Re: [PATCH v9 07/17] PM / devfreq: tegra30: Support interconnect and OPPs from device-tree

Dmitry Osipenko
2020-11-17T14:17:54Z

17.11.2020 13:07, Viresh Kumar пишет:
> On 16-11-20, 00:29, Dmitry Osipenko wrote:
>> This patch moves ACTMON driver away from generating OPP table by itself,
>> transitioning it to use the table which comes from device-tree. This
>> change breaks compatibility with older device-trees in order to bring
>> support for the interconnect framework to the driver. This is a mandatory
>> change which needs to be done in order to implement interconnect-based
>> memory DVFS. Users of legacy device-trees will get a message telling that
>> theirs DT needs to be upgraded. Now ACTMON issues memory bandwidth request
>> using dev_pm_opp_set_bw(), instead of driving EMC clock rate directly.
>>
>> Tested-by: Peter Geis <pgwipeout@gmail.com>
>> Tested-by: Nicolas Chauvet <kwizart@gmail.com>
>> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>> drivers/devfreq/tegra30-devfreq.c | 86 ++++++++++++++++---------------
>> 1 file changed, 44 insertions(+), 42 deletions(-)
>>
>> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
>> index 38cc0d014738..ed6d4469c8c7 100644
>> --- a/drivers/devfreq/tegra30-devfreq.c
>> +++ b/drivers/devfreq/tegra30-devfreq.c
>> @@ -19,6 +19,8 @@
>> #include <linux/reset.h>
>> #include <linux/workqueue.h>
>>
>> +#include <soc/tegra/fuse.h>
>> +
>> #include "governor.h"
>>
>> #define ACTMON_GLB_STATUS 0x0
>> @@ -155,6 +157,7 @@ struct tegra_devfreq_device {
>>
>> struct tegra_devfreq {
>> struct devfreq *devfreq;
>> + struct opp_table *opp_table;
>>
>> struct reset_control *reset;
>> struct clk *clock;
>> @@ -612,34 +615,19 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
>> static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
>> u32 flags)
>> {
>> - struct tegra_devfreq *tegra = dev_get_drvdata(dev);
>> - struct devfreq *devfreq = tegra->devfreq;
>> struct dev_pm_opp *opp;
>> - unsigned long rate;
>> - int err;
>> + int ret;
>>
>> opp = devfreq_recommended_opp(dev, freq, flags);
>> if (IS_ERR(opp)) {
>> dev_err(dev, "Failed to find opp for %lu Hz\n", *freq);
>> return PTR_ERR(opp);
>> }
>> - rate = dev_pm_opp_get_freq(opp);
>> - dev_pm_opp_put(opp);
>> -
>> - err = clk_set_min_rate(tegra->emc_clock, rate * KHZ);
>> - if (err)
>> - return err;
>> -
>> - err = clk_set_rate(tegra->emc_clock, 0);
>> - if (err)
>> - goto restore_min_rate;
>>
>> - return 0;
>> -
>> -restore_min_rate:
>> - clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
>> + ret = dev_pm_opp_set_bw(dev, opp);
>> + dev_pm_opp_put(opp);
>>
>> - return err;
>> + return ret;
>> }
>>
>> static int tegra_devfreq_get_dev_status(struct device *dev,
>> @@ -655,7 +643,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
>> stat->private_data = tegra;
>>
>> /* The below are to be used by the other governors */
>> - stat->current_frequency = cur_freq;
>> + stat->current_frequency = cur_freq * KHZ;
>>
>> actmon_dev = &tegra->devices[MCALL];
>>
>> @@ -705,7 +693,12 @@ static int tegra_governor_get_target(struct devfreq *devfreq,
>> target_freq = max(target_freq, dev->target_freq);
>> }
>>
>> - *freq = target_freq;
>> + /*
>> + * tegra-devfreq driver operates with KHz units, while OPP table
>> + * entries use Hz units. Hence we need to convert the units for the
>> + * devfreq core.
>> + */
>> + *freq = target_freq * KHZ;
>>
>> return 0;
>> }
>> @@ -774,6 +767,7 @@ static struct devfreq_governor tegra_devfreq_governor = {
>>
>> static int tegra_devfreq_probe(struct platform_device *pdev)
>> {
>> + u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
>> struct tegra_devfreq_device *dev;
>> struct tegra_devfreq *tegra;
>> struct devfreq *devfreq;
>> @@ -781,6 +775,13 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>> long rate;
>> int err;
>>
>> + /* legacy device-trees don't have OPP table and must be updated */
>> + if (!device_property_present(&pdev->dev, "operating-points-v2")) {
>> + dev_err(&pdev->dev,
>> + "OPP table not found, please update your device tree\n");
>> + return -ENODEV;
>> + }
>> +
>
> You forgot to remove this ?

Yes, good catch. I'm planning to replace this code with a common helper
sometime soon, so if there won't be another reasons to make a new
revision, then I'd prefer to keep it as-is for now.