From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie James Subject: [PATCH v6 6/7] drivers/i2c: Add I2C master locking to FSI algorithm Date: Thu, 16 Nov 2017 13:53:51 -0600 Message-ID: <1510862032-12394-7-git-send-email-eajames@linux.vnet.ibm.com> References: <1510862032-12394-1-git-send-email-eajames@linux.vnet.ibm.com> Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41378 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758436AbdKPTyZ (ORCPT ); Thu, 16 Nov 2017 14:54:25 -0500 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vAGJsJMC103665 for ; Thu, 16 Nov 2017 14:54:24 -0500 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0b-001b2d01.pphosted.com with ESMTP id 2e9etu83kt-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 16 Nov 2017 14:54:23 -0500 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 16 Nov 2017 12:54:22 -0700 In-Reply-To: <1510862032-12394-1-git-send-email-eajames@linux.vnet.ibm.com> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org 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" 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