From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38377) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b9yV8-0005vo-6G for qemu-devel@nongnu.org; Mon, 06 Jun 2016 13:39:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b9yV1-0002DG-Q1 for qemu-devel@nongnu.org; Mon, 06 Jun 2016 13:39:45 -0400 Received: from mail-wm0-x235.google.com ([2a00:1450:400c:c09::235]:36157) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b9yV1-0002D4-Fo for qemu-devel@nongnu.org; Mon, 06 Jun 2016 13:39:39 -0400 Received: by mail-wm0-x235.google.com with SMTP id n184so103252666wmn.1 for ; Mon, 06 Jun 2016 10:39:39 -0700 (PDT) From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <1465064165-14885-5-git-send-email-drjones@redhat.com> Date: Mon, 06 Jun 2016 18:39:50 +0100 Message-ID: <87vb1mgqs9.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [kvm-unit-tests PATCH v2 04/10] arm/arm64: add some delay routines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrew Jones Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, pbonzini@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, andre.przywara@arm.com, peter.maydell@linaro.org, christoffer.dall@linaro.org, marc.zyngier@arm.com Andrew Jones writes: > Allow a thread to wait some specified amount of time. Can > specify in cycles, usecs, and msecs. I wonder if delay() and mdelay() can be in common code with just the freq and count getting functions in specific code? I guess that would need a lib/arm-generic/ or some such? Otherwise: Reviewed-by: Alex Bennée > > Signed-off-by: Andrew Jones > --- > lib/arm/asm/processor.h | 19 +++++++++++++++++++ > lib/arm/processor.c | 15 +++++++++++++++ > lib/arm64/asm/processor.h | 19 +++++++++++++++++++ > lib/arm64/processor.c | 15 +++++++++++++++ > 4 files changed, 68 insertions(+) > > diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h > index d2048f5f5f7e6..afc903ca7d4ab 100644 > --- a/lib/arm/asm/processor.h > +++ b/lib/arm/asm/processor.h > @@ -5,7 +5,9 @@ > * > * This work is licensed under the terms of the GNU LGPL, version 2. > */ > +#include > #include > +#include > > enum vector { > EXCPTN_RST, > @@ -51,4 +53,21 @@ extern int mpidr_to_cpu(unsigned long 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) > +{ > + u64 vct; > + isb(); > + asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (vct)); > + return vct; > +} > + > +extern void delay(u64 cycles); > +extern void udelay(unsigned long usecs); > + > +static inline void mdelay(unsigned long msecs) > +{ > + while (msecs--) > + udelay(1000); > +} > + > #endif /* _ASMARM_PROCESSOR_H_ */ > diff --git a/lib/arm/processor.c b/lib/arm/processor.c > index 54fdb87ef0196..c2ee360df6884 100644 > --- a/lib/arm/processor.c > +++ b/lib/arm/processor.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > > static const char *processor_modes[] = { > "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , > @@ -141,3 +142,17 @@ bool is_user(void) > { > return current_thread_info()->flags & TIF_USER_MODE; > } > + > +void delay(u64 cycles) > +{ > + u64 start = get_cntvct(); > + while ((get_cntvct() - start) < cycles) > + cpu_relax(); > +} > + > +void udelay(unsigned long usec) > +{ > + unsigned int frq; > + asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (frq)); > + delay((u64)usec * frq / 1000000); > +} > diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h > index 7e448dc81a6aa..94f7ce35b65c1 100644 > --- a/lib/arm64/asm/processor.h > +++ b/lib/arm64/asm/processor.h > @@ -17,8 +17,10 @@ > #define SCTLR_EL1_M (1 << 0) > > #ifndef __ASSEMBLY__ > +#include > #include > #include > +#include > > enum vector { > EL1T_SYNC, > @@ -89,5 +91,22 @@ extern int mpidr_to_cpu(unsigned long 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) > +{ > + u64 vct; > + isb(); > + asm volatile("mrs %0, cntvct_el0" : "=r" (vct)); > + return vct; > +} > + > +extern void delay(u64 cycles); > +extern void udelay(unsigned long usecs); > + > +static inline void mdelay(unsigned long msecs) > +{ > + while (msecs--) > + udelay(1000); > +} > + > #endif /* !__ASSEMBLY__ */ > #endif /* _ASMARM64_PROCESSOR_H_ */ > diff --git a/lib/arm64/processor.c b/lib/arm64/processor.c > index deeab4ec9c8ac..50fa835c6f1e3 100644 > --- a/lib/arm64/processor.c > +++ b/lib/arm64/processor.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > > static const char *vector_names[] = { > "el1t_sync", > @@ -253,3 +254,17 @@ bool is_user(void) > { > return current_thread_info()->flags & TIF_USER_MODE; > } > + > +void delay(u64 cycles) > +{ > + u64 start = get_cntvct(); > + while ((get_cntvct() - start) < cycles) > + cpu_relax(); > +} > + > +void udelay(unsigned long usec) > +{ > + unsigned int frq; > + asm volatile("mrs %0, cntfrq_el0" : "=r" (frq)); > + delay((u64)usec * frq / 1000000); > +} -- Alex Bennée