| Message ID | 20161208175030.12269-4-drjones@redhat.com |
|---|---|
| State | New |
| Headers | show |
Hi, On 08/12/16 17:50, Andrew Jones wrote: > Allow a thread to wait some specified amount of time. Can > specify in cycles, usecs, and msecs. > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > --- > v8: rewrote basing on new sysreg framework. Also decided delay > functions warrant their own files (delay.[ch]) > --- > arm/Makefile.common | 1 + > lib/arm/asm/delay.h | 14 ++++++++++++++ > lib/arm/asm/processor.h | 15 +++++++++++++++ > lib/arm64/asm/delay.h | 1 + > lib/arm64/asm/processor.h | 12 ++++++++++++ > lib/arm/delay.c | 29 +++++++++++++++++++++++++++++ > 6 files changed, 72 insertions(+) > create mode 100644 lib/arm/asm/delay.h > create mode 100644 lib/arm64/asm/delay.h > create mode 100644 lib/arm/delay.c > > diff --git a/arm/Makefile.common b/arm/Makefile.common > index b2c0fc8a2fdc..89fe3f69eb44 100644 > --- a/arm/Makefile.common > +++ b/arm/Makefile.common > @@ -48,6 +48,7 @@ cflatobjs += lib/arm/mmu.o > cflatobjs += lib/arm/bitops.o > cflatobjs += lib/arm/psci.o > cflatobjs += lib/arm/smp.o > +cflatobjs += lib/arm/delay.o > > libeabi = lib/arm/libeabi.a > eabiobjs = lib/arm/eabi_compat.o > diff --git a/lib/arm/asm/delay.h b/lib/arm/asm/delay.h > new file mode 100644 > index 000000000000..2436b28c77ae > --- /dev/null > +++ b/lib/arm/asm/delay.h > @@ -0,0 +1,14 @@ > +#ifndef _ASMARM_DELAY_H_ > +#define _ASMARM_DELAY_H_ > +/* > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#include <libcflat.h> > + > +extern void delay(u64 cycles); Nit: Shouldn't this parameter be called "ticks"? Cycles might be a bit misleading, especially since this prototype is the only documentation on this. You might just want to fix this when applying the patches. That notwithstanding: Reviewed-by: Andre Przywara <andre.przywara@arm.com> Cheers, Andre. > +extern void udelay(unsigned long usecs); > +extern void mdelay(unsigned long msecs); > + > +#endif /* _ASMARM_DELAY_H_ */ > diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h > index 6b0d36b87817..857bdd96a3cc 100644 > --- a/lib/arm/asm/processor.h > +++ b/lib/arm/asm/processor.h > @@ -7,6 +7,7 @@ > */ > #include <asm/ptrace.h> > #include <asm/sysreg.h> > +#include <asm/barrier.h> > > enum vector { > EXCPTN_RST, > @@ -51,4 +52,18 @@ extern int mpidr_to_cpu(uint64_t mpidr); > extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); > extern bool is_user(void); > > +#define CNTVCT __ACCESS_CP15_64(1, c14) > +#define CNTFRQ __ACCESS_CP15(c14, 0, c0, 0) > + > +static inline u64 get_cntvct(void) > +{ > + isb(); > + return read_sysreg(CNTVCT); > +} > + > +static inline u32 get_cntfrq(void) > +{ > + return read_sysreg(CNTFRQ); > +} > + > #endif /* _ASMARM_PROCESSOR_H_ */ > diff --git a/lib/arm64/asm/delay.h b/lib/arm64/asm/delay.h > new file mode 100644 > index 000000000000..288e4b3fe610 > --- /dev/null > +++ b/lib/arm64/asm/delay.h > @@ -0,0 +1 @@ > +#include "../../arm/asm/delay.h" > diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h > index 48abf2c9e358..0898d89f9761 100644 > --- a/lib/arm64/asm/processor.h > +++ b/lib/arm64/asm/processor.h > @@ -20,6 +20,7 @@ > #include <asm/ptrace.h> > #include <asm/esr.h> > #include <asm/sysreg.h> > +#include <asm/barrier.h> > > enum vector { > EL1T_SYNC, > @@ -83,5 +84,16 @@ extern int mpidr_to_cpu(uint64_t mpidr); > extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); > extern bool is_user(void); > > +static inline u64 get_cntvct(void) > +{ > + isb(); > + return read_sysreg(cntvct_el0); > +} > + > +static inline u32 get_cntfrq(void) > +{ > + return read_sysreg(cntfrq_el0); > +} > + > #endif /* !__ASSEMBLY__ */ > #endif /* _ASMARM64_PROCESSOR_H_ */ > diff --git a/lib/arm/delay.c b/lib/arm/delay.c > new file mode 100644 > index 000000000000..fa65e2dc9e35 > --- /dev/null > +++ b/lib/arm/delay.c > @@ -0,0 +1,29 @@ > +/* > + * Delay loops > + * > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#include <libcflat.h> > +#include <asm/processor.h> > +#include <asm/barrier.h> > + > +void delay(u64 cycles) > +{ > + u64 start = get_cntvct(); > + > + while ((get_cntvct() - start) < cycles) > + cpu_relax(); > +} > + > +void udelay(unsigned long usec) > +{ > + delay((u64)usec * get_cntfrq() / 1000000); > +} > + > +void mdelay(unsigned long msecs) > +{ > + while (msecs--) > + udelay(1000); > +} >
On Fri, Dec 09, 2016 at 11:41:06AM +0000, Andre Przywara wrote: > Hi, > > On 08/12/16 17:50, Andrew Jones wrote: > > Allow a thread to wait some specified amount of time. Can > > specify in cycles, usecs, and msecs. > > > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > > > --- > > v8: rewrote basing on new sysreg framework. Also decided delay > > functions warrant their own files (delay.[ch]) > > --- > > arm/Makefile.common | 1 + > > lib/arm/asm/delay.h | 14 ++++++++++++++ > > lib/arm/asm/processor.h | 15 +++++++++++++++ > > lib/arm64/asm/delay.h | 1 + > > lib/arm64/asm/processor.h | 12 ++++++++++++ > > lib/arm/delay.c | 29 +++++++++++++++++++++++++++++ > > 6 files changed, 72 insertions(+) > > create mode 100644 lib/arm/asm/delay.h > > create mode 100644 lib/arm64/asm/delay.h > > create mode 100644 lib/arm/delay.c > > > > diff --git a/arm/Makefile.common b/arm/Makefile.common > > index b2c0fc8a2fdc..89fe3f69eb44 100644 > > --- a/arm/Makefile.common > > +++ b/arm/Makefile.common > > @@ -48,6 +48,7 @@ cflatobjs += lib/arm/mmu.o > > cflatobjs += lib/arm/bitops.o > > cflatobjs += lib/arm/psci.o > > cflatobjs += lib/arm/smp.o > > +cflatobjs += lib/arm/delay.o > > > > libeabi = lib/arm/libeabi.a > > eabiobjs = lib/arm/eabi_compat.o > > diff --git a/lib/arm/asm/delay.h b/lib/arm/asm/delay.h > > new file mode 100644 > > index 000000000000..2436b28c77ae > > --- /dev/null > > +++ b/lib/arm/asm/delay.h > > @@ -0,0 +1,14 @@ > > +#ifndef _ASMARM_DELAY_H_ > > +#define _ASMARM_DELAY_H_ > > +/* > > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > > + * > > + * This work is licensed under the terms of the GNU LGPL, version 2. > > + */ > > +#include <libcflat.h> > > + > > +extern void delay(u64 cycles); > > Nit: Shouldn't this parameter be called "ticks"? Cycles might be a bit > misleading, especially since this prototype is the only documentation on > this. You might just want to fix this when applying the patches. Right or wrong the kernel uses 'cycles' for this function, named __timer_delay for arm and __delay for arm64. I guess I prefer consistency here. > > That notwithstanding: > Reviewed-by: Andre Przywara <andre.przywara@arm.com> Thanks! drew
Andrew Jones <drjones@redhat.com> writes: > Allow a thread to wait some specified amount of time. Can > specify in cycles, usecs, and msecs. > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > --- > v8: rewrote basing on new sysreg framework. Also decided delay > functions warrant their own files (delay.[ch]) > --- > arm/Makefile.common | 1 + > lib/arm/asm/delay.h | 14 ++++++++++++++ > lib/arm/asm/processor.h | 15 +++++++++++++++ > lib/arm64/asm/delay.h | 1 + > lib/arm64/asm/processor.h | 12 ++++++++++++ > lib/arm/delay.c | 29 +++++++++++++++++++++++++++++ > 6 files changed, 72 insertions(+) > create mode 100644 lib/arm/asm/delay.h > create mode 100644 lib/arm64/asm/delay.h > create mode 100644 lib/arm/delay.c > > diff --git a/arm/Makefile.common b/arm/Makefile.common > index b2c0fc8a2fdc..89fe3f69eb44 100644 > --- a/arm/Makefile.common > +++ b/arm/Makefile.common > @@ -48,6 +48,7 @@ cflatobjs += lib/arm/mmu.o > cflatobjs += lib/arm/bitops.o > cflatobjs += lib/arm/psci.o > cflatobjs += lib/arm/smp.o > +cflatobjs += lib/arm/delay.o > > libeabi = lib/arm/libeabi.a > eabiobjs = lib/arm/eabi_compat.o > diff --git a/lib/arm/asm/delay.h b/lib/arm/asm/delay.h > new file mode 100644 > index 000000000000..2436b28c77ae > --- /dev/null > +++ b/lib/arm/asm/delay.h > @@ -0,0 +1,14 @@ > +#ifndef _ASMARM_DELAY_H_ > +#define _ASMARM_DELAY_H_ > +/* > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#include <libcflat.h> > + > +extern void delay(u64 cycles); > +extern void udelay(unsigned long usecs); > +extern void mdelay(unsigned long msecs); > + > +#endif /* _ASMARM_DELAY_H_ */ > diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h > index 6b0d36b87817..857bdd96a3cc 100644 > --- a/lib/arm/asm/processor.h > +++ b/lib/arm/asm/processor.h > @@ -7,6 +7,7 @@ > */ > #include <asm/ptrace.h> > #include <asm/sysreg.h> > +#include <asm/barrier.h> Hmm this fails to apply cleanly to master and doesn't build as sysreg.h isn't in my tree. What happened to it? > > enum vector { > EXCPTN_RST, > @@ -51,4 +52,18 @@ extern int mpidr_to_cpu(uint64_t mpidr); > extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); > extern bool is_user(void); > > +#define CNTVCT __ACCESS_CP15_64(1, c14) > +#define CNTFRQ __ACCESS_CP15(c14, 0, c0, 0) > + > +static inline u64 get_cntvct(void) > +{ > + isb(); > + return read_sysreg(CNTVCT); > +} > + > +static inline u32 get_cntfrq(void) > +{ > + return read_sysreg(CNTFRQ); > +} > + > #endif /* _ASMARM_PROCESSOR_H_ */ > diff --git a/lib/arm64/asm/delay.h b/lib/arm64/asm/delay.h > new file mode 100644 > index 000000000000..288e4b3fe610 > --- /dev/null > +++ b/lib/arm64/asm/delay.h > @@ -0,0 +1 @@ > +#include "../../arm/asm/delay.h" > diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h > index 48abf2c9e358..0898d89f9761 100644 > --- a/lib/arm64/asm/processor.h > +++ b/lib/arm64/asm/processor.h > @@ -20,6 +20,7 @@ > #include <asm/ptrace.h> > #include <asm/esr.h> > #include <asm/sysreg.h> > +#include <asm/barrier.h> > > enum vector { > EL1T_SYNC, > @@ -83,5 +84,16 @@ extern int mpidr_to_cpu(uint64_t mpidr); > extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); > extern bool is_user(void); > > +static inline u64 get_cntvct(void) > +{ > + isb(); > + return read_sysreg(cntvct_el0); > +} > + > +static inline u32 get_cntfrq(void) > +{ > + return read_sysreg(cntfrq_el0); > +} > + > #endif /* !__ASSEMBLY__ */ > #endif /* _ASMARM64_PROCESSOR_H_ */ > diff --git a/lib/arm/delay.c b/lib/arm/delay.c > new file mode 100644 > index 000000000000..fa65e2dc9e35 > --- /dev/null > +++ b/lib/arm/delay.c > @@ -0,0 +1,29 @@ > +/* > + * Delay loops > + * > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#include <libcflat.h> > +#include <asm/processor.h> > +#include <asm/barrier.h> > + > +void delay(u64 cycles) > +{ > + u64 start = get_cntvct(); > + > + while ((get_cntvct() - start) < cycles) > + cpu_relax(); > +} > + > +void udelay(unsigned long usec) > +{ > + delay((u64)usec * get_cntfrq() / 1000000); > +} > + > +void mdelay(unsigned long msecs) > +{ > + while (msecs--) > + udelay(1000); > +} -- Alex Bennée
Alex Bennée <alex.bennee@linaro.org> writes: > Andrew Jones <drjones@redhat.com> writes: > >> Allow a thread to wait some specified amount of time. Can >> specify in cycles, usecs, and msecs. <snip> >> diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h >> index 6b0d36b87817..857bdd96a3cc 100644 >> --- a/lib/arm/asm/processor.h >> +++ b/lib/arm/asm/processor.h >> @@ -7,6 +7,7 @@ >> */ >> #include <asm/ptrace.h> >> #include <asm/sysreg.h> >> +#include <asm/barrier.h> > > Hmm this fails to apply cleanly to master and doesn't build as sysreg.h > isn't in my tree. What happened to it? <snip> Ahh I missed this is based on arm/next -- Alex Bennée
On 12/09/2016 07:15 AM, Andrew Jones wrote: > On Fri, Dec 09, 2016 at 11:41:06AM +0000, Andre Przywara wrote: >> Hi, >> >> On 08/12/16 17:50, Andrew Jones wrote: >>> Allow a thread to wait some specified amount of time. Can >>> specify in cycles, usecs, and msecs. >>> +++ b/lib/arm/asm/delay.h >>> @@ -0,0 +1,14 @@ >>> +#ifndef _ASMARM_DELAY_H_ >>> +#define _ASMARM_DELAY_H_ >>> +/* >>> + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> >>> + * >>> + * This work is licensed under the terms of the GNU LGPL, version 2. >>> + */ >>> +#include <libcflat.h> >>> + >>> +extern void delay(u64 cycles); >> >> Nit: Shouldn't this parameter be called "ticks"? Cycles might be a bit >> misleading, especially since this prototype is the only documentation on >> this. You might just want to fix this when applying the patches. > > Right or wrong the kernel uses 'cycles' for this function, named > __timer_delay for arm and __delay for arm64. I guess I prefer > consistency here. I too expect timers to tick and CPUs to cycle. The benefit of parameter-name-precise consistency with the Linux source is not obvious to me. Cov
On Tue, Dec 27, 2016 at 10:27:25AM -0500, Christopher Covington wrote: > On 12/09/2016 07:15 AM, Andrew Jones wrote: > > On Fri, Dec 09, 2016 at 11:41:06AM +0000, Andre Przywara wrote: > >> Hi, > >> > >> On 08/12/16 17:50, Andrew Jones wrote: > >>> Allow a thread to wait some specified amount of time. Can > >>> specify in cycles, usecs, and msecs. > > >>> +++ b/lib/arm/asm/delay.h > >>> @@ -0,0 +1,14 @@ > >>> +#ifndef _ASMARM_DELAY_H_ > >>> +#define _ASMARM_DELAY_H_ > >>> +/* > >>> + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > >>> + * > >>> + * This work is licensed under the terms of the GNU LGPL, version 2. > >>> + */ > >>> +#include <libcflat.h> > >>> + > >>> +extern void delay(u64 cycles); > >> > >> Nit: Shouldn't this parameter be called "ticks"? Cycles might be a bit > >> misleading, especially since this prototype is the only documentation on > >> this. You might just want to fix this when applying the patches. > > > > Right or wrong the kernel uses 'cycles' for this function, named > > __timer_delay for arm and __delay for arm64. I guess I prefer > > consistency here. > > I too expect timers to tick and CPUs to cycle. The benefit of > parameter-name-precise consistency with the Linux source is not > obvious to me. > I just didn't have a strong enough opinion on it to change it. It appears I'm in a minority though. As this is in master already, patches welcome :) Thanks, drew
diff --git a/arm/Makefile.common b/arm/Makefile.common index b2c0fc8a2fdc..89fe3f69eb44 100644 --- a/arm/Makefile.common +++ b/arm/Makefile.common @@ -48,6 +48,7 @@ cflatobjs += lib/arm/mmu.o cflatobjs += lib/arm/bitops.o cflatobjs += lib/arm/psci.o cflatobjs += lib/arm/smp.o +cflatobjs += lib/arm/delay.o libeabi = lib/arm/libeabi.a eabiobjs = lib/arm/eabi_compat.o diff --git a/lib/arm/asm/delay.h b/lib/arm/asm/delay.h new file mode 100644 index 000000000000..2436b28c77ae --- /dev/null +++ b/lib/arm/asm/delay.h @@ -0,0 +1,14 @@ +#ifndef _ASMARM_DELAY_H_ +#define _ASMARM_DELAY_H_ +/* + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2. + */ +#include <libcflat.h> + +extern void delay(u64 cycles); +extern void udelay(unsigned long usecs); +extern void mdelay(unsigned long msecs); + +#endif /* _ASMARM_DELAY_H_ */ diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h index 6b0d36b87817..857bdd96a3cc 100644 --- a/lib/arm/asm/processor.h +++ b/lib/arm/asm/processor.h @@ -7,6 +7,7 @@ */ #include <asm/ptrace.h> #include <asm/sysreg.h> +#include <asm/barrier.h> enum vector { EXCPTN_RST, @@ -51,4 +52,18 @@ extern int mpidr_to_cpu(uint64_t mpidr); extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); extern bool is_user(void); +#define CNTVCT __ACCESS_CP15_64(1, c14) +#define CNTFRQ __ACCESS_CP15(c14, 0, c0, 0) + +static inline u64 get_cntvct(void) +{ + isb(); + return read_sysreg(CNTVCT); +} + +static inline u32 get_cntfrq(void) +{ + return read_sysreg(CNTFRQ); +} + #endif /* _ASMARM_PROCESSOR_H_ */ diff --git a/lib/arm64/asm/delay.h b/lib/arm64/asm/delay.h new file mode 100644 index 000000000000..288e4b3fe610 --- /dev/null +++ b/lib/arm64/asm/delay.h @@ -0,0 +1 @@ +#include "../../arm/asm/delay.h" diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h index 48abf2c9e358..0898d89f9761 100644 --- a/lib/arm64/asm/processor.h +++ b/lib/arm64/asm/processor.h @@ -20,6 +20,7 @@ #include <asm/ptrace.h> #include <asm/esr.h> #include <asm/sysreg.h> +#include <asm/barrier.h> enum vector { EL1T_SYNC, @@ -83,5 +84,16 @@ extern int mpidr_to_cpu(uint64_t mpidr); extern void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr); extern bool is_user(void); +static inline u64 get_cntvct(void) +{ + isb(); + return read_sysreg(cntvct_el0); +} + +static inline u32 get_cntfrq(void) +{ + return read_sysreg(cntfrq_el0); +} + #endif /* !__ASSEMBLY__ */ #endif /* _ASMARM64_PROCESSOR_H_ */ diff --git a/lib/arm/delay.c b/lib/arm/delay.c new file mode 100644 index 000000000000..fa65e2dc9e35 --- /dev/null +++ b/lib/arm/delay.c @@ -0,0 +1,29 @@ +/* + * Delay loops + * + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2. + */ +#include <libcflat.h> +#include <asm/processor.h> +#include <asm/barrier.h> + +void delay(u64 cycles) +{ + u64 start = get_cntvct(); + + while ((get_cntvct() - start) < cycles) + cpu_relax(); +} + +void udelay(unsigned long usec) +{ + delay((u64)usec * get_cntfrq() / 1000000); +} + +void mdelay(unsigned long msecs) +{ + while (msecs--) + udelay(1000); +}
Allow a thread to wait some specified amount of time. Can specify in cycles, usecs, and msecs. Signed-off-by: Andrew Jones <drjones@redhat.com> --- v8: rewrote basing on new sysreg framework. Also decided delay functions warrant their own files (delay.[ch]) --- arm/Makefile.common | 1 + lib/arm/asm/delay.h | 14 ++++++++++++++ lib/arm/asm/processor.h | 15 +++++++++++++++ lib/arm64/asm/delay.h | 1 + lib/arm64/asm/processor.h | 12 ++++++++++++ lib/arm/delay.c | 29 +++++++++++++++++++++++++++++ 6 files changed, 72 insertions(+) create mode 100644 lib/arm/asm/delay.h create mode 100644 lib/arm64/asm/delay.h create mode 100644 lib/arm/delay.c