Re: [PATCH v1 5/8] scsi: ufs: qcom: Expose the reset controller for PHY

[Stephen Boyd]

Quoting Evan Green (2019-01-11 15:01:26)
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 3aeadb14aae1e..db46f9a64b54c 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -16,6 +16,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/phy/phy.h>
> +#include <linux/reset.h>

Shouldn't this be <linux/reset-controller.h>?

>  
>  #include "ufshcd.h"
>  #include "ufshcd-pltfrm.h"
> @@ -255,11 +261,6 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>         if (is_rate_B)
>                 phy_set_mode(phy, PHY_MODE_UFS_HS_B);
>  
> -       /* Assert PHY reset and apply PHY calibration values */
> -       ufs_qcom_assert_reset(hba);
> -       /* provide 1ms delay to let the reset pulse propagate */
> -       usleep_range(1000, 1100);
> -
>         /* phy initialization - calibrate the phy */
>         ret = phy_init(phy);
>         if (ret) {
> @@ -268,15 +269,6 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>                 goto out;
>         }
>  
> -       /* De-assert PHY reset and start serdes */
> -       ufs_qcom_deassert_reset(hba);
> -
> -       /*
> -        * after reset deassertion, phy will need all ref clocks,
> -        * voltage, current to settle down before starting serdes.
> -        */
> -       usleep_range(1000, 1100);
> -
>         /* power on phy - start serdes and phy's power and clocks */
>         ret = phy_power_on(phy);
>         if (ret) {
> @@ -290,7 +282,6 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>         return 0;
>  
>  out_disable_phy:
> -       ufs_qcom_assert_reset(hba);
>         phy_exit(phy);
>  out:
>         return ret;
> @@ -554,21 +545,10 @@ static int ufs_qcom_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>                 ufs_qcom_disable_lane_clks(host);
>                 phy_power_off(phy);
>  
> -               /* Assert PHY soft reset */
> -               ufs_qcom_assert_reset(hba);
> -               goto out;
> -       }
> -
> -       /*
> -        * If UniPro link is not active, PHY ref_clk, main PHY analog power
> -        * rail and low noise analog power rail for PLL can be switched off.

We lost this comment?

> -        */
> -       if (!ufs_qcom_is_link_active(hba)) {
> +       } else if (!ufs_qcom_is_link_active(hba)) {
>                 ufs_qcom_disable_lane_clks(host);
> -               phy_power_off(phy);

And now this looks similar to the above if statement, so can they be
combined?

>  
> -out:
>         return ret;
>  }
>  
> @@ -578,21 +558,26 @@ static int ufs_qcom_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>         struct phy *phy = host->generic_phy;
>         int err;
>  
> -       err = phy_power_on(phy);
> -       if (err) {
> -               dev_err(hba->dev, "%s: failed enabling regs, err = %d\n",
> -                       __func__, err);
> -               goto out;
> -       }
> +       if (ufs_qcom_is_link_off(hba)) {
> +               err = phy_power_on(phy);
> +               if (err) {
> +                       dev_err(hba->dev, "%s: failed enabling regs, err = %d\n",

Not a problem with this translation, but I would expect this error to
say something more like 'failed to power on phy' instead of 'enabling
regs'.

> +                               __func__, err);
> +                       return err;
> +               }
>  
> -       err = ufs_qcom_enable_lane_clks(host);
> -       if (err)
> -               goto out;
> +               err = ufs_qcom_enable_lane_clks(host);
> +               if (err)
> +                       return err;
>  
> -       hba->is_sys_suspended = false;
> +       } else if (!ufs_qcom_is_link_active(hba)) {
> +               err = ufs_qcom_enable_lane_clks(host);
> +               if (err)
> +                       return err;
> +       }
>  
> -out:
> -       return err;
> +       hba->is_sys_suspended = false;
> +       return 0;
>  }
>  
>  struct ufs_qcom_dev_params {
> @@ -1118,8 +1103,6 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>                 return 0;
>  
>         if (on && (status == POST_CHANGE)) {
> -               phy_power_on(host->generic_phy);
> -

How is it ok to remove this call here?

>                 /* enable the device ref clock for HS mode*/
>                 if (ufshcd_is_hs_mode(&hba->pwr_info))
>                         ufs_qcom_dev_ref_clk_ctrl(host, true);
> @@ -1131,9 +1114,6 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>                 if (!ufs_qcom_is_link_active(hba)) {
>                         /* disable device ref_clk */
>                         ufs_qcom_dev_ref_clk_ctrl(host, false);
> -
> -                       /* powering off PHY during aggressive clk gating */
> -                       phy_power_off(host->generic_phy);

And here?

>                 }
>  
>                 vote = host->bus_vote.min_bw_vote;
> @@ -1147,6 +1127,39 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>         return err;
>  }
>  
> +static int
> +ufs_qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
> +{
> +       struct ufs_qcom_host *host = rcdev_to_ufs_host(rcdev);
> +
> +       WARN_ON(id);

Nitpick: Add a comment explaining that there's only one reset expected?

> +       ufs_qcom_assert_reset(host->hba);
> +       /* provide 1ms delay to let the reset pulse propagate */
> +       usleep_range(1000, 1100);
> +       return 0;
> +}
> +
> +static int
> +ufs_qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
> +{
> +       struct ufs_qcom_host *host = rcdev_to_ufs_host(rcdev);
> +
> +       WARN_ON(id);

Same nitpick.

> +       ufs_qcom_deassert_reset(host->hba);
> +
> +       /*
> +        * after reset deassertion, phy will need all ref clocks,
> +        * voltage, current to settle down before starting serdes.
> +        */
> +       usleep_range(1000, 1100);
> +       return 0;
> +}
> +
> +const struct reset_control_ops ufs_qcom_reset_ops = {

Can it be static?

> +       .assert = ufs_qcom_reset_assert,
> +       .deassert = ufs_qcom_reset_deassert,
> +};
> +
>  #define        ANDROID_BOOT_DEV_MAX    30
>  static char android_boot_dev[ANDROID_BOOT_DEV_MAX];
>