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Message-ID: <20240124082231.GA4906@thinkpad>
Date: Wed, 24 Jan 2024 13:52:31 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Nitin Rawat <quic_nitirawa@...cinc.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Vinod Koul <vkoul@...nel.org>,
Kishon Vijay Abraham I <kishon@...nel.org>,
"James E.J. Bottomley" <jejb@...ux.ibm.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Philipp Zabel <p.zabel@...gutronix.de>,
linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
Can Guo <quic_cang@...cinc.com>,
Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
Subject: Re: [PATCH V1 1/2] scsi: ufs: qcom : Refactor phy_power_on/off calls
On Fri, Jan 12, 2024 at 09:03:47PM +0530, Nitin Rawat wrote:
> Commit 3f6d1767b1a0 ("phy: ufs-qcom: Refactor all init steps into
> phy_poweron") removes the phy_power_on/off from ufs_qcom_setup_clocks
s/removes/moved
> to suspend/resume func.
>
> To have a better power saving, remove the phy_power_on/off calls from
> resume/suspend path and put them back to ufs_qcom_setup_clocks, so that
> PHY's regulators & clks can be turned on/off along with UFS's clocks.
>
> Since phy phy_power_on is separated out from phy calibrate, make
> separate calls to phy_power_on and phy_calibrate calls from ufs qcom
> driver.
>
Above change should be in a separate patch.
> Also add a mutex lock to protect the usage of is_phy_pwr_on against
> possible racing.
>
> Co-developed-by: Can Guo <quic_cang@...cinc.com>
> Signed-off-by: Can Guo <quic_cang@...cinc.com>
> Co-developed-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Nitin Rawat <quic_nitirawa@...cinc.com>
> ---
> drivers/ufs/host/ufs-qcom.c | 104 +++++++++++++++++++++++-------------
> drivers/ufs/host/ufs-qcom.h | 4 ++
> 2 files changed, 72 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 39eef470f8fa..2721a30f0db8 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -338,6 +338,46 @@ static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
> return UFS_HS_G3;
> }
>
> +static int ufs_qcom_phy_power_on(struct ufs_hba *hba)
> +{
> + struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> + struct phy *phy = host->generic_phy;
> + int ret = 0;
> +
> + mutex_lock(&host->phy_mutex);
You do not need mutex to protect a variable. If you want to ensure that the
access to the flag is atomic, you can use test_and_{set/clear}_bit helpers.
> + if (!host->is_phy_pwr_on) {
> + ret = phy_power_on(phy);
> + if (ret) {
> + mutex_unlock(&host->phy_mutex);
> + return ret;
> + }
> + host->is_phy_pwr_on = true;
> + }
> + mutex_unlock(&host->phy_mutex);
> +
> + return ret;
> +}
> +
> +static int ufs_qcom_phy_power_off(struct ufs_hba *hba)
> +{
> + struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> + struct phy *phy = host->generic_phy;
> + int ret = 0;
> +
> + mutex_lock(&host->phy_mutex);
> + if (host->is_phy_pwr_on) {
> + ret = phy_power_off(phy);
> + if (ret) {
> + mutex_unlock(&host->phy_mutex);
> + return ret;
> + }
> + host->is_phy_pwr_on = false;
> + }
> + mutex_unlock(&host->phy_mutex);
> +
> + return ret;
> +}
> +
> static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
> {
> struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> @@ -378,13 +418,18 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
> goto out_disable_phy;
>
> /* power on phy - start serdes and phy's power and clocks */
> - ret = phy_power_on(phy);
> + ret = ufs_qcom_phy_power_on(hba);
> if (ret) {
> dev_err(hba->dev, "%s: phy power on failed, ret = %d\n",
> __func__, ret);
> goto out_disable_phy;
> }
>
> + ret = phy_calibrate(phy);
> + if (ret) {
> + dev_err(hba->dev, "%s: Failed to calibrate PHY %d\n",
> + __func__, ret);
Even though the driver already has a lot of "__func__" to print the function
names in error log, please do not add more. I will get rid of the existing ones
at some point.
- Mani
--
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