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SubjectRe: [PATCH V2 3/3] scsi: ufs-qcom: configure VCC voltage level in vendor file
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.

https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2399116.html

Regards,
Nitin

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