Re: [PATCH 2/7] phy: qcom-qmp-combo: Move phy_mutex out of com_init/exit

Johan Hovold
2023-05-02T10:43:52Z

On Mon, Apr 24, 2023 at 08:40:05PM -0700, Bjorn Andersson wrote:
> With the upcoming introduction of USB Type-C orientation switching the
> region of mutual exclusion needs to be extended to cover both the common
> init/exit as well as the individual functions.
>
> So move the phy_mutex one step up the stack.
>
> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> ---
> drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 51 +++++++++++++----------
> 1 file changed, 30 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> index 6850e04c329b..7280f7141961 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> @@ -2463,16 +2463,13 @@ static int qmp_combo_com_init(struct qmp_combo *qmp)
> void __iomem *com = qmp->com;
> int ret;
>
> - mutex_lock(&qmp->phy_mutex);
> - if (qmp->init_count++) {
> - mutex_unlock(&qmp->phy_mutex);
> + if (qmp->init_count++)
> return 0;
> - }
>
> ret = regulator_bulk_enable(cfg->num_vregs, qmp->vregs);
> if (ret) {
> dev_err(qmp->dev, "failed to enable regulators, err=%d\n", ret);
> - goto err_unlock;
> + goto err;

I was going to say that you can just return ret directly but then
realised we have a counter imbalance here that should be fixed.

I've just sent a couple of fixes which you could rebase on:

https://lore.kernel.org/r/20230502103810.12061-1-johan+linaro@kernel.org

> }
>
> ret = reset_control_bulk_assert(cfg->num_resets, qmp->resets);
> @@ -2514,16 +2511,13 @@ static int qmp_combo_com_init(struct qmp_combo *qmp)
> qphy_setbits(qmp->pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
> SW_PWRDN);
>
> - mutex_unlock(&qmp->phy_mutex);
> -
> return 0;
>
> err_assert_reset:
> reset_control_bulk_assert(cfg->num_resets, qmp->resets);
> err_disable_regulators:
> regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
> -err_unlock:
> - mutex_unlock(&qmp->phy_mutex);
> +err:
>
> return ret;
> }

> @@ -2686,14 +2683,19 @@ static int qmp_combo_usb_init(struct phy *phy)
> struct qmp_combo *qmp = phy_get_drvdata(phy);
> int ret;
>
> + mutex_lock(&qmp->phy_mutex);

Nit: I think adding a newline here would improve readability.

> ret = qmp_combo_com_init(qmp);
> if (ret)
> - return ret;
> + goto out_unlock;
>
> ret = qmp_combo_usb_power_on(phy);
> - if (ret)
> + if (ret) {
> qmp_combo_com_exit(qmp);
> + goto out_unlock;
> + }
>
> +out_unlock:
> + mutex_unlock(&qmp->phy_mutex);

Same here.

> return ret;
> }
>
> @@ -2702,11 +2704,18 @@ static int qmp_combo_usb_exit(struct phy *phy)
> struct qmp_combo *qmp = phy_get_drvdata(phy);
> int ret;
>
> + mutex_lock(&qmp->phy_mutex);

And here.

> ret = qmp_combo_usb_power_off(phy);
> if (ret)
> - return ret;
> + goto out_unlock;
>
> - return qmp_combo_com_exit(qmp);
> + ret = qmp_combo_com_exit(qmp);
> + if (ret)
> + goto out_unlock;
> +
> +out_unlock:
> + mutex_unlock(&qmp->phy_mutex);

And here.

> + return ret;
> }
>
> static int qmp_combo_usb_set_mode(struct phy *phy, enum phy_mode mode, int submode)

Looks good otherwise:

Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Johan