Message ID | 1397728407-13909-3-git-send-email-geert+renesas@glider.be (mailing list archive) |
---|---|
State | Not Applicable |
Headers | show |
On 17 April 2014 15:23, Geert Uytterhoeven <geert+renesas@glider.be> wrote: > If the clock doesn't exist, clk_get_rate() returns -EINVAL You clk_get_rate() isn't written well then, it should return zero. @Mike: I didn't see this clearly mentioned in clk.h, should we fix that? >, which becomes > a large number (freq is u32), failing the "freq < min_cpufreq" test. > Explicitly test for "(u32)-EINVAL" to fix this. That's a bad check. We should have done this instead: (s32)freq < 0; but that would be true for high values of clock. And that's why clk_get_rate() must return zero for errors. > Update the comment, and fix a grammer issue while we're at it. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > drivers/cpufreq/ppc-corenet-cpufreq.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c > index 53881d78a931..7027eab814ce 100644 > --- a/drivers/cpufreq/ppc-corenet-cpufreq.c > +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c > @@ -179,10 +179,11 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) > clk = of_clk_get(data->parent, i); > freq = clk_get_rate(clk); > /* > - * the clock is valid if its frequency is not masked > - * and large than minimum allowed frequency. > + * the clock is valid if it exists, its frequency is not > + * masked, and larger than minimum allowed frequency. > */ > - if (freq < min_cpufreq || (mask & (1 << i))) > + if (freq == (u32)-EINVAL || freq < min_cpufreq || > + (mask & (1 << i))) > table[i].frequency = CPUFREQ_ENTRY_INVALID; > else > table[i].frequency = freq / 1000; > -- > 1.7.9.5 >
Hi Viresh, On Mon, Apr 21, 2014 at 8:01 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote: > On 17 April 2014 15:23, Geert Uytterhoeven <geert+renesas@glider.be> wrote: >> If the clock doesn't exist, clk_get_rate() returns -EINVAL > > You clk_get_rate() isn't written well then, it should return zero. You're right, thanks! Once again I looked at the wrong clk_get_rate() implementation :-( These non-CCF variants should die soon... So the original code was correct: if the clock is not valid, freq == 0, and thus "freq < min_cpufreq" is true. > @Mike: I didn't see this clearly mentioned in clk.h, should we fix > that? > >>, which becomes >> a large number (freq is u32), failing the "freq < min_cpufreq" test. >> Explicitly test for "(u32)-EINVAL" to fix this. > > That's a bad check. We should have done this instead: > > (s32)freq < 0; but that would be true for high values of clock. And that's > why clk_get_rate() must return zero for errors. > >> Update the comment, and fix a grammer issue while we're at it. >> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> --- >> drivers/cpufreq/ppc-corenet-cpufreq.c | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c >> index 53881d78a931..7027eab814ce 100644 >> --- a/drivers/cpufreq/ppc-corenet-cpufreq.c >> +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c >> @@ -179,10 +179,11 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) >> clk = of_clk_get(data->parent, i); >> freq = clk_get_rate(clk); >> /* >> - * the clock is valid if its frequency is not masked >> - * and large than minimum allowed frequency. >> + * the clock is valid if it exists, its frequency is not >> + * masked, and larger than minimum allowed frequency. >> */ >> - if (freq < min_cpufreq || (mask & (1 << i))) >> + if (freq == (u32)-EINVAL || freq < min_cpufreq || >> + (mask & (1 << i))) >> table[i].frequency = CPUFREQ_ENTRY_INVALID; >> else >> table[i].frequency = freq / 1000; Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c index 53881d78a931..7027eab814ce 100644 --- a/drivers/cpufreq/ppc-corenet-cpufreq.c +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c @@ -179,10 +179,11 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) clk = of_clk_get(data->parent, i); freq = clk_get_rate(clk); /* - * the clock is valid if its frequency is not masked - * and large than minimum allowed frequency. + * the clock is valid if it exists, its frequency is not + * masked, and larger than minimum allowed frequency. */ - if (freq < min_cpufreq || (mask & (1 << i))) + if (freq == (u32)-EINVAL || freq < min_cpufreq || + (mask & (1 << i))) table[i].frequency = CPUFREQ_ENTRY_INVALID; else table[i].frequency = freq / 1000;
If the clock doesn't exist, clk_get_rate() returns -EINVAL, which becomes a large number (freq is u32), failing the "freq < min_cpufreq" test. Explicitly test for "(u32)-EINVAL" to fix this. Update the comment, and fix a grammer issue while we're at it. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- drivers/cpufreq/ppc-corenet-cpufreq.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)