From patchwork Sat Jan 16 00:31:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Veera Sundaram Sankaran X-Patchwork-Id: 364889 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, 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 523C7C433DB for ; Sat, 16 Jan 2021 00:39:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CB9022AAC for ; Sat, 16 Jan 2021 00:39:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725881AbhAPAjy (ORCPT ); Fri, 15 Jan 2021 19:39:54 -0500 Received: from alexa-out-sd-01.qualcomm.com ([199.106.114.38]:9718 "EHLO alexa-out-sd-01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725815AbhAPAjy (ORCPT ); Fri, 15 Jan 2021 19:39:54 -0500 X-Greylist: delayed 445 seconds by postgrey-1.27 at vger.kernel.org; Fri, 15 Jan 2021 19:39:54 EST Received: from unknown (HELO ironmsg05-sd.qualcomm.com) ([10.53.140.145]) by alexa-out-sd-01.qualcomm.com with ESMTP; 15 Jan 2021 16:31:49 -0800 X-QCInternal: smtphost Received: from veeras-linux.qualcomm.com ([10.134.68.137]) by ironmsg05-sd.qualcomm.com with ESMTP; 15 Jan 2021 16:31:48 -0800 Received: by veeras-linux.qualcomm.com (Postfix, from userid 330320) id AA12421B72; Fri, 15 Jan 2021 16:31:48 -0800 (PST) From: Veera Sundaram Sankaran To: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, sumit.semwal@linaro.org, gustavo@padovan.org, airlied@linux.ie, daniel@ffwll.ch, john.stultz@linaro.org Cc: Veera Sundaram Sankaran , robdclark@gmail.com, sean@poorly.run, pdhaval@codeaurora.org, abhinavk@codeaurora.org, jsanka@codeaurora.org Subject: [PATCH v4 1/2] dma-fence: allow signaling drivers to set fence timestamp Date: Fri, 15 Jan 2021 16:31:46 -0800 Message-Id: <1610757107-11892-1-git-send-email-veeras@codeaurora.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Some drivers have hardware capability to get the precise HW timestamp of certain events based on which the fences are triggered. The delta between the event HW timestamp & current HW reference timestamp can be used to calculate the timestamp in kernel's CLOCK_MONOTONIC time domain. This allows it to set accurate timestamp factoring out any software and IRQ latencies. Add a timestamp variant of fence signal function, dma_fence_signal_timestamp to allow drivers to update the precise timestamp for fences. Changes in v2: - Add a new fence signal variant instead of modifying fence struct Changes in v3: - Add timestamp domain information to commit-text and dma_fence_signal_timestamp documentation Signed-off-by: Veera Sundaram Sankaran Reviewed-by: John Stultz --- drivers/dma-buf/dma-fence.c | 70 ++++++++++++++++++++++++++++++++++++++++----- include/linux/dma-fence.h | 3 ++ 2 files changed, 66 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 7475e09..b83e9fa 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -312,22 +312,25 @@ void __dma_fence_might_wait(void) /** - * dma_fence_signal_locked - signal completion of a fence + * dma_fence_signal_timestamp_locked - signal completion of a fence * @fence: the fence to signal + * @timestamp: fence signal timestamp in kernel's CLOCK_MONOTONIC time domain * * Signal completion for software callbacks on a fence, this will unblock * dma_fence_wait() calls and run all the callbacks added with * dma_fence_add_callback(). Can be called multiple times, but since a fence * can only go from the unsignaled to the signaled state and not back, it will - * only be effective the first time. + * only be effective the first time. Set the timestamp provided as the fence + * signal timestamp. * - * Unlike dma_fence_signal(), this function must be called with &dma_fence.lock - * held. + * Unlike dma_fence_signal_timestamp(), this function must be called with + * &dma_fence.lock held. * * Returns 0 on success and a negative error value when @fence has been * signalled already. */ -int dma_fence_signal_locked(struct dma_fence *fence) +int dma_fence_signal_timestamp_locked(struct dma_fence *fence, + ktime_t timestamp) { struct dma_fence_cb *cur, *tmp; struct list_head cb_list; @@ -341,7 +344,7 @@ int dma_fence_signal_locked(struct dma_fence *fence) /* Stash the cb_list before replacing it with the timestamp */ list_replace(&fence->cb_list, &cb_list); - fence->timestamp = ktime_get(); + fence->timestamp = timestamp; set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags); trace_dma_fence_signaled(fence); @@ -352,6 +355,59 @@ int dma_fence_signal_locked(struct dma_fence *fence) return 0; } +EXPORT_SYMBOL(dma_fence_signal_timestamp_locked); + +/** + * dma_fence_signal_timestamp - signal completion of a fence + * @fence: the fence to signal + * @timestamp: fence signal timestamp in kernel's CLOCK_MONOTONIC time domain + * + * Signal completion for software callbacks on a fence, this will unblock + * dma_fence_wait() calls and run all the callbacks added with + * dma_fence_add_callback(). Can be called multiple times, but since a fence + * can only go from the unsignaled to the signaled state and not back, it will + * only be effective the first time. Set the timestamp provided as the fence + * signal timestamp. + * + * Returns 0 on success and a negative error value when @fence has been + * signalled already. + */ +int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp) +{ + unsigned long flags; + int ret; + + if (!fence) + return -EINVAL; + + spin_lock_irqsave(fence->lock, flags); + ret = dma_fence_signal_timestamp_locked(fence, timestamp); + spin_unlock_irqrestore(fence->lock, flags); + + return ret; +} +EXPORT_SYMBOL(dma_fence_signal_timestamp); + +/** + * dma_fence_signal_locked - signal completion of a fence + * @fence: the fence to signal + * + * Signal completion for software callbacks on a fence, this will unblock + * dma_fence_wait() calls and run all the callbacks added with + * dma_fence_add_callback(). Can be called multiple times, but since a fence + * can only go from the unsignaled to the signaled state and not back, it will + * only be effective the first time. + * + * Unlike dma_fence_signal(), this function must be called with &dma_fence.lock + * held. + * + * Returns 0 on success and a negative error value when @fence has been + * signalled already. + */ +int dma_fence_signal_locked(struct dma_fence *fence) +{ + return dma_fence_signal_timestamp_locked(fence, ktime_get()); +} EXPORT_SYMBOL(dma_fence_signal_locked); /** @@ -379,7 +435,7 @@ int dma_fence_signal(struct dma_fence *fence) tmp = dma_fence_begin_signalling(); spin_lock_irqsave(fence->lock, flags); - ret = dma_fence_signal_locked(fence); + ret = dma_fence_signal_timestamp_locked(fence, ktime_get()); spin_unlock_irqrestore(fence->lock, flags); dma_fence_end_signalling(tmp); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 09e23ad..9f12efa 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -372,6 +372,9 @@ static inline void __dma_fence_might_wait(void) {} int dma_fence_signal(struct dma_fence *fence); int dma_fence_signal_locked(struct dma_fence *fence); +int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp); +int dma_fence_signal_timestamp_locked(struct dma_fence *fence, + ktime_t timestamp); signed long dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout); int dma_fence_add_callback(struct dma_fence *fence,