Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753768AbbBFA6K (ORCPT ); Thu, 5 Feb 2015 19:58:10 -0500 Received: from mga09.intel.com ([134.134.136.24]:14139 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753530AbbBFA6H (ORCPT ); Thu, 5 Feb 2015 19:58:07 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="450513663" From: Lv Zheng To: "Rafael J. Wysocki" , Len Brown Cc: Lv Zheng , Lv Zheng , , linux-acpi@vger.kernel.org Subject: [PATCH v2 2/5] ACPI / EC: Add command flushing support. Date: Fri, 6 Feb 2015 08:57:59 +0800 Message-Id: <991bf8b675e1a0a04ddf3af8d8dd792239ffef03.1423183648.git.lv.zheng@intel.com> X-Mailer: git-send-email 1.7.10 In-Reply-To: References: <20141119121615.GA2514@node.dhcp.inet.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5579 Lines: 162 This patch implements the EC command flushing support. During the grace period indicated by EC_FLAGS_STARTED and EC_FLAGS_STOPPED, all submitted EC command transactions can be completed and new submissions are prevented before suspending so that the EC hardware can be ensured to be in the idle state when the system is resumed. There is a good indicator for flush support: All acpi_ec_submit_request() is invoked after checking driver state with acpi_ec_started() except the first one. This means all code paths can be flushed as fast as possible by discarding the requests occurred after the flush operation. The reference increased for such kind of code path is wrapped by acpi_ec_submit_flushable_request(). Signed-off-by: Lv Zheng Tested-by: Ortwin Glück --- drivers/acpi/ec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++--- drivers/acpi/internal.h | 1 + 2 files changed, 66 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index a6179b7..1fa1463 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -145,6 +145,11 @@ static bool acpi_ec_started(struct acpi_ec *ec) !test_bit(EC_FLAGS_STOPPED, &ec->flags); } +static bool acpi_ec_flushed(struct acpi_ec *ec) +{ + return ec->reference_count == 1; +} + /* -------------------------------------------------------------------------- * EC Registers * -------------------------------------------------------------------------- */ @@ -266,6 +271,44 @@ static inline void acpi_ec_clear_gpe(struct acpi_ec *ec) * Transaction Management * -------------------------------------------------------------------------- */ +static void acpi_ec_submit_request(struct acpi_ec *ec) +{ + ec->reference_count++; + if (ec->reference_count == 1) + acpi_ec_enable_gpe(ec, true); +} + +static void acpi_ec_complete_request(struct acpi_ec *ec) +{ + bool flushed = false; + + ec->reference_count--; + if (ec->reference_count == 0) + acpi_ec_disable_gpe(ec, true); + flushed = acpi_ec_flushed(ec); + if (flushed) + wake_up(&ec->wait); +} + +/* + * acpi_ec_submit_flushable_request() - Increase the reference count unless + * the flush operation is not in + * progress + * @ec: the EC device + * + * This function must be used before taking a new action that should hold + * the reference count. If this function returns false, then the action + * must be discarded or it will prevent the flush operation from being + * completed. + */ +static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec) +{ + if (!acpi_ec_started(ec)) + return false; + acpi_ec_submit_request(ec); + return true; +} + static void acpi_ec_submit_query(struct acpi_ec *ec) { if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) { @@ -426,7 +469,8 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, udelay(ACPI_EC_MSI_UDELAY); /* start transaction */ spin_lock_irqsave(&ec->lock, tmp); - if (!acpi_ec_started(ec)) { + /* Enable GPE for command processing (IBF=0/OBF=1) */ + if (!acpi_ec_submit_flushable_request(ec)) { ret = -EINVAL; goto unlock; } @@ -441,6 +485,8 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, pr_debug("***** Command(%s) stopped *****\n", acpi_ec_cmd_string(t->command)); ec->curr = NULL; + /* Disable GPE for command processing (IBF=0/OBF=1) */ + acpi_ec_complete_request(ec); unlock: spin_unlock_irqrestore(&ec->lock, tmp); return ret; @@ -614,13 +660,25 @@ static void acpi_ec_start(struct acpi_ec *ec, bool resuming) spin_lock_irqsave(&ec->lock, flags); if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) { pr_debug("+++++ Starting EC +++++\n"); + /* Enable GPE for event processing (SCI_EVT=1) */ if (!resuming) - acpi_ec_enable_gpe(ec, true); + acpi_ec_submit_request(ec); pr_info("+++++ EC started +++++\n"); } spin_unlock_irqrestore(&ec->lock, flags); } +static bool acpi_ec_stopped(struct acpi_ec *ec) +{ + unsigned long flags; + bool flushed; + + spin_lock_irqsave(&ec->lock, flags); + flushed = acpi_ec_flushed(ec); + spin_unlock_irqrestore(&ec->lock, flags); + return flushed; +} + static void acpi_ec_stop(struct acpi_ec *ec, bool suspending) { unsigned long flags; @@ -629,8 +687,12 @@ static void acpi_ec_stop(struct acpi_ec *ec, bool suspending) if (acpi_ec_started(ec)) { pr_debug("+++++ Stopping EC +++++\n"); set_bit(EC_FLAGS_STOPPED, &ec->flags); + spin_unlock_irqrestore(&ec->lock, flags); + wait_event(ec->wait, acpi_ec_stopped(ec)); + spin_lock_irqsave(&ec->lock, flags); + /* Disable GPE for event processing (SCI_EVT=1) */ if (!suspending) - acpi_ec_disable_gpe(ec, true); + acpi_ec_complete_request(ec); clear_bit(EC_FLAGS_STARTED, &ec->flags); clear_bit(EC_FLAGS_STOPPED, &ec->flags); pr_info("+++++ EC stopped +++++\n"); diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 63e3495..6a4420d 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -129,6 +129,7 @@ struct acpi_ec { unsigned long data_addr; unsigned long global_lock; unsigned long flags; + unsigned long reference_count; struct mutex mutex; wait_queue_head_t wait; struct list_head list; -- 1.7.10 -- 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/