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

Stephen Boyd
2019-01-18T22:31:07Z

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];
>