Hi Peng,
On 2/4/26 01:57, Peng Fan wrote:
On Wed, Jan 28, 2026 at 11:31:17AM +0100, Arnaud Pouliquen wrote:
On systems with multiple remote processors, the remoteproc device
enumeration is not stable as it depends on the probe ordering.
As a result, the /sys/class/remoteproc/remoteproc<x> entries do not
always refer to the same remote processor instance, which complicates
userspace applications.
Inspired by the SPI implementation, this commit allows board-specific
numbering to be defined in device tree while still supporting dynamically
registered remote processors.
For instance, on STM32MP25 Soc this can be used by defining:
aliases {
rproc0 = &m33_rproc;
rproc1 = &m0_rproc;
};
When a "rproc<x>" DT alias is present, use it to assign a fixed
"/sys/class/remoteproc/remoteproc<x>" entry.
If no remoteproc alias is defined, keep the legacy index allocation.
If only some remoteproc instances have an alias, allocate dynamic
index starting after the highest alias index declared.
Signed-off-by: Arnaud Pouliquen <[email protected]>
Tested this patch on i.MX943-EVK(patches for this platform still in my local)
with dual CM7 and one CM33S:
/sys/devices/platform/imx943-cm70/remoteproc/remoteproc1/firmware
/sys/devices/platform/imx943-cm33s/remoteproc/remoteproc0/firmware
/sys/devices/platform/imx943-cm71/remoteproc/remoteproc2/firmware
Tested-by: Peng Fan <[email protected]>
One nit below:
---
V2:
- Introduces rproc_get_index based on Mathieu Poirier's suggestion.
An update compared to Mathieu's version is that the call to
ida_alloc_range is retained if an alias is found for the remote device,
to balance with ida_free().
- Rename DT alias stem from "remoteproc" to "rproc" to be consistent with
keytone driver.
---
drivers/remoteproc/remoteproc_core.c | 40 ++++++++++++++++++++++++++--
include/linux/remoteproc.h | 3 +++
2 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/drivers/remoteproc/remoteproc_core.c
b/drivers/remoteproc/remoteproc_core.c
index aada2780b343..38d6eb1c9483 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -2433,6 +2433,43 @@ static int rproc_alloc_ops(struct rproc *rproc, const
struct rproc_ops *ops)
return 0;
}
+/**
+ * rproc_get_index - assign a unique device index for a remote processor
+ * @dev: device associated with the remote processor
+ *
+ * Look for a static index coming from the "rproc" DT alias
+ * (e.g. "rproc0"). If none is found, start allocating
+ * dynamic IDs after the highest alias in use.
+ *
+ * Return: a non-negative index on success, or a negative error code on
failure.
+ */
+static int rproc_get_index(struct device *dev)
+{
+ int index;
+
+ /* No DT to deal with */
+ if (!dev->of_node)
+ goto legacy;
+
+ /* See if an alias has been assigned to this remoteproc */
+ index = of_alias_get_id(dev->of_node, RPROC_ALIAS);
+ if (index >= 0)
+ return ida_alloc_range(&rproc_dev_index, index, index,
+ GFP_KERNEL);
Nit: "return ida_alloc_range"
Thanks for the test and the review!
I will send a V3
Arnaud
Regards,
Peng
