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[34.147.45.103]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-aa20e086244sm187758166b.177.2024.11.15.07.52.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Nov 2024 07:52:42 -0800 (PST) From: =?utf-8?q?=C5=81ukasz_Bartosik?= To: Heikki Krogerus , Greg Kroah-Hartman , Benson Leung Cc: Abhishek Pandit-Subedi , Jameson Thies , Pavan Holla , Tzung-Bi Shih , linux-usb@vger.kernel.org, chrome-platform@lists.linux.dev Subject: [PATCH v7 3/3] usb: typec: cros_ec_ucsi: Recover from write timeouts Date: Fri, 15 Nov 2024 15:52:34 +0000 Message-ID: <20241115155234.1587589-4-ukaszb@chromium.org> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog In-Reply-To: <20241115155234.1587589-1-ukaszb@chromium.org> References: <20241115155234.1587589-1-ukaszb@chromium.org> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Abhishek Pandit-Subedi In a suspend-resume edge case, the OPM is timing out in ucsi_resume and the PPM is getting stuck waiting for a command complete ack. Add a write timeout recovery task that will get us out of this state. Signed-off-by: Abhishek Pandit-Subedi Signed-off-by: Łukasz Bartosik --- drivers/usb/typec/ucsi/cros_ec_ucsi.c | 83 ++++++++++++++++++++++++++- 1 file changed, 82 insertions(+), 1 deletion(-) diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi.c b/drivers/usb/typec/ucsi/cros_ec_ucsi.c index aae0bf106494..3e6b59aba275 100644 --- a/drivers/usb/typec/ucsi/cros_ec_ucsi.c +++ b/drivers/usb/typec/ucsi/cros_ec_ucsi.c @@ -7,6 +7,7 @@ #include #include +#include #include #include #include @@ -29,6 +30,9 @@ */ #define WRITE_TMO_MS 5000 +/* Number of times to attempt recovery from a write timeout before giving up. */ +#define WRITE_TMO_CTR_MAX 5 + struct cros_ucsi_data { struct device *dev; struct ucsi *ucsi; @@ -36,6 +40,8 @@ struct cros_ucsi_data { struct cros_ec_device *ec; struct notifier_block nb; struct work_struct work; + struct delayed_work write_tmo; + int tmo_counter; struct completion complete; unsigned long flags; @@ -101,7 +107,33 @@ static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd) static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd) { - return ucsi_sync_control_common(ucsi, cmd); + struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi); + int ret; + + ret = ucsi_sync_control_common(ucsi, cmd); + if (ret) + goto out; + + /* Successful write. Cancel any pending recovery work. */ + cancel_delayed_work_sync(&udata->write_tmo); + + return 0; +out: + /* EC may return -EBUSY if CCI.busy is set. Convert this to a timeout. + */ + if (ret == -EBUSY) + ret = -ETIMEDOUT; + + /* Schedule recovery attempt when we timeout or tried to send a command + * while still busy. + */ + if (ret == -ETIMEDOUT) { + cancel_delayed_work_sync(&udata->write_tmo); + schedule_delayed_work(&udata->write_tmo, + msecs_to_jiffies(WRITE_TMO_MS)); + } + + return ret; } struct ucsi_operations cros_ucsi_ops = { @@ -123,6 +155,54 @@ static void cros_ucsi_work(struct work_struct *work) ucsi_notify_common(udata->ucsi, cci); } +static void cros_ucsi_write_timeout(struct work_struct *work) +{ + struct cros_ucsi_data *udata = + container_of(work, struct cros_ucsi_data, write_tmo.work); + u32 cci; + u64 cmd; + + if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) { + dev_err(udata->dev, + "Reading CCI failed; no write timeout recovery possible."); + return; + } + + if (cci & UCSI_CCI_BUSY) { + udata->tmo_counter++; + + if (udata->tmo_counter <= WRITE_TMO_CTR_MAX) + schedule_delayed_work(&udata->write_tmo, + msecs_to_jiffies(WRITE_TMO_MS)); + else + dev_err(udata->dev, + "PPM unresponsive - too many write timeouts."); + + return; + } + + /* No longer busy means we can reset our timeout counter. */ + udata->tmo_counter = 0; + + /* Need to ack previous command which may have timed out. */ + if (cci & UCSI_CCI_COMMAND_COMPLETE) { + cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE; + cros_ucsi_async_control(udata->ucsi, &cmd); + + /* Check again after a few seconds that the system has + * recovered to make sure our async write above was successful. + */ + schedule_delayed_work(&udata->write_tmo, + msecs_to_jiffies(WRITE_TMO_MS)); + return; + } + + /* We recovered from a previous timeout. Treat this as a recovery from + * suspend and call resume. + */ + ucsi_resume(udata->ucsi); +} + static int cros_ucsi_event(struct notifier_block *nb, unsigned long host_event, void *_notify) { @@ -167,6 +247,7 @@ static int cros_ucsi_probe(struct platform_device *pdev) platform_set_drvdata(pdev, udata); INIT_WORK(&udata->work, cros_ucsi_work); + INIT_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout); init_completion(&udata->complete); udata->ucsi = ucsi_create(dev, &cros_ucsi_ops);