Re: [PATCH 1/6] remoteproc: Introduce rproc_detach_device() wrapper

Bjorn Andersson
2021-05-28T04:19:34Z

On Fri 21 May 19:03 CDT 2021, Suman Anna wrote:

> The .attach() rproc ops is invoked through the helper
> rproc_attach_device(), but the .detach() ops is invoked
> directly at present. Introduce a similar wrapper function
> rproc_detach_device() for .detach() ops so that the code
> is symmetric.
>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
> drivers/remoteproc/remoteproc_core.c | 2 +-
> drivers/remoteproc/remoteproc_internal.h | 8 ++++++++
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 6348aaa42bbb..6019f46001c8 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1869,7 +1869,7 @@ static int __rproc_detach(struct rproc *rproc)
> }
>
> /* Tell the remote processor the core isn't available anymore */
> - ret = rproc->ops->detach(rproc);
> + ret = rproc_detach_device(rproc);
> if (ret) {
> dev_err(dev, "can't detach from rproc: %d\n", ret);
> return ret;
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index a328e634b1de..931d50b6a0d1 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -121,6 +121,14 @@ static inline int rproc_attach_device(struct rproc *rproc)
> return 0;
> }
>
> +static inline int rproc_detach_device(struct rproc *rproc)
> +{
> + if (rproc->ops->detach)
> + return rproc->ops->detach(rproc);
> +
> + return 0;

I was going to complain that this will silently succeed to detach a
remoteproc when the driver doesn't implement detach, but then I realized
that in the current code path we just failed if it wasn't set.

So this only becomes a problem if we're out of sync between the wish to
detach and the implementation of detach, in the later patch.

But based on this, why do we allow rproc_attach_device() to succeed even
though a driver doesn't implement attach? Could we achieve the symmetry
by going the other way?

Regards,
Bjorn

> +}
> +
> static inline
> int rproc_fw_sanity_check(struct rproc *rproc, const struct firmware *fw)
> {
> --
> 2.30.1