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Date: Tue, 4 Jun 2024 10:54:00 +0530
From: Beleswar Prasad Padhi <b-padhi@...com>
To: Andrew Davis <afd@...com>, <andersson@...nel.org>,
<mathieu.poirier@...aro.org>
CC: <hnagalla@...com>, <u-kumar1@...com>, <linux-remoteproc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] remoteproc: k3-r5: Acquire mailbox handle during
probe
Hi Andrew,
On 30/05/24 19:46, Andrew Davis wrote:
> On 5/30/24 4:07 AM, 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@...com>
>> ---
>> drivers/remoteproc/ti_k3_r5_remoteproc.c | 66 ++++++++----------------
>> 1 file changed, 21 insertions(+), 45 deletions(-)
>>
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index 26362a509ae3..157e8fd57665 100644
>> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> @@ -391,6 +391,7 @@ static int k3_r5_rproc_request_mbox(struct rproc
>> *rproc)
>> struct mbox_client *client = &kproc->client;
>> struct device *dev = kproc->dev;
>> int ret;
>> + long err;
>> client->dev = dev;
>> client->tx_done = NULL;
>> @@ -400,10 +401,9 @@ static int k3_r5_rproc_request_mbox(struct rproc
>> *rproc)
>> 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;
>> + err = PTR_ERR(kproc->mbox);
>> + dev_err(dev, "mbox_request_channel failed: %ld\n", err);
>> + return (err == -EPROBE_DEFER) ? -EPROBE_DEFER : -EBUSY;
>
> Why turn all other errors into EBUSY? If you just return the error
> as-is you
> can simply make these 3 lines just:
>
> return dev_err_probe(dev, PTR_ERR(kproc->mbox), "mbox_request_channel
> failed\n");
>
>> }
>> /*
>> @@ -552,10 +552,6 @@ 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 +560,7 @@ 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;
>> + goto out;
>
> The label "out" doesn't do anything, just directly `return ret;` here and
> in the other cases below.
>
>> /* unhalt/run all applicable cores */
>> if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
>> @@ -581,12 +577,12 @@ static int k3_r5_rproc_start(struct rproc *rproc)
>> dev_err(dev, "%s: can not start core 1 before core 0\n",
>> __func__);
>> ret = -EPERM;
>> - goto put_mbox;
>> + goto out;
>> }
>> ret = k3_r5_core_run(core);
>> if (ret)
>> - goto put_mbox;
>> + goto out;
>> }
>> return 0;
>> @@ -596,8 +592,7 @@ 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);
>> +out:
>> return ret;
>> }
>> @@ -658,8 +653,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> goto out;
>> }
>> - mbox_free_channel(kproc->mbox);
>> -
>> return 0;
>> unroll_core_halt:
>> @@ -674,42 +667,21 @@ 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 for
>> sanity sake.
>> */
>> -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.
>> */
>> -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; }
>
> Do we still need to disable the mbox channel somehow here to prevent
> receiving more messages from the detached core?
>
>> /*
>> * This function implements the .get_loaded_rsc_table() callback
>> and is used
>> @@ -1277,6 +1249,10 @@ static int k3_r5_cluster_rproc_init(struct
>> platform_device *pdev)
>> kproc->rproc = rproc;
>> core->rproc = rproc;
>> + ret = k3_r5_rproc_request_mbox(rproc);
>
> Now that we get the channel here in init you'll want to add a matching
> mbox_free_channel() call to k3_r5_cluster_rproc_exit().
>
> Andrew
Thanks for the review! I have sent out v2 addressing these comments:
https://lore.kernel.org/all/20240604051722.3608750-1-b-padhi@ti.com/
>
>> + if (ret)
>> + return ret;
>> +
>> ret = k3_r5_rproc_configure_mode(kproc);
>> if (ret < 0)
>> goto err_config;
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