From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932586AbcI3I5W (ORCPT ); Fri, 30 Sep 2016 04:57:22 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:39807 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752864AbcI3I42 (ORCPT ); Fri, 30 Sep 2016 04:56:28 -0400 Message-ID: <1475225778.25044.35.camel@mtksdaap41> Subject: Re: [PATCH v14 2/4] CMDQ: Mediatek CMDQ driver From: Horng-Shyang Liao To: CK Hu CC: Rob Herring , Matthias Brugger , Jassi Brar , "Daniel Kurtz" , Sascha Hauer , , , , , , Sascha Hauer , "Philipp Zabel" , Nicolas Boichat , cawa cheng , Bibby Hsieh , YT Shen , Daoyuan Huang , Damon Chu , "Josh-YC Liu" , Glory Hung , Jiaguang Zhang , Dennis-YC Hsieh , Monica Wang , Date: Fri, 30 Sep 2016 16:56:18 +0800 In-Reply-To: <1475204778.13398.28.camel@mtksdaap41> References: <1473039885-24009-1-git-send-email-hs.liao@mediatek.com> <1473039885-24009-3-git-send-email-hs.liao@mediatek.com> <1475204778.13398.28.camel@mtksdaap41> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi CK, Please see my inline reply. On Fri, 2016-09-30 at 11:06 +0800, CK Hu wrote: > Hi, HS: > > On Mon, 2016-09-05 at 09:44 +0800, HS Liao wrote: > > This patch is first version of Mediatek Command Queue(CMDQ) driver. The > > CMDQ is used to help write registers with critical time limitation, > > such as updating display configuration during the vblank. It controls > > Global Command Engine (GCE) hardware to achieve this requirement. > > Currently, CMDQ only supports display related hardwares, but we expect > > it can be extended to other hardwares for future requirements. > > > > Signed-off-by: HS Liao > > Signed-off-by: CK Hu > > --- > > [snip...] > > > + > > +struct cmdq_task { > > + struct cmdq *cmdq; > > + struct list_head list_entry; > > + void *va_base; > > + dma_addr_t pa_base; > > + size_t cmd_buf_size; /* command occupied size */ > > + size_t buf_size; /* real buffer size */ > > + bool finalized; > > + struct cmdq_thread *thread; > > I think thread info could be removed from cmdq_task. Only > cmdq_task_handle_error() and cmdq_task_insert_into_thread() use > task->thread and caller of both function has the thread info. So you > could just pass thread info into these two function and remove thread > info in cmdq_task. This modification will remove 1 pointer but add 2 pointers. Moreover, more pointers will need to be delivered between functions for future extension. IMHO, it would be better to keep thread pointer inside cmdq_task. > > + struct cmdq_task_cb cb; > > I think this callback function is equal to mailbox client tx_done > callback. It's better to use already-defined interface rather than > creating your own. This is because CMDQ driver allows different callback functions for different tasks, but mailbox only allows one callback function per channel. But, I think I can add a wrapper for tx_done to call CMDQ callback functions. So, I will use tx_done in CMDQ v15. > > +}; > > + > > [snip...] > > > + > > +static int cmdq_suspend(struct device *dev) > > +{ > > + struct cmdq *cmdq = dev_get_drvdata(dev); > > + struct cmdq_thread *thread; > > + int i; > > + bool task_running = false; > > + > > + mutex_lock(&cmdq->task_mutex); > > + cmdq->suspended = true; > > + mutex_unlock(&cmdq->task_mutex); > > + > > + for (i = 0; i < ARRAY_SIZE(cmdq->thread); i++) { > > + thread = &cmdq->thread[i]; > > + if (!list_empty(&thread->task_busy_list)) { > > + mod_timer(&thread->timeout, jiffies + 1); > > + task_running = true; > > + } > > + } > > + > > + if (task_running) { > > + dev_warn(dev, "exist running task(s) in suspend\n"); > > + msleep(20); > > Why sleep here? It looks like a recovery but could 20ms recovery > something? I think warning message is enough because you see the warning > message, and you fix the bug, so no need to recovery anything. My purpose is context switch to finish timer's work. I will replace it by schedule(). > > + } > > + > > + clk_unprepare(cmdq->clock); > > + return 0; > > +} > > + > > Regards, > CK Thanks, HS