Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751387Ab1D1EDG (ORCPT ); Thu, 28 Apr 2011 00:03:06 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:57336 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750817Ab1D1EDD (ORCPT ); Thu, 28 Apr 2011 00:03:03 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=lnXepHztt1dsH0EBUrt3Twhnp0Y2DXikH1yobALcnsv2lpJXvGpPaFhCDWjzvUWnnV MpO3PVdm5ch/xvYX81M2U2snId+s6UmUsfF5Kmy3yQMw6/mw9u9HFzJAXOSHIdt46HTw tZ4aBxFrZPKUfdjm93vV/uElxzLR4Hl7xhyBQ= From: Haojian Zhuang To: haojian.zhuang@marvell.com, eric.y.miao@gmail.com, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, ben-linux@fluff.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Haojian Zhuang Subject: [PATCH 1/3] i2c: append hardware lock with bus lock Date: Thu, 28 Apr 2011 12:02:36 +0800 Message-Id: <1303963358-4652-1-git-send-email-haojian.zhuang@gmail.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <2011042801> References: <2011042801> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2457 Lines: 88 Both AP and CP are contained in Marvell PXA910 silicon. These two ARM cores are sharing one pair of I2C pins. In order to keep I2C transaction operated with atomic, hardware lock (RIPC) is required. Because of this, bus lock in AP side can't afford this requirement. Now hardware lock is appended. Signed-off-by: Haojian Zhuang Cc: Ben Dooks --- drivers/i2c/i2c-core.c | 22 ++++++++++++++++++---- include/linux/i2c.h | 3 +++ 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 045ba6e..412c7a5 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -448,8 +448,11 @@ void i2c_lock_adapter(struct i2c_adapter *adapter) if (parent) i2c_lock_adapter(parent); - else + else { rt_mutex_lock(&adapter->bus_lock); + if (adapter->hardware_lock) + adapter->hardware_lock(); + } } EXPORT_SYMBOL_GPL(i2c_lock_adapter); @@ -460,11 +463,19 @@ EXPORT_SYMBOL_GPL(i2c_lock_adapter); static int i2c_trylock_adapter(struct i2c_adapter *adapter) { struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); + int ret = 0; if (parent) return i2c_trylock_adapter(parent); - else - return rt_mutex_trylock(&adapter->bus_lock); + else { + ret = rt_mutex_trylock(&adapter->bus_lock); + if (ret && adapter->hardware_trylock) { + ret = adapter->hardware_trylock(); + if (!ret) + i2c_unlock_adapter(adapter); + } + return ret; + } } /** @@ -477,8 +488,11 @@ void i2c_unlock_adapter(struct i2c_adapter *adapter) if (parent) i2c_unlock_adapter(parent); - else + else { + if (adapter->hardware_unlock) + adapter->hardware_unlock(); rt_mutex_unlock(&adapter->bus_lock); + } } EXPORT_SYMBOL_GPL(i2c_unlock_adapter); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 06a8d9c..b283b4e 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -361,6 +361,9 @@ struct i2c_adapter { /* data fields that are valid for all devices */ struct rt_mutex bus_lock; + void (*hardware_lock)(void); + void (*hardware_unlock)(void); + int (*hardware_trylock)(void); int timeout; /* in jiffies */ int retries; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/