RE: [EXT] [PATCH] crypto: caam: map job ring registers without claiming region

[Sahil Malhotra]

Hi Rosen,

Thanks for the fix.

Tested-by: Sahil Malhotra <sahil.malhotra@xxxxxxx> # i.MX8MM-EVK

> -----Original Message-----
> From: Rosen Penev <rosenp@xxxxxxxxx>
> Sent: 02 September 2026 02:08
> To: linux-crypto@xxxxxxxxxxxxxxx
> Cc: Horia Geanta <horia.geanta@xxxxxxx>; Pankaj Gupta
> <pankaj.gupta@xxxxxxx>; Gaurav Jain <gaurav.jain@xxxxxxx>; Herbert Xu
> <herbert@xxxxxxxxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>;
Rosen
> Penev <rosenp@xxxxxxxxx>; open list <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: [EXT] [PATCH] crypto: caam: map job ring registers without
claiming
> region
> 
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> 
> 
> devm_platform_ioremap_resource() ends up calling request_mem_region(),
> which fails with -EBUSY on i.MX SoCs:
> 
> There the job rings are modelled as sub-regions of their parent
> fsl,sec-v4.0 register window, and caam_probe() already reserves the whole
> window exclusively via devm_of_iomap() before the children are populated.
> Every job ring therefore collides with its own parent and fails to probe,
taking the
> hardware RNG offline (seen on i.MX6, i.MX7 and i.MX8 boards such as
colibri-
> imx7 and verdin-imx8mp).
> 
> Map the job ring registers with devm_ioremap() instead, which does not
claim the
> (already owned) region.
> 
> Fixes: 9a955c0a7d11 ("crypto: caam - simplify probe resource and IRQ
handling")
> Assisted-by: opencode:big-pickle
> Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
> ---
>  drivers/crypto/caam/jr.c | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c index
> f9e029945b51..2ed8229d4733 100644
> --- a/drivers/crypto/caam/jr.c
> +++ b/drivers/crypto/caam/jr.c
> @@ -583,12 +583,29 @@ static int caam_jr_probe(struct platform_device
> *pdev)
>         struct caam_drv_private_jr *jrpriv;
>         static int total_jobrs;
>         void __iomem *ctrl;
> +       struct resource *r;
>         int error;
>         int irq;
> 
> -       ctrl = devm_platform_ioremap_resource(pdev, 0);
> -       if (IS_ERR(ctrl))
> -               return PTR_ERR(ctrl);
> +       /*
> +        * The job rings live inside the register window of their parent
> +        * fsl,sec-v4.0 node, which caam_probe() already reserves (and
maps)
> +        * via devm_of_iomap().  A requested region that overlaps that
> +        * reservation, e.g. from devm_platform_ioremap_resource(), would
> +        * therefore fail with -EBUSY, so map the registers without
claiming
> +        * the region here.
> +        */
> +       r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!r) {
> +               dev_err(&pdev->dev, "platform_get_resource() failed\n");
> +               return -EINVAL;
> +       }
> +
> +       ctrl = devm_ioremap(&pdev->dev, r->start, resource_size(r));
> +       if (!ctrl) {
> +               dev_err(&pdev->dev, "devm_ioremap() failed\n");
> +               return -ENOMEM;
> +       }
> 
>         irq = platform_get_irq(pdev, 0);
>         if (irq < 0)
> --
> 2.55.0
>

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