> -----Original Message----- > From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> > Sent: Tuesday, March 21, 2023 5:35 AM > To: linux-wireless@xxxxxxxxxxxxxxx > Cc: Yan-Hsuan Chuang <tony0620emma@xxxxxxxxx>; Kalle Valo <kvalo@xxxxxxxxxx>; Ulf Hansson > <ulf.hansson@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > linux-mmc@xxxxxxxxxxxxxxx; Chris Morgan <macroalpha82@xxxxxxxxx>; Nitin Gupta <nitin.gupta981@xxxxxxxxx>; > Neo Jou <neojou@xxxxxxxxx>; Ping-Ke Shih <pkshih@xxxxxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; > Larry Finger <Larry.Finger@xxxxxxxxxxxx>; Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> > Subject: [PATCH v3 1/9] wifi: rtw88: Clear RTW_FLAG_POWERON early in rtw_mac_power_switch() > > The SDIO HCI implementation needs to know when the MAC is powered on. > This is needed because 32-bit register access has to be split into 4x > 8-bit register access when the MAC is not fully powered on or while > powering off. When the MAC is powered on 32-bit register access can be > used to reduce the number of transfers but splitting into 4x 8-bit > register access still works in that case. > > During the power on sequence is how RTW_FLAG_POWERON is only set when > the power on sequence has completed successfully. During power off > however RTW_FLAG_POWERON is set. This means that the upcoming SDIO HCI > implementation does not know that it has to use 4x 8-bit register > accessors. Clear the RTW_FLAG_POWERON flag early when powering off the > MAC so the whole power off sequence is processed with RTW_FLAG_POWERON > unset. This will make it possible to use the RTW_FLAG_POWERON flag in > the upcoming SDIO HCI implementation. > > Note that a failure in rtw_pwr_seq_parser() while applying > chip->pwr_off_seq can theoretically result in the RTW_FLAG_POWERON > flag being cleared while the chip is still powered on. However, > depending on when the failure occurs in the power off sequence the > chip may be on or off. Even the original approach of clearing > RTW_FLAG_POWERON only when the power off sequence has been applied > successfully could end up in some corner case where the chip is > powered off but RTW_FLAG_POWERON was not cleared. > > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> Reviewed-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx> > --- > Changes since v2: > - improve patch description about corner cases when clearing > RTW_FLAG_POWERON > > Changes since v1: > - This replaces a previous patch called "rtw88: hci: Add an optional > power_switch() callback to rtw_hci_ops" which added a new callback > to the HCI ops. > > > drivers/net/wireless/realtek/rtw88/mac.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/realtek/rtw88/mac.c b/drivers/net/wireless/realtek/rtw88/mac.c > index f3a566cf979b..cfdfc8a2c836 100644 > --- a/drivers/net/wireless/realtek/rtw88/mac.c > +++ b/drivers/net/wireless/realtek/rtw88/mac.c > @@ -273,6 +273,9 @@ static int rtw_mac_power_switch(struct rtw_dev *rtwdev, bool pwr_on) > if (pwr_on == cur_pwr) > return -EALREADY; > > + if (!pwr_on) > + clear_bit(RTW_FLAG_POWERON, rtwdev->flags); > + > pwr_seq = pwr_on ? chip->pwr_on_seq : chip->pwr_off_seq; > ret = rtw_pwr_seq_parser(rtwdev, pwr_seq); > if (ret) > @@ -280,8 +283,6 @@ static int rtw_mac_power_switch(struct rtw_dev *rtwdev, bool pwr_on) > > if (pwr_on) > set_bit(RTW_FLAG_POWERON, rtwdev->flags); > - else > - clear_bit(RTW_FLAG_POWERON, rtwdev->flags); > > return 0; > } > -- > 2.40.0
