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Subject: Re: [PATCH v1 3/3] scsi: ufs-mediatek: enable low-power mode for
 hibern8 state
To:     Stanley Chu <stanley.chu@mediatek.com>, linux-scsi@vger.kernel.org,
        martin.petersen@oracle.com, avri.altman@wdc.com,
        alim.akhtar@samsung.com, jejb@linux.ibm.com
Cc:     beanhuo@micron.com, cang@codeaurora.org, matthias.bgg@gmail.com,
        bvanassche@acm.org, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kuohong.wang@mediatek.com, peter.wang@mediatek.com,
        chun-hung.wu@mediatek.com, andy.teng@mediatek.com
References: <20200117035108.19699-1-stanley.chu@mediatek.com>
 <20200117035108.19699-4-stanley.chu@mediatek.com>
From:   "Asutosh Das (asd)" <asutoshd@codeaurora.org>
Message-ID: <38b2614d-1fdd-8bad-63a1-e9bc5698cc66@codeaurora.org>
Date:   Mon, 20 Jan 2020 12:52:17 -0800
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On 1/16/2020 7:51 PM, Stanley Chu wrote:
> In MediaTek Chipsets, UniPro link and ufshci can enter proprietary
> low-power mode while link is in hibern8 state.
> 
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> ---

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

>   drivers/scsi/ufs/ufs-mediatek.c | 53 +++++++++++++++++++++++++++++++++
>   1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index d5194d0c4ef5..f32f3f34f6d0 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -382,11 +382,60 @@ static void ufs_mtk_device_reset(struct ufs_hba *hba)
>   	dev_info(hba->dev, "device reset done\n");
>   }
>   
> +static int ufs_mtk_link_set_hpm(struct ufs_hba *hba)
> +{
> +	int err;
> +
> +	err = ufshcd_hba_enable(hba);
> +	if (err)
> +		return err;
> +
> +	err = ufshcd_dme_set(hba,
> +			     UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
> +			     0);
> +	if (err)
> +		return err;
> +
> +	err = ufshcd_uic_hibern8_exit(hba);
> +	if (!err)
> +		ufshcd_set_link_active(hba);
> +	else
> +		return err;
> +
> +	err = ufshcd_make_hba_operational(hba);
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static int ufs_mtk_link_set_lpm(struct ufs_hba *hba)
> +{
> +	int err;
> +
> +	err = ufshcd_dme_set(hba,
> +			     UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
> +			     1);
> +	if (err) {
> +		/* Resume UniPro state for following error recovery */
> +		ufshcd_dme_set(hba,
> +			       UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
> +			       0);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
>   static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>   {
> +	int err;
>   	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
>   
>   	if (ufshcd_is_link_hibern8(hba)) {
> +		err = ufs_mtk_link_set_lpm(hba);
> +		if (err)
> +			return -EAGAIN;
>   		phy_power_off(host->mphy);
>   		ufs_mtk_setup_ref_clk(hba, false);
>   	}
> @@ -397,10 +446,14 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>   static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>   {
>   	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
> +	int err;
>   
>   	if (ufshcd_is_link_hibern8(hba)) {
>   		ufs_mtk_setup_ref_clk(hba, true);
>   		phy_power_on(host->mphy);
> +		err = ufs_mtk_link_set_hpm(hba);
> +		if (err)
> +			return err;
>   	}
>   
>   	return 0;
> 


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