From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752142AbaILO4v (ORCPT ); Fri, 12 Sep 2014 10:56:51 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:49192 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751372AbaILO4g (ORCPT ); Fri, 12 Sep 2014 10:56:36 -0400 X-AuditID: cbfec7f5-b7f776d000003e54-db-541309a17c8c From: Krzysztof Kozlowski To: Russell King , Dan Williams , Vinod Koul , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Ulf Hansson , Grant Likely , Lars-Peter Clausen , Michal Simek Cc: Kyungmin Park , Marek Szyprowski , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski Subject: [RFC PATCH v2 2/2] dma: pl330: add Power Management support Date: Fri, 12 Sep 2014 16:56:19 +0200 Message-id: <1410533779-3310-3-git-send-email-k.kozlowski@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1410533779-3310-1-git-send-email-k.kozlowski@samsung.com> References: <1410533779-3310-1-git-send-email-k.kozlowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprNLMWRmVeSWpSXmKPExsVy+t/xy7oLOYVDDPqXClhsnLGe1WL61AuM Fqun/mW1OPBnB6PF6xeGFmeb3rBbLJk8n9Xi8q45bBa3L/NarD1yl93i3csIi+Nrwy1e9u1n ceD1aGnuYfNYvOclk8eda3vYPJa8OcTq0bdlFaPH501yHns//2YJYI/isklJzcksSy3St0vg ylj2+Tt7wRzjitsHzrM3MJ7R6mLk5JAQMJHoe7WQHcIWk7hwbz1bFyMXh5DAUkaJOZOPMUI4 fUwS3x40soFUsQkYS2xevgSsSkTgEpPEr3uv2UEcZoGjjBLTe98ygVQJC7hIvN+3hxnEZhFQ lTj6YCZYN6+Am8TZ3XuZIPbJSZw8NpkVxOYUcJfYvXci0DoOoHVuEh+3WU5g5F3AyLCKUTS1 NLmgOCk910ivODG3uDQvXS85P3cTIyRAv+5gXHrM6hCjAAejEg/vh1zBECHWxLLiytxDjBIc zEoivDdeCYUI8aYkVlalFuXHF5XmpBYfYmTi4JRqYJzs9lJn3+SzExOKnscoeG/e/Ofn8u79 eY4axl9n26+x2bKx5n/ctB8PcxJTCis05nfOS/9gvTv6Uarfq5pYi5TJHLlZ60yfTuNVF0+Q vfluzTLz65oa07YdatpSvueIAne9za8t9anM/48xLzvhcfjpOqN3d+QzLvvncSTMZT+m1H0r q6olu1eJpTgj0VCLuag4EQDk/MXILgIAAA== 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 W-AFTR low power mode on Exynos3250. The driver uses different runtime PM functions than amba bus driver (drivers/amba/bus.c). Resuming the device may happen in atomic context (during call device_issue_pending()) so pm_runtime_irq_safe() is used. During suspend and resume the AMBA bus clock is only disabled/enabled (not unprepared/prepared) but this is sufficient for gating the clock and for reducing energy usage. Suggested-by: Bartlomiej Zolnierkiewicz Signed-off-by: Krzysztof Kozlowski --- drivers/dma/pl330.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 65 insertions(+), 4 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 4839bfa74a10..8868d8be72fd 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 @@ -1958,6 +1959,7 @@ 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 +1974,17 @@ 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 +1999,12 @@ 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 +2019,10 @@ static void pl330_tasklet(unsigned long data) } } spin_unlock_irqrestore(&pch->lock, flags); + + /* If work list empty, power down */ + if (power_down) + pm_runtime_put(pch->dmac->ddma.dev); } bool pl330_filter(struct dma_chan *chan, void *param) @@ -2073,6 +2092,7 @@ 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 +2119,14 @@ 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_put(pl330->ddma.dev); break; case DMA_SLAVE_CONFIG: slave_config = (struct dma_slave_config *)arg; @@ -2138,6 +2162,7 @@ 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 +2172,7 @@ 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_put(pch->dmac->ddma.dev); } static enum dma_status @@ -2162,6 +2188,15 @@ 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 +2620,26 @@ static int pl330_dma_device_slave_caps(struct dma_chan *dchan, return 0; } +static int __maybe_unused pl330_suspend(struct device *dev) +{ + struct amba_device *pcdev = to_amba_device(dev); + + if (!pm_runtime_suspended(dev)) + amba_pclk_disable(pcdev); + return 0; +} + +static int __maybe_unused pl330_resume(struct device *dev) +{ + struct amba_device *pcdev = to_amba_device(dev); + + if (!pm_runtime_suspended(dev)) + return amba_pclk_enable(pcdev); + return 0; +} + +static UNIVERSAL_DEV_PM_OPS(pl330_pm, pl330_suspend, pl330_resume, NULL); + static int pl330_probe(struct amba_device *adev, const struct amba_id *id) { @@ -2738,6 +2793,9 @@ 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_put_noidle(&adev->dev); + return 0; probe_err3: /* Idle the DMAC */ @@ -2764,6 +2822,8 @@ 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 +2862,7 @@ 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