Messages in this thread | | | Date | Mon, 15 Nov 2021 12:29:10 -0600 | From | Bjorn Andersson <> | Subject | Re: [PATCH v5 18/22] crypto: qce: Defer probing if BAM dma channel is not yet initialized |
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On Wed 10 Nov 04:59 CST 2021, Bhupesh Sharma wrote:
> Since the Qualcomm qce crypto driver needs the BAM dma driver to be > setup first (to allow crypto operations), it makes sense to defer > the qce crypto driver probing in case the BAM dma driver is not yet > probed. >
To me this sentence implies that qce_crypto_probe() doesn't return -EPROBE_DEFER from qce_dma_request(), but looking at the code I don't see why this would be...
> Move the code leg requesting dma channels earlier in the > probe() flow. This fixes the qce probe failure issues when both qce > and BMA dma are compiled as static part of the kernel. >
As far as I can tell the only actual difference is that you're moving the qce_dma_request() above the icc_set_bw() call and the three clk_prepare_enable() calls.
This is a very valid optimization, but where does qce_crypto_probe() fail and why does it need the BAM driver to have probed before we try to turn on the clocks and (our) interconnect vote?
> Cc: Thara Gopinath <thara.gopinath@linaro.org> > Cc: Bjorn Andersson <bjorn.andersson@linaro.org> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org> > --- > drivers/crypto/qce/core.c | 23 ++++++++++++++--------- > 1 file changed, 14 insertions(+), 9 deletions(-) > > diff --git a/drivers/crypto/qce/core.c b/drivers/crypto/qce/core.c > index 7c90401a2ef1..84ed9e253d5d 100644 > --- a/drivers/crypto/qce/core.c > +++ b/drivers/crypto/qce/core.c > @@ -209,9 +209,19 @@ static int qce_crypto_probe(struct platform_device *pdev) > if (ret < 0) > return ret; > > + /* qce driver requires BAM dma driver to be setup first. > + * In case the dma channel are not set yet, this check > + * helps use to return -EPROBE_DEFER earlier. > + */
This comment warrants the change, but I don't see that it will add value in the code once the patch is merged. Please drop it.
> + ret = qce_dma_request(qce->dev, &qce->dma); > + if (ret)
I presume this is where your added dev_err() in err: comes in handy. I definitely think this warrants an error print; so return dev_err_probe() here would be the right thing to do (in the previous patch).
> + return ret; > + > qce->mem_path = devm_of_icc_get(qce->dev, "memory"); > - if (IS_ERR(qce->mem_path)) > - return PTR_ERR(qce->mem_path);
But I see no reason for moving it above devm_of_icc_get() and the devm_clk_get*() calls - as they don't actually do anything, but moving qce_dma_request() above them forces the introduction of goto here.
Regards, Bjorn
> + if (IS_ERR(qce->mem_path)) { > + ret = PTR_ERR(qce->mem_path); > + goto err; > + } > > qce->core = devm_clk_get_optional(qce->dev, "core"); > if (IS_ERR(qce->core)) { > @@ -247,10 +257,6 @@ static int qce_crypto_probe(struct platform_device *pdev) > if (ret) > goto err_clks_iface; > > - ret = qce_dma_request(qce->dev, &qce->dma); > - if (ret) > - goto err_clks; > - > ret = qce_check_version(qce); > if (ret) > goto err_clks; > @@ -265,12 +271,10 @@ static int qce_crypto_probe(struct platform_device *pdev) > > ret = qce_register_algs(qce); > if (ret) > - goto err_dma; > + goto err_clks; > > return 0; > > -err_dma: > - qce_dma_release(&qce->dma); > err_clks: > clk_disable_unprepare(qce->bus); > err_clks_iface: > @@ -280,6 +284,7 @@ static int qce_crypto_probe(struct platform_device *pdev) > err_mem_path_disable: > icc_set_bw(qce->mem_path, 0, 0); > err: > + qce_dma_release(&qce->dma); > dev_err(dev, "%s failed : %d\n", __func__, ret); > return ret; > } > -- > 2.31.1 >
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