On Thu, 22 Sept 2022 at 08:08, Vinod Koul <vkoul@xxxxxxxxxx> wrote:
>
> On 21-09-22, 08:36, Bhupesh Sharma wrote:
> > From: Thara Gopinath <thara.gopinath@xxxxxxxxx>
> >
> > BAM dma engine associated with certain hardware blocks could require
> > relevant interconnect pieces be initialized prior to the dma engine
> > initialization. For e.g. crypto bam dma engine on sm8250. Such requirement
> > is passed on to the bam dma driver from dt via the "interconnects"
> > property. Add support in bam_dma driver to check whether the interconnect
> > path is accessible/enabled prior to attempting driver intializations.
> >
> > If interconnects are not yet setup, defer the BAM DMA driver probe().
> >
> > Cc: Bjorn Andersson <andersson@xxxxxxxxxx>
> > Cc: Rob Herring <robh@xxxxxxxxxx>
> > Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxx>
> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx>
> > [Bhupesh: Make header file inclusion alphabetical and use 'devm_of_icc_get()']
> > ---
> > drivers/dma/qcom/bam_dma.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> > index 2ff787df513e..a5b0cf28ffb7 100644
> > --- a/drivers/dma/qcom/bam_dma.c
> > +++ b/drivers/dma/qcom/bam_dma.c
> > @@ -26,6 +26,7 @@
> > #include <linux/kernel.h>
> > #include <linux/io.h>
> > #include <linux/init.h>
> > +#include <linux/interconnect.h>
> > #include <linux/slab.h>
> > #include <linux/module.h>
> > #include <linux/interrupt.h>
> > @@ -394,6 +395,7 @@ struct bam_device {
> > const struct reg_offset_data *layout;
> >
> > struct clk *bamclk;
> > + struct icc_path *mem_path;
> > int irq;
> >
> > /* dma start transaction tasklet */
> > @@ -1294,6 +1296,14 @@ static int bam_dma_probe(struct platform_device *pdev)
> > if (IS_ERR(bdev->bamclk))
> > return PTR_ERR(bdev->bamclk);
> >
> > + /* Ensure that interconnects are initialized */
> > + bdev->mem_path = devm_of_icc_get(bdev->dev, "memory");
> > + if (IS_ERR(bdev->mem_path)) {
> > + ret = dev_err_probe(bdev->dev, PTR_ERR(bdev->mem_path),
> > + "failed to acquire icc path\n");
> > + return ret;
> > + }
>
> So this makes us fail on older DT where icc path may not be present.
> Should this not be an optional thing?
That's a good point. I am not sure if Thara tried this on platforms
which don't have the icc path available.
I will fix this in v8.
Thanks,
Bhupesh
> > +
> > ret = clk_prepare_enable(bdev->bamclk);
> > if (ret) {
> > dev_err(bdev->dev, "failed to prepare/enable clock\n");
> > --
> > 2.37.1
>
> --
> ~Vinod
