[PATCH RFC v2 09/11] remoteproc: imx_rproc: always use non-blocking mailboxes
From: Francesco Valla
Date: Sun Nov 01 2026 - 18:28:08 EST
Blocking mailboxes may lead to sleep during the kick operation, which
conflicts with some virtio devices (e.g.: virtio-can) that kicks their
virtqueues with spinlock(s) held.
Align to the behavior of all the other remoteproc drivers that use a
mailbox to perform the kick (i.e.: omap, st, stm32, ti_k3_*, xlnx_r5)
and move to a non-blocking mailbox here as well. Messages need to be
allocated and freed on-the-fly, since they might be sent after
imx_rproc_kick() returns and cannot thus live on the stack.
As a side effect of this modification, the close-reopen action on
the mailboxes during restart and shutdown can be removed, since it was
performed only to have a non-blocking mailbox.
Signed-off-by: Francesco Valla <francesco@xxxxxxxx>
---
drivers/remoteproc/imx_rproc.c | 76 ++++++++++++++++--------------------------
drivers/remoteproc/imx_rproc.h | 1 -
2 files changed, 28 insertions(+), 49 deletions(-)
diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 581bb07f5893..a792b9ca5edd 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -96,7 +96,7 @@ struct imx_rproc_mem {
/* Linux has permission to handle the Logical Machine of remote cores */
#define IMX_RPROC_FLAGS_SM_LMM_CTRL BIT(0)
-static int imx_rproc_xtr_mbox_init(struct rproc *rproc, bool tx_block);
+static int imx_rproc_xtr_mbox_init(struct rproc *rproc);
static void imx_rproc_free_mbox(void *data);
/* Forward declarations for platform operations */
@@ -441,7 +441,7 @@ static int imx_rproc_start(struct rproc *rproc)
struct device *dev = priv->dev;
int ret;
- ret = imx_rproc_xtr_mbox_init(rproc, true);
+ ret = imx_rproc_xtr_mbox_init(rproc);
if (ret)
return ret;
@@ -696,28 +696,45 @@ static void imx_rproc_kick(struct rproc *rproc, int vqid)
{
struct imx_rproc *priv = rproc->priv;
int err;
- __u32 mmsg;
+ __u32 *mmsg;
if (!priv->tx_ch) {
dev_err(priv->dev, "No initialized mbox tx channel\n");
return;
}
+ mmsg = kzalloc_obj(*mmsg, GFP_ATOMIC);
+ if (!mmsg) {
+ dev_err_ratelimited(priv->dev, "cannot allocate kick message\n");
+ return;
+ }
+
/*
* Send the index of the triggered virtqueue as the mu payload.
* Let remote processor know which virtqueue is used.
*/
- mmsg = vqid << 16;
+ *mmsg = vqid << 16;
- err = mbox_send_message(priv->tx_ch, (void *)&mmsg);
- if (err < 0)
+ err = mbox_send_message(priv->tx_ch, (void *)mmsg);
+ if (err < 0) {
dev_err(priv->dev, "%s: failed (%d, err:%d)\n",
__func__, vqid, err);
+ kfree(mmsg);
+ }
+}
+
+static void imx_rproc_kick_tx_done(struct mbox_client *cl, void *mmsg, int r)
+{
+ if (r != 0)
+ dev_err_ratelimited(cl->dev, "failed to kick vqid %u: %d\n",
+ *(__u32 *)mmsg >> 16, r);
+
+ kfree(mmsg);
}
static int imx_rproc_attach(struct rproc *rproc)
{
- return imx_rproc_xtr_mbox_init(rproc, true);
+ return imx_rproc_xtr_mbox_init(rproc);
}
static int imx_rproc_scu_api_detach(struct rproc *rproc)
@@ -872,7 +889,7 @@ static void imx_rproc_rx_callback(struct mbox_client *cl, void *msg)
idr_for_each(&rproc->notifyids, imx_rproc_notified_idr_cb, rproc);
}
-static int imx_rproc_xtr_mbox_init(struct rproc *rproc, bool tx_block)
+static int imx_rproc_xtr_mbox_init(struct rproc *rproc)
{
struct imx_rproc *priv = rproc->priv;
struct device *dev = priv->dev;
@@ -895,10 +912,10 @@ static int imx_rproc_xtr_mbox_init(struct rproc *rproc, bool tx_block)
cl = &priv->cl;
cl->dev = dev;
- cl->tx_block = tx_block;
- cl->tx_tout = 100;
+ cl->tx_block = false;
cl->knows_txdone = false;
cl->rx_callback = imx_rproc_rx_callback;
+ cl->tx_done = imx_rproc_kick_tx_done;
priv->tx_ch = mbox_request_channel_byname(cl, "tx");
if (IS_ERR(priv->tx_ch))
@@ -1218,22 +1235,6 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
return priv->ops->detect_mode(priv->rproc);
}
-static int imx_rproc_sys_off_handler(struct sys_off_data *data)
-{
- struct rproc *rproc = data->cb_data;
- int ret;
-
- imx_rproc_free_mbox(rproc);
-
- ret = imx_rproc_xtr_mbox_init(rproc, false);
- if (ret) {
- dev_err(&rproc->dev, "Failed to request non-blocking mbox\n");
- return NOTIFY_BAD;
- }
-
- return NOTIFY_DONE;
-}
-
static int imx_rproc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -1262,7 +1263,7 @@ static int imx_rproc_probe(struct platform_device *pdev)
dev_set_drvdata(dev, rproc);
- ret = imx_rproc_xtr_mbox_init(rproc, true);
+ ret = imx_rproc_xtr_mbox_init(rproc);
if (ret)
return ret;
@@ -1292,26 +1293,6 @@ static int imx_rproc_probe(struct platform_device *pdev)
if (rproc->state != RPROC_DETACHED)
rproc->auto_boot = of_property_read_bool(np, "fsl,auto-boot");
- if (dcfg->flags & IMX_RPROC_NEED_SYSTEM_OFF) {
- /*
- * setup mailbox to non-blocking mode in
- * [SYS_OFF_MODE_POWER_OFF_PREPARE, SYS_OFF_MODE_RESTART_PREPARE]
- * phase before invoking [SYS_OFF_MODE_POWER_OFF, SYS_OFF_MODE_RESTART]
- * atomic chain, see kernel/reboot.c.
- */
- ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF_PREPARE,
- SYS_OFF_PRIO_DEFAULT,
- imx_rproc_sys_off_handler, rproc);
- if (ret)
- return dev_err_probe(dev, ret, "register power off handler failure\n");
-
- ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART_PREPARE,
- SYS_OFF_PRIO_DEFAULT,
- imx_rproc_sys_off_handler, rproc);
- if (ret)
- return dev_err_probe(dev, ret, "register restart handler failure\n");
- }
-
pm_runtime_enable(dev);
ret = pm_runtime_resume_and_get(dev);
if (ret)
@@ -1424,7 +1405,6 @@ static const struct imx_rproc_dcfg imx_rproc_cfg_imx8ulp = {
static const struct imx_rproc_dcfg imx_rproc_cfg_imx7ulp = {
.att = imx_rproc_att_imx7ulp,
.att_size = ARRAY_SIZE(imx_rproc_att_imx7ulp),
- .flags = IMX_RPROC_NEED_SYSTEM_OFF,
};
static const struct imx_rproc_dcfg imx_rproc_cfg_imx7d = {
diff --git a/drivers/remoteproc/imx_rproc.h b/drivers/remoteproc/imx_rproc.h
index 0d7d48352a10..9a1400d0d081 100644
--- a/drivers/remoteproc/imx_rproc.h
+++ b/drivers/remoteproc/imx_rproc.h
@@ -16,7 +16,6 @@ struct imx_rproc_att {
};
/* dcfg flags */
-#define IMX_RPROC_NEED_SYSTEM_OFF BIT(0)
#define IMX_RPROC_NEED_CLKS BIT(1)
struct imx_rproc_plat_ops {
--
2.56.0