Re: [PATCH v7 45/47] PM / devfreq: tegra30: Support interconnect and OPPs from device-tree

Chanwoo Choi
2020-11-05T02:08:25Z

Hi Dmitry,

On 11/5/20 1:49 AM, 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>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/devfreq/tegra30-devfreq.c | 96 +++++++++++++++++--------------
> 1 file changed, 54 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index 38cc0d014738..4db027ca17e1 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;
> }
> @@ -774,13 +767,22 @@ 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 opp_table *opp_table;
> struct devfreq *devfreq;
> unsigned int i;
> 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;
> + }
> +
> tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
> if (!tegra)
> return -ENOMEM;
> @@ -822,11 +824,31 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> return err;
> }
>
> + tegra->opp_table = dev_pm_opp_get_opp_table(&pdev->dev);
> + err = PTR_ERR_OR_ZERO(tegra->opp_table);
> + if (err) {
> + dev_err(&pdev->dev, "Failed to prepare OPP table: %d\n", err);
> + return err;
> + }
> +
> + opp_table = dev_pm_opp_set_supported_hw(&pdev->dev, &hw_version, 1);
> + err = PTR_ERR_OR_ZERO(opp_table);
> + if (err) {
> + dev_err(&pdev->dev, "Failed to set supported HW: %d\n", err);
> + goto put_table;
> + }
> +
> + err = dev_pm_opp_of_add_table(&pdev->dev);
> + if (err) {
> + dev_err(&pdev->dev, "Failed to add OPP table: %d\n", err);
> + goto put_hw;
> + }
> +
> err = clk_prepare_enable(tegra->clock);
> if (err) {
> dev_err(&pdev->dev,
> "Failed to prepare and enable ACTMON clock\n");
> - return err;
> + goto remove_table;
> }
>
> err = reset_control_reset(tegra->reset);
> @@ -850,23 +872,6 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> dev->regs = tegra->regs + dev->config->offset;
> }
>
> - for (rate = 0; rate <= tegra->max_freq * KHZ; rate++) {
> - rate = clk_round_rate(tegra->emc_clock, rate);
> -
> - if (rate < 0) {
> - dev_err(&pdev->dev,
> - "Failed to round clock rate: %ld\n", rate);
> - err = rate;
> - goto remove_opps;
> - }
> -
> - err = dev_pm_opp_add(&pdev->dev, rate / KHZ, 0);
> - if (err) {
> - dev_err(&pdev->dev, "Failed to add OPP: %d\n", err);
> - goto remove_opps;
> - }
> - }
> -
> platform_set_drvdata(pdev, tegra);
>
> tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb;
> @@ -882,7 +887,6 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> }
>
> tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
> - tegra_devfreq_profile.initial_freq /= KHZ;
>
> devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
> "tegra_actmon", NULL);
> @@ -902,6 +906,12 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> reset_control_reset(tegra->reset);
> disable_clk:
> clk_disable_unprepare(tegra->clock);
> +remove_table:
> + dev_pm_opp_of_remove_table(&pdev->dev);
> +put_hw:
> + dev_pm_opp_put_supported_hw(tegra->opp_table);
> +put_table:
> + dev_pm_opp_put_opp_table(tegra->opp_table);
>
> return err;
> }
> @@ -913,11 +923,13 @@ static int tegra_devfreq_remove(struct platform_device *pdev)
> devfreq_remove_device(tegra->devfreq);
> devfreq_remove_governor(&tegra_devfreq_governor);
>
> - dev_pm_opp_remove_all_dynamic(&pdev->dev);
> -
> reset_control_reset(tegra->reset);
> clk_disable_unprepare(tegra->clock);
>
> + dev_pm_opp_of_remove_table(&pdev->dev);
> + dev_pm_opp_put_supported_hw(tegra->opp_table);
> + dev_pm_opp_put_opp_table(tegra->opp_table);
> +
> return 0;
> }
>
>

Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

--
Best Regards,
Chanwoo Choi
Samsung Electronics