Re: [PATCH v5 4/4] phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800

From: Vivek Gautam
Date: Thu Aug 28 2014 - 00:29:12 EST

Hi Jingoo,


On Wed, Aug 27, 2014 at 7:28 AM, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote:
> On Thursday, August 21, 2014 11:55 PM, 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
>>
>> Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
>> ---
>> drivers/phy/phy-exynos5-usbdrd.c | 169 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 169 insertions(+)
>>
>> diff --git a/drivers/phy/phy-exynos5-usbdrd.c b/drivers/phy/phy-exynos5-usbdrd.c
>> index 47f47fe..fa13784 100644
>> --- a/drivers/phy/phy-exynos5-usbdrd.c
>> +++ b/drivers/phy/phy-exynos5-usbdrd.c
>> @@ -89,8 +89,20 @@
>> #define PHYCLKRST_COMMONONN BIT(0)
>>
>> #define EXYNOS5_DRD_PHYREG0 0x14
>> +
>> +#define EXYNOS5_DRD_PHYREG0_SSC_REF_CLK_SEL BIT(21)
>> +#define EXYNOS5_DRD_PHYREG0_SSC_RANGE BIT(20)
>> +#define EXYNOS5_DRD_PHYREG0_CR_WRITE BIT(19)
>> +#define EXYNOS5_DRD_PHYREG0_CR_READ BIT(18)
>> +#define EXYNOS5_DRD_PHYREG0_CR_DATA_IN(_x) ((_x) << 2)
>> +#define EXYNOS5_DRD_PHYREG0_CR_CAP_DATA BIT(1)
>> +#define EXYNOS5_DRD_PHYREG0_CR_CAP_ADDR BIT(0)
>> +
>> #define EXYNOS5_DRD_PHYREG1 0x18
>>
>> +#define EXYNOS5_DRD_PHYREG1_CR_DATA_OUT(_x) ((_x) << 1)
>> +#define EXYNOS5_DRD_PHYREG1_CR_ACK BIT(0)
>> +
>> #define EXYNOS5_DRD_PHYPARAM0 0x1c
>>
>> #define PHYPARAM0_REF_USE_PAD BIT(31)
>> @@ -118,6 +130,26 @@
>> #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)
>> +
>
> Please remove unnecessary line.

Sure will remove extra lines.

[snip]

>> +static void crport_ctrl_write(struct exynos5_usbdrd_phy *phy_drd,
>> + u32 addr, u32 data)
>> +{
>> + /* Write Address */
>> + crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(addr),
>> + EXYNOS5_DRD_PHYREG0_CR_CAP_ADDR);
>
> According to the guidance from H/W team, before calling crport_handshake(),
> write access for EXYNOS5_DRD_PHYREG0 register is necessary.
>
> Please, add the write access as follows.
>
> + /* Write Address */
> + writel(EXYNOS5_DRD_PHYREG0_CR_DATA_IN(addr),
> + phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> + crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(addr),
> + EXYNOS5_DRD_PHYREG0_CR_CAP_ADDR);

Sure will add this, thanks for getting the information from H/W team
and suggesting.

>
> Best regards,
> Jingoo Han
>
>> +
>> + /* Write Data */
>> + crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(data),
>> + EXYNOS5_DRD_PHYREG0_CR_CAP_DATA);
>> + crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(data),
>> + EXYNOS5_DRD_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:
>> + default:
>> + temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_24M;
>> + break;
>> + }
>> +
>> + crport_ctrl_write(phy_drd,
>> + EXYNOS5_DRD_PHYSS_LANE0_TX_DEBUG,
>> + temp);
>> +}
>> +
>> +/* Calibrate PIPE3 PHY settings, if any */
>> +static int exynos5_usbdrd_pipe3_calibrate(struct phy_usb_instance *inst)
>> +{
>> + struct exynos5_usbdrd_phy *phy_drd = to_usbdrd_phy(inst);
>> +
>> + /* Call respective phy_calibrate given by certain platform */
>> + if (phy_drd->drv_data->calibrate)
>> + phy_drd->drv_data->calibrate(phy_drd);
>> +
>> + return 0;
>> +}
>> +
>> +static int exynos5_usbdrd_phy_calibrate(struct phy *phy)
>> +{
>> + struct phy_usb_instance *inst = phy_get_drvdata(phy);
>> +
>> + if (inst->phy_cfg->phy_calibrate)
>> + inst->phy_cfg->phy_calibrate(inst);
>> +
>> + return 0;
>> +}
>> +
>> static struct phy *exynos5_usbdrd_phy_xlate(struct device *dev,
>> struct of_phandle_args *args)
>> {
>> @@ -503,6 +669,7 @@ static struct phy_ops exynos5_usbdrd_phy_ops = {
>> .exit = exynos5_usbdrd_phy_exit,
>> .power_on = exynos5_usbdrd_phy_power_on,
>> .power_off = exynos5_usbdrd_phy_power_off,
>> + .calibrate = exynos5_usbdrd_phy_calibrate,
>> .owner = THIS_MODULE,
>> };
>>
>> @@ -518,6 +685,7 @@ static const struct exynos5_usbdrd_phy_config phy_cfg_exynos5[] = {
>> .phy_isol = exynos5_usbdrd_phy_isol,
>> .phy_init = exynos5_usbdrd_pipe3_init,
>> .set_refclk = exynos5_usbdrd_pipe3_set_refclk,
>> + .phy_calibrate = exynos5_usbdrd_pipe3_calibrate,
>> },
>> };
>>
>> @@ -525,6 +693,7 @@ static const struct exynos5_usbdrd_phy_drvdata exynos5420_usbdrd_phy = {
>> .phy_cfg = phy_cfg_exynos5,
>> .pmu_offset_usbdrd0_phy = EXYNOS5_USBDRD_PHY_CONTROL,
>> .pmu_offset_usbdrd1_phy = EXYNOS5420_USBDRD1_PHY_CONTROL,
>> + .calibrate = exynos5420_usbdrd_phy_calibrate,
>
> Hmm, how about adding just flag for this, instead of function callback?
> It looks a little bit confusing.

Yeah, i understand the function pointer name looks a bit confusing
since we are using same name in struct phy_ops too.
But i think keeping a function here for each platform may help in
adding any such support in future SoCs too.

May be we can rename it to phy_exynos_calibrate, if you think
that's fine.
Please let me know your opinion about this.




--
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/