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Wysocki" , Inki Dae Subject: [PATCH v3 4/4] dmaengine: pl330: Don't require irq-safe runtime PM Date: Tue, 10 Jan 2017 08:12:39 +0100 Message-id: <1484032359-8311-5-git-send-email-m.szyprowski@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1484032359-8311-1-git-send-email-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrMIsWRmVeSWpSXmKPExsWy7djP87qrO0siDObPVbDYOGM9q8XqqX9Z LSbdn8Bicf78BnaLTY+vsVp87j3CaDHj/D4mi7VH7rJbnDl9idXi+Npwi5d9+1kcuD0W73nJ 5LFpVSebx51re9g8Ni+p99hytZ3Fo2/LKkaPz5vkAtijuGxSUnMyy1KL9O0SuDLO3tnPWjA3 pmLDxWvMDYxLfLoYOTkkBEwkZr34xwphi0lcuLeerYuRi0NIYBmjxIP5Z1ghnM+MEsdXLmaC 6eh/foERrmra38XsEE4Dk8Spk41sIFVsAoYSXW+7wGaJCDQxSrydvxyshVlgKZPE5vaXQC0c HMIC3hJ3rriDNLAIqErM/dfGAmLzCrhLrF12mhFinZzEyWOTwQ7kFPCQePftCBtEfBG7xOpT HiBjJARkJTYdYIYIu0h8PPYL6h9hiVfHt7BD2DISnR0HoT7oZ5RoatWGsGcwSpx7ywthW0sc Pn4RrJdZgE9i0rbpzBDjeSU62oQgSjwkerc+ZIUIO0pMu1wMEhYSmM0osXxz1gRGmQWMDKsY RVJLi3PTU4sN9YoTc4tL89L1kvNzNzECo/70v+PvdzA+bQ45xCjAwajEw7thUnGEEGtiWXFl 7iFGCQ5mJRFegdaSCCHelMTKqtSi/Pii0pzU4kOM0hwsSuK8exdcCRcSSE8sSc1OTS1ILYLJ MnFwSjUwVly7O/lset7hh3bnoo7+ivTniu1/sbHpk/Ppd9x3PwkcKGc4VNXsxfOEL/G2YNsK ny0P5/XOjvgjVKp8+Ef55ZVnK2ub8ksTr9udKquce/xDw9+HW+bq12jc2yl6scmh972uVVZm 6M4Tq56dEvT7lLPl06WLvn+PV8YHxH2+2H++PKhKTmLpXSWW4oxEQy3mouJEANXEkGH2AgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmplkeLIzCtJLcpLzFFi42I5/e/4Vd3bnSURBg+WSFlsnLGe1WL11L+s FpPuT2CxOH9+A7vFpsfXWC0+9x5htJhxfh+Txdojd9ktzpy+xGpxfG24xcu+/SwO3B6L97xk 8ti0qpPN4861PWwem5fUe2y52s7i0bdlFaPH501yAexRbjYZqYkpqUUKqXnJ+SmZeem2SqEh broWSgp5ibmptkoRur4hQUoKZYk5pUCekQEacHAOcA9W0rdLcMs4e2c/a8HcmIoNF68xNzAu 8eli5OSQEDCR6H9+gRHCFpO4cG89WxcjF4eQwBJGifldnYwQThOTxKmzf5lAqtgEDCW63nax gdgiAk2MEgd/eYAUMQssZ5LYMv0CexcjB4ewgLfEnSvuIDUsAqoSc/+1sYDYvALuEmuXnYba Jidx8thkVhCbU8BD4t23I2AzhYBqZv36zTaBkXcBI8MqRpHU0uLc9NxiQ73ixNzi0rx0veT8 3E2MwCjYduzn5h2MlzYGH2IU4GBU4uHdMKk4Qog1say4MvcQowQHs5IIr0BrSYQQb0piZVVq UX58UWlOavEhRlOgoyYyS4km5wMjNK8k3tDE0NzS0MjYwsLcyEhJnLfkw5VwIYH0xJLU7NTU gtQimD4mDk6pBkaBtlduHZU8KwpNqpPZ71jo+SVc+BSSfGrZdJ53gRXnrQ6GBL+ftThkylH+ O+tN3/i9/BP2uvqxGkNF2i3x/35d/EcWmG2+6XF89QPu+y73p6/gWJexXG8xq6r3latTd/TP 9xa9cCyjOGPTQddjM/YbPnlvO79jVkTC8Z77d5bPuGyw8dC0L93LlViKMxINtZiLihMBqOWW wpgCAAA= X-MTR: 20000000000000000@CPGS X-CMS-MailID: 20170110071344eucas1p1361cafbd9d3b08a4e94e91ae6646cfd1 X-Msg-Generator: CA X-Sender-IP: 182.198.249.179 X-Local-Sender: =?UTF-8?B?TWFyZWsgU3p5cHJvd3NraRtTUlBPTC1LZXJuZWwgKFRQKRs=?= =?UTF-8?B?7IK87ISx7KCE7J6QG1NlbmlvciBTb2Z0d2FyZSBFbmdpbmVlcg==?= X-Global-Sender: =?UTF-8?B?TWFyZWsgU3p5cHJvd3NraRtTUlBPTC1LZXJuZWwgKFRQKRtT?= =?UTF-8?B?YW1zdW5nIEVsZWN0cm9uaWNzG1NlbmlvciBTb2Z0d2FyZSBFbmdpbmVlcg==?= X-Sender-Code: =?UTF-8?B?QzEwG0VIURtDMTBDRDAyQ0QwMjczOTI=?= CMS-TYPE: 201P X-HopCount: 7 X-CMS-RootMailID: 20170110071344eucas1p1361cafbd9d3b08a4e94e91ae6646cfd1 X-RootMTR: 20170110071344eucas1p1361cafbd9d3b08a4e94e91ae6646cfd1 References: <1484032359-8311-1-git-send-email-m.szyprowski@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org This patch replaces irq-safe runtime PM with non-irq-safe version based on the new approach. Existing, irq-safe runtime PM implementation for PL330 was not bringing much benefits of its own - only clocks were enabled/disabled. Till now non-irq-safe runtime PM implementation was only possible by calling pm_runtime_get/put functions from alloc/free_chan_resources. All other DMA engine API functions cannot be called from a context, which permits sleeping. Such implementation, in practice would result in keeping DMA controller's device active almost all the time, because most of the slave device drivers (DMA engine clients) acquire DMA channel in their probe() function and released it during driver removal. This patch provides a new, different approach. It is based on an observation that there can be only one slave device using each DMA channel. PL330 hardware always has dedicated channels for each peripheral device. Using recently introduced device dependencies (links) infrastructure one can ensure proper runtime PM state of PL330 DMA controller basing on the runtime PM state of the slave device. In this approach in pl330_alloc_chan_resources() function a new dependency is being created between PL330 DMA controller device (as a supplier) and given slave device (as a consumer). This way PL330 DMA controller device runtime active counter is increased when the slave device is resumed and decreased the same time when given slave device is put to suspend. This way it has been ensured to keep PL330 DMA controller runtime active if there is an active used of any of its DMA channels. Slave device pointer is initially stored in per-channel data in of_dma_xlate callback. This is similar to what has been already implemented in Exynos IOMMU driver in commit 2f5f44f205cc95 ("iommu/exynos: Use device dependency links to control runtime pm"). If slave device doesn't implement runtime PM or keeps device runtime active all the time, then PL330 DMA controller will be runtime active all the time when channel is being allocated. The goal is however to have runtime PM added to all devices in the system, because it lets respective power domains to be turned off, what gives the best results in terms of power saving. If one requests memory-to-memory channel, runtime active counter is increased unconditionally. This might be a drawback of this approach, but PL330 is not really used for memory-to-memory operations due to poor performance in such operations compared to the CPU. Introducing non-irq-safe runtime power management finally allows to turn off audio power domain on Exynos5 SoCs. Removal of irq-safe runtime PM is based on the revert of the following commits: 1. commit 5c9e6c2b2ba3 "dmaengine: pl330: fix runtime pm support" 2. commit 81cc6edc0870 "dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards" 3. commit ae43b3289186 "ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12" Signed-off-by: Marek Szyprowski Reviewed-by: Krzysztof Kozlowski --- drivers/dma/pl330.c | 124 ++++++++++++++++++++++++++-------------------------- 1 file changed, 61 insertions(+), 63 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 4489d4d13012..c7612bb0cfc8 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -268,9 +268,6 @@ enum pl330_byteswap { #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; @@ -449,8 +446,8 @@ struct dma_pl330_chan { bool cyclic; /* for runtime pm tracking */ - bool active; struct device *slave; + struct device_link *slave_link; }; struct pl330_dmac { @@ -2016,7 +2013,6 @@ 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); @@ -2031,18 +2027,10 @@ static void pl330_tasklet(unsigned long data) /* Try to submit a req imm. next to the last completed cookie */ fill_queue(pch); - if (list_empty(&pch->work_list)) { - spin_lock(&pch->thread->dmac->lock); - _stop(pch->thread); - spin_unlock(&pch->thread->dmac->lock); - power_down = true; - pch->active = false; - } else { - /* Make sure the PL330 Channel thread is active */ - spin_lock(&pch->thread->dmac->lock); - _start(pch->thread); - spin_unlock(&pch->thread->dmac->lock); - } + /* 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)) { struct dmaengine_desc_callback cb; @@ -2055,13 +2043,6 @@ static void pl330_tasklet(unsigned long data) if (pch->cyclic) { desc->status = PREP; list_move_tail(&desc->node, &pch->work_list); - if (power_down) { - pch->active = true; - 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); @@ -2076,12 +2057,6 @@ 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); - } } static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec, @@ -2113,11 +2088,52 @@ static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec, return dma_get_slave_channel(&pl330->peripherals[chan_id].chan); } +static int pl330_add_slave_link(struct pl330_dmac *pl330, + struct dma_pl330_chan *pch) +{ + struct device_link *link; + int i; + + if (pch->slave_link) + return 0; + + link = device_link_add(pch->slave, pl330->ddma.dev, + DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE); + if (!link) + return -ENODEV; + + for (i = 0; i < pl330->num_peripherals; i++) + if (pl330->peripherals[i].slave == pch->slave) + pl330->peripherals[i].slave_link = link; + return 0; +} + +static void pl330_del_slave_link(struct pl330_dmac *pl330, + struct dma_pl330_chan *pch) +{ + struct device_link *link = pch->slave_link; + int i, count = 0; + + for (i = 0; i < pl330->num_peripherals; i++) + if (pl330->peripherals[i].slave == pch->slave && + pl330->peripherals[i].thread) + count++; + + if (count > 0) + return; + + device_link_del(link); + for (i = 0; i < pl330->num_peripherals; i++) + if (pl330->peripherals[i].slave == pch->slave) + pch->slave_link = NULL; +} + static int pl330_alloc_chan_resources(struct dma_chan *chan) { struct dma_pl330_chan *pch = to_pchan(chan); struct pl330_dmac *pl330 = pch->dmac; unsigned long flags; + int ret = 0; spin_lock_irqsave(&pch->lock, flags); @@ -2134,6 +2150,14 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan) spin_unlock_irqrestore(&pch->lock, flags); + if (pch->slave) + ret = pl330_add_slave_link(pl330, pch); + else + ret = pm_runtime_get_sync(pl330->ddma.dev); + + if (ret < 0) + return ret; + return 1; } @@ -2168,9 +2192,7 @@ static int pl330_terminate_all(struct dma_chan *chan) unsigned long flags; struct pl330_dmac *pl330 = pch->dmac; LIST_HEAD(list); - bool power_down = false; - pm_runtime_get_sync(pl330->ddma.dev); spin_lock_irqsave(&pch->lock, flags); spin_lock(&pl330->lock); _stop(pch->thread); @@ -2179,8 +2201,6 @@ static int pl330_terminate_all(struct dma_chan *chan) pch->thread->req[0].desc = NULL; pch->thread->req[1].desc = NULL; pch->thread->req_running = -1; - power_down = pch->active; - pch->active = false; /* Mark all desc done */ list_for_each_entry(desc, &pch->submitted_list, node) { @@ -2197,10 +2217,6 @@ static int pl330_terminate_all(struct dma_chan *chan) 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); - if (power_down) - pm_runtime_put_autosuspend(pl330->ddma.dev); - pm_runtime_put_autosuspend(pl330->ddma.dev); return 0; } @@ -2218,7 +2234,6 @@ static int pl330_pause(struct dma_chan *chan) struct pl330_dmac *pl330 = pch->dmac; unsigned long flags; - pm_runtime_get_sync(pl330->ddma.dev); spin_lock_irqsave(&pch->lock, flags); spin_lock(&pl330->lock); @@ -2226,8 +2241,6 @@ static int pl330_pause(struct dma_chan *chan) spin_unlock(&pl330->lock); spin_unlock_irqrestore(&pch->lock, flags); - pm_runtime_mark_last_busy(pl330->ddma.dev); - pm_runtime_put_autosuspend(pl330->ddma.dev); return 0; } @@ -2235,11 +2248,11 @@ static int pl330_pause(struct dma_chan *chan) static void pl330_free_chan_resources(struct dma_chan *chan) { struct dma_pl330_chan *pch = to_pchan(chan); + struct pl330_dmac *pl330 = pch->dmac; unsigned long flags; tasklet_kill(&pch->task); - pm_runtime_get_sync(pch->dmac->ddma.dev); spin_lock_irqsave(&pch->lock, flags); pl330_release_channel(pch->thread); @@ -2249,19 +2262,20 @@ 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); + + if (pch->slave) + pl330_del_slave_link(pl330, pch); + else + pm_runtime_put(pl330->ddma.dev); } static int pl330_get_current_xferred_count(struct dma_pl330_chan *pch, struct dma_pl330_desc *desc) { struct pl330_thread *thrd = pch->thread; - struct pl330_dmac *pl330 = pch->dmac; void __iomem *regs = thrd->dmac->base; u32 val, addr; - pm_runtime_get_sync(pl330->ddma.dev); val = addr = 0; if (desc->rqcfg.src_inc) { val = readl(regs + SA(thrd->id)); @@ -2270,8 +2284,6 @@ static int pl330_get_current_xferred_count(struct dma_pl330_chan *pch, val = readl(regs + DA(thrd->id)); addr = desc->px.dst_addr; } - pm_runtime_mark_last_busy(pch->dmac->ddma.dev); - pm_runtime_put_autosuspend(pl330->ddma.dev); /* If DMAMOV hasn't finished yet, SAR/DAR can be zero */ if (!val) @@ -2357,16 +2369,6 @@ 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)); - pch->active = true; - pm_runtime_get_sync(pch->dmac->ddma.dev); - } list_splice_tail_init(&pch->submitted_list, &pch->work_list); spin_unlock_irqrestore(&pch->lock, flags); @@ -2984,11 +2986,7 @@ static int __maybe_unused pl330_resume(struct device *dev) 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); + pm_runtime_put(&adev->dev); return 0; probe_err3: