From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pl0-x241.google.com ([2607:f8b0:400e:c01::241]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1f6jqv-0005ta-0M for barebox@lists.infradead.org; Thu, 12 Apr 2018 21:33:58 +0000 Received: by mail-pl0-x241.google.com with SMTP id 59-v6so4771130plc.13 for ; Thu, 12 Apr 2018 14:33:46 -0700 (PDT) From: Andrey Smirnov Date: Thu, 12 Apr 2018 14:33:17 -0700 Message-Id: <20180412213317.13199-6-andrew.smirnov@gmail.com> In-Reply-To: <20180412213317.13199-1-andrew.smirnov@gmail.com> References: <20180412213317.13199-1-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v2 5/5] serdev: Allow polling interval to be adjusted at runtime To: barebox@lists.infradead.org Cc: Andrey Smirnov Due to blocking, synchronous, polling driven nature of Barebox's serial communication handling trying to use two or more serial ports at high (1Mbaud+) baudrates results in data loss and noticeable perofmance degradation. This happens as soon as individual message being sent around start exceeding HW Rx FIFO in size. A good example of such a usecase would be using a system that has a serdev driver (operating @ 1Mbaud+) and trying to do a X/YMODEM transfer via serial console at comparable baudrates. To at least partially ameliorate the problem, add code that will expose "polling_interval" as a parameter, so that the user would have an option of temporarily disabling (or significatly decreasing the rate) of a given serdev's polling. Signed-off-by: Andrey Smirnov --- common/serdev.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/common/serdev.c b/common/serdev.c index 50eadc804..4a6dbefe6 100644 --- a/common/serdev.c +++ b/common/serdev.c @@ -34,12 +34,26 @@ static void serdev_device_poller(void *context) serdev->polling_interval, serdev_device_poller, serdev); + } else { + poller_async_cancel(&serdev->poller); } } +static int serdev_device_set_polling_interval(struct param_d *param, void *serdev) +{ + /* + * We execute poller ever time polling_interval changes to get + * any unprocessed immediate Rx data as well as to propagate + * polling_interval chagnes to outstanging async pollers. + */ + serdev_device_poller(serdev); + return 0; +} + int serdev_device_open(struct serdev_device *serdev) { struct console_device *cdev = to_console_device(serdev); + struct param_d *p; int ret; if (!cdev->putc || !cdev->getc) @@ -57,7 +71,17 @@ int serdev_device_open(struct serdev_device *serdev) if (ret) return ret; - return console_open(cdev); + ret = console_open(cdev); + if (ret) + return ret; + + p = dev_add_param_uint64(serdev->dev, "polling_interval", + serdev_device_set_polling_interval, NULL, + &serdev->polling_interval, "%llu", serdev); + if (IS_ERR(p)) + return PTR_ERR(p); + + return 0; } unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, -- 2.14.3 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox