From: Claudiu Beznea Date: Tue, 26 May 2026 08:47:06 +0000 (+0300) Subject: dmaengine: sh: rz-dmac: Add runtime PM support X-Git-Tag: v7.2-rc1~55^2~31 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=7c27a4d54d48d0774518390e4ce6cf3309aac141;p=thirdparty%2Fkernel%2Flinux.git dmaengine: sh: rz-dmac: Add runtime PM support Protect the driver exposed APIs with runtime PM suspend/resume calls before accessing HW registers. As the current driver leaves runtime PM enabled in probe, the purpose of the changes in this patch is to avoid accessing HW registers after a failed system suspend leaves the runtime PM state of the device improperly reinitialized. In that case, the driver remains bound to the device, the APIs are still exposed, and any access to HW registers without runtime resuming the device may lead to synchronous aborts. To avoid leaking resources in case of runtime PM failures, save the error code returned by PM_RUNTIME_ACQUIRE_ERR() in rz_dmac_terminate_all() and return it only at the end of the function to allow the cleanup code to run. A similar approach is used in rz_dmac_free_chan_resources(). Because some exposed APIs (e.g. ->device_terminate_all()) may be called from atomic context according to the documentation, mark the DMA device as pm_runtime_irq_safe(). This patch prepares the driver for suspend-to-RAM support. Tested-by: John Madieu Signed-off-by: Claudiu Beznea Tested-by: Tommaso Merciai Link: https://patch.msgid.link/20260526084710.3491480-15-claudiu.beznea@kernel.org Signed-off-by: Vinod Koul --- diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c index 93394b9934c89..bd4ca8e939f17 100644 --- a/drivers/dma/sh/rz-dmac.c +++ b/drivers/dma/sh/rz-dmac.c @@ -549,12 +549,22 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan) struct rz_dmac *dmac = to_rz_dmac(chan->device); struct rz_dmac_desc *desc, *_desc; unsigned long flags; + int ret; + + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) { + dev_err(dmac->dev, "RPM resume failed for channel %s, ret=%d\n!", + dma_chan_name(chan), ret); + } spin_lock_irqsave(&channel->vc.lock, flags); rz_lmdesc_setup(channel, channel->lmdesc.base); - rz_dmac_disable_hw(channel); + /* Skip touching HW if RPM resume failed. Let the cleanup do its jobs. */ + if (!ret) + rz_dmac_disable_hw(channel); if (channel->mid_rid >= 0) { clear_bit(channel->mid_rid, dmac->modules); @@ -697,11 +707,22 @@ rz_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, static int rz_dmac_terminate_all(struct dma_chan *chan) { struct rz_dmac_chan *channel = to_rz_dmac_chan(chan); + struct rz_dmac *dmac = to_rz_dmac(chan->device); unsigned long flags; LIST_HEAD(head); + int ret; + + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) { + dev_err(dmac->dev, "RPM resume failed for channel %s, ret=%d\n!", + dma_chan_name(chan), ret); + } spin_lock_irqsave(&channel->vc.lock, flags); - rz_dmac_disable_hw(channel); + /* Don't return if RPM failed. Let the cleanup do its jobs. */ + if (!ret) + rz_dmac_disable_hw(channel); rz_lmdesc_setup(channel, channel->lmdesc.base); if (channel->desc) { @@ -716,13 +737,20 @@ static int rz_dmac_terminate_all(struct dma_chan *chan) spin_unlock_irqrestore(&channel->vc.lock, flags); vchan_dma_desc_free_list(&channel->vc, &head); - return 0; + return ret; } static void rz_dmac_issue_pending(struct dma_chan *chan) { struct rz_dmac_chan *channel = to_rz_dmac_chan(chan); + struct rz_dmac *dmac = to_rz_dmac(chan->device); unsigned long flags; + int ret; + + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) + return; spin_lock_irqsave(&channel->vc.lock, flags); @@ -807,6 +835,11 @@ static void rz_dmac_device_synchronize(struct dma_chan *chan) vchan_synchronize(&channel->vc); + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) + return; + ret = read_poll_timeout(rz_dmac_ch_readl, chstat, !(chstat & CHSTAT_EN), 100, 100000, false, channel, CHSTAT, 1); if (ret < 0) @@ -866,6 +899,7 @@ static int rz_dmac_chan_get_residue(struct device *dev, struct rz_dmac_chan *cha struct rz_dmac_desc *desc = NULL; struct virt_dma_desc *vd; u32 crla, crtb, i; + int ret; vd = vchan_find_desc(&channel->vc, cookie); if (vd) { @@ -884,6 +918,11 @@ static int rz_dmac_chan_get_residue(struct device *dev, struct rz_dmac_chan *cha return 0; } + PM_RUNTIME_ACQUIRE_IF_ENABLED(dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) + return ret; + /* * We need to read two registers. Make sure the hardware does not move * to next lmdesc while reading the current lmdesc. Trying it 3 times @@ -965,6 +1004,13 @@ set_bit: static int rz_dmac_device_pause(struct dma_chan *chan) { struct rz_dmac_chan *channel = to_rz_dmac_chan(chan); + struct rz_dmac *dmac = to_rz_dmac(chan->device); + int ret; + + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) + return ret; guard(spinlock_irqsave)(&channel->vc.lock); @@ -994,6 +1040,13 @@ static int rz_dmac_device_resume_set(struct rz_dmac_chan *channel, static int rz_dmac_device_resume(struct dma_chan *chan) { struct rz_dmac_chan *channel = to_rz_dmac_chan(chan); + struct rz_dmac *dmac = to_rz_dmac(chan->device); + int ret; + + PM_RUNTIME_ACQUIRE_IF_ENABLED(dmac->dev, pm); + ret = PM_RUNTIME_ACQUIRE_ERR(&pm); + if (ret) + return ret; guard(spinlock_irqsave)(&channel->vc.lock); @@ -1274,6 +1327,7 @@ static int rz_dmac_probe(struct platform_device *pdev) return dev_err_probe(&pdev->dev, PTR_ERR(dmac->rstc), "failed to get resets\n"); + pm_runtime_irq_safe(&pdev->dev); pm_runtime_enable(&pdev->dev); ret = pm_runtime_resume_and_get(&pdev->dev); if (ret < 0) {