LKML Archive on
help / color / mirror / Atom feed
From: Vivek Gautam <>
To: Bjorn Andersson <>
	"" <>
Subject: Re: [PATCH 1/1] scsi/ufs: qcom: Don't enable PHY_QCOM_UFS by default
Date: Fri, 20 Apr 2018 00:21:56 +0530	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20180417231109.GO18510@minitux>

Hi Bjorn,

On 4/18/2018 4:41 AM, Bjorn Andersson wrote:
> On Mon 09 Apr 23:31 PDT 2018, Vivek Gautam wrote:
>> On 4/10/2018 1:39 AM, Bjorn Andersson wrote:
>>> On Mon 09 Apr 10:38 PDT 2018, Vivek Gautam wrote:
>>>> On 4/9/2018 10:21 PM, Bjorn Andersson wrote:
>>>>> On Mon 09 Apr 06:24 PDT 2018, Vivek Gautam wrote:
>>> [..]
>>>>>> diff --git a/include/linux/phy/phy-qcom-ufs.h b/include/linux/phy/phy-qcom-ufs.h
>>>>>> index 0a2c18a9771d..1388c2a2965e 100644
>>>>>> --- a/include/linux/phy/phy-qcom-ufs.h
>>>>>> +++ b/include/linux/phy/phy-qcom-ufs.h
>>>>>> @@ -31,8 +31,21 @@ void ufs_qcom_phy_enable_dev_ref_clk(struct phy *phy);
>>>>>>      */
>>>>>>     void ufs_qcom_phy_disable_dev_ref_clk(struct phy *phy);
>>>>>>     int ufs_qcom_phy_set_tx_lane_enable(struct phy *phy, u32 tx_lanes);
>>>>>>     void ufs_qcom_phy_save_controller_version(struct phy *phy,
>>>>>> -			u8 major, u16 minor, u16 step);
>>>>>> +					  u8 major, u16 minor, u16 step);
>>>>>> +#else
>>>>>> +static inline int ufs_qcom_phy_set_tx_lane_enable(struct phy *phy, u32 tx_lanes)
>>>>>> +{
>>>>>> +	return -ENOSYS;
>>>>>> +}
>>>>>> +
>>>>>> +static inline void ufs_qcom_phy_save_controller_version(struct phy *phy,
>>>>>> +							u8 major, u16 minor,
>>>>>> +							u16 step)
>>>>>> +{
>>>>>> +}
>>>>>> +#endif /* PHY_QCOM_UFS */
>>>>> What's the timeline for getting rid of the references to these
>>>>> functions? I presume that code depending on these being here will
>>>>> compile but won't actually work?
>>>> Yes, these inline definitions are just to keep ufs-qcom happy with the
>>>> direct
>>>> calls that it makes to these functions.
>>>> As you would know these couple of functions are just used by the 20nm phy.
>>>> However, we don't have any platform yet in the upstream that enables this
>>>> phy.
>>>> I am hoping that we will eventually get rid of these functions when we
>>>> further
>>>> clean up ufs-qcom driver.
>>> I see, but that means that we're calling this function with a struct phy
>>> that might not be a struct ufs_qcom_phy and as such a defconfig with
>>> both enabled will have undefined outcome for the migrated phys.
>> No, we will have to add support for separate phys as sdm845 has phy per each
>> lane,
>> and the older struct phy will exist alongside.
>> We will call this function only with the older phy pointer.
>>> In particular we do expect that the same kernel will boot on db820c and
>>> sdm845-mtp, so we will have to enable support for the 14nm & 20nm phy
>>> driver (and we don't want random crashes because someone happened to
>>> enable it).
>> Right, so we create new struct phy while keeping older one intact to keep
>> the
>> ufs-qcom work with both - ufs_qcom_phy and qmp_phy.
>> Some of the controller drivers, such as usb/dwc3/ keep support for old and
>> new phys,
>> although there the difference is between generic phy and the usb-phy.
>> So, I am assuming that if we want to keep ufs-qcom on platforms using 20nm,
>> 14nm and 10nm phys happy, we will have to keep the phys separately for
>> sometime.
>> What do you say about it?
> My concern is only that the UFS HCI driver doesn't have a way to know if
> it's the new or old "type" of phy, but if you can get that working then
> I don't have any objections about doing so for a transitional period.
> But, you may not use kernel config options to handle this, the same
> Image should boot on msm8916, msm8996 and sdm845 (with appropriate dtb
> for each one).

Right, i get your concern. I will try to refactor the UFS HCI code to 
handle the two
'types' of phys.
I think Can Guo (CC'ed here) was already working on this. I will check 
with him
if he already has some code to do this.

>> On db820c, we can still work with the ufs_qcom_phy.
> I do not have an issue with that.
> Regards,
> Bjorn
> --
> To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
> the body of a message to
> More majordomo info at

      reply	other threads:[~2018-04-19 18:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-09 13:24 Vivek Gautam
2018-04-09 16:51 ` Bjorn Andersson
2018-04-09 17:38   ` Vivek Gautam
2018-04-09 20:09     ` Bjorn Andersson
2018-04-10  6:31       ` Vivek Gautam
2018-04-17 23:11         ` Bjorn Andersson
2018-04-19 18:51           ` Vivek Gautam [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH 1/1] scsi/ufs: qcom: Don'\''t enable PHY_QCOM_UFS by default' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).