[PATCH] cpufreq: ppc-corenet-cpu-freq: do_div use quotient

[PATCH] cpufreq: ppc-corenet-cpu-freq: do_div use quotient

[Ed Swarthout]

6712d2931933ada259b82f06c03a855b19937074 (cpufreq:
ppc-corenet-cpufreq: Fix __udivdi3 modpost error) used the remainder
from do_div instead of the quotient. Fix that and add one to ensure
minimum is met.

Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
---
 drivers/cpufreq/ppc-corenet-cpufreq.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
index 0af618a..3607070 100644
--- a/drivers/cpufreq/ppc-corenet-cpufreq.c
+++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
@@ -138,7 +138,7 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	struct cpufreq_frequency_table *table;
 	struct cpu_data *data;
 	unsigned int cpu = policy->cpu;
-	u64 transition_latency_hz;
+	u64 u64temp;
 
 	np = of_get_cpu_node(cpu, NULL);
 	if (!np)
@@ -206,9 +206,10 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	for_each_cpu(i, per_cpu(cpu_mask, cpu))
 		per_cpu(cpu_data, i) = data;
 
-	transition_latency_hz = 12ULL * NSEC_PER_SEC;
-	policy->cpuinfo.transition_latency =
-		do_div(transition_latency_hz, fsl_get_sys_freq());
+	/* Minimum transition latency is 12 platform clocks */
+	u64temp = 12ULL * NSEC_PER_SEC;
+	do_div(u64temp, fsl_get_sys_freq());
+	policy->cpuinfo.transition_latency = u64temp + 1;
 
 	of_node_put(np);
 
-- 
1.9.1

Re: [PATCH] cpufreq: ppc-corenet-cpu-freq: do_div use quotient

[Tim Gardner]

On 06/04/2014 02:32 PM, Ed Swarthout wrote:
> 6712d2931933ada259b82f06c03a855b19937074 (cpufreq:
> ppc-corenet-cpufreq: Fix __udivdi3 modpost error) used the remainder
> from do_div instead of the quotient. Fix that and add one to ensure
> minimum is met.
> 
> Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
> ---
>  drivers/cpufreq/ppc-corenet-cpufreq.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
> index 0af618a..3607070 100644
> --- a/drivers/cpufreq/ppc-corenet-cpufreq.c
> +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
> @@ -138,7 +138,7 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
>  	struct cpufreq_frequency_table *table;
>  	struct cpu_data *data;
>  	unsigned int cpu = policy->cpu;
> -	u64 transition_latency_hz;
> +	u64 u64temp;
>  
>  	np = of_get_cpu_node(cpu, NULL);
>  	if (!np)
> @@ -206,9 +206,10 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
>  	for_each_cpu(i, per_cpu(cpu_mask, cpu))
>  		per_cpu(cpu_data, i) = data;
>  
> -	transition_latency_hz = 12ULL * NSEC_PER_SEC;
> -	policy->cpuinfo.transition_latency =
> -		do_div(transition_latency_hz, fsl_get_sys_freq());
> +	/* Minimum transition latency is 12 platform clocks */
> +	u64temp = 12ULL * NSEC_PER_SEC;
> +	do_div(u64temp, fsl_get_sys_freq());
> +	policy->cpuinfo.transition_latency = u64temp + 1;
>  
>  	of_node_put(np);
>  
> 

Whoops, what was I thinking ? You should also add "Cc:
stable@vger.kernel.org # 3.15+" since this patch will likely miss 3.15
final.

Acked-by: Tim Gardner <tim.gardner@canonical.com>

-- 
Tim Gardner tim.gardner@canonical.com