RE: [PATCH] scsi: ufs: Additional clock initialization in Cadence UFS

[Anil Joy Varughese]

Hi Vignesh,

You are correct I have tested the code here and .setup_clock is not needed anymore; CDNS_UFS_REG_HCLKDIV configured in .hce_enable_notify() is enough. I will fix this in patch v2. 

Thanks,
Anil

-----Original Message-----
From: Vignesh Raghavendra <vigneshr@xxxxxx> 
Sent: Wednesday, July 31, 2019 10:05 PM
To: Anil Joy Varughese <aniljoy@xxxxxxxxxxx>; alim.akhtar@xxxxxxxxxxx; avri.altman@xxxxxxx; pedrom.sousa@xxxxxxxxxxxx
Cc: jejb@xxxxxxxxxxxxx; martin.petersen@xxxxxxxxxx; hare@xxxxxxx; Rafal Ciepiela <rafalc@xxxxxxxxxxx>; Milind Parab <mparab@xxxxxxxxxxx>; Jan Kotas <jank@xxxxxxxxxxx>; linux-scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] scsi: ufs: Additional clock initialization in Cadence UFS

EXTERNAL MAIL


Hi,

On 31-Jul-19 2:06 PM, Anil Varughese wrote:
> Configure CDNS_UFS_REG_HCLKDIV in .hce_enable_notify() because if 
> UFSHCD resets the controller ip because of phy or device related 
> errors then CDNS_UFS_REG_HCLKDIV is reset to default value and 
> .setup_clock() is not called later in the sequence whereas 
> hce_enable_notify will be called everytime controller is reenabled.
>
So, now that CDNS_UFS_REG_HCLKDIV is configured in .hce_enable_notify(), is it still required to have the same code in .setup_clock() as well?
Isn't setting up CDNS_UFS_REG_HCLKDIV in .hce_enable_notify() alone not sufficient?

Regards
Vignesh

> Signed-off-by: Anil Varughese <aniljoy@xxxxxxxxxxx>
> ---
>  drivers/scsi/ufs/cdns-pltfrm.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/cdns-pltfrm.c 
> b/drivers/scsi/ufs/cdns-pltfrm.c index 86dbb723f..15ee54d28 100644
> --- a/drivers/scsi/ufs/cdns-pltfrm.c
> +++ b/drivers/scsi/ufs/cdns-pltfrm.c
> @@ -78,6 +78,22 @@ static int cdns_ufs_setup_clocks(struct ufs_hba *hba, bool on,
>  	return cdns_ufs_set_hclkdiv(hba);
>  }
>  
> +/**
> + * Called before and after HCE enable bit is set.
> + * @hba: host controller instance
> + * @status: notify stage (pre, post change)
> + *
> + * Return zero for success and non-zero for failure  */ static int 
> +cdns_ufs_hce_enable_notify(struct ufs_hba *hba,
> +				      enum ufs_notify_change_status status) {
> +	if (status != PRE_CHANGE)
> +		return 0;
> +
> +	return cdns_ufs_set_hclkdiv(hba);
> +}
> +
>  /**
>   * cdns_ufs_init - performs additional ufs initialization
>   * @hba: host controller instance
> @@ -115,12 +131,14 @@ static int 
> cdns_ufs_m31_16nm_phy_initialization(struct ufs_hba *hba)  static const struct ufs_hba_variant_ops cdns_ufs_pltfm_hba_vops = {
>  	.name = "cdns-ufs-pltfm",
>  	.setup_clocks = cdns_ufs_setup_clocks,
> +	.hce_enable_notify = cdns_ufs_hce_enable_notify,
>  };
>  
>  static const struct ufs_hba_variant_ops cdns_ufs_m31_16nm_pltfm_hba_vops = {
>  	.name = "cdns-ufs-pltfm",
>  	.init = cdns_ufs_init,
>  	.setup_clocks = cdns_ufs_setup_clocks,
> +	.hce_enable_notify = cdns_ufs_hce_enable_notify,
>  	.phy_initialization = cdns_ufs_m31_16nm_phy_initialization,
>  };
>  
>