Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760524Ab1D1PQJ (ORCPT ); Thu, 28 Apr 2011 11:16:09 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:59953 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932882Ab1D1PQH (ORCPT ); Thu, 28 Apr 2011 11:16:07 -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=PtHoOr74+DivJzwd2nCxGuxDfcUxNL1oirxVNYteG5OpMRs6F5fdfUAWrKDjBuKxcw FVIMHiBR23fDZVmm5fTdGKFRSNGs2yLBqe0VJ4GclWX5H6mHE5k5c7Xfa4czkGat0y4B Zc8Lg1j7Wkp3a41Oweih833q5KwU7q+IyJcGs= From: Haojian Zhuang To: eric.y.miao@gmail.com, khali@linux-fr.org, ben-linux@fluff.org, linux-i2c@vger.kernel.org, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Haojian Zhuang , Haojian Zhuang Subject: [PATCH 1/3] i2c: append hardware lock with bus lock Date: Thu, 28 Apr 2011 23:15:44 +0800 Message-Id: <1304003746-12127-1-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: 2564 Lines: 89 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 Cc: Jean Delvare --- 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..132d46c 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(adapter); + } } 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(adapter); + 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(adapter); 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..f4ef5b0 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)(struct i2c_adapter *); + void (*hardware_unlock)(struct i2c_adapter *); + int (*hardware_trylock)(struct i2c_adapter *); 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/