Re: [PATCH v4 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe routine

Mathieu Poirier
2024-08-14T15:52:40Z

Hi Beleswar,

On Thu, Aug 08, 2024 at 01:11:26PM +0530, Beleswar Padhi wrote:
> Acquire the mailbox handle during device probe and do not release handle
> in stop/detach routine or error paths. This removes the redundant
> requests for mbox handle later during rproc start/attach. This also
> allows to defer remoteproc driver's probe if mailbox is not probed yet.
>
> Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
> ---
> drivers/remoteproc/ti_k3_r5_remoteproc.c | 78 +++++++++---------------
> 1 file changed, 30 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 57067308b3c0..8a63a9360c0f 100644
> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -194,6 +194,10 @@ 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) {
> @@ -229,6 +233,10 @@ 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)
> @@ -399,12 +407,9 @@ static int k3_r5_rproc_request_mbox(struct rproc *rproc)
> client->knows_txdone = false;
>
> kproc->mbox = mbox_request_channel(client, 0);
> - if (IS_ERR(kproc->mbox)) {
> - ret = -EBUSY;
> - dev_err(dev, "mbox_request_channel failed: %ld\n",
> - PTR_ERR(kproc->mbox));
> - return ret;
> - }
> + if (IS_ERR(kproc->mbox))
> + return dev_err_probe(dev, PTR_ERR(kproc->mbox),
> + "mbox_request_channel failed\n");
>
> /*
> * Ping the remote processor, this is only for sanity-sake for now;
> @@ -552,10 +557,6 @@ static int k3_r5_rproc_start(struct rproc *rproc)
> u32 boot_addr;
> int ret;
>
> - ret = k3_r5_rproc_request_mbox(rproc);
> - if (ret)
> - return ret;
> -
> boot_addr = rproc->bootaddr;
> /* TODO: add boot_addr sanity checking */
> dev_dbg(dev, "booting R5F core using boot addr = 0x%x\n", boot_addr);
> @@ -564,7 +565,7 @@ static int k3_r5_rproc_start(struct rproc *rproc)
> core = kproc->core;
> ret = ti_sci_proc_set_config(core->tsp, boot_addr, 0, 0);
> if (ret)
> - goto put_mbox;
> + return ret;
>
> /* unhalt/run all applicable cores */
> if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
> @@ -580,13 +581,12 @@ static int k3_r5_rproc_start(struct rproc *rproc)
> if (core != core0 && core0->rproc->state == RPROC_OFFLINE) {
> dev_err(dev, "%s: can not start core 1 before core 0\n",
> __func__);
> - ret = -EPERM;
> - goto put_mbox;
> + return -EPERM;
> }
>
> ret = k3_r5_core_run(core);
> if (ret)
> - goto put_mbox;
> + return ret;
> }
>
> return 0;
> @@ -596,8 +596,6 @@ static int k3_r5_rproc_start(struct rproc *rproc)
> if (k3_r5_core_halt(core))
> dev_warn(core->dev, "core halt back failed\n");
> }
> -put_mbox:
> - mbox_free_channel(kproc->mbox);
> return ret;
> }
>
> @@ -658,8 +656,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
> goto out;
> }
>
> - mbox_free_channel(kproc->mbox);
> -
> return 0;
>
> unroll_core_halt:
> @@ -674,42 +670,22 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
> /*
> * Attach to a running R5F remote processor (IPC-only mode)
> *
> - * The R5F attach callback only needs to request the mailbox, the remote
> - * processor is already booted, so there is no need to issue any TI-SCI
> - * commands to boot the R5F cores in IPC-only mode. This callback is invoked
> - * only in IPC-only mode.
> + * The R5F attach callback is a NOP. The remote processor is already booted, and
> + * all required resources have been acquired during probe routine, so there is
> + * no need to issue any TI-SCI commands to boot the R5F cores in IPC-only mode.
> + * This callback is invoked only in IPC-only mode and exists because
> + * rproc_validate() checks for its existence.

Excellent documentation.

> */
> -static int k3_r5_rproc_attach(struct rproc *rproc)
> -{
> - struct k3_r5_rproc *kproc = rproc->priv;
> - struct device *dev = kproc->dev;
> - int ret;
> -
> - ret = k3_r5_rproc_request_mbox(rproc);
> - if (ret)
> - return ret;
> -
> - dev_info(dev, "R5F core initialized in IPC-only mode\n");
> - return 0;
> -}
> +static int k3_r5_rproc_attach(struct rproc *rproc) { return 0; }
>
> /*
> * Detach from a running R5F remote processor (IPC-only mode)
> *
> - * The R5F detach callback performs the opposite operation to attach callback
> - * and only needs to release the mailbox, the R5F cores are not stopped and
> - * will be left in booted state in IPC-only mode. This callback is invoked
> - * only in IPC-only mode.
> + * The R5F detach callback is a NOP. The R5F cores are not stopped and will be
> + * left in booted state in IPC-only mode. This callback is invoked only in
> + * IPC-only mode and exists for sanity sake.

I would add the part about detach() being a NOP to attach() above...

> */
> -static int k3_r5_rproc_detach(struct rproc *rproc)
> -{
> - struct k3_r5_rproc *kproc = rproc->priv;
> - struct device *dev = kproc->dev;
> -
> - mbox_free_channel(kproc->mbox);
> - dev_info(dev, "R5F core deinitialized in IPC-only mode\n");
> - return 0;
> -}
> +static int k3_r5_rproc_detach(struct rproc *rproc) { return 0; }

... and just remove this.

Otherwise this patch looks good.

>
> /*
> * This function implements the .get_loaded_rsc_table() callback and is used
> @@ -1278,6 +1254,10 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> kproc->rproc = rproc;
> core->rproc = rproc;
>
> + ret = k3_r5_rproc_request_mbox(rproc);
> + if (ret)
> + return ret;
> +
> ret = k3_r5_rproc_configure_mode(kproc);
> if (ret < 0)
> goto out;
> @@ -1392,6 +1372,8 @@ static void k3_r5_cluster_rproc_exit(void *data)
> }
> }
>
> + mbox_free_channel(kproc->mbox);
> +
> rproc_del(rproc);
>
> k3_r5_reserved_mem_exit(kproc);
> --
> 2.34.1
>