Messages in this thread |  | | Date | Mon, 1 Dec 2025 15:22:36 +0200 | | Subject | Re: [PATCH v8 17/18] media: ti: j721e-csi2rx: Support runtime suspend | | From | Tomi Valkeinen <> |
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Hi,
On 12/11/2025 13:54, Rishikesh Donadkar wrote: > From: Jai Luthra <jai.luthra@ideasonboard.com> > > Add support for runtime power-management to enable powering off the > shared power domain between Cadence CSI2RX and TI CSI2RX wrapper when > the device(s) are not in use. > > When powering off the IP, the PSI-L endpoint loses the paired DMA > channels. Thus we have to release the DMA channels at runtime suspend > and request them again at resume.
I'm not an expert on the dmaengine, but to me this sounds like a bug in the dma driver. It just sounds very wrong...
> Tested-by: Rishikesh Donadkar <r-donadkar@ti.com> > Reviewed-by: Rishikesh Donadkar <r-donadkar@ti.com> > Signed-off-by: Jai Luthra <jai.luthra@ideasonboard.com> > Signed-off-by: Rishikesh Donadkar <r-donadkar@ti.com> > --- > drivers/media/platform/ti/Kconfig | 1 + > .../platform/ti/j721e-csi2rx/j721e-csi2rx.c | 55 ++++++++++++++++++- > 2 files changed, 54 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/platform/ti/Kconfig b/drivers/media/platform/ti/Kconfig > index 3bc4aa35887e6..a808063e24779 100644 > --- a/drivers/media/platform/ti/Kconfig > +++ b/drivers/media/platform/ti/Kconfig > @@ -70,6 +70,7 @@ config VIDEO_TI_J721E_CSI2RX > depends on VIDEO_CADENCE_CSI2RX > depends on PHY_CADENCE_DPHY_RX || COMPILE_TEST > depends on ARCH_K3 || COMPILE_TEST > + depends on PM > select VIDEOBUF2_DMA_CONTIG > select V4L2_FWNODE > help > diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > index 528041ee78cf3..21e032c64b901 100644 > --- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > +++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > @@ -13,6 +13,7 @@ > #include <linux/module.h> > #include <linux/of_platform.h> > #include <linux/platform_device.h> > +#include <linux/pm_runtime.h> > #include <linux/property.h> > > #include <media/cadence/cdns-csi2rx.h> > @@ -963,12 +964,16 @@ static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count) > unsigned long flags; > int ret = 0; > > + ret = pm_runtime_resume_and_get(csi->dev); > + if (ret) > + return ret; > + > spin_lock_irqsave(&dma->lock, flags); > if (list_empty(&dma->queue)) > ret = -EIO; > spin_unlock_irqrestore(&dma->lock, flags); > if (ret) > - return ret; > + goto err; > > ret = video_device_pipeline_start(&ctx->vdev, &csi->pipe); > if (ret) > @@ -1024,6 +1029,8 @@ static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count) > writel(0, csi->shim + SHIM_DMACNTX(ctx->idx)); > err: > ti_csi2rx_cleanup_buffers(ctx, VB2_BUF_STATE_QUEUED); > + pm_runtime_put(csi->dev); > + > return ret; > } > > @@ -1055,6 +1062,7 @@ static void ti_csi2rx_stop_streaming(struct vb2_queue *vq) > > ti_csi2rx_stop_dma(ctx); > ti_csi2rx_cleanup_buffers(ctx, VB2_BUF_STATE_ERROR); > + pm_runtime_put(csi->dev); > } > > static const struct vb2_ops csi_vb2_qops = { > @@ -1261,7 +1269,9 @@ static void ti_csi2rx_cleanup_notifier(struct ti_csi2rx_dev *csi) > > static void ti_csi2rx_cleanup_ctx(struct ti_csi2rx_ctx *ctx) > { > - dma_release_channel(ctx->dma.chan); > + if (!pm_runtime_status_suspended(ctx->csi->dev)) > + dma_release_channel(ctx->dma.chan); > + > vb2_queue_release(&ctx->vidq); > > video_unregister_device(&ctx->vdev); > @@ -1512,6 +1522,39 @@ static int ti_csi2rx_init_ctx(struct ti_csi2rx_ctx *ctx) > return ret; > } > > +static int ti_csi2rx_runtime_suspend(struct device *dev) > +{ > + struct ti_csi2rx_dev *csi = dev_get_drvdata(dev); > + int i; > + > + if (csi->enable_count != 0) > + return -EBUSY; > + > + for (i = 0; i < csi->num_ctx; i++) > + dma_release_channel(csi->ctx[i].dma.chan); > + > + return 0; > +} > + > +static int ti_csi2rx_runtime_resume(struct device *dev) > +{ > + struct ti_csi2rx_dev *csi = dev_get_drvdata(dev); > + int ret, i; > + > + for (i = 0; i < csi->num_ctx; i++) { > + ret = ti_csi2rx_init_dma(&csi->ctx[i]);
If runtime_resume always requests the dma channels, is the call to ti_csi2rx_init_dma() in ti_csi2rx_init_ctx() needed? If not, you could inline the code from ti_csi2rx_init_dma() to here and also drop the dma_release_channel() call from ti_csi2rx_cleanup_ctx(), making the flow more understandable.
> + if (ret) > + return ret; > + } > + > + return 0; > +} > + > +static const struct dev_pm_ops ti_csi2rx_pm_ops = { > + RUNTIME_PM_OPS(ti_csi2rx_runtime_suspend, ti_csi2rx_runtime_resume, > + NULL) > +}; > + > static int ti_csi2rx_probe(struct platform_device *pdev) > { > struct device_node *np = pdev->dev.of_node; > @@ -1579,6 +1622,10 @@ static int ti_csi2rx_probe(struct platform_device *pdev) > goto err_notifier; > } > > + pm_runtime_set_active(csi->dev); > + pm_runtime_enable(csi->dev); > + pm_request_idle(csi->dev);
I always forget what exactly the runtime_pm funcs do. What's the idea here? If you do something else than the plain standard pm_runtime_enable(), I think it's good to mention what/why in a comment.
> return 0; > > err_notifier: > @@ -1609,6 +1656,9 @@ static void ti_csi2rx_remove(struct platform_device *pdev) > mutex_destroy(&csi->mutex); > dma_free_coherent(csi->dev, csi->drain.len, csi->drain.vaddr, > csi->drain.paddr); > + pm_runtime_disable(&pdev->dev); > + pm_runtime_set_suspended(&pdev->dev); > + > } > > static const struct of_device_id ti_csi2rx_of_match[] = { > @@ -1623,6 +1673,7 @@ static struct platform_driver ti_csi2rx_pdrv = { > .driver = { > .name = TI_CSI2RX_MODULE_NAME, > .of_match_table = ti_csi2rx_of_match, > + .pm = &ti_csi2rx_pm_ops, > }, > }; >
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