Messages in this thread | | | Date | Fri, 04 Jun 2021 02:01:33 +0530 | From | nitirawa@codeauro ... | Subject | Re: [PATCH V2 3/3] scsi: ufs-qcom: configure VCC voltage level in vendor file |
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On 2021-05-26 12:53, nitirawa@codeaurora.org wrote: > On 2021-04-01 20:42, Bjorn Andersson wrote: >> On Thu 01 Apr 09:58 CDT 2021, nitirawa@codeaurora.org wrote: >> >>> On 2021-03-31 23:49, Bjorn Andersson wrote: >>> > On Wed 24 Mar 16:55 CDT 2021, nitirawa@codeaurora.org wrote: >>> > >>> > > On 2021-03-23 20:58, Bjorn Andersson wrote: >>> > > > On Sun 21 Mar 16:57 CDT 2021, Nitin Rawat wrote: >>> > > > >>> > > > > As a part of vops handler, VCC voltage is updated >>> > > > > as per the ufs device probed after reading the device >>> > > > > descriptor. We follow below steps to configure voltage >>> > > > > level. >>> > > > > >>> > > > > 1. Set the device to SLEEP state. >>> > > > > 2. Disable the Vcc Regulator. >>> > > > > 3. Set the vcc voltage according to the device type and reenable >>> > > > > the regulator. >>> > > > > 4. Set the device mode back to ACTIVE. >>> > > > > >>> > > > >>> > > > When we discussed this a while back this was described as a requirement >>> > > > from the device specification, you only operate on objects "owned" by >>> > > > ufshcd and you invoke ufshcd operations to perform the actions. >>> > > > >>> > > > So why is this a ufs-qcom patch and not something in ufshcd? >>> > > > >>> > > > Regards, >>> > > > Bjorn >>> > > > >>> > > > > Signed-off-by: Nitin Rawat <nitirawa@codeaurora.org> >>> > > > > Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org> >>> > > > > --- >>> > > > > drivers/scsi/ufs/ufs-qcom.c | 51 >>> > > > > +++++++++++++++++++++++++++++++++++++++++++++ >>> > > > > 1 file changed, 51 insertions(+) >>> > > > > >>> > > > > diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c >>> > > > > index f97d7b0..ca35f5c 100644 >>> > > > > --- a/drivers/scsi/ufs/ufs-qcom.c >>> > > > > +++ b/drivers/scsi/ufs/ufs-qcom.c >>> > > > > @@ -21,6 +21,17 @@ >>> > > > > #define UFS_QCOM_DEFAULT_DBG_PRINT_EN \ >>> > > > > (UFS_QCOM_DBG_PRINT_REGS_EN | UFS_QCOM_DBG_PRINT_TEST_BUS_EN) >>> > > > > >>> > > > > +#define ANDROID_BOOT_DEV_MAX 30 >>> > > > > +static char android_boot_dev[ANDROID_BOOT_DEV_MAX]; >>> > > > > + >>> > > > > +/* Min and Max VCC voltage values for ufs 2.x and >>> > > > > + * ufs 3.x devices >>> > > > > + */ >>> > > > > +#define UFS_3X_VREG_VCC_MIN_UV 2540000 /* uV */ >>> > > > > +#define UFS_3X_VREG_VCC_MAX_UV 2700000 /* uV */ >>> > > > > +#define UFS_2X_VREG_VCC_MIN_UV 2950000 /* uV */ >>> > > > > +#define UFS_2X_VREG_VCC_MAX_UV 2960000 /* uV */ >>> > > > > + >>> > > > > enum { >>> > > > > TSTBUS_UAWM, >>> > > > > TSTBUS_UARM, >>> > > > > @@ -1293,6 +1304,45 @@ static void >>> > > > > ufs_qcom_print_hw_debug_reg_all(struct ufs_hba *hba, >>> > > > > print_fn(hba, reg, 9, "UFS_DBG_RD_REG_TMRLUT ", priv); >>> > > > > } >>> > > > > >>> > > > > + /** >>> > > > > + * ufs_qcom_setup_vcc_regulators - Update VCC voltage >>> > > > > + * @hba: host controller instance >>> > > > > + * Update VCC voltage based on UFS device(ufs 2.x or >>> > > > > + * ufs 3.x probed) >>> > > > > + */ >>> > > > > +static int ufs_qcom_setup_vcc_regulators(struct ufs_hba *hba) >>> > > > > +{ >>> > > > > + struct ufs_dev_info *dev_info = &hba->dev_info; >>> > > > > + struct ufs_vreg *vreg = hba->vreg_info.vcc; >>> > > > > + int ret; >>> > > > > + >>> > > > > + /* Put the device in sleep before lowering VCC level */ >>> > > > > + ret = ufshcd_set_dev_pwr_mode(hba, UFS_SLEEP_PWR_MODE); >>> > > > > + >>> > > > > + /* Switch off VCC before switching it ON at 2.5v or 2.96v */ >>> > > > > + ret = ufshcd_disable_vreg(hba->dev, vreg); >>> > > > > + >>> > > > > + /* add ~2ms delay before renabling VCC at lower voltage */ >>> > > > > + usleep_range(2000, 2100); >>> > > > > + >>> > > > > + /* set VCC min and max voltage according to ufs device type */ >>> > > > > + if (dev_info->wspecversion >= 0x300) { >>> > > > > + vreg->min_uV = UFS_3X_VREG_VCC_MIN_UV; >>> > > > > + vreg->max_uV = UFS_3X_VREG_VCC_MAX_UV; >>> > > > > + } >>> > > > > + >>> > > > > + else { >>> > > > > + vreg->min_uV = UFS_2X_VREG_VCC_MIN_UV; >>> > > > > + vreg->max_uV = UFS_2X_VREG_VCC_MAX_UV; >>> > > > > + } >>> > > > > + >>> > > > > + ret = ufshcd_enable_vreg(hba->dev, vreg); >>> > > > > + >>> > > > > + /* Bring the device in active now */ >>> > > > > + ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE); >>> > > > > + return ret; >>> > > > > +} >>> > > > > + >>> > > > > static void ufs_qcom_enable_test_bus(struct ufs_qcom_host *host) >>> > > > > { >>> > > > > if (host->dbg_print_en & UFS_QCOM_DBG_PRINT_TEST_BUS_EN) { >>> > > > > @@ -1490,6 +1540,7 @@ static const struct ufs_hba_variant_ops >>> > > > > ufs_hba_qcom_vops = { >>> > > > > .device_reset = ufs_qcom_device_reset, >>> > > > > .config_scaling_param = ufs_qcom_config_scaling_param, >>> > > > > .program_key = ufs_qcom_ice_program_key, >>> > > > > + .setup_vcc_regulators = ufs_qcom_setup_vcc_regulators, >>> > > > > }; >>> > > > > >>> > > > > /** >>> > > > > -- >>> > > > > 2.7.4 >>> > > > > >>> > > >>> > > Hi Bjorn, >>> > > Thanks for your review. >>> > > But As per the earlier discussion regarding handling of vcc voltage >>> > > for platform supporting both ufs 2.x and ufs 3.x , it was finally >>> > > concluded >>> > > to >>> > > use "vops and let vendors handle it, until specs or someone >>> > > has a better suggestion". Please correct me in case i am wrong. >>> > > >>> > >>> > I was under the impression that this would result in something custom >>> > per platform, but what I'm objecting to now that I see the code is that >>> > this is completely generic. >>> > >>> > And the concerns we discussed regarding these regulators being shared >>> > with other devices is not considered in this implementation. But in >>> > practice I don't see how you could support 2.x, 3.x and rail sharing at >>> > the same time. >>> > >>> > Regards, >>> > Bjorn >>> > >>> > > https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2399116.html >>> > > >>> > > Regards, >>> > > Nitin >>> >>> Hi Bjorn, >>> Thanks for your feedback. >>> Regarding your query for regulator being shared with other device, >>> Imho, the soc/pmic designer should share only those device >>> with ufs regulator which has the same voltage range (2.4-3.6v). >>> If that is not considered by the pmic designer, >>> wouldn't that would be a board design issue ??? >>> >> >> It's not only that the rail needs to stay within 2.4-3.6V, depending >> on >> operating mode of this device it either need to be at 2.54-2.7V or >> 2.95-2.96V depending on wspecversion for this instance. >> >> So either that other device need to be completely flexible in that >> range >> and support the voltage jumping between them without notice, or such >> design isn't possible. >> >> And as you say, that would be something that the hardware designers >> would need to handle for us. >> >>> And I agree with you that - the code looks generic but >>> since the below steps is not part of the specs, >>> I had to keep it in vendor specific file for which I >>> had to export few api from ufshcd.c to use in vendor >>> specific files. >>> >>> 1. Set the device to SLEEP state. >>> 2. Disable the Vcc Regulator. >>> 3. Set the vcc voltage according to the device type and reenable >>> the regulator. >>> 4. Set the device mode back to ACTIVE. >>> >>> Please correct me if my understanding is not correct. >>> >> >> Are you saying that steps 1 to 4 here are not defined in the >> specification and therefor Qualcomm specific? Do we expect other >> vendors >> to not follow this sequence, or do they simply not have these voltage >> constraints? >> >> And again, isn't this the voltage for the attached UFS device? (Rather >> than a Qualcomm thing) >> >> Regards, >> Bjorn > > > Hi Bjorn, > Sorry for quite late reply. > Yes Bjorn above steps(1-4) are not mentioned in the specs. But > definitely other > vendor can follow the same steps . If no vendor have any concerns, > I can put these steps as generic in ufshcd.c file. > Let me know what's you opinion on this ?? > > Thanks, > Nitin
Hi Bjorn/Stanley, Please could you let me know your views/suggestion on my last comment.
Regards, Nitin
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