ifndef CONFIG_64BIT - "\tsll %0, 0" -#endif - : "=r" (*result)); - return 0; -} - #ifdef __OCTEON__ /* * All gcc versions that have OCTEON support define __OCTEON__ and have the diff --git a/arch/mips/include/asm/octeon/octeon.h b/arch/mips/include/asm/octeon/octeon.h index c29debe7a8ad..917a6c413b1a 100644 --- a/arch/mips/include/asm/octeon/octeon.h +++ b/arch/mips/include/asm/octeon/octeon.h @@ -50,6 +50,7 @@ extern void octeon_crypto_disable(struct octeon_cop2_state *state, extern asmlinkage void octeon_cop2_restore(struct octeon_cop2_state *task); extern void octeon_init_cvmcount(void); +extern void octeon_setup_delays(void); #define OCTEON_ARGV_MAX_ARGS 64 #define OCTOEN_SERIAL_LEN 20