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Message-ID: <124fb13c-c41a-42b0-a521-158876b1b00c@quicinc.com>
Date: Thu, 10 Apr 2025 21:07:37 +0530
From: Nitin Rawat <quic_nitirawa@...cinc.com>
To: Bjorn Andersson <andersson@...nel.org>
CC: <vkoul@...nel.org>, <kishon@...nel.org>,
<manivannan.sadhasivam@...aro.org>,
<James.Bottomley@...senpartnership.com>, <martin.petersen@...cle.com>,
<konrad.dybcio@....qualcomm.com>, <quic_rdwivedi@...cinc.com>,
<linux-arm-msm@...r.kernel.org>, <linux-phy@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH V2 3/6] phy: qcom-qmp-ufs: Refactor UFS PHY reset
On 3/19/2025 1:16 AM, Bjorn Andersson wrote:
> On Tue, Mar 18, 2025 at 08:19:41PM +0530, Nitin Rawat wrote:
>> Refactor the UFS PHY reset handling to parse the reset logic only once
>> during probe, instead of every resume.
>>
>
> This looks very reasonable! But it would be preferred to see the commit
> messages following the what format outlines in
> https://docs.kernel.org/process/submitting-patches.html#describe-your-changes
> with a clear problem description followed by a description of the
> technical solution.
>
>> Move the UFS PHY reset parsing logic from qmp_phy_power_on to
>> qmp_ufs_probe to avoid unnecessary parsing during resume.
>
> Please add ()-suffix to function names in your commit messages.
>
> Also, this series moves things around a lot, can you confirm that UFS is
> working inbetween each one of this patches, so that the branch is
> bisectable when this is being picked up?
Hi Bjorn,
Thanks for the review. I've addressed the bisectability compliance in my
latest patch set (patchset #3) that I posted today. I just realized I
missed your other comments about adding the ()-suffix to function names
in commit messages. Sorry about that. I'll make sure to include this in
my next patch set.
Thanks,
Nitin
>
>>
>> Co-developed-by: Ram Kumar Dwivedi <quic_rdwivedi@...cinc.com>
>> Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@...cinc.com>
>> Signed-off-by: Nitin Rawat <quic_nitirawa@...cinc.com>
>> ---
>> drivers/phy/qualcomm/phy-qcom-qmp-ufs.c | 104 ++++++++++++------------
>> 1 file changed, 50 insertions(+), 54 deletions(-)
>>
>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c b/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
>> index 0089ee80f852..3a80c2c110d2 100644
>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
>> @@ -1757,32 +1757,6 @@ static void qmp_ufs_init_registers(struct qmp_ufs *qmp, const struct qmp_phy_cfg
>> qmp_ufs_init_all(qmp, &cfg->tbls_hs_b);
>> }
>>
>> -static int qmp_ufs_com_init(struct qmp_ufs *qmp)
>> -{
>> - const struct qmp_phy_cfg *cfg = qmp->cfg;
>> - void __iomem *pcs = qmp->pcs;
>> - int ret;
>> -
>> - ret = regulator_bulk_enable(cfg->num_vregs, qmp->vregs);
>> - if (ret) {
>> - dev_err(qmp->dev, "failed to enable regulators, err=%d\n", ret);
>> - return ret;
>> - }
>> -
>> - ret = clk_bulk_prepare_enable(qmp->num_clks, qmp->clks);
>> - if (ret)
>> - goto err_disable_regulators;
>> -
>> - qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL], SW_PWRDN);
>> -
>> - return 0;
>> -
>> -err_disable_regulators:
>> - regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
>> -
>> - return ret;
>> -}
>> -
>> static int qmp_ufs_com_exit(struct qmp_ufs *qmp)
>> {
>> const struct qmp_phy_cfg *cfg = qmp->cfg;
>> @@ -1800,41 +1774,27 @@ static int qmp_ufs_power_on(struct phy *phy)
>> {
>> struct qmp_ufs *qmp = phy_get_drvdata(phy);
>> const struct qmp_phy_cfg *cfg = qmp->cfg;
>> + void __iomem *pcs = qmp->pcs;
>
> This is only used once, perhaps not worth a local variable to save 5
> characters on that line?
>
>> int ret;
>> - dev_vdbg(qmp->dev, "Initializing QMP phy\n");
>> -
>> - if (cfg->no_pcs_sw_reset) {
>> - /*
>> - * Get UFS reset, which is delayed until now to avoid a
>> - * circular dependency where UFS needs its PHY, but the PHY
>> - * needs this UFS reset.
>> - */
>> - if (!qmp->ufs_reset) {
>> - qmp->ufs_reset =
>> - devm_reset_control_get_exclusive(qmp->dev,
>> - "ufsphy");
>> -
>> - if (IS_ERR(qmp->ufs_reset)) {
>> - ret = PTR_ERR(qmp->ufs_reset);
>> - dev_err(qmp->dev,
>> - "failed to get UFS reset: %d\n",
>> - ret);
>> -
>> - qmp->ufs_reset = NULL;
>> - return ret;
>> - }
>> - }
>>
>> - ret = reset_control_assert(qmp->ufs_reset);
>> - if (ret)
>> - return ret;
>> + ret = regulator_bulk_enable(cfg->num_vregs, qmp->vregs);
>> + if (ret) {
>> + dev_err(qmp->dev, "failed to enable regulators, err=%d\n", ret);
>
> regulator_bulk_enable() will already have printed a more useful error
> message, letting you know which of the vregs[] it was that failed to
> enable.
>
>> + return ret;
>> }
>>
>> - ret = qmp_ufs_com_init(qmp);
>> + ret = clk_bulk_prepare_enable(qmp->num_clks, qmp->clks);
>> if (ret)
>> - return ret;
>> + goto err_disable_regulators;
>> +
>> + qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL], SW_PWRDN);
>>
>> return 0;
>> +
>> +err_disable_regulators:
>> + regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
>> +
>> + return ret;
>> }
>>
>> static int qmp_ufs_phy_calibrate(struct phy *phy)
>> @@ -1846,6 +1806,10 @@ static int qmp_ufs_phy_calibrate(struct phy *phy)
>> unsigned int val;
>> int ret;
>>
>> + ret = reset_control_assert(qmp->ufs_reset);
>> + if (ret)
>> + return ret;
>> +
>> qmp_ufs_init_registers(qmp, cfg);
>>
>> ret = reset_control_deassert(qmp->ufs_reset);
>> @@ -2088,6 +2052,34 @@ static int qmp_ufs_parse_dt(struct qmp_ufs *qmp)
>> return 0;
>> }
>>
>> +static int qmp_ufs_get_phy_reset(struct qmp_ufs *qmp)
>> +{
>> + const struct qmp_phy_cfg *cfg = qmp->cfg;
>> + int ret;
>> +
>> + if (!cfg->no_pcs_sw_reset)
>> + return 0;
>> +
>> + /*
>> + * Get UFS reset, which is delayed until now to avoid a
>> + * circular dependency where UFS needs its PHY, but the PHY
>> + * needs this UFS reset.
>
> This is invoked only once, from qcom_ufs_probe(), so it doesn't seem
> accurate anymore. How come this is no longer needed? Please describe
> what changed int he commit message.
>
>> + */
>> + if (!qmp->ufs_reset) {
>> + qmp->ufs_reset =
>> + devm_reset_control_get_exclusive(qmp->dev, "ufsphy");
>
> The line break here is really weird, are you sure checkpatch --strict
> didn't complain about this one?
>
>> +
>> + if (IS_ERR(qmp->ufs_reset)) {
>> + ret = PTR_ERR(qmp->ufs_reset);
>> + dev_err(qmp->dev, "failed to get PHY reset: %d\n", ret);
>
> return dev_err_probe(qmp->dev, PTR_ERR(qmp->ufs_reset), "failed to...: %pe\n", qmp->ufs_reset);
>
> While being more succinct, it also stores the reason for failing the
> probe so that you can find it in /sys/kernel/debug/devices_deferred
>
>> + qmp->ufs_reset = NULL;
>
> Use a local variable if you're worried about someone accessing the stale
> error code after returning here.
>
> Regards,
> Bjorn
>
>> + return ret;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int qmp_ufs_probe(struct platform_device *pdev)
>> {
>> struct device *dev = &pdev->dev;
>> @@ -2114,6 +2106,10 @@ static int qmp_ufs_probe(struct platform_device *pdev)
>> if (ret)
>> return ret;
>>
>> + ret = qmp_ufs_get_phy_reset(qmp);
>> + if (ret)
>> + return ret;
>> +
>> /* Check for legacy binding with child node. */
>> np = of_get_next_available_child(dev->of_node, NULL);
>> if (np) {
>> --
>> 2.48.1
>>
>>
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