On Tue 26 Jan 15:18 CST 2021, 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.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
And from John on IRC:
Tested-by: John Stultz <john.stultz@xxxxxxxxxx>
Regards,
Bjorn
> ---
>
> v1->v2:
> - As per Shawn's suggestion, use devm_clk_get_optional to get the
> bam clock if the "controlled_remotely" property is set so that
> the clock code takes care of setting the bam clock to NULL if
> not specified by dt.
> - Remove the check for "controlled_remotely" property in
> bam_dma_resume now that clock enable / disable is based on
> whether bamclk is NULL or not.
> - Rebased to v5.11-rc5
>
> drivers/dma/qcom/bam_dma.c | 29 +++++++++++++++--------------
> 1 file changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index 88579857ca1d..c8a77b428b52 100644
> --- a/drivers/dma/qcom/bam_dma.c
> +++ b/drivers/dma/qcom/bam_dma.c
> @@ -1270,13 +1270,13 @@ static int bam_dma_probe(struct platform_device *pdev)
> dev_err(bdev->dev, "num-ees unspecified in dt\n");
> }
>
> - bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
> - if (IS_ERR(bdev->bamclk)) {
> - if (!bdev->controlled_remotely)
> - return PTR_ERR(bdev->bamclk);
> + if (bdev->controlled_remotely)
> + bdev->bamclk = devm_clk_get_optional(bdev->dev, "bam_clk");
> + else
> + bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
>
> - bdev->bamclk = NULL;
> - }
> + if (IS_ERR(bdev->bamclk))
> + return PTR_ERR(bdev->bamclk);
>
> ret = clk_prepare_enable(bdev->bamclk);
> if (ret) {
> @@ -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 +1451,13 @@ 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);
> + }
>
> return 0;
> }
> --
> 2.25.1
>
