Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752229AbaKFIi0 (ORCPT ); Thu, 6 Nov 2014 03:38:26 -0500 Received: from mailout2.w1.samsung.com ([210.118.77.12]:27067 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949AbaKFIhE (ORCPT ); Thu, 6 Nov 2014 03:37:04 -0500 X-AuditID: cbfec7f5-b7f956d000005ed7-90-545b332eead9 From: Krzysztof Kozlowski To: "Rafael J. Wysocki" , Len Brown , Pavel Machek , Russell King , Dan Williams , Vinod Koul , Ulf Hansson , Alan Stern , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Lars-Peter Clausen , Michal Simek Cc: Kevin Hilman , Laurent Pinchart , Kyungmin Park , Marek Szyprowski , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski Subject: [PATCH v10 4/5] dmaengine: pl330: add Power Management support Date: Thu, 06 Nov 2014 09:36:49 +0100 Message-id: <1415263010-7992-5-git-send-email-k.kozlowski@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1415263010-7992-1-git-send-email-k.kozlowski@samsung.com> References: <1415263010-7992-1-git-send-email-k.kozlowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrELMWRmVeSWpSXmKPExsVy+t/xK7p6xtEhBuenyVpsnLGe1WL61AuM Fqun/mW1eP3C0OLp5sdMFmeb3rBbLJk8n9Wic+ISdotZU/YyWVzeNYfN4nPvEUaL25d5LdYe uctu8e5lhMXdU0fZLM6cvsRqMeH3BTaL42vDLV727WdxEPZoae5h85jdMZPVY/Gel0wem1Z1 snncubaHzWPJm0OsHluutrN4zL77g9Gjb8sqRo8Vq7+ze3zeJOex9/NvlgCeKC6blNSczLLU In27BK6M08deMhZctqn492AXSwPjUqMuRk4OCQETiZmLHrFC2GISF+6tZ+ti5OIQEljKKPHn +0tmCKePSeLnzJfsIFVsAsYSm5cvAasSEbjOLNH9uJ8FJMEssIhJommqIogtLOAucWD7aUYQ m0VAVWLV5T6wZl4BN4kVy+YwQayTkzh5bDLYak6g+l9LPoDFhYBq2r/OZp/AyLuAkWEVo2hq aXJBcVJ6rpFecWJucWleul5yfu4mRkg8fN3BuPSY1SFGAQ5GJR7eCPboECHWxLLiytxDjBIc zEoivBF6QCHelMTKqtSi/Pii0pzU4kOMTBycUg2MKxMr98xvrfpdyqkys76kIudPvW7NJ62K FaUPxKIn5j37uZzlAWt54N5vN2et/zB7jfaS9ZdN93RXSlbVpv7k2JAaafvvrELoamVRb44g 4yf6YQXBnU2zli+JX9wquOTzg0Dx9qBlnz8qOPTta4xREFdUKJm1LvKLiMAnj4ZzUguaXrAk r9ulxFKckWioxVxUnAgAv629C2UCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds both normal PM suspend/resume support and runtime PM support to pl330 DMA engine driver. The runtime power management for pl330 DMA driver allows gating of AMBA clock (PDMA) in FSYS clock domain, when the device is not processing any requests. This is necessary to enter low power modes on Exynos SoCs (e.g. LPA on Exynos4x12 or W-AFTR on Exynos3250). Runtime PM resuming of the device may happen in atomic context (during call device_issue_pending()) so pm_runtime_irq_safe() is used. This will lead only to disabling/enabling of the clock but this is sufficient for gating the clock and for reducing energy usage. During system sleep the AMBA bus clock is also unprepared. Suggested-by: Bartlomiej Zolnierkiewicz Signed-off-by: Krzysztof Kozlowski Reviewed-by: Ulf Hansson --- drivers/dma/pl330.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 92 insertions(+), 4 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 4839bfa74a10..2bb0d08239bb 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "dmaengine.h" #define PL330_MAX_CHAN 8 @@ -265,6 +266,9 @@ static unsigned cmd_line; #define NR_DEFAULT_DESC 16 +/* Delay for runtime PM autosuspend, ms */ +#define PL330_AUTOSUSPEND_DELAY 20 + /* Populated by the PL330 core driver for DMA API driver's info */ struct pl330_config { u32 periph_id; @@ -1958,6 +1962,7 @@ static void pl330_tasklet(unsigned long data) struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data; struct dma_pl330_desc *desc, *_dt; unsigned long flags; + bool power_down = false; spin_lock_irqsave(&pch->lock, flags); @@ -1972,10 +1977,17 @@ static void pl330_tasklet(unsigned long data) /* Try to submit a req imm. next to the last completed cookie */ fill_queue(pch); - /* Make sure the PL330 Channel thread is active */ - spin_lock(&pch->thread->dmac->lock); - _start(pch->thread); - spin_unlock(&pch->thread->dmac->lock); + if (list_empty(&pch->work_list)) { + spin_lock(&pch->thread->dmac->lock); + _stop(pch->thread); + spin_unlock(&pch->thread->dmac->lock); + power_down = true; + } else { + /* Make sure the PL330 Channel thread is active */ + spin_lock(&pch->thread->dmac->lock); + _start(pch->thread); + spin_unlock(&pch->thread->dmac->lock); + } while (!list_empty(&pch->completed_list)) { dma_async_tx_callback callback; @@ -1990,6 +2002,12 @@ static void pl330_tasklet(unsigned long data) if (pch->cyclic) { desc->status = PREP; list_move_tail(&desc->node, &pch->work_list); + if (power_down) { + spin_lock(&pch->thread->dmac->lock); + _start(pch->thread); + spin_unlock(&pch->thread->dmac->lock); + power_down = false; + } } else { desc->status = FREE; list_move_tail(&desc->node, &pch->dmac->desc_pool); @@ -2004,6 +2022,12 @@ static void pl330_tasklet(unsigned long data) } } spin_unlock_irqrestore(&pch->lock, flags); + + /* If work list empty, power down */ + if (power_down) { + pm_runtime_mark_last_busy(pch->dmac->ddma.dev); + pm_runtime_put_autosuspend(pch->dmac->ddma.dev); + } } bool pl330_filter(struct dma_chan *chan, void *param) @@ -2073,6 +2097,7 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned switch (cmd) { case DMA_TERMINATE_ALL: + pm_runtime_get_sync(pl330->ddma.dev); spin_lock_irqsave(&pch->lock, flags); spin_lock(&pl330->lock); @@ -2099,10 +2124,15 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned dma_cookie_complete(&desc->txd); } + if (!list_empty(&pch->work_list)) + pm_runtime_put(pl330->ddma.dev); + list_splice_tail_init(&pch->submitted_list, &pl330->desc_pool); list_splice_tail_init(&pch->work_list, &pl330->desc_pool); list_splice_tail_init(&pch->completed_list, &pl330->desc_pool); spin_unlock_irqrestore(&pch->lock, flags); + pm_runtime_mark_last_busy(pl330->ddma.dev); + pm_runtime_put_autosuspend(pl330->ddma.dev); break; case DMA_SLAVE_CONFIG: slave_config = (struct dma_slave_config *)arg; @@ -2138,6 +2168,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan) tasklet_kill(&pch->task); + pm_runtime_get_sync(pch->dmac->ddma.dev); spin_lock_irqsave(&pch->lock, flags); pl330_release_channel(pch->thread); @@ -2147,6 +2178,8 @@ static void pl330_free_chan_resources(struct dma_chan *chan) list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool); spin_unlock_irqrestore(&pch->lock, flags); + pm_runtime_mark_last_busy(pch->dmac->ddma.dev); + pm_runtime_put_autosuspend(pch->dmac->ddma.dev); } static enum dma_status @@ -2162,6 +2195,15 @@ static void pl330_issue_pending(struct dma_chan *chan) unsigned long flags; spin_lock_irqsave(&pch->lock, flags); + if (list_empty(&pch->work_list)) { + /* + * Warn on nothing pending. Empty submitted_list may + * break our pm_runtime usage counter as it is + * updated on work_list emptiness status. + */ + WARN_ON(list_empty(&pch->submitted_list)); + pm_runtime_get_sync(pch->dmac->ddma.dev); + } list_splice_tail_init(&pch->submitted_list, &pch->work_list); spin_unlock_irqrestore(&pch->lock, flags); @@ -2585,6 +2627,43 @@ static int pl330_dma_device_slave_caps(struct dma_chan *dchan, return 0; } +/* + * Runtime PM callbacks are provided by amba/bus.c driver. + * + * It is assumed here that IRQ safe runtime PM is chosen in probe and amba + * bus driver will only disable/enable the clock in runtime PM suspend/resume. + */ +static int __maybe_unused pl330_suspend(struct device *dev) +{ + struct amba_device *pcdev = to_amba_device(dev); + int ret; + + ret = pm_runtime_force_suspend(dev); + if (ret) + return ret; + + amba_pclk_unprepare(pcdev); + + return 0; +} + +static int __maybe_unused pl330_resume(struct device *dev) +{ + struct amba_device *pcdev = to_amba_device(dev); + + amba_pclk_prepare(pcdev); + + /* + * TODO: Idea for future. The device should not be woken up after + * system resume if it is not needed. It could stay runtime suspended + * waiting for DMA requests. However for safe suspend and resume we + * forcibly resume the device here. + */ + return pm_runtime_force_resume(dev); +} + +static SIMPLE_DEV_PM_OPS(pl330_pm, pl330_suspend, pl330_resume); + static int pl330_probe(struct amba_device *adev, const struct amba_id *id) { @@ -2738,6 +2817,12 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan, pcfg->num_peri, pcfg->num_events); + pm_runtime_irq_safe(&adev->dev); + pm_runtime_use_autosuspend(&adev->dev); + pm_runtime_set_autosuspend_delay(&adev->dev, PL330_AUTOSUSPEND_DELAY); + pm_runtime_mark_last_busy(&adev->dev); + pm_runtime_put_autosuspend(&adev->dev); + return 0; probe_err3: /* Idle the DMAC */ @@ -2764,6 +2849,8 @@ static int pl330_remove(struct amba_device *adev) struct pl330_dmac *pl330 = amba_get_drvdata(adev); struct dma_pl330_chan *pch, *_p; + pm_runtime_get_noresume(pl330->ddma.dev); + if (adev->dev.of_node) of_dma_controller_free(adev->dev.of_node); @@ -2802,6 +2889,7 @@ static struct amba_driver pl330_driver = { .drv = { .owner = THIS_MODULE, .name = "dma-pl330", + .pm = &pl330_pm, }, .id_table = pl330_ids, .probe = pl330_probe, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/