Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 2020-11-30 22:54, Stanley Chu wrote:
Hi Asutosh,
On Mon, 2020-11-30 at 19:07 -0800, Asutosh Das (asd) wrote:
On 11/30/2020 5:25 PM, Stanley Chu wrote:
> On Mon, 2020-11-30 at 15:54 -0800, Asutosh Das (asd) wrote:
>> On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
>>> On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
>>>
On 11/30/2020 1:16 AM, Stanley Chu wrote:
> UFS specficication allows different VCC configurations for UFS devices,
> for example,
>(1). 2.70V - 3.60V (By default)
>(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> device tree)
>(3). 2.40V - 2.70V (Supported since UFS 3.x)
>
> With the introduction of UFS 3.x products, an issue is happening that
> UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> regulator on UFU 3.x products with VCC configuration (3) used.
>
> To solve this issue, we simply remove pre-defined initial VCC voltage
> values in UFS driver with below reasons,
>
> 1. UFS specifications do not define how to detect the VCC configuration
> supported by attached device.
>
> 2. Device tree already supports standard regulator properties.
>
> Therefore VCC voltage shall be defined correctly in device tree, and
> shall not be changed by UFS driver. What UFS driver needs to do is simply
> enabling or disabling the VCC regulator only.
>
> This is a RFC conceptional patch. Please help review this and feel
> free to feedback any ideas. Once this concept is accepted, and then
> I would post a more completed patch series to fix this issue.
>
> Signed-off-by: Stanley Chu
> ---
> drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index a6f76399b3ae..3965be03c136 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev,
const char *name,
>vreg->max_uA = 0;
>}
> - if (!strcmp(name, "vcc")) {
> - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> - } else {
> - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> - }
> - } else if (!strcmp(name, "vccq")) {
> + if (!strcmp(name, "vccq")) {
>vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
>vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
>} else if (!strcmp(name, "vccq2")) {
>
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards something
similar.
Would it be possible for you to take into account the scenario in which the
same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
>>>
>>> What is the actual voltage requirement for these devices and how does
>>> the software know what voltage to pick in this range?
>>>
>>> Regards,
>>> Bjorn
>>>
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
>>
>> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
>> voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the
>> ufs device at 2.95v & reads the version and if the device is 3.x, it may
>> do the following:
>> - Set the device power mode to SLEEP
>> - Disable the Vcc
>> - Enable the Vcc and set it to 2.5v
>> - Set the device power mode to ACTIVE
>>
>> All of the above may be done at HS-G1 & moved to max supported gear
>> based on the device version, perhaps?
>
> Hi Asutosh,
>
> Thanks for sharing this idea.
>
> 1. I did not see above flow defined in UFS specifications, please
> correct me if I was wrong.
>
> 2. For above flow, the concern is that I am not sure if all devices
> supporting VCC (2.4v - 2.7v) can accept higher voltage, say 2.95v, for
> version detection.
>
> 3. For version detection, another concern is that I am not sure if all
> 3.x devices support VCC (2.4v - 2.7v) only, or in other words, I am not
> sure if all 2.x devices support VCC (2.7v - 3.6v) only. The above rule
> will break any devices not obeying this "conventions".
>
> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v),
>
> It would be good for UFS drivers detecting the correct voltage if the
> protocol is well-defined in specifications. Until that day, any
> "non-standard" way may be better implemented in vendor's
RE: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
> > Hi Stanley > > > > Thanks for the patch. Bao (nguyenb) was also working towards > something > > similar. > > Would it be possible for you to take into account the scenario in > which the > > same platform supports both 2.x and 3.x UFS devices? > > > > These've different voltage requirements, 2.4v-3.6v. > > I'm not sure if standard dts regulator properties can support this. > > > > >>> > > >>> What is the actual voltage requirement for these devices and how > does > > >>> the software know what voltage to pick in this range? > > >>> > > >>> Regards, > > >>> Bjorn > > >>> > > -asd > > > > > > -- > > The Qualcomm Innovation Center, Inc. is a member of the Code > Aurora Forum, > > Linux Foundation Collaborative Project > > >> > > >> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the > > >> voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the > > >> ufs device at 2.95v & reads the version and if the device is 3.x, it may > > >> do the following: > > >> - Set the device power mode to SLEEP > > >> - Disable the Vcc > > >> - Enable the Vcc and set it to 2.5v > > >> - Set the device power mode to ACTIVE > > >> > > >> All of the above may be done at HS-G1 & moved to max supported gear > > >> based on the device version, perhaps? > > > > > > Hi Asutosh, > > > > > > Thanks for sharing this idea. > > > > > > 1. I did not see above flow defined in UFS specifications, please > > > correct me if I was wrong. > > > > > > 2. For above flow, the concern is that I am not sure if all devices > > > supporting VCC (2.4v - 2.7v) can accept higher voltage, say 2.95v, for > > > version detection. > > > > > > 3. For version detection, another concern is that I am not sure if all > > > 3.x devices support VCC (2.4v - 2.7v) only, or in other words, I am not > > > sure if all 2.x devices support VCC (2.7v - 3.6v) only. The above rule > > > will break any devices not obeying this "conventions". > > > > > > For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), > > > > > > It would be good for UFS drivers detecting the correct voltage if the > > > protocol is well-defined in specifications. Until that day, any > > > "non-standard" way may be better implemented in vendor's ops? > > > > > > If the vop concept works on your platform, we could still keep struct > > > ufs_vreg and allow vendors to configure proper min_uV and max_uV to > make > > > regulator_set_voltage() works during VCC toggling flow. Without specific > > > vendor configurations, min_uV and max_uV would be NULL by default > and > > > UFS core driver will only enable/disasble VCC regulator only without > > > adjusting its voltage. > > > > > > > I think this would work. Do you plan to implement this? > > If not, I can take this up. Please let me know. > > Thanks for the understanding and support. > > I would like to re-post this patch to simply removing the pre-defined > initial values of all device powers. > > For vop idea supporting the voltage detection way, could you please take > it up since this would be better to fit what you need for fixing this > issue? Again - why vop and not a dts flag? The platform owner is aware of which device ships on which platform, isn't it? Thanks, Avri
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
Hi Asutosh,
On Mon, 2020-11-30 at 19:07 -0800, Asutosh Das (asd) wrote:
> On 11/30/2020 5:25 PM, Stanley Chu wrote:
> > On Mon, 2020-11-30 at 15:54 -0800, Asutosh Das (asd) wrote:
> >> On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
> >>> On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
> >>>
> On 11/30/2020 1:16 AM, Stanley Chu wrote:
> > UFS specficication allows different VCC configurations for UFS devices,
> > for example,
> > (1). 2.70V - 3.60V (By default)
> > (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> > device tree)
> > (3). 2.40V - 2.70V (Supported since UFS 3.x)
> >
> > With the introduction of UFS 3.x products, an issue is happening that
> > UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> > regulator on UFU 3.x products with VCC configuration (3) used.
> >
> > To solve this issue, we simply remove pre-defined initial VCC voltage
> > values in UFS driver with below reasons,
> >
> > 1. UFS specifications do not define how to detect the VCC configuration
> > supported by attached device.
> >
> > 2. Device tree already supports standard regulator properties.
> >
> > Therefore VCC voltage shall be defined correctly in device tree, and
> > shall not be changed by UFS driver. What UFS driver needs to do is
> > simply
> > enabling or disabling the VCC regulator only.
> >
> > This is a RFC conceptional patch. Please help review this and feel
> > free to feedback any ideas. Once this concept is accepted, and then
> > I would post a more completed patch series to fix this issue.
> >
> > Signed-off-by: Stanley Chu
> > ---
> > drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> > 1 file changed, 1 insertion(+), 9 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > index a6f76399b3ae..3965be03c136 100644
> > --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device
> > *dev, const char *name,
> > vreg->max_uA = 0;
> > }
> > - if (!strcmp(name, "vcc")) {
> > - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> > - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> > - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> > - } else {
> > - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> > - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> > - }
> > - } else if (!strcmp(name, "vccq")) {
> > + if (!strcmp(name, "vccq")) {
> > vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> > vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> > } else if (!strcmp(name, "vccq2")) {
> >
>
> Hi Stanley
>
> Thanks for the patch. Bao (nguyenb) was also working towards something
> similar.
> Would it be possible for you to take into account the scenario in which
> the
> same platform supports both 2.x and 3.x UFS devices?
>
> These've different voltage requirements, 2.4v-3.6v.
> I'm not sure if standard dts regulator properties can support this.
>
> >>>
> >>> What is the actual voltage requirement for these devices and how does
> >>> the software know what voltage to pick in this range?
> >>>
> >>> Regards,
> >>> Bjorn
> >>>
> -asd
>
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum,
> Linux Foundation Collaborative Project
> >>
> >> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
> >> voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the
> >> ufs device at 2.95v & reads the version and if the device is 3.x, it may
> >> do the following:
> >> - Set the device power mode to SLEEP
> >> - Disable the Vcc
> >> - Enable the Vcc and set it to 2.5v
> >> - Set the device power mode to ACTIVE
> >>
> >> All of the above may be done at HS-G1 & moved to max supported gear
> >> based on the device version, perhaps?
> >
> > Hi Asutosh,
> >
> > Thanks for sharing this idea.
> >
> > 1. I did not see above flow defined in UFS specifications, please
> > correct me if I was wrong.
> >
> > 2. For above flow, the concern is that I am not sure if all devices
> > supporting VCC (2.4v - 2.7v) can accept higher voltage, say 2.95v, for
> > version detection.
> >
> > 3. For version detection, another concern is that I am not sure if all
> > 3.x devices support VCC (2.4v - 2.7v) only, or in other words, I am not
> > sure if all 2.x devices support VCC (2.7v - 3.6v) only. The above rule
> > will break any devices not obeying this "conventions".
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On Mon 30 Nov 21:19 CST 2020, Asutosh Das (asd) wrote:
> On 11/30/2020 6:53 PM, Bjorn Andersson wrote:
> > On Mon 30 Nov 17:54 CST 2020, Asutosh Das (asd) wrote:
> >
> > > On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
> > > > On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
> > > >
> > > > > On 11/30/2020 1:16 AM, Stanley Chu wrote:
> > > > > > UFS specficication allows different VCC configurations for UFS
> > > > > > devices,
> > > > > > for example,
> > > > > > (1). 2.70V - 3.60V (By default)
> > > > > > (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> > > > > > device tree)
> > > > > > (3). 2.40V - 2.70V (Supported since UFS 3.x)
> > > > > >
> > > > > > With the introduction of UFS 3.x products, an issue is happening
> > > > > > that
> > > > > > UFS driver will use wrong "min_uV/max_uV" configuration to toggle
> > > > > > VCC
> > > > > > regulator on UFU 3.x products with VCC configuration (3) used.
> > > > > >
> > > > > > To solve this issue, we simply remove pre-defined initial VCC
> > > > > > voltage
> > > > > > values in UFS driver with below reasons,
> > > > > >
> > > > > > 1. UFS specifications do not define how to detect the VCC
> > > > > > configuration
> > > > > > supported by attached device.
> > > > > >
> > > > > > 2. Device tree already supports standard regulator properties.
> > > > > >
> > > > > > Therefore VCC voltage shall be defined correctly in device tree, and
> > > > > > shall not be changed by UFS driver. What UFS driver needs to do is
> > > > > > simply
> > > > > > enabling or disabling the VCC regulator only.
> > > > > >
> > > > > > This is a RFC conceptional patch. Please help review this and feel
> > > > > > free to feedback any ideas. Once this concept is accepted, and then
> > > > > > I would post a more completed patch series to fix this issue.
> > > > > >
> > > > > > Signed-off-by: Stanley Chu
> > > > > > ---
> > > > > > drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> > > > > > 1 file changed, 1 insertion(+), 9 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > > > b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > > > index a6f76399b3ae..3965be03c136 100644
> > > > > > --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > > > +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > > > @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device
> > > > > > *dev, const char *name,
> > > > > > vreg->max_uA = 0;
> > > > > > }
> > > > > > - if (!strcmp(name, "vcc")) {
> > > > > > - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> > > > > > - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> > > > > > - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> > > > > > - } else {
> > > > > > - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> > > > > > - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> > > > > > - }
> > > > > > - } else if (!strcmp(name, "vccq")) {
> > > > > > + if (!strcmp(name, "vccq")) {
> > > > > > vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> > > > > > vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> > > > > > } else if (!strcmp(name, "vccq2")) {
> > > > > >
> > > > >
> > > > > Hi Stanley
> > > > >
> > > > > Thanks for the patch. Bao (nguyenb) was also working towards something
> > > > > similar.
> > > > > Would it be possible for you to take into account the scenario in
> > > > > which the
> > > > > same platform supports both 2.x and 3.x UFS devices?
> > > > >
> > > > > These've different voltage requirements, 2.4v-3.6v.
> > > > > I'm not sure if standard dts regulator properties can support this.
> > > > >
> > > >
> > > > What is the actual voltage requirement for these devices and how does
> > > > the software know what voltage to pick in this range?
> > > >
> > > > Regards,
> > > > Bjorn
> > > >
> > > > > -asd
> > > > >
> > > > >
> > > > > --
> > > > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> > > > > Forum,
> > > > > Linux Foundation Collaborative Project
> > >
> > > For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
> > > voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the ufs
> > > device at 2.95v & reads the version and if the device is 3.x, it may do
> > > the
> > > following:
> > > - Set the device power mode to SLEEP
> > > - Disable the Vcc
> > > - Enable the Vcc and set it to 2.5v
> > > - Set the device power mode to ACTIVE
> > >
> > > All of the above may be done at HS-G1 & moved to max supported gear based
> > > on
> > > the device version, perhaps?
> > >
> > > Am open to other ideas though.
> > >
> >
> > But that means that for a board where we don't know (don't want to know)
> > if we have a 2.x or 3.x device we need to set:
> >
> >regulator-min-microvolt = <2.4V>
> >regulator-max-microvolt
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 2020-12-01 11:19, Asutosh Das (asd) wrote:
On 11/30/2020 6:53 PM, Bjorn Andersson wrote:
On Mon 30 Nov 17:54 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 1:16 AM, Stanley Chu wrote:
UFS specficication allows different VCC configurations for UFS
devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening
that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle
VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC
voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC
configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree,
and
shall not be changed by UFS driver. What UFS driver needs to do is
simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and
then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device
*dev, const char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards
something
similar.
Would it be possible for you to take into account the scenario in
which the
same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
What is the actual voltage requirement for these devices and how
does
the software know what voltage to pick in this range?
Regards,
Bjorn
-asd
-- The Qualcomm Innovation Center, Inc. is a member of the Code
Aurora Forum,
Linux Foundation Collaborative Project
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v),
the
voltage requirements (Vcc) are 2.4v-3.6v. The software initializes
the ufs
device at 2.95v & reads the version and if the device is 3.x, it may
do the
following:
- Set the device power mode to SLEEP
- Disable the Vcc
- Enable the Vcc and set it to 2.5v
- Set the device power mode to ACTIVE
All of the above may be done at HS-G1 & moved to max supported gear
based on
the device version, perhaps?
Am open to other ideas though.
But that means that for a board where we don't know (don't want to
know)
if we have a 2.x or 3.x device we need to set:
regulator-min-microvolt = <2.4V>
regulator-max-microvolt = <3.6V>
And the 2.5V and the two ranges should be hard coded into the ufshcd
(in
particular if they come from the specification).
For devices with only 2.x or 3.x devices,
regulator-{min,max}-microvolt
should be adjusted accordingly.
Note that driving the regulators outside these ranges will either
damage
the hardware or cause it to misbehave, so these values should be
defined
in the board.dts anyways.
Also note that regulator_set_voltage(2.4V, 3.6V) won't give you "a
voltage between 2.4V and 3.6V, it will most likely give either 2.4V or
any more specific voltage that we've specified in the board file
because
the regulator happens to be shared with some other consumer and
changing
it in runtime would be bad.
Regards,
Bjorn
Understood.
I also understand that assumptions on the regulator limits in the
driver is a bad idea. I'm not sure how it's designed, but I should
think the power-grid design should take care of regulator sharing; if
it's being shared and the platform supports both 2.x and 3.x. Perhaps,
such platforms be identified using a dts flag - not
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 11/30/2020 6:53 PM, Bjorn Andersson wrote:
On Mon 30 Nov 17:54 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 1:16 AM, Stanley Chu wrote:
UFS specficication allows different VCC configurations for UFS devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree, and
shall not be changed by UFS driver. What UFS driver needs to do is simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const
char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards something
similar.
Would it be possible for you to take into account the scenario in which the
same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
What is the actual voltage requirement for these devices and how does
the software know what voltage to pick in this range?
Regards,
Bjorn
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the ufs
device at 2.95v & reads the version and if the device is 3.x, it may do the
following:
- Set the device power mode to SLEEP
- Disable the Vcc
- Enable the Vcc and set it to 2.5v
- Set the device power mode to ACTIVE
All of the above may be done at HS-G1 & moved to max supported gear based on
the device version, perhaps?
Am open to other ideas though.
But that means that for a board where we don't know (don't want to know)
if we have a 2.x or 3.x device we need to set:
regulator-min-microvolt = <2.4V>
regulator-max-microvolt = <3.6V>
And the 2.5V and the two ranges should be hard coded into the ufshcd (in
particular if they come from the specification).
For devices with only 2.x or 3.x devices, regulator-{min,max}-microvolt
should be adjusted accordingly.
Note that driving the regulators outside these ranges will either damage
the hardware or cause it to misbehave, so these values should be defined
in the board.dts anyways.
Also note that regulator_set_voltage(2.4V, 3.6V) won't give you "a
voltage between 2.4V and 3.6V, it will most likely give either 2.4V or
any more specific voltage that we've specified in the board file because
the regulator happens to be shared with some other consumer and changing
it in runtime would be bad.
Regards,
Bjorn
Understood.
I also understand that assumptions on the regulator limits in the driver
is a bad idea. I'm not sure how it's designed, but I should think the
power-grid design should take care of regulator sharing; if it's being
shared and the platform supports both 2.x and 3.x. Perhaps, such
platforms be identified using a dts flag - not sure if that's such a
good idea though.
I like Stanley's proposal of a vops and let
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 11/30/2020 5:25 PM, Stanley Chu wrote:
On Mon, 2020-11-30 at 15:54 -0800, Asutosh Das (asd) wrote:
On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 1:16 AM, Stanley Chu wrote:
UFS specficication allows different VCC configurations for UFS devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree, and
shall not be changed by UFS driver. What UFS driver needs to do is simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const
char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards something
similar.
Would it be possible for you to take into account the scenario in which the
same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
What is the actual voltage requirement for these devices and how does
the software know what voltage to pick in this range?
Regards,
Bjorn
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the
ufs device at 2.95v & reads the version and if the device is 3.x, it may
do the following:
- Set the device power mode to SLEEP
- Disable the Vcc
- Enable the Vcc and set it to 2.5v
- Set the device power mode to ACTIVE
All of the above may be done at HS-G1 & moved to max supported gear
based on the device version, perhaps?
Hi Asutosh,
Thanks for sharing this idea.
1. I did not see above flow defined in UFS specifications, please
correct me if I was wrong.
2. For above flow, the concern is that I am not sure if all devices
supporting VCC (2.4v - 2.7v) can accept higher voltage, say 2.95v, for
version detection.
3. For version detection, another concern is that I am not sure if all
3.x devices support VCC (2.4v - 2.7v) only, or in other words, I am not
sure if all 2.x devices support VCC (2.7v - 3.6v) only. The above rule
will break any devices not obeying this "conventions".
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v),
It would be good for UFS drivers detecting the correct voltage if the
protocol is well-defined in specifications. Until that day, any
"non-standard" way may be better implemented in vendor's ops?
If the vop concept works on your platform, we could still keep struct
ufs_vreg and allow vendors to configure proper min_uV and max_uV to make
regulator_set_voltage() works during VCC toggling flow. Without specific
vendor configurations, min_uV and max_uV would be NULL by default and
UFS core driver will only enable/disasble VCC regulator only without
adjusting its voltage.
I think this would work. Do you plan to implement this?
If not, I can take this up. Please let me know.
Maybe one possible another idea is to decide the correct voltage
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On Mon 30 Nov 17:54 CST 2020, Asutosh Das (asd) wrote:
> On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
> > On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
> >
> > > On 11/30/2020 1:16 AM, Stanley Chu wrote:
> > > > UFS specficication allows different VCC configurations for UFS devices,
> > > > for example,
> > > > (1). 2.70V - 3.60V (By default)
> > > > (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> > > > device tree)
> > > > (3). 2.40V - 2.70V (Supported since UFS 3.x)
> > > >
> > > > With the introduction of UFS 3.x products, an issue is happening that
> > > > UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> > > > regulator on UFU 3.x products with VCC configuration (3) used.
> > > >
> > > > To solve this issue, we simply remove pre-defined initial VCC voltage
> > > > values in UFS driver with below reasons,
> > > >
> > > > 1. UFS specifications do not define how to detect the VCC configuration
> > > > supported by attached device.
> > > >
> > > > 2. Device tree already supports standard regulator properties.
> > > >
> > > > Therefore VCC voltage shall be defined correctly in device tree, and
> > > > shall not be changed by UFS driver. What UFS driver needs to do is
> > > > simply
> > > > enabling or disabling the VCC regulator only.
> > > >
> > > > This is a RFC conceptional patch. Please help review this and feel
> > > > free to feedback any ideas. Once this concept is accepted, and then
> > > > I would post a more completed patch series to fix this issue.
> > > >
> > > > Signed-off-by: Stanley Chu
> > > > ---
> > > >drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> > > >1 file changed, 1 insertion(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > index a6f76399b3ae..3965be03c136 100644
> > > > --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > > > @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device
> > > > *dev, const char *name,
> > > > vreg->max_uA = 0;
> > > > }
> > > > - if (!strcmp(name, "vcc")) {
> > > > - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> > > > - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> > > > - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> > > > - } else {
> > > > - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> > > > - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> > > > - }
> > > > - } else if (!strcmp(name, "vccq")) {
> > > > + if (!strcmp(name, "vccq")) {
> > > > vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> > > > vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> > > > } else if (!strcmp(name, "vccq2")) {
> > > >
> > >
> > > Hi Stanley
> > >
> > > Thanks for the patch. Bao (nguyenb) was also working towards something
> > > similar.
> > > Would it be possible for you to take into account the scenario in which
> > > the
> > > same platform supports both 2.x and 3.x UFS devices?
> > >
> > > These've different voltage requirements, 2.4v-3.6v.
> > > I'm not sure if standard dts regulator properties can support this.
> > >
> >
> > What is the actual voltage requirement for these devices and how does
> > the software know what voltage to pick in this range?
> >
> > Regards,
> > Bjorn
> >
> > > -asd
> > >
> > >
> > > --
> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > > Linux Foundation Collaborative Project
>
> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
> voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the ufs
> device at 2.95v & reads the version and if the device is 3.x, it may do the
> following:
> - Set the device power mode to SLEEP
> - Disable the Vcc
> - Enable the Vcc and set it to 2.5v
> - Set the device power mode to ACTIVE
>
> All of the above may be done at HS-G1 & moved to max supported gear based on
> the device version, perhaps?
>
> Am open to other ideas though.
>
But that means that for a board where we don't know (don't want to know)
if we have a 2.x or 3.x device we need to set:
regulator-min-microvolt = <2.4V>
regulator-max-microvolt = <3.6V>
And the 2.5V and the two ranges should be hard coded into the ufshcd (in
particular if they come from the specification).
For devices with only 2.x or 3.x devices, regulator-{min,max}-microvolt
should be adjusted accordingly.
Note that driving the regulators outside these ranges will either damage
the hardware or cause it to misbehave, so these values should be defined
in the board.dts anyways.
Also note that regulator_set_voltage(2.4V, 3.6V) won't give you "a
voltage between 2.4V and 3.6V, it will most likely give either 2.4V or
any more specific voltage that we've specified in
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On Mon, 2020-11-30 at 15:54 -0800, Asutosh Das (asd) wrote:
> On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
> > On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
> >
> >> On 11/30/2020 1:16 AM, Stanley Chu wrote:
> >>> UFS specficication allows different VCC configurations for UFS devices,
> >>> for example,
> >>> (1). 2.70V - 3.60V (By default)
> >>> (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> >>> device tree)
> >>> (3). 2.40V - 2.70V (Supported since UFS 3.x)
> >>>
> >>> With the introduction of UFS 3.x products, an issue is happening that
> >>> UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> >>> regulator on UFU 3.x products with VCC configuration (3) used.
> >>>
> >>> To solve this issue, we simply remove pre-defined initial VCC voltage
> >>> values in UFS driver with below reasons,
> >>>
> >>> 1. UFS specifications do not define how to detect the VCC configuration
> >>> supported by attached device.
> >>>
> >>> 2. Device tree already supports standard regulator properties.
> >>>
> >>> Therefore VCC voltage shall be defined correctly in device tree, and
> >>> shall not be changed by UFS driver. What UFS driver needs to do is simply
> >>> enabling or disabling the VCC regulator only.
> >>>
> >>> This is a RFC conceptional patch. Please help review this and feel
> >>> free to feedback any ideas. Once this concept is accepted, and then
> >>> I would post a more completed patch series to fix this issue.
> >>>
> >>> Signed-off-by: Stanley Chu
> >>> ---
> >>>drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> >>>1 file changed, 1 insertion(+), 9 deletions(-)
> >>>
> >>> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> >>> b/drivers/scsi/ufs/ufshcd-pltfrm.c
> >>> index a6f76399b3ae..3965be03c136 100644
> >>> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> >>> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> >>> @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev,
> >>> const char *name,
> >>> vreg->max_uA = 0;
> >>> }
> >>> - if (!strcmp(name, "vcc")) {
> >>> - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> >>> - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> >>> - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> >>> - } else {
> >>> - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> >>> - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> >>> - }
> >>> - } else if (!strcmp(name, "vccq")) {
> >>> + if (!strcmp(name, "vccq")) {
> >>> vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> >>> vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> >>> } else if (!strcmp(name, "vccq2")) {
> >>>
> >>
> >> Hi Stanley
> >>
> >> Thanks for the patch. Bao (nguyenb) was also working towards something
> >> similar.
> >> Would it be possible for you to take into account the scenario in which the
> >> same platform supports both 2.x and 3.x UFS devices?
> >>
> >> These've different voltage requirements, 2.4v-3.6v.
> >> I'm not sure if standard dts regulator properties can support this.
> >>
> >
> > What is the actual voltage requirement for these devices and how does
> > the software know what voltage to pick in this range?
> >
> > Regards,
> > Bjorn
> >
> >> -asd
> >>
> >>
> >> --
> >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> >> Linux Foundation Collaborative Project
>
> For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
> voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the
> ufs device at 2.95v & reads the version and if the device is 3.x, it may
> do the following:
> - Set the device power mode to SLEEP
> - Disable the Vcc
> - Enable the Vcc and set it to 2.5v
> - Set the device power mode to ACTIVE
>
> All of the above may be done at HS-G1 & moved to max supported gear
> based on the device version, perhaps?
Hi Asutosh,
Thanks for sharing this idea.
1. I did not see above flow defined in UFS specifications, please
correct me if I was wrong.
2. For above flow, the concern is that I am not sure if all devices
supporting VCC (2.4v - 2.7v) can accept higher voltage, say 2.95v, for
version detection.
3. For version detection, another concern is that I am not sure if all
3.x devices support VCC (2.4v - 2.7v) only, or in other words, I am not
sure if all 2.x devices support VCC (2.7v - 3.6v) only. The above rule
will break any devices not obeying this "conventions".
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v),
It would be good for UFS drivers detecting the correct voltage if the
protocol is well-defined in specifications. Until that day, any
"non-standard" way may be better implemented in vendor's ops?
If the vop concept works on your platform, we could still keep struct
ufs_vreg and allow vendors to configure proper min_uV and max_uV to make
regulator_set_voltage() works during VCC toggling flow. Without
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 11/30/2020 3:14 PM, Bjorn Andersson wrote:
On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
On 11/30/2020 1:16 AM, Stanley Chu wrote:
UFS specficication allows different VCC configurations for UFS devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree, and
shall not be changed by UFS driver. What UFS driver needs to do is simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const
char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards something
similar.
Would it be possible for you to take into account the scenario in which the
same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
What is the actual voltage requirement for these devices and how does
the software know what voltage to pick in this range?
Regards,
Bjorn
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the
voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the
ufs device at 2.95v & reads the version and if the device is 3.x, it may
do the following:
- Set the device power mode to SLEEP
- Disable the Vcc
- Enable the Vcc and set it to 2.5v
- Set the device power mode to ACTIVE
All of the above may be done at HS-G1 & moved to max supported gear
based on the device version, perhaps?
Am open to other ideas though.
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote:
> On 11/30/2020 1:16 AM, Stanley Chu wrote:
> > UFS specficication allows different VCC configurations for UFS devices,
> > for example,
> > (1). 2.70V - 3.60V (By default)
> > (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> >device tree)
> > (3). 2.40V - 2.70V (Supported since UFS 3.x)
> >
> > With the introduction of UFS 3.x products, an issue is happening that
> > UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> > regulator on UFU 3.x products with VCC configuration (3) used.
> >
> > To solve this issue, we simply remove pre-defined initial VCC voltage
> > values in UFS driver with below reasons,
> >
> > 1. UFS specifications do not define how to detect the VCC configuration
> > supported by attached device.
> >
> > 2. Device tree already supports standard regulator properties.
> >
> > Therefore VCC voltage shall be defined correctly in device tree, and
> > shall not be changed by UFS driver. What UFS driver needs to do is simply
> > enabling or disabling the VCC regulator only.
> >
> > This is a RFC conceptional patch. Please help review this and feel
> > free to feedback any ideas. Once this concept is accepted, and then
> > I would post a more completed patch series to fix this issue.
> >
> > Signed-off-by: Stanley Chu
> > ---
> > drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> > 1 file changed, 1 insertion(+), 9 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > index a6f76399b3ae..3965be03c136 100644
> > --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> > +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> > @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev,
> > const char *name,
> > vreg->max_uA = 0;
> > }
> > - if (!strcmp(name, "vcc")) {
> > - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> > - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> > - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> > - } else {
> > - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> > - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> > - }
> > - } else if (!strcmp(name, "vccq")) {
> > + if (!strcmp(name, "vccq")) {
> > vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> > vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> > } else if (!strcmp(name, "vccq2")) {
> >
>
> Hi Stanley
>
> Thanks for the patch. Bao (nguyenb) was also working towards something
> similar.
> Would it be possible for you to take into account the scenario in which the
> same platform supports both 2.x and 3.x UFS devices?
>
> These've different voltage requirements, 2.4v-3.6v.
> I'm not sure if standard dts regulator properties can support this.
>
What is the actual voltage requirement for these devices and how does
the software know what voltage to pick in this range?
Regards,
Bjorn
> -asd
>
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> Linux Foundation Collaborative Project
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On Mon 30 Nov 03:16 CST 2020, Stanley Chu wrote:
> UFS specficication allows different VCC configurations for UFS devices,
> for example,
> (1). 2.70V - 3.60V (By default)
> (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> device tree)
> (3). 2.40V - 2.70V (Supported since UFS 3.x)
>
> With the introduction of UFS 3.x products, an issue is happening that
> UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
> regulator on UFU 3.x products with VCC configuration (3) used.
>
> To solve this issue, we simply remove pre-defined initial VCC voltage
> values in UFS driver with below reasons,
>
> 1. UFS specifications do not define how to detect the VCC configuration
>supported by attached device.
>
> 2. Device tree already supports standard regulator properties.
>
> Therefore VCC voltage shall be defined correctly in device tree, and
> shall not be changed by UFS driver. What UFS driver needs to do is simply
> enabling or disabling the VCC regulator only.
>
> This is a RFC conceptional patch. Please help review this and feel
> free to feedback any ideas. Once this concept is accepted, and then
> I would post a more completed patch series to fix this issue.
>
> Signed-off-by: Stanley Chu
Reviewed-by: Bjorn Andersson
This is the correct thing to do and I would prefer that we did the same
for vccq and vccq2 as well - and thereby remove the min_uV and max_uV
from ufs_vreg.
Regards,
Bjorn
> ---
> drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c
> b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index a6f76399b3ae..3965be03c136 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev,
> const char *name,
> vreg->max_uA = 0;
> }
>
> - if (!strcmp(name, "vcc")) {
> - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> - } else {
> - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> - }
> - } else if (!strcmp(name, "vccq")) {
> + if (!strcmp(name, "vccq")) {
> vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> } else if (!strcmp(name, "vccq2")) {
> --
> 2.18.0
>
Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
On 11/30/2020 1:16 AM, Stanley Chu wrote:
UFS specficication allows different VCC configurations for UFS devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree, and
shall not be changed by UFS driver. What UFS driver needs to do is simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const
char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
Hi Stanley
Thanks for the patch. Bao (nguyenb) was also working towards something
similar.
Would it be possible for you to take into account the scenario in which
the same platform supports both 2.x and 3.x UFS devices?
These've different voltage requirements, 2.4v-3.6v.
I'm not sure if standard dts regulator properties can support this.
-asd
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project
[RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values
UFS specficication allows different VCC configurations for UFS devices,
for example,
(1). 2.70V - 3.60V (By default)
(2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
device tree)
(3). 2.40V - 2.70V (Supported since UFS 3.x)
With the introduction of UFS 3.x products, an issue is happening that
UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC
regulator on UFU 3.x products with VCC configuration (3) used.
To solve this issue, we simply remove pre-defined initial VCC voltage
values in UFS driver with below reasons,
1. UFS specifications do not define how to detect the VCC configuration
supported by attached device.
2. Device tree already supports standard regulator properties.
Therefore VCC voltage shall be defined correctly in device tree, and
shall not be changed by UFS driver. What UFS driver needs to do is simply
enabling or disabling the VCC regulator only.
This is a RFC conceptional patch. Please help review this and feel
free to feedback any ideas. Once this concept is accepted, and then
I would post a more completed patch series to fix this issue.
Signed-off-by: Stanley Chu
---
drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +-
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index a6f76399b3ae..3965be03c136 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const
char *name,
vreg->max_uA = 0;
}
- if (!strcmp(name, "vcc")) {
- if (of_property_read_bool(np, "vcc-supply-1p8")) {
- vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
- } else {
- vreg->min_uV = UFS_VREG_VCC_MIN_UV;
- vreg->max_uV = UFS_VREG_VCC_MAX_UV;
- }
- } else if (!strcmp(name, "vccq")) {
+ if (!strcmp(name, "vccq")) {
vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
} else if (!strcmp(name, "vccq2")) {
--
2.18.0
