On Thu, Jan 21, 2021 at 09:52:51PM -0500, Thara Gopinath wrote:
> When bam dma is "controlled remotely", thus far clocks were not controlled
> from the Linux. In this scenario, Linux was disabling runtime pm in bam dma
> driver and not doing any clock management in suspend/resume hooks.
>
> With introduction of crypto engine bam dma, the clock is a rpmh resource
> that can be controlled from both Linux and TZ/remote side. Now bam dma
> clock is getting enabled during probe even though the bam dma can be
> "controlled remotely". But due to clocks not being handled properly,
> bam_suspend generates a unbalanced clk_unprepare warning during system
> suspend.
>
> To fix the above issue and to enable proper clock-management, this patch
> enables runtim-pm and handles bam dma clocks in suspend/resume hooks if
> the clock node is present irrespective of controlled_remotely property.
Shouldn't the following probe code need some update? Now we have both
controlled_remotely and clocks handle for cryptobam node. For example,
if devm_clk_get() returns -EPROBE_DEFER, we do not want to continue with
bamclk forcing to be NULL, right?
bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
if (IS_ERR(bdev->bamclk)) {
if (!bdev->controlled_remotely)
return PTR_ERR(bdev->bamclk);
bdev->bamclk = NULL;
}
>
> Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
> ---
> drivers/dma/qcom/bam_dma.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index 88579857ca1d..b3a34be63e99 100644
> --- a/drivers/dma/qcom/bam_dma.c
> +++ b/drivers/dma/qcom/bam_dma.c
> @@ -1350,7 +1350,7 @@ static int bam_dma_probe(struct platform_device *pdev)
> if (ret)
> goto err_unregister_dma;
>
> - if (bdev->controlled_remotely) {
> + if (!bdev->bamclk) {
> pm_runtime_disable(&pdev->dev);
> return 0;
> }
> @@ -1438,10 +1438,10 @@ static int __maybe_unused bam_dma_suspend(struct device *dev)
> {
> struct bam_device *bdev = dev_get_drvdata(dev);
>
> - if (!bdev->controlled_remotely)
> + if (bdev->bamclk) {
> pm_runtime_force_suspend(dev);
> -
> - clk_unprepare(bdev->bamclk);
> + clk_unprepare(bdev->bamclk);
> + }
>
> return 0;
> }
> @@ -1451,12 +1451,14 @@ static int __maybe_unused bam_dma_resume(struct device *dev)
> struct bam_device *bdev = dev_get_drvdata(dev);
> int ret;
>
> - ret = clk_prepare(bdev->bamclk);
> - if (ret)
> - return ret;
> + if (bdev->bamclk) {
> + ret = clk_prepare(bdev->bamclk);
> + if (ret)
> + return ret;
>
> - if (!bdev->controlled_remotely)
> - pm_runtime_force_resume(dev);
> + if (!bdev->controlled_remotely)
Why do we still need controlled_remotely check here?
Shawn
> + pm_runtime_force_resume(dev);
> + }
>
> return 0;
> }
> --
> 2.25.1
>
