[PATCH v3 0/2] remoteproc: stm32: add support of detaching a remote processor

[PATCH v3 0/2] remoteproc: stm32: add support of detaching a remote processor

[Arnaud Pouliquen]

Update from V2:
Fix comment and changelog in patch 2/2.

This patchset is the stm32mp1 platform implementation of the detach operation
added in series [1].

On detach, the stm32 rproc driver sends a mailbox signal to the remote 
processor to inform it that it will be detached. 

Applied and tested on Bjorn's "for_next" branch (2b81aa17008e)

[1] https://patchwork.kernel.org/project/linux-remoteproc/list/?series=447171

Arnaud Pouliquen (2):
  dt-bindings: remoteproc: stm32-rproc: add new mailbox channel for
    detach
  remoteproc: stm32: add capability to detach

 .../bindings/remoteproc/st,stm32-rproc.yaml   | 11 +++++-
 drivers/remoteproc/stm32_rproc.c              | 39 ++++++++++++++++++-
 2 files changed, 46 insertions(+), 4 deletions(-)

-- 
2.17.1

[PATCH v3 1/2] dt-bindings: remoteproc: stm32-rproc: add new mailbox channel for detach

[Arnaud Pouliquen]

Add the "detach" mailbox item, that allows to define a mailbox to
send a IPCC signal to the remote processor on remoteproc detach action.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
No Update from V2.

Update from V1:
Fix indentation error reported by 'make dt_binding_check'.

---
 .../bindings/remoteproc/st,stm32-rproc.yaml           | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
index a1171dfba024..64afdcfb613d 100644
--- a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
+++ b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
@@ -65,16 +65,23 @@ properties:
           Unidirectional channel:
             - from local to remote, where ACK from the remote means that it is
               ready for shutdown
+      - description: |
+          A channel (d) used by the local proc to notify the remote proc that it
+          has to stop interprocessor communnication.
+          Unidirectional channel:
+            - from local to remote, where ACK from the remote means that communnication
+              as been stopped on the remote side.
     minItems: 1
-    maxItems: 3
+    maxItems: 4
 
   mbox-names:
     items:
       - const: vq0
       - const: vq1
       - const: shutdown
+      - const: detach
     minItems: 1
-    maxItems: 3
+    maxItems: 4
 
   memory-region:
     description:
-- 
2.17.1

[PATCH v3 2/2] remoteproc: stm32: add capability to detach

[Arnaud Pouliquen]

A mechanism similar to the shutdown mailbox signal is implemented to
detach a remote processor.

Upon detachment, a signal is sent to the remote firmware, allowing it
to perform specific actions such as stopping rpmsg communication.

The Cortex-M hold boot is also disabled to allow the remote processor
to restart in case of crash.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/remoteproc/stm32_rproc.c | 39 ++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
index 3d45f51de4d0..7353f9e7e7af 100644
--- a/drivers/remoteproc/stm32_rproc.c
+++ b/drivers/remoteproc/stm32_rproc.c
@@ -28,7 +28,7 @@
 #define RELEASE_BOOT		1
 
 #define MBOX_NB_VQ		2
-#define MBOX_NB_MBX		3
+#define MBOX_NB_MBX		4
 
 #define STM32_SMC_RCC		0x82001000
 #define STM32_SMC_REG_WRITE	0x1
@@ -38,6 +38,7 @@
 #define STM32_MBX_VQ1		"vq1"
 #define STM32_MBX_VQ1_ID	1
 #define STM32_MBX_SHUTDOWN	"shutdown"
+#define STM32_MBX_DETACH	"detach"
 
 #define RSC_TBL_SIZE		1024
 
@@ -336,6 +337,15 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
 			.tx_done = NULL,
 			.tx_tout = 500, /* 500 ms time out */
 		},
+	},
+	{
+		.name = STM32_MBX_DETACH,
+		.vq_id = -1,
+		.client = {
+			.tx_block = true,
+			.tx_done = NULL,
+			.tx_tout = 200, /* 200 ms time out to detach should be fair enough */
+		},
 	}
 };
 
@@ -461,6 +471,25 @@ static int stm32_rproc_attach(struct rproc *rproc)
 	return stm32_rproc_set_hold_boot(rproc, true);
 }
 
+static int stm32_rproc_detach(struct rproc *rproc)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	int err, dummy_data, idx;
+
+	/* Inform the remote processor of the detach */
+	idx = stm32_rproc_mbox_idx(rproc, STM32_MBX_DETACH);
+	if (idx >= 0 && ddata->mb[idx].chan) {
+		/* A dummy data is sent to allow to block on transmit */
+		err = mbox_send_message(ddata->mb[idx].chan,
+					&dummy_data);
+		if (err < 0)
+			dev_warn(&rproc->dev, "warning: remote FW detach without ack\n");
+	}
+
+	/* Allow remote processor to auto-reboot */
+	return stm32_rproc_set_hold_boot(rproc, false);
+}
+
 static int stm32_rproc_stop(struct rproc *rproc)
 {
 	struct stm32_rproc *ddata = rproc->priv;
@@ -597,7 +626,12 @@ stm32_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
 	}
 
 done:
-	/* Assuming the resource table fits in 1kB is fair */
+	/*
+	 * Assuming the resource table fits in 1kB is fair.
+	 * Notice for the detach, that this 1 kB memory area has to be reserved in the coprocessor
+	 * firmware for the resource table. On detach, the remoteproc core re-initializes this
+	 * entire area by overwriting it with the initial values stored in rproc->clean_table.
+	 */
 	*table_sz = RSC_TBL_SIZE;
 	return (struct resource_table *)ddata->rsc_va;
 }
@@ -607,6 +641,7 @@ static const struct rproc_ops st_rproc_ops = {
 	.start		= stm32_rproc_start,
 	.stop		= stm32_rproc_stop,
 	.attach		= stm32_rproc_attach,
+	.detach		= stm32_rproc_detach,
 	.kick		= stm32_rproc_kick,
 	.load		= rproc_elf_load_segments,
 	.parse_fw	= stm32_rproc_parse_fw,
-- 
2.17.1

Re: [PATCH v3 1/2] dt-bindings: remoteproc: stm32-rproc: add new mailbox channel for detach

[Arnaud POULIQUEN]

Hello Rob,

Seems I made a mistake in my mailing list, you are not in...
Please could you review the bindings?
if it is easier for you i can resend the series.

Thanks,
Arnaud

On 3/26/21 10:42 AM, Arnaud Pouliquen wrote:
> Add the "detach" mailbox item, that allows to define a mailbox to
> send a IPCC signal to the remote processor on remoteproc detach action.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> No Update from V2.
> 
> Update from V1:
> Fix indentation error reported by 'make dt_binding_check'.
> 
> ---
>  .../bindings/remoteproc/st,stm32-rproc.yaml           | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
> index a1171dfba024..64afdcfb613d 100644
> --- a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
> @@ -65,16 +65,23 @@ properties:
>            Unidirectional channel:
>              - from local to remote, where ACK from the remote means that it is
>                ready for shutdown
> +      - description: |
> +          A channel (d) used by the local proc to notify the remote proc that it
> +          has to stop interprocessor communnication.
> +          Unidirectional channel:
> +            - from local to remote, where ACK from the remote means that communnication
> +              as been stopped on the remote side.
>      minItems: 1
> -    maxItems: 3
> +    maxItems: 4
>  
>    mbox-names:
>      items:
>        - const: vq0
>        - const: vq1
>        - const: shutdown
> +      - const: detach
>      minItems: 1
> -    maxItems: 3
> +    maxItems: 4
>  
>    memory-region:
>      description:
>