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 {
remoteproc0 = &m33_rproc;
remoteproc1 = &m0_rproc;
};
When a "remoteproc<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]>
---
Notes:
- This patch is submitted as an RFC in this first version.
The main reason is that support for the Cortex-M33 and Cortex-M0 on
the STM32MP25 SoC is not yet upstream. The primary objective is to
trigger discussion on the concept; if there is agreement, I can drop
the RFC tag in a next version.
- The keystone_remoteproc driver also uses DT aliases. As it uses the
"rproc" alias only to construct the firmware name, it should remain
compatible with this change.
---
drivers/remoteproc/remoteproc_core.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/drivers/remoteproc/remoteproc_core.c
b/drivers/remoteproc/remoteproc_core.c
index aada2780b343..8da6c410870a 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -2461,6 +2461,8 @@ struct rproc *rproc_alloc(struct device *dev, const char
*name,
const char *firmware, int len)
{
struct rproc *rproc;
+ int index = -ENODEV;
+ int first_dynamic;
if (!dev || !name || !ops)
return NULL;
@@ -2481,8 +2483,27 @@ struct rproc *rproc_alloc(struct device *dev, const char
*name,
rproc->dev.driver_data = rproc;
idr_init(&rproc->notifyids);
- /* Assign a unique device index and name */
- rproc->index = ida_alloc(&rproc_dev_index, GFP_KERNEL);
+ /*
+ * Assign a unique device index and name
+ * Look for a static index coming from the "remoteproc" DT alias
+ * (e.g. "remoteproc0"). If none is found, start allocating
+ * dynamic IDs after the highest alias in use.
+ */
+ if (dev->of_node)
+ index = of_alias_get_id(dev->of_node, "remoteproc");
+ if (index < 0) {
+ first_dynamic = of_alias_get_highest_id("remoteproc");
+ if (first_dynamic < 0)
+ first_dynamic = 0;
+ else
+ first_dynamic++;
+ rproc->index = ida_alloc_range(&rproc_dev_index, first_dynamic,
+ ~0, GFP_KERNEL);
+ } else {
+ rproc->index = ida_alloc_range(&rproc_dev_index, index,
+ index, GFP_KERNEL);
+ }
+
if (rproc->index < 0) {
dev_err(dev, "ida_alloc failed: %d\n", rproc->index);
goto put_device;
base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
--
2.43.0
