| Message ID | 20220630094635.389645-2-adnan.chowdhury@sifive.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | Added a blocking wait function that waits until a certain condition is satisfied or timeout occurs | expand |
On Thu, Jun 30, 2022 at 3:16 PM Adnan Rahman Chowdhury <adnan.chowdhury@sifive.com> wrote: > > Motivation: Suppose a peripheral needs to be configured to transmit > data. There is an SFR bit which indicates that the peripheral is ready > to transmit. The firmware should check the bit and will only transmit > data when the peripheral is ready. When the firmware starts polling the > SFR, the peripheral could be busy transmitting/receiving other data so > the firmware must wait till that completes. Assuming that there is no > other way, the firmware shouldn't wait indefinitely. > > The function sbi_timer_waitms_until() will constantly check whether a > certain condition is satisfied, or timeout occurs. It can be used for > the cases when a timeout is required. > > Signed-off-by: Adnan Rahman Chowdhury <adnan.chowdhury@sifive.com> > Reviewed-by: Xiang W <wxjstz@126.com> Looks good to me. Reviewed-by: Anup Patel <anup@brainfault.org> Regards, Anup > --- > include/sbi/sbi_timer.h | 18 ++++++++++++++++++ > lib/sbi/sbi_timer.c | 13 +++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/include/sbi/sbi_timer.h b/include/sbi/sbi_timer.h > index 63ef1af..ac48e2b 100644 > --- a/include/sbi/sbi_timer.h > +++ b/include/sbi/sbi_timer.h > @@ -48,6 +48,24 @@ static inline void sbi_timer_udelay(ulong usecs) > sbi_timer_delay_loop(usecs, 1000000, NULL, NULL); > } > > +/** > + * A blocking function that will wait until @p predicate returns true or > + * @p timeout_ms milliseconds elapsed. @p arg will be passed as argument to > + * @p predicate function. > + * > + * @param predicate Pointer to a function that returns true if certain > + * condition is met. It shouldn't block the code execution. > + * @param arg Argument to pass to @p predicate. > + * @param timeout_ms Timeout value in milliseconds. The function will return > + * false if @p timeout_ms time period elapsed but still @p predicate doesn't > + * return true. > + * > + * @return true if @p predicate returns true within @p timeout_ms, false > + * otherwise. > + */ > +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, > + uint64_t timeout_ms); > + > /** Get timer value for current HART */ > u64 sbi_timer_value(void); > > diff --git a/lib/sbi/sbi_timer.c b/lib/sbi/sbi_timer.c > index acdba92..649a4e6 100644 > --- a/lib/sbi/sbi_timer.c > +++ b/lib/sbi/sbi_timer.c > @@ -81,6 +81,19 @@ void sbi_timer_delay_loop(ulong units, u64 unit_freq, > delay_fn(opaque); > } > > +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, > + uint64_t timeout_ms) > +{ > + uint64_t start_time = sbi_timer_value(); > + uint64_t ticks = > + (sbi_timer_get_device()->timer_freq / 1000) * > + timeout_ms; > + while(!predicate(arg)) > + if (sbi_timer_value() - start_time >= ticks) > + return false; > + return true; > +} > + > u64 sbi_timer_value(void) > { > if (get_time_val) > -- > 2.30.2 > > > -- > opensbi mailing list > opensbi@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/opensbi
On Wed, Jul 6, 2022 at 8:53 AM Anup Patel <anup@brainfault.org> wrote: > > On Thu, Jun 30, 2022 at 3:16 PM Adnan Rahman Chowdhury > <adnan.chowdhury@sifive.com> wrote: > > > > Motivation: Suppose a peripheral needs to be configured to transmit > > data. There is an SFR bit which indicates that the peripheral is ready > > to transmit. The firmware should check the bit and will only transmit > > data when the peripheral is ready. When the firmware starts polling the > > SFR, the peripheral could be busy transmitting/receiving other data so > > the firmware must wait till that completes. Assuming that there is no > > other way, the firmware shouldn't wait indefinitely. > > > > The function sbi_timer_waitms_until() will constantly check whether a > > certain condition is satisfied, or timeout occurs. It can be used for > > the cases when a timeout is required. > > > > Signed-off-by: Adnan Rahman Chowdhury <adnan.chowdhury@sifive.com> > > Reviewed-by: Xiang W <wxjstz@126.com> > > Looks good to me. > > Reviewed-by: Anup Patel <anup@brainfault.org> I have shortened the patch subject at time of merging this patch. Applied this patch to the riscv/opensbi repo Thanks, Anup > > Regards, > Anup > > > --- > > include/sbi/sbi_timer.h | 18 ++++++++++++++++++ > > lib/sbi/sbi_timer.c | 13 +++++++++++++ > > 2 files changed, 31 insertions(+) > > > > diff --git a/include/sbi/sbi_timer.h b/include/sbi/sbi_timer.h > > index 63ef1af..ac48e2b 100644 > > --- a/include/sbi/sbi_timer.h > > +++ b/include/sbi/sbi_timer.h > > @@ -48,6 +48,24 @@ static inline void sbi_timer_udelay(ulong usecs) > > sbi_timer_delay_loop(usecs, 1000000, NULL, NULL); > > } > > > > +/** > > + * A blocking function that will wait until @p predicate returns true or > > + * @p timeout_ms milliseconds elapsed. @p arg will be passed as argument to > > + * @p predicate function. > > + * > > + * @param predicate Pointer to a function that returns true if certain > > + * condition is met. It shouldn't block the code execution. > > + * @param arg Argument to pass to @p predicate. > > + * @param timeout_ms Timeout value in milliseconds. The function will return > > + * false if @p timeout_ms time period elapsed but still @p predicate doesn't > > + * return true. > > + * > > + * @return true if @p predicate returns true within @p timeout_ms, false > > + * otherwise. > > + */ > > +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, > > + uint64_t timeout_ms); > > + > > /** Get timer value for current HART */ > > u64 sbi_timer_value(void); > > > > diff --git a/lib/sbi/sbi_timer.c b/lib/sbi/sbi_timer.c > > index acdba92..649a4e6 100644 > > --- a/lib/sbi/sbi_timer.c > > +++ b/lib/sbi/sbi_timer.c > > @@ -81,6 +81,19 @@ void sbi_timer_delay_loop(ulong units, u64 unit_freq, > > delay_fn(opaque); > > } > > > > +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, > > + uint64_t timeout_ms) > > +{ > > + uint64_t start_time = sbi_timer_value(); > > + uint64_t ticks = > > + (sbi_timer_get_device()->timer_freq / 1000) * > > + timeout_ms; > > + while(!predicate(arg)) > > + if (sbi_timer_value() - start_time >= ticks) > > + return false; > > + return true; > > +} > > + > > u64 sbi_timer_value(void) > > { > > if (get_time_val) > > -- > > 2.30.2 > > > > > > -- > > opensbi mailing list > > opensbi@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/opensbi
diff --git a/include/sbi/sbi_timer.h b/include/sbi/sbi_timer.h index 63ef1af..ac48e2b 100644 --- a/include/sbi/sbi_timer.h +++ b/include/sbi/sbi_timer.h @@ -48,6 +48,24 @@ static inline void sbi_timer_udelay(ulong usecs) sbi_timer_delay_loop(usecs, 1000000, NULL, NULL); } +/** + * A blocking function that will wait until @p predicate returns true or + * @p timeout_ms milliseconds elapsed. @p arg will be passed as argument to + * @p predicate function. + * + * @param predicate Pointer to a function that returns true if certain + * condition is met. It shouldn't block the code execution. + * @param arg Argument to pass to @p predicate. + * @param timeout_ms Timeout value in milliseconds. The function will return + * false if @p timeout_ms time period elapsed but still @p predicate doesn't + * return true. + * + * @return true if @p predicate returns true within @p timeout_ms, false + * otherwise. + */ +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, + uint64_t timeout_ms); + /** Get timer value for current HART */ u64 sbi_timer_value(void); diff --git a/lib/sbi/sbi_timer.c b/lib/sbi/sbi_timer.c index acdba92..649a4e6 100644 --- a/lib/sbi/sbi_timer.c +++ b/lib/sbi/sbi_timer.c @@ -81,6 +81,19 @@ void sbi_timer_delay_loop(ulong units, u64 unit_freq, delay_fn(opaque); } +bool sbi_timer_waitms_until(bool (*predicate)(void *), void *arg, + uint64_t timeout_ms) +{ + uint64_t start_time = sbi_timer_value(); + uint64_t ticks = + (sbi_timer_get_device()->timer_freq / 1000) * + timeout_ms; + while(!predicate(arg)) + if (sbi_timer_value() - start_time >= ticks) + return false; + return true; +} + u64 sbi_timer_value(void) { if (get_time_val)