Hi,
I add one minor comment (KHZ -> hz).
On 19. 4. 15. 오후 11:54, Dmitry Osipenko wrote:
> The kHz to Hz is incorrectly converted in a few places in the code,
> this results in a wrong frequency being calculated because devfreq core
> uses OPP frequencies that are given in Hz to clamp the rate, while
> tegra-devfreq gives to the core value in kHz and then it also expects to
> receive value in kHz from the core. In a result memory freq is always set
> to a value which is close to ULONG_MAX because of the bug. Hence the EMC
> frequency is always capped to the maximum and the driver doesn't do
> anything useful. This patch was tested on Tegra30 and Tegra124 SoC's, EMC
> frequency scaling works properly now.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.14+
> Tested-by: Steev Klimaszewski <steev@xxxxxxxx>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> drivers/devfreq/tegra-devfreq.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
> index c89ba7b834ff..02905978abe1 100644
> --- a/drivers/devfreq/tegra-devfreq.c
> +++ b/drivers/devfreq/tegra-devfreq.c
> @@ -486,9 +486,9 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
> {
> struct tegra_devfreq *tegra = dev_get_drvdata(dev);
> struct dev_pm_opp *opp;
> - unsigned long rate = *freq * KHZ;
> + unsigned long rate;
>
> - opp = devfreq_recommended_opp(dev, &rate, flags);
> + opp = devfreq_recommended_opp(dev, freq, flags);
> if (IS_ERR(opp)) {
> dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
Need to change it as following:
- KHz -> Hz
> return PTR_ERR(opp);
> @@ -499,8 +499,6 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
> clk_set_min_rate(tegra->emc_clock, rate);
> clk_set_rate(tegra->emc_clock, 0);
>
> - *freq = rate;
> -
> return 0;
> }
>
> @@ -510,7 +508,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
> struct tegra_devfreq *tegra = dev_get_drvdata(dev);
> struct tegra_devfreq_device *actmon_dev;
>
> - stat->current_frequency = tegra->cur_freq;
> + stat->current_frequency = tegra->cur_freq * KHZ;
>
> /* To be used by the tegra governor */
> stat->private_data = tegra;
> @@ -565,7 +563,7 @@ static int tegra_governor_get_target(struct devfreq *devfreq,
> target_freq = max(target_freq, dev->target_freq);
> }
>
> - *freq = target_freq;
> + *freq = target_freq * KHZ;
>
> return 0;
> }
>
It looks good to me if modify it in accordance with my comment.
Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Regards,
Chanwoo Choi
--
Best Regards,
Chanwoo Choi
Samsung Electronics
