From: Roger Quadros <rogerq@ti.com> To: <balbi@kernel.org> Cc: <tony@atomide.com>, <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-omap@vger.kernel.org>, Roger Quadros <rogerq@ti.com> Subject: [PATCH] usb: dwc3: Allow disabling of metastability workaround Date: Tue, 31 Oct 2017 15:11:55 +0200 [thread overview] Message-ID: <1509455515-5992-1-git-send-email-rogerq@ti.com> (raw) Some platforms (e.g. TI's DRA7 USB2 instance) have more trouble with the metastability workaround as it supports only a High-Speed PHY and the PHY can enter into an Erratic state [1] when the controller is set in SuperSpeed mode as part of the metastability workaround. This causes upto 2 seconds delay in enumeration on DRA7's USB2 instance in gadget mode. If these platforms can be better off without the workaround, provide a device tree property to suggest that so the workaround is avoided. [1] Device mode enumeration trace showing PHY Erratic Error. irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0] Signed-off-by: Roger Quadros <rogerq@ti.com> --- Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++ drivers/usb/dwc3/core.c | 3 +++ drivers/usb/dwc3/core.h | 3 +++ drivers/usb/dwc3/gadget.c | 6 ++++-- 4 files changed, 12 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index 52fb410..44e8bab 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -47,6 +47,8 @@ Optional properties: from P0 to P1/P2/P3 without delay. - snps,dis-tx-ipgap-linecheck-quirk: when set, disable u2mac linestate check during HS transmit. + - snps,dis_metastability_quirk: when set, disable metastability workaround. + CAUTION: use only if you are absolutely sure of it. - 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 03474d3..18984b9c 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1072,6 +1072,9 @@ static void dwc3_get_properties(struct dwc3 *dwc) device_property_read_u32(dev, "snps,quirk-frame-length-adjustment", &dwc->fladj); + dwc->dis_metastability_quirk = device_property_read_bool(dev, + "snps,dis_metastability_quirk"); + dwc->lpm_nyet_threshold = lpm_nyet_threshold; dwc->tx_de_emphasis = tx_de_emphasis; diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index ea910ac..c521a02 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -863,6 +863,7 @@ struct dwc3_scratchpad_array { * 1 - -3.5dB de-emphasis * 2 - No de-emphasis * 3 - Reserved + * @dis_metastability_quirk: set to disable metastability quirk. * @imod_interval: set the interrupt moderation interval in 250ns * increments or 0 to disable. */ @@ -1016,6 +1017,8 @@ struct dwc3 { unsigned tx_de_emphasis_quirk:1; unsigned tx_de_emphasis:2; + unsigned dis_metastability_quirk:1; + u16 imod_interval; }; diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 9f27ec0..472499b 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2027,7 +2027,8 @@ static void dwc3_gadget_set_speed(struct usb_gadget *g, * STAR#9000525659: Clock Domain Crossing on DCTL in * USB 2.0 Mode */ - if (dwc->revision < DWC3_REVISION_220A) { + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) { reg |= DWC3_DCFG_SUPERSPEED; } else { switch (speed) { @@ -3256,7 +3257,8 @@ int dwc3_gadget_init(struct dwc3 *dwc) * is less than super speed because we don't have means, yet, to tell * composite.c that we are USB 2.0 + LPM ECN. */ - if (dwc->revision < DWC3_REVISION_220A) + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) dev_info(dwc->dev, "changing max_speed on rev %08x\n", dwc->revision); -- cheers, -roger Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
WARNING: multiple messages have this Message-ID (diff)
From: Roger Quadros <rogerq@ti.com> To: balbi@kernel.org Cc: tony@atomide.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Roger Quadros <rogerq@ti.com> Subject: [PATCH] usb: dwc3: Allow disabling of metastability workaround Date: Tue, 31 Oct 2017 15:11:55 +0200 [thread overview] Message-ID: <1509455515-5992-1-git-send-email-rogerq@ti.com> (raw) Some platforms (e.g. TI's DRA7 USB2 instance) have more trouble with the metastability workaround as it supports only a High-Speed PHY and the PHY can enter into an Erratic state [1] when the controller is set in SuperSpeed mode as part of the metastability workaround. This causes upto 2 seconds delay in enumeration on DRA7's USB2 instance in gadget mode. If these platforms can be better off without the workaround, provide a device tree property to suggest that so the workaround is avoided. [1] Device mode enumeration trace showing PHY Erratic Error. irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0] Signed-off-by: Roger Quadros <rogerq@ti.com> --- Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++ drivers/usb/dwc3/core.c | 3 +++ drivers/usb/dwc3/core.h | 3 +++ drivers/usb/dwc3/gadget.c | 6 ++++-- 4 files changed, 12 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index 52fb410..44e8bab 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -47,6 +47,8 @@ Optional properties: from P0 to P1/P2/P3 without delay. - snps,dis-tx-ipgap-linecheck-quirk: when set, disable u2mac linestate check during HS transmit. + - snps,dis_metastability_quirk: when set, disable metastability workaround. + CAUTION: use only if you are absolutely sure of it. - 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 03474d3..18984b9c 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1072,6 +1072,9 @@ static void dwc3_get_properties(struct dwc3 *dwc) device_property_read_u32(dev, "snps,quirk-frame-length-adjustment", &dwc->fladj); + dwc->dis_metastability_quirk = device_property_read_bool(dev, + "snps,dis_metastability_quirk"); + dwc->lpm_nyet_threshold = lpm_nyet_threshold; dwc->tx_de_emphasis = tx_de_emphasis; diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index ea910ac..c521a02 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -863,6 +863,7 @@ struct dwc3_scratchpad_array { * 1 - -3.5dB de-emphasis * 2 - No de-emphasis * 3 - Reserved + * @dis_metastability_quirk: set to disable metastability quirk. * @imod_interval: set the interrupt moderation interval in 250ns * increments or 0 to disable. */ @@ -1016,6 +1017,8 @@ struct dwc3 { unsigned tx_de_emphasis_quirk:1; unsigned tx_de_emphasis:2; + unsigned dis_metastability_quirk:1; + u16 imod_interval; }; diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 9f27ec0..472499b 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2027,7 +2027,8 @@ static void dwc3_gadget_set_speed(struct usb_gadget *g, * STAR#9000525659: Clock Domain Crossing on DCTL in * USB 2.0 Mode */ - if (dwc->revision < DWC3_REVISION_220A) { + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) { reg |= DWC3_DCFG_SUPERSPEED; } else { switch (speed) { @@ -3256,7 +3257,8 @@ int dwc3_gadget_init(struct dwc3 *dwc) * is less than super speed because we don't have means, yet, to tell * composite.c that we are USB 2.0 + LPM ECN. */ - if (dwc->revision < DWC3_REVISION_220A) + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) dev_info(dwc->dev, "changing max_speed on rev %08x\n", dwc->revision); -- cheers, -roger Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next reply other threads:[~2017-10-31 13:12 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-31 13:11 Roger Quadros [this message] 2017-10-31 13:11 ` [PATCH] usb: dwc3: Allow disabling of metastability workaround Roger Quadros
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