[PATCH v2 0/3] Defer TI's Remoteproc's Probe until Mailbox is Probed

[PATCH v2 0/3] Defer TI's Remoteproc's Probe until Mailbox is Probed

[Beleswar Padhi]

Hello All,

This series adds deferred probe functionality in the TI's Remoteproc
drivers. The remoteproc drivers are dependent on the omap-mailbox driver
for mbox functionalities. Sometimes, the remoteproc driver could be
probed before the mailbox driver leading to rproc boot failures. Thus,
defer the probe routine of remoteproc drivers until mailbox driver is
probed by checking the mbox_request_channel handle in probe. 

Also, use the acquired mbox handle in probe during rproc start/attach
routine instead of re-requesting. Do not free mbox handle during
stop/detach routine or error paths. This makes our k3_rproc_attach() &
k3_rproc_detach() functions NOP.

Also, use the devm_rproc_alloc() helper to automatically free created
rprocs incase of a probe defer.

v2: Changelog:
1) Added a check in k3_mbox_callback() to prevent forwarding messages to
a detached core.
2) Addressed Andrew's comments in v1 regarding some cleanup (Using
dev_err_probe, removing unused labels, adding matching mbox_free_channel
call during device removal).

Link to v1:
https://lore.kernel.org/all/20240530090737.655054-1-b-padhi@ti.com/

Beleswar Padhi (3):
  remoteproc: k3-r5: Use devm_rproc_alloc() helper
  remoteproc: k3-r5: Acquire mailbox handle during probe
  remoteproc: k3-dsp: Acquire mailbox handle during probe routine

 drivers/remoteproc/ti_k3_dsp_remoteproc.c | 76 ++++++++-------------
 drivers/remoteproc/ti_k3_r5_remoteproc.c  | 80 ++++++++---------------
 2 files changed, 54 insertions(+), 102 deletions(-)

-- 
2.34.1

[PATCH v2 1/3] remoteproc: k3-r5: Use devm_rproc_alloc() helper

[Beleswar Padhi]

Use the device lifecycle managed allocation function. This helps prevent
mistakes like freeing out of order in cleanup functions and forgetting
to free on error paths.

Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
---
 drivers/remoteproc/ti_k3_r5_remoteproc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 50e486bcfa103..26362a509ae3c 100644
--- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
@@ -1258,8 +1258,8 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
 			goto out;
 		}
 
-		rproc = rproc_alloc(cdev, dev_name(cdev), &k3_r5_rproc_ops,
-				    fw_name, sizeof(*kproc));
+		rproc = devm_rproc_alloc(cdev, dev_name(cdev), &k3_r5_rproc_ops,
+					 fw_name, sizeof(*kproc));
 		if (!rproc) {
 			ret = -ENOMEM;
 			goto out;
@@ -1351,7 +1351,6 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
 err_add:
 	k3_r5_reserved_mem_exit(kproc);
 err_config:
-	rproc_free(rproc);
 	core->rproc = NULL;
 out:
 	/* undo core0 upon any failures on core1 in split-mode */
@@ -1398,7 +1397,6 @@ static void k3_r5_cluster_rproc_exit(void *data)
 
 		k3_r5_reserved_mem_exit(kproc);
 
-		rproc_free(rproc);
 		core->rproc = NULL;
 	}
 }
-- 
2.34.1

[PATCH v2 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe

[Beleswar Padhi]

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 | 74 +++++++++---------------
 1 file changed, 26 insertions(+), 48 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 26362a509ae3c..7e02e3472ce25 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 to a detached core */
+	if (kproc->rproc->state == RPROC_DETACHED)
+		return;
+
 	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
 
 	switch (msg) {
@@ -399,12 +403,9 @@ 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 +553,6 @@ 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 +561,7 @@ 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 +577,12 @@ 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 +592,6 @@ 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 +652,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
 			goto out;
 	}
 
-	mbox_free_channel(kproc->mbox);
-
 	return 0;
 
 unroll_core_halt:
@@ -674,42 +666,22 @@ 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.
  */
-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; }
 
 /*
  * 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);
+		if (ret)
+			return ret;
+
 		ret = k3_r5_rproc_configure_mode(kproc);
 		if (ret < 0)
 			goto err_config;
@@ -1393,6 +1369,8 @@ 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

Re: [PATCH v2 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe

[Andrew Davis]

On 6/4/24 12:17 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@ti.com>
> ---
>   drivers/remoteproc/ti_k3_r5_remoteproc.c | 74 +++++++++---------------
>   1 file changed, 26 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 26362a509ae3c..7e02e3472ce25 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 to a detached core */

s/to/from

This is the receive side from the core.

> +	if (kproc->rproc->state == RPROC_DETACHED)
> +		return;
> +

Do we need a similar check when sending messages to the core in
k3_r5_rproc_kick()? No one should be sending anything as they
all should have detached at this point, but something to double
check on.

>   	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>   
>   	switch (msg) {
> @@ -399,12 +403,9 @@ 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");

This is good cleanup, but maybe something for its own patch.

>   
>   	/*
>   	 * Ping the remote processor, this is only for sanity-sake for now;
> @@ -552,10 +553,6 @@ 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 +561,7 @@ 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 +577,12 @@ 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 +592,6 @@ 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 +652,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>   			goto out;
>   	}
>   
> -	mbox_free_channel(kproc->mbox);
> -
>   	return 0;
>   
>   unroll_core_halt:
> @@ -674,42 +666,22 @@ 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.
>    */
> -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; }

I wonder if rproc_validate() should be updated to allow not
having an attach/detach for cases like this. Then we could drop
this function completely.

Andrew

>   
>   /*
>    * 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; }
>   
>   /*
>    * 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);
> +		if (ret)
> +			return ret;
> +
>   		ret = k3_r5_rproc_configure_mode(kproc);
>   		if (ret < 0)
>   			goto err_config;
> @@ -1393,6 +1369,8 @@ static void k3_r5_cluster_rproc_exit(void *data)
>   			}
>   		}
>   
> +		mbox_free_channel(kproc->mbox);
> +
>   		rproc_del(rproc);
>   
>   		k3_r5_reserved_mem_exit(kproc);

Re: [PATCH v2 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe

[Beleswar Prasad Padhi]

Hi Andrew,

On 04/06/24 22:40, Andrew Davis wrote:
> On 6/4/24 12:17 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@ti.com>
>> ---
>>   drivers/remoteproc/ti_k3_r5_remoteproc.c | 74 +++++++++---------------
>>   1 file changed, 26 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c 
>> b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index 26362a509ae3c..7e02e3472ce25 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 to a detached core */
>
> s/to/from
>
> This is the receive side from the core.
>
>> +    if (kproc->rproc->state == RPROC_DETACHED)
>> +        return;
>> +
>
> Do we need a similar check when sending messages to the core in
> k3_r5_rproc_kick()? No one should be sending anything as they
> all should have detached at this point, but something to double
> check on.
>
>>       dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>>         switch (msg) {
>> @@ -399,12 +403,9 @@ 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");
>
> This is good cleanup, but maybe something for its own patch.
>
>>         /*
>>        * Ping the remote processor, this is only for sanity-sake for 
>> now;
>> @@ -552,10 +553,6 @@ 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 +561,7 @@ 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 +577,12 @@ 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 +592,6 @@ 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 +652,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>>               goto out;
>>       }
>>   -    mbox_free_channel(kproc->mbox);
>> -
>>       return 0;
>>     unroll_core_halt:
>> @@ -674,42 +666,22 @@ 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.
>>    */
>> -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; }
>
> I wonder if rproc_validate() should be updated to allow not
> having an attach/detach for cases like this. Then we could drop
> this function completely.


Not sure if we can update rproc_validate() for this usecase. Ideally, it 
checks for an attach function if the core is detached, which should be 
correct, right?
Will address all other comments in the next revision!

>
> Andrew
>
>>     /*
>>    * 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; }
>>     /*
>>    * 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);
>> +        if (ret)
>> +            return ret;
>> +
>>           ret = k3_r5_rproc_configure_mode(kproc);
>>           if (ret < 0)
>>               goto err_config;
>> @@ -1393,6 +1369,8 @@ static void k3_r5_cluster_rproc_exit(void *data)
>>               }
>>           }
>>   +        mbox_free_channel(kproc->mbox);
>> +
>>           rproc_del(rproc);
>>             k3_r5_reserved_mem_exit(kproc);

Re: [PATCH v2 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe

[Beleswar Prasad Padhi]

Hi Andrew,

On 04/06/24 22:40, Andrew Davis wrote:
> On 6/4/24 12:17 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@ti.com>
>> ---
>>   drivers/remoteproc/ti_k3_r5_remoteproc.c | 74 +++++++++---------------
>>   1 file changed, 26 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c 
>> b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index 26362a509ae3c..7e02e3472ce25 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 to a detached core */
>
> s/to/from
>
> This is the receive side from the core.
>
>> +    if (kproc->rproc->state == RPROC_DETACHED)
>> +        return;
>> +
>
> Do we need a similar check when sending messages to the core in
> k3_r5_rproc_kick()? No one should be sending anything as they
> all should have detached at this point, but something to double
> check on.
Will add this in the next revision.
>
>>       dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>>         switch (msg) {
>> @@ -399,12 +403,9 @@ 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");
>
> This is good cleanup, but maybe something for its own patch.
I think this cleanup is dependent to this patch itself. The current 
patch moves the mbox_handle_request to probe routine. And the cleanup 
returns an -EDEFER_PROBE ERR code. So, this cleanup is only valid if the 
current patch is applied. Else, if this err code is returned at any 
point after creation of child devices, it could lead to a infinite 
loop[0]. Please correct me if I am wrong..?

[0]: 
https://www.kernel.org/doc/html/v6.5-rc3/driver-api/driver-model/driver.html#callbacks
>
>>         /*
>>        * Ping the remote processor, this is only for sanity-sake for 
>> now;
>> @@ -552,10 +553,6 @@ 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 +561,7 @@ 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 +577,12 @@ 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 +592,6 @@ 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 +652,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>>               goto out;
>>       }
>>   -    mbox_free_channel(kproc->mbox);
>> -
>>       return 0;
>>     unroll_core_halt:
>> @@ -674,42 +666,22 @@ 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.
>>    */
>> -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; }
>
> I wonder if rproc_validate() should be updated to allow not
> having an attach/detach for cases like this. Then we could drop
> this function completely.
>
> Andrew
>
>>     /*
>>    * 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; }
>>     /*
>>    * 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);
>> +        if (ret)
>> +            return ret;
>> +
>>           ret = k3_r5_rproc_configure_mode(kproc);
>>           if (ret < 0)
>>               goto err_config;
>> @@ -1393,6 +1369,8 @@ static void k3_r5_cluster_rproc_exit(void *data)
>>               }
>>           }
>>   +        mbox_free_channel(kproc->mbox);
>> +
>>           rproc_del(rproc);
>>             k3_r5_reserved_mem_exit(kproc);

Re: [PATCH v2 2/3] remoteproc: k3-r5: Acquire mailbox handle during probe

[Andrew Davis]

On 6/21/24 6:14 AM, Beleswar Prasad Padhi wrote:
> Hi Andrew,
> 
> On 04/06/24 22:40, Andrew Davis wrote:
>> On 6/4/24 12:17 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@ti.com>
>>> ---
>>>   drivers/remoteproc/ti_k3_r5_remoteproc.c | 74 +++++++++---------------
>>>   1 file changed, 26 insertions(+), 48 deletions(-)
>>>
>>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>>> index 26362a509ae3c..7e02e3472ce25 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 to a detached core */
>>
>> s/to/from
>>
>> This is the receive side from the core.
>>
>>> +    if (kproc->rproc->state == RPROC_DETACHED)
>>> +        return;
>>> +
>>
>> Do we need a similar check when sending messages to the core in
>> k3_r5_rproc_kick()? No one should be sending anything as they
>> all should have detached at this point, but something to double
>> check on.
> Will add this in the next revision.
>>
>>>       dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>>>         switch (msg) {
>>> @@ -399,12 +403,9 @@ 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");
>>
>> This is good cleanup, but maybe something for its own patch.
> I think this cleanup is dependent to this patch itself. The current patch moves the mbox_handle_request to probe routine. And the cleanup returns an -EDEFER_PROBE ERR code. So, this cleanup is only valid if the current patch is applied. Else, if this err code is returned at any point after creation of child devices, it could lead to a infinite loop[0]. Please correct me if I am wrong..?
> 

Okay I see what you are saying, k3_r5_rproc_request_mbox() is now called from
probe() and not start() as it was before. Then you are correct.

Andrew

> [0]: https://www.kernel.org/doc/html/v6.5-rc3/driver-api/driver-model/driver.html#callbacks
>>
>>>         /*
>>>        * Ping the remote processor, this is only for sanity-sake for now;
>>> @@ -552,10 +553,6 @@ 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 +561,7 @@ 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 +577,12 @@ 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 +592,6 @@ 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 +652,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>>>               goto out;
>>>       }
>>>   -    mbox_free_channel(kproc->mbox);
>>> -
>>>       return 0;
>>>     unroll_core_halt:
>>> @@ -674,42 +666,22 @@ 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.
>>>    */
>>> -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; }
>>
>> I wonder if rproc_validate() should be updated to allow not
>> having an attach/detach for cases like this. Then we could drop
>> this function completely.
>>
>> Andrew
>>
>>>     /*
>>>    * 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; }
>>>     /*
>>>    * 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);
>>> +        if (ret)
>>> +            return ret;
>>> +
>>>           ret = k3_r5_rproc_configure_mode(kproc);
>>>           if (ret < 0)
>>>               goto err_config;
>>> @@ -1393,6 +1369,8 @@ static void k3_r5_cluster_rproc_exit(void *data)
>>>               }
>>>           }
>>>   +        mbox_free_channel(kproc->mbox);
>>> +
>>>           rproc_del(rproc);
>>>             k3_r5_reserved_mem_exit(kproc);

[PATCH v2 3/3] remoteproc: k3-dsp: Acquire mailbox handle during probe routine

[Beleswar Padhi]

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_dsp_remoteproc.c | 76 ++++++++---------------
 1 file changed, 26 insertions(+), 50 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_dsp_remoteproc.c b/drivers/remoteproc/ti_k3_dsp_remoteproc.c
index 3555b535b1683..edaa5e91aebe9 100644
--- a/drivers/remoteproc/ti_k3_dsp_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_dsp_remoteproc.c
@@ -115,6 +115,10 @@ static void k3_dsp_rproc_mbox_callback(struct mbox_client *client, void *data)
 	const char *name = kproc->rproc->name;
 	u32 msg = omap_mbox_message(data);
 
+	/* Do not forward messages to a detached core */
+	if (kproc->rproc->state == RPROC_DETACHED)
+		return;
+
 	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
 
 	switch (msg) {
@@ -230,12 +234,9 @@ static int k3_dsp_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;
@@ -315,32 +316,23 @@ static int k3_dsp_rproc_start(struct rproc *rproc)
 	u32 boot_addr;
 	int ret;
 
-	ret = k3_dsp_rproc_request_mbox(rproc);
-	if (ret)
-		return ret;
-
 	boot_addr = rproc->bootaddr;
 	if (boot_addr & (kproc->data->boot_align_addr - 1)) {
 		dev_err(dev, "invalid boot address 0x%x, must be aligned on a 0x%x boundary\n",
 			boot_addr, kproc->data->boot_align_addr);
-		ret = -EINVAL;
-		goto put_mbox;
+		return -EINVAL;
 	}
 
 	dev_err(dev, "booting DSP core using boot addr = 0x%x\n", boot_addr);
 	ret = ti_sci_proc_set_config(kproc->tsp, boot_addr, 0, 0);
 	if (ret)
-		goto put_mbox;
+		return ret;
 
 	ret = k3_dsp_rproc_release(kproc);
 	if (ret)
-		goto put_mbox;
+		return ret;
 
 	return 0;
-
-put_mbox:
-	mbox_free_channel(kproc->mbox);
-	return ret;
 }
 
 /*
@@ -353,8 +345,6 @@ static int k3_dsp_rproc_stop(struct rproc *rproc)
 {
 	struct k3_dsp_rproc *kproc = rproc->priv;
 
-	mbox_free_channel(kproc->mbox);
-
 	k3_dsp_rproc_reset(kproc);
 
 	return 0;
@@ -363,42 +353,22 @@ static int k3_dsp_rproc_stop(struct rproc *rproc)
 /*
  * Attach to a running DSP remote processor (IPC-only mode)
  *
- * This rproc 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 DSP core. This callback is invoked only in IPC-only
- * mode.
+ * This rproc 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 DSP core. This callback
+ * is invoked only in IPC-only mode and exists because rproc_validate() checks
+ * for its existence.
  */
-static int k3_dsp_rproc_attach(struct rproc *rproc)
-{
-	struct k3_dsp_rproc *kproc = rproc->priv;
-	struct device *dev = kproc->dev;
-	int ret;
-
-	ret = k3_dsp_rproc_request_mbox(rproc);
-	if (ret)
-		return ret;
-
-	dev_info(dev, "DSP initialized in IPC-only mode\n");
-	return 0;
-}
+static int k3_dsp_rproc_attach(struct rproc *rproc) { return 0; }
 
 /*
  * Detach from a running DSP remote processor (IPC-only mode)
  *
- * This rproc detach callback performs the opposite operation to attach callback
- * and only needs to release the mailbox, the DSP core is not stopped and will
- * be left to continue to run its booted firmware. This callback is invoked only
- * in IPC-only mode.
+ * This rproc detach callback is a NOP. The DSP core is not stopped and will be
+ * left to continue to run its booted firmware. This callback is invoked only in
+ * IPC-only mode and exists for sanity sake.
  */
-static int k3_dsp_rproc_detach(struct rproc *rproc)
-{
-	struct k3_dsp_rproc *kproc = rproc->priv;
-	struct device *dev = kproc->dev;
-
-	mbox_free_channel(kproc->mbox);
-	dev_info(dev, "DSP deinitialized in IPC-only mode\n");
-	return 0;
-}
+static int k3_dsp_rproc_detach(struct rproc *rproc) { return 0; }
 
 /*
  * This function implements the .get_loaded_rsc_table() callback and is used
@@ -697,6 +667,10 @@ static int k3_dsp_rproc_probe(struct platform_device *pdev)
 	kproc->dev = dev;
 	kproc->data = data;
 
+	ret = k3_dsp_rproc_request_mbox(rproc);
+	if (ret)
+		return ret;
+
 	kproc->ti_sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
 	if (IS_ERR(kproc->ti_sci))
 		return dev_err_probe(dev, PTR_ERR(kproc->ti_sci),
@@ -789,6 +763,8 @@ static void k3_dsp_rproc_remove(struct platform_device *pdev)
 		if (ret)
 			dev_err(dev, "failed to detach proc (%pe)\n", ERR_PTR(ret));
 	}
+
+	mbox_free_channel(kproc->mbox);
 }
 
 static const struct k3_dsp_mem_data c66_mems[] = {
-- 
2.34.1