linux-kernel - Re: [PATCH] ufs: ufs-qcom: disable lane clocks during phy hibern8

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <w5mkkhxhhndrqhlfomvwohssndtl2njcw7khupyh7qechsynns@kl5ykxtwqawt>
Date: Wed, 13 Aug 2025 15:49:37 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Palash Kambar <quic_pkambar@...cinc.com>
Cc: James.Bottomley@...senpartnership.com, martin.petersen@...cle.com, 
	linux-arm-msm@...r.kernel.org, linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org, 
	quic_nitirawa@...cinc.com
Subject: Re: [PATCH] ufs: ufs-qcom: disable lane clocks during phy hibern8

On Tue, Jul 15, 2025 at 09:35:24PM GMT, Palash Kambar wrote:
> The UFS lane clocks ensure that the PHY is adequately powered and
> synchronized before initiating the link. Currently, these clocks
> remain enabled even after the link enters the Hibern8 state and
> are only turned off during runtime or system suspend.
> 
> Modify the behavior to disable the lane clocks immediately after
> the link transitions to Hibern8, thereby reducing the power
> consumption.
> 

This statement is technically misleading. You are disabling lane clocks in
ufs_qcom_setup_clocks(), which gets called during suspend/resume/clk_gate phase.

But if you want to disable the clocks immediately after Hibern8, you may want to
add the disable/enable logic in hibern8_notify() callback.

If that is not a strict requirement and you want to do it in
ufs_qcom_setup_clocks(), you have to reword the description.

- Mani

> Signed-off-by: Palash Kambar <quic_pkambar@...cinc.com>
> ---
>  drivers/ufs/host/ufs-qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 318dca7fe3d7..50e174d9b406 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -1141,6 +1141,13 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>  	case PRE_CHANGE:
>  		if (on) {
>  			ufs_qcom_icc_update_bw(host);
> +			if (ufs_qcom_is_link_hibern8(hba)) {
> +				err = ufs_qcom_enable_lane_clks(host);
> +				if (err) {
> +					dev_err(hba->dev, "enable lane clks failed, ret=%d\n", err);
> +					return err;
> +				}
> +			}
>  		} else {
>  			if (!ufs_qcom_is_link_active(hba)) {
>  				/* disable device ref_clk */
> @@ -1166,6 +1173,9 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>  			if (ufshcd_is_hs_mode(&hba->pwr_info))
>  				ufs_qcom_dev_ref_clk_ctrl(host, true);
>  		} else {
> +			if (ufs_qcom_is_link_hibern8(hba))
> +				ufs_qcom_disable_lane_clks(host);
> +
>  			ufs_qcom_icc_set_bw(host, ufs_qcom_bw_table[MODE_MIN][0][0].mem_bw,
>  					    ufs_qcom_bw_table[MODE_MIN][0][0].cfg_bw);
>  		}
> -- 
> 2.34.1
> 

-- 
மணிவண்ணன் சதாசிவம்