linux-kernel - Re: [RFC PATCH] remoteproc: k3-r5: Fix check performed in k3_r5_rproc_{mbox

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Message-ID: <CANLsYkwTYqfAi+OFg3khMs7VD_PnL=CH-k8HXE71QSdqpR1fvA@mail.gmail.com>
Date: Mon, 16 Sep 2024 09:20:57 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Siddharth Vadapalli <s-vadapalli@...com>
Cc: andersson@...nel.org, b-padhi@...com, linux-remoteproc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	u-kumar1@...com, srk@...com
Subject: Re: [RFC PATCH] remoteproc: k3-r5: Fix check performed in k3_r5_rproc_{mbox_callback/kick}

On Mon, 16 Sept 2024 at 02:31, Siddharth Vadapalli <s-vadapalli@...com> wrote:
>
> Commit f3f11cfe8907 ("remoteproc: k3-r5: Acquire mailbox handle during
> probe routine") introduced a check in the "k3_r5_rproc_mbox_callback()" and
> "k3_r5_rproc_kick()" callbacks, causing them to exit if the remote core's
> state is "RPROC_DETACHED". However, the "__rproc_attach()" function that is
> responsible for attaching to a remote core, updates the state of the remote
> core to "RPROC_ATTACHED" only after invoking "rproc_start_subdevices()".
>
> The "rproc_start_subdevices()" function triggers the probe of the Virtio
> RPMsg devices associated with the remote core, which require that the
> "k3_r5_rproc_kick()" and "k3_r5_rproc_mbox_callback()" callbacks are
> functional. Hence, drop the check in the callbacks.

Honestly, I am very tempted to just revert f3f11cfe8907 and ea1d6fb5b571.

>
> Fixes: f3f11cfe8907 ("remoteproc: k3-r5: Acquire mailbox handle during probe routine")
> Signed-off-by: Siddharth Vadapalli <s-vadapalli@...com>
> ---
>
> Hello,
>
> Since the commit being fixed is not yet a part of Mainline Linux, this
> patch is based on linux-next tagged next-20240913.
>
> An alternative to this patch will be a change to the "__rproc_attach()"
> function in the "remoteproc_core.c" driver with
> rproc->state = RPROC_ATTACHED;
> being set after "rproc_attach_device()" is invoked, but __before__
> invoking "rproc_start_subdevices()". Since this change will be performed
> in the common Remoteproc Core, it appeared to me that fixing it in the
> TI remoteproc driver is the correct approach.
>
> The equivalent of this patch for ti_k3_dsp_remoteproc.c might also be
> required, which I shall post if the current patch is acceptable.
>
> Kindly review and share your feedback on this patch.
>
> Regards,
> Siddharth.
>
>  drivers/remoteproc/ti_k3_r5_remoteproc.c | 8 --------
>  1 file changed, 8 deletions(-)
>
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 747ee467da88..4894461aa65f 100644
> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -194,10 +194,6 @@ static void k3_r5_rproc_mbox_callback(struct mbox_client *client, void *data)
>         const char *name = kproc->rproc->name;
>         u32 msg = omap_mbox_message(data);
>
> -       /* Do not forward message from a detached core */
> -       if (kproc->rproc->state == RPROC_DETACHED)
> -               return;
> -
>         dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>
>         switch (msg) {
> @@ -233,10 +229,6 @@ static void k3_r5_rproc_kick(struct rproc *rproc, int vqid)
>         mbox_msg_t msg = (mbox_msg_t)vqid;
>         int ret;
>
> -       /* Do not forward message to a detached core */
> -       if (kproc->rproc->state == RPROC_DETACHED)
> -               return;
> -
>         /* send the index of the triggered virtqueue in the mailbox payload */
>         ret = mbox_send_message(kproc->mbox, (void *)msg);
>         if (ret < 0)
> --
> 2.40.1
>