From: Dmitry Osipenko <digetx@gmail.com> To: "Laxman Dewangan" <ldewangan@nvidia.com>, "Vinod Koul" <vkoul@kernel.org>, "Dan Williams" <dan.j.williams@intel.com>, "Thierry Reding" <thierry.reding@gmail.com>, "Jonathan Hunter" <jonathanh@nvidia.com>, "Michał Mirosław" <mirq-linux@rere.qmqm.pl> Cc: dmaengine@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 10/14] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer Date: Fri, 24 Jan 2020 02:03:21 +0300 [thread overview] Message-ID: <20200123230325.3037-11-digetx@gmail.com> (raw) In-Reply-To: <20200123230325.3037-1-digetx@gmail.com> It's a bit impractical to enable hardware's clock at the time of DMA channel's allocation because most of DMA client drivers allocate DMA channel at the time of the driver's probing and thus DMA clock is kept always-enabled in practice, defeating the whole purpose of runtime PM. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- drivers/dma/tegra20-apb-dma.c | 47 ++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 22b88ccff05d..0ee28d8e3c96 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -436,6 +436,8 @@ static void tegra_dma_stop(struct tegra_dma_channel *tdc) tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status); } tdc->busy = false; + + pm_runtime_put(tdc->tdma->dev); } static void tegra_dma_start(struct tegra_dma_channel *tdc, @@ -500,18 +502,25 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc, tegra_dma_resume(tdc); } -static void tdc_start_head_req(struct tegra_dma_channel *tdc) +static bool tdc_start_head_req(struct tegra_dma_channel *tdc) { struct tegra_dma_sg_req *sg_req; + int err; if (list_empty(&tdc->pending_sg_req)) - return; + return false; + + err = pm_runtime_get_sync(tdc->tdma->dev); + if (WARN_ON_ONCE(err < 0)) + return false; sg_req = list_first_entry(&tdc->pending_sg_req, typeof(*sg_req), node); tegra_dma_start(tdc, sg_req); sg_req->configured = true; sg_req->words_xferred = 0; tdc->busy = true; + + return true; } static void tdc_configure_next_head_desc(struct tegra_dma_channel *tdc) @@ -615,6 +624,8 @@ static void handle_once_dma_done(struct tegra_dma_channel *tdc, } list_add_tail(&sgreq->node, &tdc->free_sg_req); + pm_runtime_put(tdc->tdma->dev); + /* Do not start DMA if it is going to be terminate */ if (to_terminate || list_empty(&tdc->pending_sg_req)) return; @@ -730,9 +741,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc) dev_err(tdc2dev(tdc), "No DMA request\n"); goto end; } - if (!tdc->busy) { - tdc_start_head_req(tdc); - + if (!tdc->busy && tdc_start_head_req(tdc)) { /* Continuous single mode: Configure next req */ if (tdc->cyclic) { /* @@ -775,6 +784,13 @@ static int tegra_dma_terminate_all(struct dma_chan *dc) else wcount = status; + /* + * tegra_dma_stop() will drop the RPM's usage refcount, but + * tegra_dma_resume() touches hardware and thus we should keep + * the DMA clock active while it's needed. + */ + pm_runtime_get(tdc->tdma->dev); + was_busy = tdc->busy; tegra_dma_stop(tdc); @@ -786,6 +802,8 @@ static int tegra_dma_terminate_all(struct dma_chan *dc) } tegra_dma_resume(tdc); + pm_runtime_put(tdc->tdma->dev); + skip_dma_stop: tegra_dma_abort_all(tdc); @@ -1280,22 +1298,15 @@ tegra_dma_prep_dma_cyclic(struct dma_chan *dc, dma_addr_t buf_addr, static int tegra_dma_alloc_chan_resources(struct dma_chan *dc) { struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); - struct tegra_dma *tdma = tdc->tdma; - int ret; dma_cookie_init(&tdc->dma_chan); - ret = pm_runtime_get_sync(tdma->dev); - if (ret < 0) - return ret; - return 0; } static void tegra_dma_free_chan_resources(struct dma_chan *dc) { struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); - struct tegra_dma *tdma = tdc->tdma; struct tegra_dma_desc *dma_desc; struct tegra_dma_sg_req *sg_req; struct list_head dma_desc_list; @@ -1328,7 +1339,6 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc) list_del(&sg_req->node); kfree(sg_req); } - pm_runtime_put(tdma->dev); tdc->slave_id = TEGRA_APBDMA_SLAVE_ID_INVALID; } @@ -1428,6 +1438,11 @@ static int tegra_dma_probe(struct platform_device *pdev) spin_lock_init(&tdma->global_lock); + ret = clk_prepare(tdma->dma_clk); + if (ret) + return ret; + + pm_runtime_irq_safe(&pdev->dev); pm_runtime_enable(&pdev->dev); ret = pm_runtime_get_sync(&pdev->dev); @@ -1543,6 +1558,7 @@ static int tegra_dma_probe(struct platform_device *pdev) err_pm_disable: pm_runtime_disable(&pdev->dev); + clk_unprepare(tdma->dma_clk); return ret; } @@ -1553,6 +1569,7 @@ static int tegra_dma_remove(struct platform_device *pdev) dma_async_device_unregister(&tdma->dma_dev); pm_runtime_disable(&pdev->dev); + clk_unprepare(tdma->dma_clk); return 0; } @@ -1581,7 +1598,7 @@ static int tegra_dma_runtime_suspend(struct device *dev) TEGRA_APBDMA_CHAN_WCOUNT); } - clk_disable_unprepare(tdma->dma_clk); + clk_disable(tdma->dma_clk); return 0; } @@ -1592,7 +1609,7 @@ static int tegra_dma_runtime_resume(struct device *dev) unsigned int i; int ret; - ret = clk_prepare_enable(tdma->dma_clk); + ret = clk_enable(tdma->dma_clk); if (ret < 0) { dev_err(dev, "clk_enable failed: %d\n", ret); return ret; -- 2.24.0
WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> To: "Laxman Dewangan" <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, "Vinod Koul" <vkoul-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, "Dan Williams" <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, "Thierry Reding" <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, "Jonathan Hunter" <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, "Michał Mirosław" <mirq-linux-CoA6ZxLDdyEEUmgCuDUIdw@public.gmane.org> Cc: dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: [PATCH v5 10/14] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer Date: Fri, 24 Jan 2020 02:03:21 +0300 [thread overview] Message-ID: <20200123230325.3037-11-digetx@gmail.com> (raw) In-Reply-To: <20200123230325.3037-1-digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> It's a bit impractical to enable hardware's clock at the time of DMA channel's allocation because most of DMA client drivers allocate DMA channel at the time of the driver's probing and thus DMA clock is kept always-enabled in practice, defeating the whole purpose of runtime PM. Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> --- drivers/dma/tegra20-apb-dma.c | 47 ++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 22b88ccff05d..0ee28d8e3c96 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -436,6 +436,8 @@ static void tegra_dma_stop(struct tegra_dma_channel *tdc) tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status); } tdc->busy = false; + + pm_runtime_put(tdc->tdma->dev); } static void tegra_dma_start(struct tegra_dma_channel *tdc, @@ -500,18 +502,25 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc, tegra_dma_resume(tdc); } -static void tdc_start_head_req(struct tegra_dma_channel *tdc) +static bool tdc_start_head_req(struct tegra_dma_channel *tdc) { struct tegra_dma_sg_req *sg_req; + int err; if (list_empty(&tdc->pending_sg_req)) - return; + return false; + + err = pm_runtime_get_sync(tdc->tdma->dev); + if (WARN_ON_ONCE(err < 0)) + return false; sg_req = list_first_entry(&tdc->pending_sg_req, typeof(*sg_req), node); tegra_dma_start(tdc, sg_req); sg_req->configured = true; sg_req->words_xferred = 0; tdc->busy = true; + + return true; } static void tdc_configure_next_head_desc(struct tegra_dma_channel *tdc) @@ -615,6 +624,8 @@ static void handle_once_dma_done(struct tegra_dma_channel *tdc, } list_add_tail(&sgreq->node, &tdc->free_sg_req); + pm_runtime_put(tdc->tdma->dev); + /* Do not start DMA if it is going to be terminate */ if (to_terminate || list_empty(&tdc->pending_sg_req)) return; @@ -730,9 +741,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc) dev_err(tdc2dev(tdc), "No DMA request\n"); goto end; } - if (!tdc->busy) { - tdc_start_head_req(tdc); - + if (!tdc->busy && tdc_start_head_req(tdc)) { /* Continuous single mode: Configure next req */ if (tdc->cyclic) { /* @@ -775,6 +784,13 @@ static int tegra_dma_terminate_all(struct dma_chan *dc) else wcount = status; + /* + * tegra_dma_stop() will drop the RPM's usage refcount, but + * tegra_dma_resume() touches hardware and thus we should keep + * the DMA clock active while it's needed. + */ + pm_runtime_get(tdc->tdma->dev); + was_busy = tdc->busy; tegra_dma_stop(tdc); @@ -786,6 +802,8 @@ static int tegra_dma_terminate_all(struct dma_chan *dc) } tegra_dma_resume(tdc); + pm_runtime_put(tdc->tdma->dev); + skip_dma_stop: tegra_dma_abort_all(tdc); @@ -1280,22 +1298,15 @@ tegra_dma_prep_dma_cyclic(struct dma_chan *dc, dma_addr_t buf_addr, static int tegra_dma_alloc_chan_resources(struct dma_chan *dc) { struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); - struct tegra_dma *tdma = tdc->tdma; - int ret; dma_cookie_init(&tdc->dma_chan); - ret = pm_runtime_get_sync(tdma->dev); - if (ret < 0) - return ret; - return 0; } static void tegra_dma_free_chan_resources(struct dma_chan *dc) { struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); - struct tegra_dma *tdma = tdc->tdma; struct tegra_dma_desc *dma_desc; struct tegra_dma_sg_req *sg_req; struct list_head dma_desc_list; @@ -1328,7 +1339,6 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc) list_del(&sg_req->node); kfree(sg_req); } - pm_runtime_put(tdma->dev); tdc->slave_id = TEGRA_APBDMA_SLAVE_ID_INVALID; } @@ -1428,6 +1438,11 @@ static int tegra_dma_probe(struct platform_device *pdev) spin_lock_init(&tdma->global_lock); + ret = clk_prepare(tdma->dma_clk); + if (ret) + return ret; + + pm_runtime_irq_safe(&pdev->dev); pm_runtime_enable(&pdev->dev); ret = pm_runtime_get_sync(&pdev->dev); @@ -1543,6 +1558,7 @@ static int tegra_dma_probe(struct platform_device *pdev) err_pm_disable: pm_runtime_disable(&pdev->dev); + clk_unprepare(tdma->dma_clk); return ret; } @@ -1553,6 +1569,7 @@ static int tegra_dma_remove(struct platform_device *pdev) dma_async_device_unregister(&tdma->dma_dev); pm_runtime_disable(&pdev->dev); + clk_unprepare(tdma->dma_clk); return 0; } @@ -1581,7 +1598,7 @@ static int tegra_dma_runtime_suspend(struct device *dev) TEGRA_APBDMA_CHAN_WCOUNT); } - clk_disable_unprepare(tdma->dma_clk); + clk_disable(tdma->dma_clk); return 0; } @@ -1592,7 +1609,7 @@ static int tegra_dma_runtime_resume(struct device *dev) unsigned int i; int ret; - ret = clk_prepare_enable(tdma->dma_clk); + ret = clk_enable(tdma->dma_clk); if (ret < 0) { dev_err(dev, "clk_enable failed: %d\n", ret); return ret; -- 2.24.0
next prev parent reply other threads:[~2020-01-23 23:11 UTC|newest] Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-23 23:03 [PATCH v5 00/14] NVIDIA Tegra APB DMA driver fixes and improvements Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 01/14] dmaengine: tegra-apb: Fix use-after-free Dmitry Osipenko 2020-01-29 10:56 ` Jon Hunter 2020-01-29 10:56 ` Jon Hunter 2020-01-29 14:38 ` Dmitry Osipenko 2020-01-29 14:38 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 02/14] dmaengine: tegra-apb: Implement synchronization hook Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 04/14] dmaengine: tegra-apb: Clean up tasklet releasing Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 05/14] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list Dmitry Osipenko 2020-01-29 11:01 ` Jon Hunter 2020-01-29 11:01 ` Jon Hunter 2020-01-29 14:39 ` Dmitry Osipenko 2020-01-29 14:39 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 06/14] dmaengine: tegra-apb: Use devm_platform_ioremap_resource Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 07/14] dmaengine: tegra-apb: Use devm_request_irq Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 08/14] dmaengine: tegra-apb: Fix coding style problems Dmitry Osipenko 2020-01-29 11:03 ` Jon Hunter 2020-01-29 11:03 ` Jon Hunter 2020-01-29 14:31 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 09/14] dmaengine: tegra-apb: Remove assumptions about unavailable runtime PM Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko [this message] 2020-01-23 23:03 ` [PATCH v5 10/14] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 11/14] dmaengine: tegra-apb: Clean up suspend-resume Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 12/14] dmaengine: tegra-apb: Add missing of_dma_controller_free Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 13/14] dmaengine: tegra-apb: Allow to compile as a loadable kernel module Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko 2020-01-23 23:03 ` [PATCH v5 14/14] dmaengine: tegra-apb: Remove MODULE_ALIAS Dmitry Osipenko 2020-01-23 23:03 ` Dmitry Osipenko
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