On Fri, Jan 19, 2024 at 02:33:32PM -0600, Andrew Halaney wrote:
> On Fri, Jan 19, 2024 at 02:07:15PM -0600, Andrew Halaney wrote:
> > On Fri, Jan 19, 2024 at 01:55:47PM -0500, Eric Chanudet wrote:
> > > On sa8775p-ride, probing the hba will go through the
> > > UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH path although the power info
> > > are same during the second init.
> > >
> > > If the host is at least v4, ufs_qcom_get_hs_gear() picked the highest
> > > supported gear when setting the host_params. After the negotiation, if
> > > the host and device are on the same gear, it is the highest gear
> > > supported between the two. Skip the re-init to save some time.
> > >
> > > Signed-off-by: Eric Chanudet <echanude@xxxxxxxxxx>
> > > ---
> > >
> > > "trace_event=ufs:ufshcd_init" reports the time spent where the re-init
> > > quirk is performed. On sa8775p-ride:
> > > Baseline:
> > > 0.355879: ufshcd_init: 1d84000.ufs: took 103377 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0
> > > With this patch:
> > > 0.297676: ufshcd_init: 1d84000.ufs: took 43553 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0
> > >
> > > drivers/ufs/host/ufs-qcom.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> > > index 39eef470f8fa..f9f161340e78 100644
> > > --- a/drivers/ufs/host/ufs-qcom.c
> > > +++ b/drivers/ufs/host/ufs-qcom.c
> > > @@ -738,8 +738,12 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
> > > * the second init can program the optimal PHY settings. This allows one to start
> > > * the first init with either the minimum or the maximum support gear.
> > > */
> > > - if (hba->ufshcd_state == UFSHCD_STATE_RESET)
> > > + if (hba->ufshcd_state == UFSHCD_STATE_RESET) {
> > > + if (host->hw_ver.major >= 0x4 &&
> >
> > Is this check really necessary?
I *think* so.
For example, if hw_ver < 4, ufs_qcom_set_phy_gear() has a comment saying
"power up the PHY using minimum supported gear (UFS_HS_G2). Switching to
max gear will be performed during reinit if supported."
> >
> > The initial phy_gear state is something like this (my phrasing of
> > ufs_qcom_set_phy_gear()):
> >
> > if hw_ver < 4:
> > # Comments about powering up with minimum gear (with no
> > # reasoning in the comment afaict), and mentions switching
> > # to higher gear in reinit quirk. This is opposite of the later
> > # versions which start at the max and scale down
> > phy_gear = UFS_HS_G2
IIUC, the device would not be able to negotiate a gear higher than the
minimum set for the phy_gear on initialization.
ufshcd_init_host_params() and ufs_qcom_get_hs_gear() both set the
controller <v4 host_params to G3. So if the device is HS capable, the
re-init would set G3, instead of the G2 selected by
ufs_qcom_set_phy_gear().
Assuming I'm not loosing track somewhere, the sequence of calls would go
something like this:
ufshcd_init
ufshcd_hba_init
ufshcd_variant_hba_init
ufshcd_vops_init
ufs_qcom_init
ufs_qcom_set_host_params /* if hw_ver < 4: phy_gear = G2 */
ufshcd_hba_enable
ufshcd_hba_execute_hce
ufshcd_vops_hce_enable_notify(PRE_CHANGE)
ufs_qcom_hce_enable_notify /* vops.hce_enable_notify */
ufs_qcom_power_up_sequence
phy_set_mode_ext(phy, mode, host->phy_gear);
async_schedule(ufshcd_async_scan, hba)
...
ufshcd_async_scan
ufshcd_device_init
ufshcd_probe_hba /* where the re-init quirk happens */
ufshcd_device_init
ufshcd_vops_pwr_change_notify(PRE_CHANGE)
So that would limit the device to G2? In this circumstances, the re-init
would instead re-initialize to G3.
> I guess what I'm saying is shouldn't the check be something like:
>
> if (dev_req_params->gear_tx == host->phy_gear) {
> // Skip reinit since we started up in the agreed upon gear
> hba->quirks &= ~UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
> }
--
Eric Chanudet
