[PATCH v3 06/23] mailbox: Allow controller specific mapping using fwnode

Anup Patel
2025-05-11T13:40:55Z

Introduce optional fw_node() callback which allows a mailbox controller
driver to provide controller specific mapping using fwnode.

The Linux OF framework already implements fwnode operations for the
Linux DD framework so the fw_xlate() callback works fine with device
tree as well.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
drivers/mailbox/mailbox.c | 48 +++++++++++++++++-------------
include/linux/mailbox_controller.h | 3 ++
2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 0593b4d03685..a7ab1b4450a3 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -399,35 +399,50 @@ EXPORT_SYMBOL_GPL(mbox_bind_client);
*/
struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
{
+ struct fwnode_reference_args fwspec;
struct device *dev = cl->dev;
struct mbox_controller *mbox;
struct of_phandle_args spec;
struct mbox_chan *chan;
- int ret;
+ int i, ret;

- if (!dev || !dev->of_node) {
- pr_debug("%s: No owner device node\n", __func__);
+ if (!dev || !dev->fwnode) {
+ pr_debug("%s: No owner device\n", __func__);
+ pr_debug("%s: No owner fwnode\n", __func__);
return ERR_PTR(-ENODEV);
}

- ret = of_parse_phandle_with_args(dev->of_node, "mboxes", "#mbox-cells",
- index, &spec);
+ ret = fwnode_property_get_reference_args(dev->fwnode, "mboxes",
+ "#mbox-cells", 0, index, &fwspec);
if (ret) {
dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
return ERR_PTR(ret);
}

+ memset(&spec, 0, sizeof(spec));
+ if (dev->of_node) {
+ spec.np = to_of_node(fwspec.fwnode);
+ spec.args_count = fwspec.nargs;
+ for (i = 0; i < spec.args_count; i++)
+ spec.args[i] = fwspec.args[i];
+ }
+
mutex_lock(&con_mutex);

chan = ERR_PTR(-EPROBE_DEFER);
- list_for_each_entry(mbox, &mbox_cons, node)
- if (mbox->dev->of_node == spec.np) {
+ list_for_each_entry(mbox, &mbox_cons, node) {
+ if (mbox->fw_xlate && mbox->dev->fwnode == fwspec.fwnode) {
+ chan = mbox->fw_xlate(mbox, &fwspec);
+ if (!IS_ERR(chan))
+ break;
+ } else if (mbox->of_xlate && mbox->dev->of_node == spec.np) {
chan = mbox->of_xlate(mbox, &spec);
if (!IS_ERR(chan))
break;
}
+ }

- of_node_put(spec.np);
+ fwnode_handle_put(fwspec.fwnode);

if (IS_ERR(chan)) {
mutex_unlock(&con_mutex);
@@ -446,15 +461,8 @@ EXPORT_SYMBOL_GPL(mbox_request_channel);
struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
const char *name)
{
- struct device_node *np = cl->dev->of_node;
- int index;
-
- if (!np) {
- dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
- return ERR_PTR(-EINVAL);
- }
+ int index = device_property_match_string(cl->dev, "mbox-names", name);

- index = of_property_match_string(np, "mbox-names", name);
if (index < 0) {
dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
__func__, name);
@@ -492,8 +500,8 @@ void mbox_free_channel(struct mbox_chan *chan)
EXPORT_SYMBOL_GPL(mbox_free_channel);

static struct mbox_chan *
-of_mbox_index_xlate(struct mbox_controller *mbox,
- const struct of_phandle_args *sp)
+fw_mbox_index_xlate(struct mbox_controller *mbox,
+ const struct fwnode_reference_args *sp)
{
int ind = sp->args[0];

@@ -544,8 +552,8 @@ int mbox_controller_register(struct mbox_controller *mbox)
spin_lock_init(&chan->lock);
}

- if (!mbox->of_xlate)
- mbox->of_xlate = of_mbox_index_xlate;
+ if (!mbox->fw_xlate && !mbox->of_xlate)
+ mbox->fw_xlate = fw_mbox_index_xlate;

mutex_lock(&con_mutex);
list_add_tail(&mbox->node, &mbox_cons);
diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
index 5fb0b65f45a2..b91379922cb3 100644
--- a/include/linux/mailbox_controller.h
+++ b/include/linux/mailbox_controller.h
@@ -66,6 +66,7 @@ struct mbox_chan_ops {
* no interrupt rises. Ignored if 'txdone_irq' is set.
* @txpoll_period: If 'txdone_poll' is in effect, the API polls for
* last TX's status after these many millisecs
+ * @fw_xlate: Controller driver specific mapping of channel via fwnode
* @of_xlate: Controller driver specific mapping of channel via DT
* @poll_hrt: API private. hrtimer used to poll for TXDONE on all
* channels.
@@ -79,6 +80,8 @@ struct mbox_controller {
bool txdone_irq;
bool txdone_poll;
unsigned txpoll_period;
+ struct mbox_chan *(*fw_xlate)(struct mbox_controller *mbox,
+ const struct fwnode_reference_args *sp);
struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox,
const struct of_phandle_args *sp);
/* Internal to API */
--
2.43.0