From edd3bdbe9db1415f744bb5da0752675ddbd9eee0 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:38 +0000 Subject: [PATCH 1/6] dmaengine: tegra-apb: Correct runtime-pm usage The tegra-apb DMA driver enables runtime-pm but never calls pm_runtime_get/put and hence the runtime-pm callbacks are never invoked. The driver manages the clocks by directly calling clk_prepare_enable() and clk_unprepare_disable(). Fix this by replacing the clk_prepare_enable() and clk_disable_unprepare() with pm_runtime_get_sync() and pm_runtime_put(), respectively. Note that the consequence of this is that if runtime-pm is disabled, then the clocks will remain on the entire time the driver is loaded. However, if runtime-pm is disabled, then power is not most likely not a concern. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 43 +++++++++++++++-------------------- 1 file changed, 18 insertions(+), 25 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index c8f79dcaaee8..f68bccf55a24 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -1186,10 +1186,12 @@ static int tegra_dma_alloc_chan_resources(struct dma_chan *dc) dma_cookie_init(&tdc->dma_chan); tdc->config_init = false; - ret = clk_prepare_enable(tdma->dma_clk); + + ret = pm_runtime_get_sync(tdma->dev); if (ret < 0) - dev_err(tdc2dev(tdc), "clk_prepare_enable failed: %d\n", ret); - return ret; + return ret; + + return 0; } static void tegra_dma_free_chan_resources(struct dma_chan *dc) @@ -1232,7 +1234,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc) list_del(&sg_req->node); kfree(sg_req); } - clk_disable_unprepare(tdma->dma_clk); + pm_runtime_put(tdma->dev); tdc->slave_id = 0; } @@ -1356,20 +1358,14 @@ static int tegra_dma_probe(struct platform_device *pdev) spin_lock_init(&tdma->global_lock); pm_runtime_enable(&pdev->dev); - if (!pm_runtime_enabled(&pdev->dev)) { + if (!pm_runtime_enabled(&pdev->dev)) ret = tegra_dma_runtime_resume(&pdev->dev); - if (ret) { - dev_err(&pdev->dev, "dma_runtime_resume failed %d\n", - ret); - goto err_pm_disable; - } - } + else + ret = pm_runtime_get_sync(&pdev->dev); - /* Enable clock before accessing registers */ - ret = clk_prepare_enable(tdma->dma_clk); if (ret < 0) { - dev_err(&pdev->dev, "clk_prepare_enable failed: %d\n", ret); - goto err_pm_disable; + pm_runtime_disable(&pdev->dev); + return ret; } /* Reset DMA controller */ @@ -1382,7 +1378,7 @@ static int tegra_dma_probe(struct platform_device *pdev) tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0); tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul); - clk_disable_unprepare(tdma->dma_clk); + pm_runtime_put(&pdev->dev); INIT_LIST_HEAD(&tdma->dma_dev.channels); for (i = 0; i < cdata->nr_channels; i++) { @@ -1485,7 +1481,6 @@ static int tegra_dma_probe(struct platform_device *pdev) tasklet_kill(&tdc->tasklet); } -err_pm_disable: pm_runtime_disable(&pdev->dev); if (!pm_runtime_status_suspended(&pdev->dev)) tegra_dma_runtime_suspend(&pdev->dev); @@ -1543,7 +1538,7 @@ static int tegra_dma_pm_suspend(struct device *dev) int ret; /* Enable clock before accessing register */ - ret = tegra_dma_runtime_resume(dev); + ret = pm_runtime_get_sync(dev); if (ret < 0) return ret; @@ -1560,7 +1555,7 @@ static int tegra_dma_pm_suspend(struct device *dev) } /* Disable clock */ - tegra_dma_runtime_suspend(dev); + pm_runtime_put(dev); return 0; } @@ -1571,7 +1566,7 @@ static int tegra_dma_pm_resume(struct device *dev) int ret; /* Enable clock before accessing register */ - ret = tegra_dma_runtime_resume(dev); + ret = pm_runtime_get_sync(dev); if (ret < 0) return ret; @@ -1592,16 +1587,14 @@ static int tegra_dma_pm_resume(struct device *dev) } /* Disable clock */ - tegra_dma_runtime_suspend(dev); + pm_runtime_put(dev); return 0; } #endif static const struct dev_pm_ops tegra_dma_dev_pm_ops = { -#ifdef CONFIG_PM - .runtime_suspend = tegra_dma_runtime_suspend, - .runtime_resume = tegra_dma_runtime_resume, -#endif + SET_RUNTIME_PM_OPS(tegra_dma_runtime_suspend, tegra_dma_runtime_resume, + NULL) SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume) }; From 286a6441a333abfa21a700683db5b3302f75a4de Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:39 +0000 Subject: [PATCH 2/6] dmaengine: tegra-apb: Use dev_get_drvdata() In the tegra_dma_runtime_suspend/resume functions, the pdev structure is not needed, and so just call dev_get_drvdata() to get the device data structure. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index f68bccf55a24..355dbc354818 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -1509,8 +1509,7 @@ static int tegra_dma_remove(struct platform_device *pdev) static int tegra_dma_runtime_suspend(struct device *dev) { - struct platform_device *pdev = to_platform_device(dev); - struct tegra_dma *tdma = platform_get_drvdata(pdev); + struct tegra_dma *tdma = dev_get_drvdata(dev); clk_disable_unprepare(tdma->dma_clk); return 0; @@ -1518,8 +1517,7 @@ static int tegra_dma_runtime_suspend(struct device *dev) static int tegra_dma_runtime_resume(struct device *dev) { - struct platform_device *pdev = to_platform_device(dev); - struct tegra_dma *tdma = platform_get_drvdata(pdev); + struct tegra_dma *tdma = dev_get_drvdata(dev); int ret; ret = clk_prepare_enable(tdma->dma_clk); From 68ae7a93fb0e6432baaa7c323a650b1b5461643f Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:40 +0000 Subject: [PATCH 3/6] dmaengine: tegra-apb: Save and restore word count Newer tegra devices have a separate word count register per channel that contains the number of words to be transferred. This register is not saved or restored by the suspend/resume helpers for these newer devices and so ensure that it is. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 355dbc354818..18a561376c63 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -1550,6 +1550,9 @@ static int tegra_dma_pm_suspend(struct device *dev) ch_reg->apb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBPTR); ch_reg->ahb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBSEQ); ch_reg->apb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBSEQ); + if (tdma->chip_data->support_separate_wcount_reg) + ch_reg->wcount = tdc_read(tdc, + TEGRA_APBDMA_CHAN_WCOUNT); } /* Disable clock */ @@ -1576,6 +1579,9 @@ static int tegra_dma_pm_resume(struct device *dev) struct tegra_dma_channel *tdc = &tdma->channels[i]; struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg; + if (tdma->chip_data->support_separate_wcount_reg) + tdc_write(tdc, TEGRA_APBDMA_CHAN_WCOUNT, + ch_reg->wcount); tdc_write(tdc, TEGRA_APBDMA_CHAN_APBSEQ, ch_reg->apb_seq); tdc_write(tdc, TEGRA_APBDMA_CHAN_APBPTR, ch_reg->apb_ptr); tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBSEQ, ch_reg->ahb_seq); From 4aad5be04088d9b6c2783d5f0fb6b1ac7bbc45c1 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:41 +0000 Subject: [PATCH 4/6] dmaengine: tegra-apb: Only save channel state for those in use Currently the tegra-apb DMA driver suspend/resume helpers, save and restore the registers for all channels regardless of whether they are in use or not. Change this so that only channels that have been allocated and configured are saved and restored. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 18a561376c63..d4cabd6931e5 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -1545,6 +1545,10 @@ static int tegra_dma_pm_suspend(struct device *dev) struct tegra_dma_channel *tdc = &tdma->channels[i]; struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg; + /* Only save the state of DMA channels that are in use */ + if (!tdc->config_init) + continue; + ch_reg->csr = tdc_read(tdc, TEGRA_APBDMA_CHAN_CSR); ch_reg->ahb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBPTR); ch_reg->apb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBPTR); @@ -1579,6 +1583,10 @@ static int tegra_dma_pm_resume(struct device *dev) struct tegra_dma_channel *tdc = &tdma->channels[i]; struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg; + /* Only restore the state of DMA channels that are in use */ + if (!tdc->config_init) + continue; + if (tdma->chip_data->support_separate_wcount_reg) tdc_write(tdc, TEGRA_APBDMA_CHAN_WCOUNT, ch_reg->wcount); From 8fe9739bc3ed616fb8cf935fb5099051493c2424 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:42 +0000 Subject: [PATCH 5/6] dmaengine: tegra-apb: Update driver to use GFP_NOWAIT The tegra20-apb-dma driver currently uses the flag GFP_ATOMIC when allocating memory for structures used in conjunction with the DMA descriptors. It is preferred that dmaengine drivers use GFP_NOWAIT instead and so the emergency memory pool will not be used by these drivers. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index d4cabd6931e5..754c1f54d4fe 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -296,7 +296,7 @@ static struct tegra_dma_desc *tegra_dma_desc_get( spin_unlock_irqrestore(&tdc->lock, flags); /* Allocate DMA desc */ - dma_desc = kzalloc(sizeof(*dma_desc), GFP_ATOMIC); + dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT); if (!dma_desc) { dev_err(tdc2dev(tdc), "dma_desc alloc failed\n"); return NULL; @@ -336,7 +336,7 @@ static struct tegra_dma_sg_req *tegra_dma_sg_req_get( } spin_unlock_irqrestore(&tdc->lock, flags); - sg_req = kzalloc(sizeof(struct tegra_dma_sg_req), GFP_ATOMIC); + sg_req = kzalloc(sizeof(struct tegra_dma_sg_req), GFP_NOWAIT); if (!sg_req) dev_err(tdc2dev(tdc), "sg_req alloc failed\n"); return sg_req; From 05e866b42e65c2f68dea7fc7be4fcf534f4d8a12 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 13 Nov 2015 16:39:43 +0000 Subject: [PATCH 6/6] dmaengine: tegra-apb: Free interrupts before killing tasklets On probe failure or driver removal, before killing any tasklets, ensure that the channel interrupt is freed to ensure that another channel interrupt cannot occur and schedule the tasklet again. Signed-off-by: Jon Hunter Signed-off-by: Vinod Koul --- drivers/dma/tegra20-apb-dma.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 754c1f54d4fe..935da8192f59 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -1396,8 +1396,7 @@ static int tegra_dma_probe(struct platform_device *pdev) } tdc->irq = res->start; snprintf(tdc->name, sizeof(tdc->name), "apbdma.%d", i); - ret = devm_request_irq(&pdev->dev, tdc->irq, - tegra_dma_isr, 0, tdc->name, tdc); + ret = request_irq(tdc->irq, tegra_dma_isr, 0, tdc->name, tdc); if (ret) { dev_err(&pdev->dev, "request_irq failed with err %d channel %d\n", @@ -1478,6 +1477,8 @@ static int tegra_dma_probe(struct platform_device *pdev) err_irq: while (--i >= 0) { struct tegra_dma_channel *tdc = &tdma->channels[i]; + + free_irq(tdc->irq, tdc); tasklet_kill(&tdc->tasklet); } @@ -1497,6 +1498,7 @@ static int tegra_dma_remove(struct platform_device *pdev) for (i = 0; i < tdma->chip_data->nr_channels; ++i) { tdc = &tdma->channels[i]; + free_irq(tdc->irq, tdc); tasklet_kill(&tdc->tasklet); }