From patchwork Wed Dec 27 04:39:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Hu X-Patchwork-Id: 758907 Received: from mx2.zhaoxin.com (mx2.zhaoxin.com [203.110.167.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 714793C2C for ; Wed, 27 Dec 2023 04:39:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zhaoxin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zhaoxin.com X-ASG-Debug-ID: 1703651994-1eb14e0c7f05720003-PT6Irj Received: from ZXSHMBX1.zhaoxin.com (ZXSHMBX1.zhaoxin.com [10.28.252.163]) by mx2.zhaoxin.com with ESMTP id 15J0DVzvPjF9j8ff (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Wed, 27 Dec 2023 12:39:55 +0800 (CST) X-Barracuda-Envelope-From: HansHu-oc@zhaoxin.com X-Barracuda-RBL-Trusted-Forwarder: 10.28.252.163 Received: from ZXBJMBX02.zhaoxin.com (10.29.252.6) by ZXSHMBX1.zhaoxin.com (10.28.252.163) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Wed, 27 Dec 2023 12:39:55 +0800 Received: from ml-HP-ProDesk-680-G4-MT.zhaoxin.com (10.28.66.68) by ZXBJMBX02.zhaoxin.com (10.29.252.6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Wed, 27 Dec 2023 12:39:54 +0800 X-Barracuda-RBL-Trusted-Forwarder: 10.28.252.163 From: Hans Hu X-Barracuda-RBL-Trusted-Forwarder: 10.29.252.6 To: , CC: , , Subject: [PATCH v4 6/8] i2c: wmt: fix a bug when thread blocked Date: Wed, 27 Dec 2023 12:39:49 +0800 X-ASG-Orig-Subj: [PATCH v4 6/8] i2c: wmt: fix a bug when thread blocked Message-ID: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: zxbjmbx1.zhaoxin.com (10.29.252.163) To ZXBJMBX02.zhaoxin.com (10.29.252.6) X-Barracuda-Connect: ZXSHMBX1.zhaoxin.com[10.28.252.163] X-Barracuda-Start-Time: 1703651995 X-Barracuda-Encrypted: ECDHE-RSA-AES128-GCM-SHA256 X-Barracuda-URL: https://10.28.252.36:4443/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at zhaoxin.com X-Barracuda-Scan-Msg-Size: 3073 X-Barracuda-BRTS-Status: 0 X-Barracuda-Bayes: INNOCENT GLOBAL 0.0000 1.0000 -2.0210 X-Barracuda-Spam-Score: -2.02 X-Barracuda-Spam-Status: No, SCORE=-2.02 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.118618 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- During each byte access, the host performs clock stretching. In this case, the thread may be interrupted by preemption, resulting in a long stretching time. However, some touchpad can only tolerate host clock stretching of no more than 200 ms. We reduce the impact of this through a retransmission mechanism. Signed-off-by: Hans Hu --- drivers/i2c/busses/i2c-viai2c-common.c | 37 +++++++++++++++++++++----- drivers/i2c/busses/i2c-viai2c-common.h | 2 ++ 2 files changed, 33 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-viai2c-common.c b/drivers/i2c/busses/i2c-viai2c-common.c index 60a4d4ccaf12..e5eca10efedc 100644 --- a/drivers/i2c/busses/i2c-viai2c-common.c +++ b/drivers/i2c/busses/i2c-viai2c-common.c @@ -2,7 +2,8 @@ #include #include "i2c-viai2c-common.h" -#define VIAI2C_TIMEOUT (msecs_to_jiffies(1000)) +#define VIAI2C_TIMEOUT (msecs_to_jiffies(1000)) +#define VIAI2C_STRETCHING_TIMEOUT 200 static int viai2c_wait_bus_ready(struct viai2c *i2c) { @@ -25,12 +26,35 @@ static int viai2c_wait_bus_ready(struct viai2c *i2c) static int viai2c_wait_status(struct viai2c *i2c) { int ret = 0; - unsigned long wait_result; + unsigned long time_left; + unsigned long delta_ms; + + time_left = wait_for_completion_timeout(&i2c->complete, + VIAI2C_TIMEOUT); + if (!time_left) { + dev_err(i2c->dev, "bus transfer timeout\n"); + return -EIO; + } - wait_result = wait_for_completion_timeout(&i2c->complete, - msecs_to_jiffies(500)); - if (!wait_result) - return -ETIMEDOUT; + /* + * During each byte access, the host performs clock stretching. + * In this case, the thread may be interrupted by preemption, + * resulting in a long stretching time. + * However, some touchpad can only tolerate host clock stretching + * of no more than 200 ms. We reduce the impact of this through + * a retransmission mechanism. + */ + local_irq_disable(); + i2c->to = ktime_get(); + delta_ms = ktime_to_ms(ktime_sub(i2c->to, i2c->ti)); + if (delta_ms > VIAI2C_STRETCHING_TIMEOUT) { + local_irq_enable(); + dev_warn(i2c->dev, "thread blocked more than %ldms\n", + delta_ms); + return -EAGAIN; + } + i2c->ti = i2c->to; + local_irq_enable(); if (i2c->cmd_status & VIAI2C_ISR_NACK_ADDR) ret = -EIO; @@ -184,6 +208,7 @@ int viai2c_xfer(struct i2c_adapter *adap, int ret = 0; struct viai2c *i2c = i2c_get_adapdata(adap); + i2c->to = i2c->ti = ktime_get(); for (i = 0; ret >= 0 && i < num; i++) { pmsg = &msgs[i]; if (!(pmsg->flags & I2C_M_NOSTART)) { diff --git a/drivers/i2c/busses/i2c-viai2c-common.h b/drivers/i2c/busses/i2c-viai2c-common.h index f171f81e4d0f..73a88398d763 100644 --- a/drivers/i2c/busses/i2c-viai2c-common.h +++ b/drivers/i2c/busses/i2c-viai2c-common.h @@ -58,6 +58,8 @@ struct viai2c { u16 tcr; int irq; u16 cmd_status; + ktime_t ti; + ktime_t to; }; int viai2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num);