From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: [PATCH] i2c: designware-baytrail: Fix race when resetting the semaphore Date: Sun, 1 Jan 2017 12:30:22 +0100 Message-ID: <20170101113022.6791-2-hdegoede@redhat.com> References: <20170101113022.6791-1-hdegoede@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32860 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755067AbdAALa3 (ORCPT ); Sun, 1 Jan 2017 06:30:29 -0500 In-Reply-To: <20170101113022.6791-1-hdegoede@redhat.com> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Jarkko Nikula , Wolfram Sang , Len Brown , Andy Shevchenko Cc: Mika Westerberg , Jani Nikula , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Takashi Iwai , "russianneuromancer @ ya . ru" , linux-i2c@vger.kernel.org, intel-gfx , Hans de Goede Use iosf_mbi_modify instead of iosf_mbi_read + iosf_mbi_write so that we keep the iosf_mbi_lock locked during the read-modify-write done to reset the semaphore. Signed-off-by: Hans de Goede --- drivers/i2c/busses/i2c-designware-baytrail.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c index 9481411..9634544 100644 --- a/drivers/i2c/busses/i2c-designware-baytrail.c +++ b/drivers/i2c/busses/i2c-designware-baytrail.c @@ -64,18 +64,16 @@ static int get_sem(struct dw_i2c_dev *dev, u32 *sem) static void reset_semaphore(struct dw_i2c_dev *dev) { - u32 addr = get_sem_addr(dev); - u32 data; + int ret; - if (iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &data)) { - dev_err(dev->dev, "iosf failed to reset punit semaphore during read\n"); + ret = iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, get_sem_addr(dev), + 0, PUNIT_SEMAPHORE_BIT); + if (ret) { + dev_err(dev->dev, "iosf failed to reset punit semaphore: %d\n", + ret); return; } - data &= ~PUNIT_SEMAPHORE_BIT; - if (iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, addr, data)) - dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n"); - pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE); } -- 2.9.3