linux-kernel - Re: [PATCH v5 4/8] scsi: ufs-qcom: Adjust bus bandwidth voting and unvoting

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Message-ID: <ca9e97dc-0328-884e-0236-91c9f9ea9f41@codeaurora.org>
Date:   Tue, 4 Feb 2020 18:17:01 -0800
From:   "Asutosh Das (asd)" <asutoshd@...eaurora.org>
To:     Can Guo <cang@...eaurora.org>, nguyenb@...eaurora.org,
        hongwus@...eaurora.org, rnayak@...eaurora.org,
        linux-scsi@...r.kernel.org, kernel-team@...roid.com,
        saravanak@...gle.com, salyzyn@...gle.com
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 4/8] scsi: ufs-qcom: Adjust bus bandwidth voting and
 unvoting

On 2/3/2020 1:17 AM, Can Guo wrote:
> The bus bandwidth voting is required to be done before the bus clocks
> are enabled, and the unvoting is required to be done only after the bus
> clocks are disabled.
> 
> Signed-off-by: Can Guo <cang@...eaurora.org>
> ---

Reviewed-by: Asutosh Das <asutoshd@...eaurora.org>

>   drivers/scsi/ufs/ufs-qcom.c | 57 +++++++++++++++++++++++++++++++--------------
>   1 file changed, 39 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index c69c29a1c..85d7c17 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -38,7 +38,6 @@ enum {
>   
>   static struct ufs_qcom_host *ufs_qcom_hosts[MAX_UFS_QCOM_HOSTS];
>   
> -static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote);
>   static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
>   static int ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(struct ufs_hba *hba,
>   						       u32 clk_cycles);
> @@ -674,7 +673,7 @@ static void ufs_qcom_get_speed_mode(struct ufs_pa_layer_attr *p, char *result)
>   	}
>   }
>   
> -static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
> +static int __ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
>   {
>   	int err = 0;
>   
> @@ -705,7 +704,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>   
>   	vote = ufs_qcom_get_bus_vote(host, mode);
>   	if (vote >= 0)
> -		err = ufs_qcom_set_bus_vote(host, vote);
> +		err = __ufs_qcom_set_bus_vote(host, vote);
>   	else
>   		err = vote;
>   
> @@ -716,6 +715,35 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>   	return err;
>   }
>   
> +static int ufs_qcom_set_bus_vote(struct ufs_hba *hba, bool on)
> +{
> +	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> +	int vote, err;
> +
> +	/*
> +	 * In case ufs_qcom_init() is not yet done, simply ignore.
> +	 * This ufs_qcom_set_bus_vote() shall be called from
> +	 * ufs_qcom_init() after init is done.
> +	 */
> +	if (!host)
> +		return 0;
> +
> +	if (on) {
> +		vote = host->bus_vote.saved_vote;
> +		if (vote == host->bus_vote.min_bw_vote)
> +			ufs_qcom_update_bus_bw_vote(host);
> +	} else {
> +		vote = host->bus_vote.min_bw_vote;
> +	}
> +
> +	err = __ufs_qcom_set_bus_vote(host, vote);
> +	if (err)
> +		dev_err(hba->dev, "%s: set bus vote failed %d\n",
> +				 __func__, err);
> +
> +	return err;
> +}
> +
>   static ssize_t
>   show_ufs_to_mem_max_bus_bw(struct device *dev, struct device_attribute *attr,
>   			char *buf)
> @@ -792,7 +820,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>   	return 0;
>   }
>   
> -static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
> +static int ufs_qcom_set_bus_vote(struct ufs_hba *host, bool on)
>   {
>   	return 0;
>   }
> @@ -1030,8 +1058,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>   				 enum ufs_notify_change_status status)
>   {
>   	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> -	int err;
> -	int vote = 0;
> +	int err = 0;
>   
>   	/*
>   	 * In case ufs_qcom_init() is not yet done, simply ignore.
> @@ -1041,28 +1068,21 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
>   	if (!host)
>   		return 0;
>   
> -	if (on && (status == POST_CHANGE)) {
> +	if (on && (status == PRE_CHANGE)) {
> +		err = ufs_qcom_set_bus_vote(hba, true);
> +	} else if (on && (status == POST_CHANGE)) {
>   		/* enable the device ref clock for HS mode*/
>   		if (ufshcd_is_hs_mode(&hba->pwr_info))
>   			ufs_qcom_dev_ref_clk_ctrl(host, true);
> -		vote = host->bus_vote.saved_vote;
> -		if (vote == host->bus_vote.min_bw_vote)
> -			ufs_qcom_update_bus_bw_vote(host);
> -
>   	} else if (!on && (status == PRE_CHANGE)) {
>   		if (!ufs_qcom_is_link_active(hba)) {
>   			/* disable device ref_clk */
>   			ufs_qcom_dev_ref_clk_ctrl(host, false);
>   		}
> -
> -		vote = host->bus_vote.min_bw_vote;
> +	} else if (!on && (status == POST_CHANGE)) {
> +		err = ufs_qcom_set_bus_vote(hba, false);
>   	}
>   
> -	err = ufs_qcom_set_bus_vote(host, vote);
> -	if (err)
> -		dev_err(hba->dev, "%s: set bus vote failed %d\n",
> -				__func__, err);
> -
>   	return err;
>   }
>   
> @@ -1238,6 +1258,7 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>   	ufs_qcom_set_caps(hba);
>   	ufs_qcom_advertise_quirks(hba);
>   
> +	ufs_qcom_set_bus_vote(hba, true);
>   	ufs_qcom_setup_clocks(hba, true, POST_CHANGE);
>   
>   	if (hba->dev->id < MAX_UFS_QCOM_HOSTS)
> 


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