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

From: Felipe Balbi
Date: Tue Sep 02 2014 - 10:35:22 EST

Hi,

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.

> #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 ?

> +
> + 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 ?

> +}
> +
> +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() ?

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.

--
balbi

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