Re: [PATCH v6 4/4] phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800

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Hi,

On Wed, Sep 03, 2014 at 12:59:27PM +0530, Vivek Gautam wrote:
> > On Tue, Sep 02, 2014 at 04:42:18PM +0530, Vivek Gautam wrote:
> >> Adding phy calibrate callback, which facilitates setting certain
> >> PHY settings post initialization of the PHY controller.
> >> Exynos5420 and Exynos5800 have 28nm USB 3.0 DRD PHY for which
> >> the Loss-of-Signal (LOS) Detector Threshold Level as well as
> >> Tx-Vboost-Level should be controlled for Super-Speed operations.
> >>
> >> Additionally set proper time to wait for RxDetect measurement,
> >> for desired PHY reference clock, so as to solve issue with enumeration
> >> of few USB 3.0 devices, like Samsung SUM-TSB16S 3.0 USB drive
> >> on the controller.
> >> We are using CR_port for this purpose to send required data
> >> to override the LOS values.
> >>
> >> On testing with USB 3.0 devices on USB 3.0 port present on
> >> SMDK5420, and peach-pit boards should see following message:
> >> usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
> >>
> >> and without this patch, should see below shown message:
> >> usb 1-1: new high-speed USB device number 2 using xhci-hcd
> >>
> >> [Also removed unnecessary extra lines in the register macro definitions]
> >>
> >> Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
> >> ---
> >>  drivers/phy/phy-exynos5-usbdrd.c |  185 ++++++++++++++++++++++++++++++++++----
> >>  1 file changed, 170 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/drivers/phy/phy-exynos5-usbdrd.c b/drivers/phy/phy-exynos5-usbdrd.c
> >> index 47f47fe..85742b0 100644
> >> --- a/drivers/phy/phy-exynos5-usbdrd.c
> >> +++ b/drivers/phy/phy-exynos5-usbdrd.c
> >> @@ -37,13 +37,11 @@
> >>
> >>  /* EXYNOS5: USB 3.0 DRD PHY registers */
> >>  #define EXYNOS5_DRD_LINKSYSTEM                       0x04
> >> -
> >>  #define LINKSYSTEM_FLADJ_MASK                        (0x3f << 1)
> >>  #define LINKSYSTEM_FLADJ(_x)                 ((_x) << 1)
> >>  #define LINKSYSTEM_XHCI_VERSION_CONTROL              BIT(27)
> >>
> >>  #define EXYNOS5_DRD_PHYUTMI                  0x08
> >> -
> >>  #define PHYUTMI_OTGDISABLE                   BIT(6)
> >>  #define PHYUTMI_FORCESUSPEND                 BIT(1)
> >>  #define PHYUTMI_FORCESLEEP                   BIT(0)
> >> @@ -51,26 +49,20 @@
> >>  #define EXYNOS5_DRD_PHYPIPE                  0x0c
> >>
> >>  #define EXYNOS5_DRD_PHYCLKRST                        0x10
> >> -
> >>  #define PHYCLKRST_EN_UTMISUSPEND             BIT(31)
> >> -
> >>  #define PHYCLKRST_SSC_REFCLKSEL_MASK         (0xff << 23)
> >>  #define PHYCLKRST_SSC_REFCLKSEL(_x)          ((_x) << 23)
> >> -
> >>  #define PHYCLKRST_SSC_RANGE_MASK             (0x03 << 21)
> >>  #define PHYCLKRST_SSC_RANGE(_x)                      ((_x) << 21)
> >> -
> >>  #define PHYCLKRST_SSC_EN                     BIT(20)
> >>  #define PHYCLKRST_REF_SSP_EN                 BIT(19)
> >>  #define PHYCLKRST_REF_CLKDIV2                        BIT(18)
> >> -
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_MASK               (0x7f << 11)
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_100MHZ_REF (0x19 << 11)
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_50M_REF    (0x32 << 11)
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_24MHZ_REF  (0x68 << 11)
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_20MHZ_REF  (0x7d << 11)
> >>  #define PHYCLKRST_MPLL_MULTIPLIER_19200KHZ_REF       (0x02 << 11)
> >> -
> >>  #define PHYCLKRST_FSEL_UTMI_MASK             (0x7 << 5)
> >>  #define PHYCLKRST_FSEL_PIPE_MASK             (0x7 << 8)
> >>  #define PHYCLKRST_FSEL(_x)                   ((_x) << 5)
> >> @@ -78,46 +70,68 @@
> >>  #define PHYCLKRST_FSEL_PAD_24MHZ             (0x2a << 5)
> >>  #define PHYCLKRST_FSEL_PAD_20MHZ             (0x31 << 5)
> >>  #define PHYCLKRST_FSEL_PAD_19_2MHZ           (0x38 << 5)
> >> -
> >>  #define PHYCLKRST_RETENABLEN                 BIT(4)
> >> -
> >>  #define PHYCLKRST_REFCLKSEL_MASK             (0x03 << 2)
> >>  #define PHYCLKRST_REFCLKSEL_PAD_REFCLK               (0x2 << 2)
> >>  #define PHYCLKRST_REFCLKSEL_EXT_REFCLK               (0x3 << 2)
> >> -
> >>  #define PHYCLKRST_PORTRESET                  BIT(1)
> >>  #define PHYCLKRST_COMMONONN                  BIT(0)
> >>
> >>  #define EXYNOS5_DRD_PHYREG0                  0x14
> >> +#define PHYREG0_SSC_REF_CLK_SEL                      BIT(21)
> >> +#define PHYREG0_SSC_RANGE                    BIT(20)
> >> +#define PHYREG0_CR_WRITE                     BIT(19)
> >> +#define PHYREG0_CR_READ                              BIT(18)
> >> +#define PHYREG0_CR_DATA_IN(_x)                       ((_x) << 2)
> >> +#define PHYREG0_CR_CAP_DATA                  BIT(1)
> >> +#define PHYREG0_CR_CAP_ADDR                  BIT(0)
> >> +
> >>  #define EXYNOS5_DRD_PHYREG1                  0x18
> >> +#define PHYREG1_CR_DATA_OUT(_x)                      ((_x) << 1)
> >> +#define PHYREG1_CR_ACK                               BIT(0)
> >>
> >>  #define EXYNOS5_DRD_PHYPARAM0                        0x1c
> >> -
> >>  #define PHYPARAM0_REF_USE_PAD                        BIT(31)
> >>  #define PHYPARAM0_REF_LOSLEVEL_MASK          (0x1f << 26)
> >>  #define PHYPARAM0_REF_LOSLEVEL                       (0x9 << 26)
> >>
> >>  #define EXYNOS5_DRD_PHYPARAM1                        0x20
> >> -
> >>  #define PHYPARAM1_PCS_TXDEEMPH_MASK          (0x1f << 0)
> >>  #define PHYPARAM1_PCS_TXDEEMPH                       (0x1c)
> >>
> >>  #define EXYNOS5_DRD_PHYTERM                  0x24
> >>
> >>  #define EXYNOS5_DRD_PHYTEST                  0x28
> >> -
> >>  #define PHYTEST_POWERDOWN_SSP                        BIT(3)
> >>  #define PHYTEST_POWERDOWN_HSP                        BIT(2)
> >>
> >>  #define EXYNOS5_DRD_PHYADP                   0x2c
> >>
> >>  #define EXYNOS5_DRD_PHYUTMICLKSEL            0x30
> >> -
> >
> > this and all above are unrelated to $subject.
> 
> True, but i have mentioned about this change in the commit message.
> It looked so trivial to me that i included it here in this patch.
> 
> Will separate it out in a separate patch if you like that. :-)

probably not necessary. Kishon's got the final word for drivers/phy,
though.

> 
> >
> >>  #define PHYUTMICLKSEL_UTMI_CLKSEL            BIT(2)
> >>
> >>  #define EXYNOS5_DRD_PHYRESUME                        0x34
> >>  #define EXYNOS5_DRD_LINKPORT                 0x44
> >>
> >> +/* USB 3.0 DRD PHY SS Function Control Reg; accessed by CR_PORT */
> >> +#define EXYNOS5_DRD_PHYSS_LOSLEVEL_OVRD_IN           (0x15)
> >> +#define LOSLEVEL_OVRD_IN_LOS_BIAS_5420                       (0x5 << 13)
> >> +#define LOSLEVEL_OVRD_IN_LOS_BIAS_DEFAULT            (0x0 << 13)
> >> +#define LOSLEVEL_OVRD_IN_EN                          (0x1 << 10)
> >> +#define LOSLEVEL_OVRD_IN_LOS_LEVEL_DEFAULT           (0x9 << 0)
> >> +
> >> +#define EXYNOS5_DRD_PHYSS_TX_VBOOSTLEVEL_OVRD_IN     (0x12)
> >> +#define TX_VBOOSTLEVEL_OVRD_IN_VBOOST_5420           (0x5 << 13)
> >> +#define TX_VBOOSTLEVEL_OVRD_IN_VBOOST_DEFAULT                (0x4 << 13)
> >> +
> >> +#define EXYNOS5_DRD_PHYSS_LANE0_TX_DEBUG             (0x1010)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_19M2_20M              (0x4 << 4)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_24M           (0x8 << 4)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_25M_26M               (0x8 << 4)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_48M_50M_52M   (0x20 << 4)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_62M5          (0x20 << 4)
> >> +#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_96M_100M              (0x40 << 4)
> >> +
> >>  #define KHZ  1000
> >>  #define MHZ  (KHZ * KHZ)
> >>
> >> @@ -135,12 +149,14 @@ struct exynos5_usbdrd_phy_config {
> >>       void (*phy_isol)(struct phy_usb_instance *inst, u32 on);
> >>       void (*phy_init)(struct exynos5_usbdrd_phy *phy_drd);
> >>       unsigned int (*set_refclk)(struct phy_usb_instance *inst);
> >> +     int (*phy_calibrate)(struct phy_usb_instance *inst);
> >>  };
> >>
> >>  struct exynos5_usbdrd_phy_drvdata {
> >>       const struct exynos5_usbdrd_phy_config *phy_cfg;
> >>       u32 pmu_offset_usbdrd0_phy;
> >>       u32 pmu_offset_usbdrd1_phy;
> >> +     void (*phy_exynos_calibrate)(struct exynos5_usbdrd_phy *phy_drd);
> >>  };
> >>
> >>  /**
> >> @@ -487,6 +503,142 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
> >>       return 0;
> >>  }
> >>
> >> +static void crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
> >> +                                             u32 val, u32 cmd)
> >> +{
> >> +     u32 usec = 100;
> >> +     u32 result;
> >> +
> >> +     writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> >> +
> >> +     do {
> >> +             result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
> >> +             if (result & PHYREG1_CR_ACK)
> >> +                     break;
> >> +
> >> +             udelay(1);
> >> +     } while (usec-- > 0);
> >> +
> >> +     if (!usec)
> >> +             dev_err(phy_drd->dev,
> >> +                     "CRPORT handshake timeout1 (0x%08x)\n", val);
> >
> > if handshake timed out, shouldn't you error out here ? IOW, make this
> > function return an int and return an error code from this point ? Why
> > would you even continue to the next step ?
> 
> Point taken, we should have error'ed out here once timeout occured.
> Will update it accordingly.
> 
> >
> >> +
> >> +     usec = 100;
> >> +
> >> +     writel(val, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> >> +
> >> +     do {
> >> +             result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
> >> +             if (!(result & PHYREG1_CR_ACK))
> >> +                     break;
> >> +
> >> +             udelay(1);
> >> +     } while (usec-- > 0);
> >> +
> >> +     if (!usec)
> >> +             dev_err(phy_drd->dev,
> >> +                     "CRPORT handshake timeout2 (0x%08x)\n", val);
> >
> > return an error ?
> sure
> 
> >
> >> +}
> >> +
> >> +static void crport_ctrl_write(struct exynos5_usbdrd_phy *phy_drd,
> >> +                                             u32 addr, u32 data)
> >> +{
> >> +     /* Write Address */
> >> +     writel(PHYREG0_CR_DATA_IN(addr),
> >> +                     phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> >> +     crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(addr),
> >> +                      PHYREG0_CR_CAP_ADDR);
> >> +
> >> +     /* Write Data */
> >> +     writel(PHYREG0_CR_DATA_IN(data),
> >> +                     phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> >> +     crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(data),
> >> +                      PHYREG0_CR_CAP_DATA);
> >> +     crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(data),
> >> +                      PHYREG0_CR_WRITE);
> >> +}
> >> +
> >> +/*
> >> + * Override PHY paramaeters using CR_PORT register to calibrate settings
> >> + * to meet meet SuperSpeed requirements, on Exynos5420 and Exynos5800 systems,
> >> + * which have 28nm USB 3.0 DRD PHY.
> >> + */
> >> +static void exynos5420_usbdrd_phy_calibrate(struct exynos5_usbdrd_phy *phy_drd)
> >> +{
> >> +     u32 temp;
> >> +
> >> +     /*
> >> +      * Change los_bias to (0x5) for 28nm PHY from a
> >> +      * default value (0x0); los_level is set as default
> >> +      * (0x9) as also reflected in los_level[30:26] bits
> >> +      * of PHYPARAM0 register.
> >> +      */
> >> +     temp = LOSLEVEL_OVRD_IN_LOS_BIAS_5420 |
> >> +             LOSLEVEL_OVRD_IN_EN |
> >> +             LOSLEVEL_OVRD_IN_LOS_LEVEL_DEFAULT;
> >> +     crport_ctrl_write(phy_drd,
> >> +                       EXYNOS5_DRD_PHYSS_LOSLEVEL_OVRD_IN,
> >> +                       temp);
> >> +
> >> +     /*
> >> +      * Set tx_vboost_lvl to (0x5) for 28nm PHY Tuning,
> >> +      * to raise Tx signal level from its default value of (0x4)
> >> +      */
> >> +     temp = TX_VBOOSTLEVEL_OVRD_IN_VBOOST_5420;
> >> +     crport_ctrl_write(phy_drd,
> >> +                       EXYNOS5_DRD_PHYSS_TX_VBOOSTLEVEL_OVRD_IN,
> >> +                       temp);
> >> +
> >> +     /*
> >> +      * Set proper time to wait for RxDetect measurement, for
> >> +      * desired reference clock of PHY, by tuning the CRPORT
> >> +      * register LANE0.TX_DEBUG which is internal to PHY.
> >> +      * This fixes issue with few USB 3.0 devices, which are
> >> +      * not detected (not even generate interrupts on the bus
> >> +      * on insertion) without this change.
> >> +      * e.g. Samsung SUM-TSB16S 3.0 USB drive.
> >> +      */
> >> +     switch (phy_drd->extrefclk) {
> >> +     case EXYNOS5_FSEL_50MHZ:
> >> +             temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_48M_50M_52M;
> >> +             break;
> >> +     case EXYNOS5_FSEL_20MHZ:
> >> +     case EXYNOS5_FSEL_19MHZ2:
> >> +             temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_19M2_20M;
> >> +             break;
> >> +     case EXYNOS5_FSEL_24MHZ:
> >
> > why can't this be done during probe() ? Are you going to change external
> > reference clock frequency during runtime ? And even if you do,
> > wouldn't it be easier to subscribe to clock rate change notifiers
> > instead of adding this ->calibrate() ?
> 
> Wait, did this patch give an impression that we are changing the reference
> clock settings ?

not, it gives the impression that you need to change RX Detect timeout
value based on external reference clock frequency :-)

> We are actually trying to override some of the PHY parameters, which
> is possible only after the controller has been reset.
> These PHY parameter overriding (on PHY registers which are not exposed
> outside) is done post initialization, only through
> EXYNOS5_DRD_PHYREG0.

so it _has_ to be done after dwc3's reset ? Don't we have phy_power_on()
for that ? It looks like you could just as well do this from
phy_power_on() ?

> > It still looks, to me, that this ->calibrate() thing is unnecessary. We
> > have a single user for it and this user could very well get this sorted
> > out during probe() or by subscribing to clock rate notifiers.
> 
> We can't program these parameters during PHY probe(), since they reset to
> their default value after the controller reset.
> So we needed a way to do this post initialization, once the controller
> has been reset.

right, and we already have a call to phy_power_on() after core has been
reset. Can't you use that ?

-- 
balbi

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