From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933850AbdKPTzs (ORCPT ); Thu, 16 Nov 2017 14:55:48 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:58764 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932967AbdKPTyi (ORCPT ); Thu, 16 Nov 2017 14:54:38 -0500 From: Eddie James To: linux-kernel@vger.kernel.org Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, wsa@the-dreams.de, robh+dt@kernel.org, joel@jms.id.au, eajames@linux.vnet.ibm.com, "Edward A. James" Subject: [PATCH v6 6/7] drivers/i2c: Add I2C master locking to FSI algorithm Date: Thu, 16 Nov 2017 13:53:51 -0600 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1510862032-12394-1-git-send-email-eajames@linux.vnet.ibm.com> References: <1510862032-12394-1-git-send-email-eajames@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17111619-0016-0000-0000-000007D1AD35 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008076; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000240; SDB=6.00946833; UDB=6.00477976; IPR=6.00727126; BA=6.00005695; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00018049; XFM=3.00000015; UTC=2017-11-16 19:54:20 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17111619-0017-0000-0000-00003C478692 Message-Id: <1510862032-12394-7-git-send-email-eajames@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-11-16_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1711160266 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Edward A. James" Since there are many ports per master, each with it's own adapter and chardev, we need some locking to prevent transfers from changing the master state while other transfers are in progress. Signed-off-by: Edward A. James --- drivers/i2c/busses/i2c-fsi.c | 43 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 39 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 5c312ef..1751c44 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -20,7 +20,9 @@ #include #include #include +#include #include +#include #define FSI_ENGID_I2C 0x7 @@ -144,6 +146,8 @@ struct fsi_i2c_master { struct fsi_device *fsi; u8 fifo_size; struct list_head ports; + wait_queue_head_t wait; + struct semaphore lock; spinlock_t reset_lock; }; @@ -178,6 +182,29 @@ static int fsi_i2c_write_reg(struct fsi_device *fsi, unsigned int reg, return fsi_device_write(fsi, reg, &data_be, sizeof(data_be)); } +static int fsi_i2c_lock_master(struct fsi_i2c_master *i2c, int timeout) +{ + int rc; + + rc = down_trylock(&i2c->lock); + if (!rc) + return 0; + + rc = wait_event_interruptible_timeout(i2c->wait, + !down_trylock(&i2c->lock), + timeout); + if (rc > 0) + return 0; + + return -EBUSY; +} + +static void fsi_i2c_unlock_master(struct fsi_i2c_master *i2c) +{ + up(&i2c->lock); + wake_up(&i2c->wait); +} + static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c) { int rc; @@ -611,25 +638,31 @@ static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, struct fsi_i2c_port *port = adap->algo_data; struct i2c_msg *msg; - rc = fsi_i2c_set_port(port); + rc = fsi_i2c_lock_master(port->master, adap->timeout); if (rc) return rc; + rc = fsi_i2c_set_port(port); + if (rc) + goto unlock; + for (i = 0; i < num; ++i) { msg = msgs + i; start_time = jiffies; rc = fsi_i2c_start(port, msg, i == num - 1); if (rc) - return rc; + goto unlock; rc = fsi_i2c_wait(port, msg, adap->timeout - (jiffies - start_time)); if (rc) - return rc; + goto unlock; } - return 0; +unlock: + fsi_i2c_unlock_master(port->master); + return rc; } static u32 fsi_i2c_functionality(struct i2c_adapter *adap) @@ -655,6 +688,8 @@ static int fsi_i2c_probe(struct device *dev) if (!i2c) return -ENOMEM; + init_waitqueue_head(&i2c->wait); + sema_init(&i2c->lock, 1); spin_lock_init(&i2c->reset_lock); i2c->fsi = to_fsi_dev(dev); INIT_LIST_HEAD(&i2c->ports); -- 1.8.3.1