This is a note to let you know that I've just added the patch titled
usb: dwc3: Allow disabling of metastability workaround
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summ...
The filename of the patch is: usb-dwc3-allow-disabling-of-metastability-workaround.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon 11 Nov 2019 10:07:22 AM CET
From: Mathieu Poirier mathieu.poirier@linaro.org Date: Thu, 5 Sep 2019 10:17:45 -0600 Subject: usb: dwc3: Allow disabling of metastability workaround To: stable@vger.kernel.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org, linux-pci@vger.kernel.org, linux-mtd@lists.infradead.org Message-ID: 20190905161759.28036-5-mathieu.poirier@linaro.org
From: Roger Quadros rogerq@ti.com
commit 42bf02ec6e420e541af9a47437d0bdf961ca2972 upstream
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 Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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(-)
--- 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 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1115,6 +1115,9 @@ static void dwc3_get_properties(struct d 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;
--- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -869,6 +869,7 @@ 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. */ @@ -1025,6 +1026,8 @@ struct dwc3 { unsigned tx_de_emphasis_quirk:1; unsigned tx_de_emphasis:2;
+ unsigned dis_metastability_quirk:1; + u16 imod_interval; };
--- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2034,7 +2034,8 @@ static void dwc3_gadget_set_speed(struct * 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) { @@ -3265,7 +3266,8 @@ 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);
Patches currently in stable-queue which might be from mathieu.poirier@linaro.org are
queue-4.14/mailbox-reset-txdone_method-txdone_by_poll-if-client-knows_txdone.patch queue-4.14/mtd-spi-nor-cadence-quadspi-add-a-delay-in-write-sequence.patch queue-4.14/misc-pci_endpoint_test-fix-bug_on-error-during-pci_disable_msi.patch queue-4.14/asoc-tlv320dac31xx-mark-expected-switch-fall-through.patch queue-4.14/pci-dra7xx-add-shutdown-handler-to-cleanly-turn-off-clocks.patch queue-4.14/asoc-tlv320aic31xx-handle-inverted-bclk-in-non-dsp-modes.patch queue-4.14/mtd-spi-nor-enable-4b-opcodes-for-mx66l51235l.patch queue-4.14/cpufreq-ti-cpufreq-add-missing-of_node_put.patch queue-4.14/asoc-davinci-kill-bug_on-usage.patch queue-4.14/mfd-palmas-assign-the-right-powerhold-mask-for-tps65917.patch queue-4.14/asoc-davinci-mcasp-fix-an-error-handling-path-in-davinci_mcasp_probe.patch queue-4.14/misc-pci_endpoint_test-prevent-some-integer-overflows.patch queue-4.14/asoc-davinci-mcasp-handle-return-value-of-devm_kasprintf.patch queue-4.14/i2c-omap-trigger-bus-recovery-in-lockup-case.patch queue-4.14/usb-dwc3-allow-disabling-of-metastability-workaround.patch