| Message ID | 1477954096-770-3-git-send-email-vgupta@synopsys.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Oct 31, 2016 at 03:48:09PM -0700, Vineet Gupta wrote: > To allow for easy movement into drivers/clocksource > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > --- > arch/arc/kernel/time.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c > index a2db010cde18..2c51e3cafad0 100644 > --- a/arch/arc/kernel/time.c > +++ b/arch/arc/kernel/time.c > @@ -153,14 +153,11 @@ static cycle_t arc_read_rtc(struct clocksource *cs) > cycle_t full; > } stamp; > > - > - __asm__ __volatile( > - "1: \n" > - " lr %0, [AUX_RTC_LOW] \n" > - " lr %1, [AUX_RTC_HIGH] \n" > - " lr %2, [AUX_RTC_CTRL] \n" > - " bbit0.nt %2, 31, 1b \n" > - : "=r" (stamp.low), "=r" (stamp.high), "=r" (status)); > + do { > + stamp.low = read_aux_reg(AUX_RTC_LOW); > + stamp.high = read_aux_reg(AUX_RTC_HIGH); > + status = read_aux_reg(AUX_RTC_CTRL); > + } while (!(status & 0x80000000UL)); Replace the literal 0x80000000UL by a macro. What is the 'status' for ? > return stamp.full; > } > -- > 2.7.4 >
On 11/03/2016 10:02 AM, Daniel Lezcano wrote: > On Mon, Oct 31, 2016 at 03:48:09PM -0700, Vineet Gupta wrote: >> To allow for easy movement into drivers/clocksource >> >> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> >> --- >> arch/arc/kernel/time.c | 13 +++++-------- >> 1 file changed, 5 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c >> index a2db010cde18..2c51e3cafad0 100644 >> --- a/arch/arc/kernel/time.c >> +++ b/arch/arc/kernel/time.c >> @@ -153,14 +153,11 @@ static cycle_t arc_read_rtc(struct clocksource *cs) >> cycle_t full; >> } stamp; >> >> - >> - __asm__ __volatile( >> - "1: \n" >> - " lr %0, [AUX_RTC_LOW] \n" >> - " lr %1, [AUX_RTC_HIGH] \n" >> - " lr %2, [AUX_RTC_CTRL] \n" >> - " bbit0.nt %2, 31, 1b \n" >> - : "=r" (stamp.low), "=r" (stamp.high), "=r" (status)); >> + do { >> + stamp.low = read_aux_reg(AUX_RTC_LOW); >> + stamp.high = read_aux_reg(AUX_RTC_HIGH); >> + status = read_aux_reg(AUX_RTC_CTRL); >> + } while (!(status & 0x80000000UL)); > > Replace the literal 0x80000000UL by a macro. OK ! > What is the 'status' for ? Hardware keeps a internal state machine for atomic readout of low/high. So if an interrupt is taken between reading low and high, or if high increments after low is read, then the bit forces a loop to retry. > >> return stamp.full; >> } >> -- >> 2.7.4 >>
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c index a2db010cde18..2c51e3cafad0 100644 --- a/arch/arc/kernel/time.c +++ b/arch/arc/kernel/time.c @@ -153,14 +153,11 @@ static cycle_t arc_read_rtc(struct clocksource *cs) cycle_t full; } stamp; - - __asm__ __volatile( - "1: \n" - " lr %0, [AUX_RTC_LOW] \n" - " lr %1, [AUX_RTC_HIGH] \n" - " lr %2, [AUX_RTC_CTRL] \n" - " bbit0.nt %2, 31, 1b \n" - : "=r" (stamp.low), "=r" (stamp.high), "=r" (status)); + do { + stamp.low = read_aux_reg(AUX_RTC_LOW); + stamp.high = read_aux_reg(AUX_RTC_HIGH); + status = read_aux_reg(AUX_RTC_CTRL); + } while (!(status & 0x80000000UL)); return stamp.full; }
To allow for easy movement into drivers/clocksource Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/kernel/time.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)