From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CF29C2D0C0 for ; Mon, 23 Dec 2019 14:19:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19F2321775 for ; Mon, 23 Dec 2019 14:19:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727593AbfLWOT0 (ORCPT ); Mon, 23 Dec 2019 09:19:26 -0500 Received: from mga07.intel.com ([134.134.136.100]:18205 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726903AbfLWORZ (ORCPT ); Mon, 23 Dec 2019 09:17:25 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Dec 2019 06:17:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,347,1571727600"; d="scan'208";a="249500509" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga002.fm.intel.com with ESMTP; 23 Dec 2019 06:17:21 -0800 Received: by black.fi.intel.com (Postfix, from userid 1001) id 76EC1720; Mon, 23 Dec 2019 16:17:17 +0200 (EET) From: Mika Westerberg To: Andy Shevchenko , Darren Hart , Lee Jones , x86@kernel.org Cc: Zha Qipeng , Rajneesh Bhardwaj , "David E . Box" , Guenter Roeck , Heikki Krogerus , Greg Kroah-Hartman , Wim Van Sebroeck , Mika Westerberg , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 07/37] platform/x86: intel_scu_ipc: Sleeping is fine when polling Date: Mon, 23 Dec 2019 17:16:46 +0300 Message-Id: <20191223141716.13727-8-mika.westerberg@linux.intel.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191223141716.13727-1-mika.westerberg@linux.intel.com> References: <20191223141716.13727-1-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is no reason why the driver would need to block other threads from running the CPU while it is waiting for the SCU IPC to complete its work. For this reason switch the driver to use usleep_range() instead with a bit more relaxed polling loop. Also add constant for the timeout and use the same value for both polling and interrupt modes. Signed-off-by: Mika Westerberg --- drivers/platform/x86/intel_scu_ipc.c | 29 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 15 deletions(-) diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c index 43eaf9400c67..8db0644900a3 100644 --- a/drivers/platform/x86/intel_scu_ipc.c +++ b/drivers/platform/x86/intel_scu_ipc.c @@ -79,6 +79,9 @@ static struct intel_scu_ipc_dev ipcdev; /* Only one for now */ #define IPC_WRITE_BUFFER 0x80 #define IPC_READ_BUFFER 0x90 +/* Timeout in jiffies */ +#define IPC_TIMEOUT (3 * HZ) + static DEFINE_MUTEX(ipclock); /* lock used to prevent multiple call to SCU */ /* @@ -132,24 +135,20 @@ static inline u32 ipc_data_readl(struct intel_scu_ipc_dev *scu, u32 offset) /* Wait till scu status is busy */ static inline int busy_loop(struct intel_scu_ipc_dev *scu) { - u32 status = ipc_read_status(scu); - u32 loop_count = 100000; + unsigned long end = jiffies + msecs_to_jiffies(IPC_TIMEOUT); - /* break if scu doesn't reset busy bit after huge retry */ - while ((status & IPC_STATUS_BUSY) && --loop_count) { - udelay(1); /* scu processing time is in few u secods */ - status = ipc_read_status(scu); - } + do { + u32 status; - if (status & IPC_STATUS_BUSY) { - dev_err(scu->dev, "IPC timed out"); - return -ETIMEDOUT; - } + status = ipc_read_status(scu); + if (!(status & IPC_STATUS_BUSY)) + return (status & IPC_STATUS_ERR) ? -EIO : 0; - if (status & IPC_STATUS_ERR) - return -EIO; + usleep_range(50, 100); + } while (time_before(jiffies, end)); - return 0; + dev_err(scu->dev, "IPC timed out"); + return -ETIMEDOUT; } /* Wait till ipc ioc interrupt is received or timeout in 3 HZ */ @@ -157,7 +156,7 @@ static inline int ipc_wait_for_interrupt(struct intel_scu_ipc_dev *scu) { int status; - if (!wait_for_completion_timeout(&scu->cmd_complete, 3 * HZ)) { + if (!wait_for_completion_timeout(&scu->cmd_complete, IPC_TIMEOUT)) { dev_err(scu->dev, "IPC timed out\n"); return -ETIMEDOUT; } -- 2.24.0