Re: [PATCH v2] usb: dwc3: add disable u2mac linestate check quirk

[wlf <wulf@rock-chips.com>]

Dear Guenter,


在 2017年04月18日 21:18, Guenter Roeck 写道:
> On Mon, Apr 17, 2017 at 10:17 PM, William Wu <william.wu@rock-chips.com> wrote:
>> This patch adds a quirk to disable USB 2.0 MAC linestate check
>> during HS transmit. Refer the dwc3 databook, we can use it for
>> some special platforms if the linestate not reflect the expected
>> line state(J) during transmission.
>>
>> When use this quirk, the controller implements a fixed 40-bit
>> TxEndDelay after the packet is given on UTMI and ignores the
>> linestate during the transmit of a token (during token-to-token
>> and token-to-data IPGAP).
>>
>> On some rockchip platforms (e.g. rk3399), it requires to disable
>> the u2mac linestate check to decrease the SSPLIT token to SETUP
>> token inter-packet delay from 566ns to 466ns, and fix the issue
>> that FS/LS devices not recognized if inserted through USB 3.0 HUB.
>>
>> Signed-off-by: William Wu <william.wu@rock-chips.com>
>> ---
>> Changes in v2:
>> - fix coding style
>>
>>   Documentation/devicetree/bindings/usb/dwc3.txt |  2 ++
>>   drivers/usb/dwc3/core.c                        | 14 ++++++++++----
>>   drivers/usb/dwc3/core.h                        |  4 ++++
>>   3 files changed, 16 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>> index f658f39..6a89f0c 100644
>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>> @@ -45,6 +45,8 @@ Optional properties:
>>                          a free-running PHY clock.
>>    - snps,dis-del-phy-power-chg-quirk: when set core will change PHY power
>>                          from P0 to P1/P2/P3 without delay.
>> + - snps,tx-ipgap-linecheck-dis-quirk: when set, disable u2mac linestate check
>> +                       during HS transmit.
> All other disable-something quirks are named
> "snps,dis-something-quirk". Maybe use the same naming convention ?
Yes, good idea！ I will fix it with "snps,dis-tx-ipgap-linecheck-quirk"  
in next patch verison.
Thanks:-)
>
>>    - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
>>                          utmi_l1_suspend_n, false when asserts utmi_sleep_n
>>    - snps,hird-threshold: HIRD threshold
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 455d89a..03429c5 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -796,15 +796,19 @@ static int dwc3_core_init(struct dwc3 *dwc)
>>                  dwc3_writel(dwc->regs, DWC3_GUCTL2, reg);
>>          }
>>
>> +       reg = dwc3_readl(dwc->regs, DWC3_GUCTL1);
>> +
> My understanding is that the register was only introduced with dwc3
> revision 2.50a. Is it ok to read and write it unconditionally ?
Yes, refer to dwc3 databook, the DWC3_GUCTL1 was introduced since 2.50a. 
Maybe it's better
to read and write it only when we know our controller version.

Is it good to fix it like the following patch?
But this patch has a problem that we need to read and write the register
twice if our controller verison > = 2.90a, and need this quirk.

--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -806,6 +806,12 @@ static int dwc3_core_init(struct dwc3 *dwc)
                 dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
         }

+       if (dwc->dis_tx_ipgap_linecheck_quirk) {
+               reg = dwc3_readl(dwc->regs, DWC3_GUCTL1);
+               reg |= DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS;
+               dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
+       }
+

Hi John & Felipe,
        Could you provide me some suggestion？
        Thank you！
>>          /*
>>           * Enable hardware control of sending remote wakeup in HS when
>>           * the device is in the L1 state.
>>           */
>> -       if (dwc->revision >= DWC3_REVISION_290A) {
>> -               reg = dwc3_readl(dwc->regs, DWC3_GUCTL1);
>> +       if (dwc->revision >= DWC3_REVISION_290A)
>>                  reg |= DWC3_GUCTL1_DEV_L1_EXIT_BY_HW;
>> -               dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
>> -       }
>> +
>> +       if (dwc->tx_ipgap_linecheck_dis_quirk)
>> +               reg |= DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS;
>> +
>> +       dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
>>
>>          return 0;
>>
>> @@ -1023,6 +1027,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>>                                  "snps,dis-u2-freeclk-exists-quirk");
>>          dwc->dis_del_phy_power_chg_quirk = device_property_read_bool(dev,
>>                                  "snps,dis-del-phy-power-chg-quirk");
>> +       dwc->tx_ipgap_linecheck_dis_quirk = device_property_read_bool(dev,
>> +                               "snps,tx-ipgap-linecheck-dis-quirk");
>>
>>          dwc->tx_de_emphasis_quirk = device_property_read_bool(dev,
>>                                  "snps,tx_de_emphasis_quirk");
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 981c77f..3c2537b 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -204,6 +204,7 @@
>>   #define DWC3_GCTL_DSBLCLKGTNG          BIT(0)
>>
>>   /* Global User Control 1 Register */
>> +#define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS     BIT(28)
>>   #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW  BIT(24)
>>
>>   /* Global USB2 PHY Configuration Register */
>> @@ -850,6 +851,8 @@ struct dwc3_scratchpad_array {
>>    *                     provide a free-running PHY clock.
>>    * @dis_del_phy_power_chg_quirk: set if we disable delay phy power
>>    *                     change quirk.
>> + * @tx_ipgap_linecheck_dis_quirk: set if we disable u2mac linestate
>> + *                     check during HS transmit.
>>    * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
>>    * @tx_de_emphasis: Tx de-emphasis value
>>    *     0       - -6dB de-emphasis
>> @@ -1004,6 +1007,7 @@ struct dwc3 {
>>          unsigned                dis_rxdet_inp3_quirk:1;
>>          unsigned                dis_u2_freeclk_exists_quirk:1;
>>          unsigned                dis_del_phy_power_chg_quirk:1;
>> +       unsigned                tx_ipgap_linecheck_dis_quirk:1;
>>
>>          unsigned                tx_de_emphasis_quirk:1;
>>          unsigned                tx_de_emphasis:2;
>> --
>> 2.0.0
>>
>>
>
>