[PATCH v4 2/2] remoteproc: stm32: add capability to detach

From: Arnaud Pouliquen
Date: Wed Mar 31 2021 - 03:36:38 EST


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@xxxxxxxxxxx>
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Tested-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
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