On 12/9/2025 4:04 PM, Daniel Baluta wrote:
After commit 67a7bc7f0358 ("remoteproc: Use of reserved_mem_region_*
functions for "memory-region"") following commands with
imx-dsp-rproc started to fail:
$ echo zephyr.elf > /sys/class/remoteproc/remoteproc0/firmware
$ echo start > /sys/class/remoteproc/remoteproc0/state
$ echo stop > /sys/class/remoteproc/remoteproc0/state
$ echo start > /sys/class/remoteproc/remoteproc0/state #! This fails
-sh: echo: write error: Device or resource busy
This happens because aforementioned commit replaced devm_ioremap_wc with
devm_ioremap_resource_wc which will "reserve" the memory region with the
first start and then will fail at the second start if the memory
region is already reserved.
So prefer using devm_ioremap_wc as there is no easy way to undo
devm_iormep_resource_wc manually.
Fixes: 67a7bc7f0358 ("remoteproc: Use of_reserved_mem_region_* functions for
"memory-region"")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/remoteproc/imx_dsp_rproc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/remoteproc/imx_dsp_rproc.c
b/drivers/remoteproc/imx_dsp_rproc.c
index 5130a35214c9..79d5c15319f3 100644
--- a/drivers/remoteproc/imx_dsp_rproc.c
+++ b/drivers/remoteproc/imx_dsp_rproc.c
@@ -709,10 +709,10 @@ static int imx_dsp_rproc_add_carveout(struct
imx_dsp_rproc *priv)
if (imx_dsp_rproc_sys_to_da(priv, res.start, resource_size(&res),
&da))
return -EINVAL;
- cpu_addr = devm_ioremap_resource_wc(dev, &res);
- if (IS_ERR(cpu_addr)) {
+ cpu_addr = devm_ioremap_wc(dev, res.start, resource_size(&res));
While this patch technically "works", it’s more of a workaround because:
- it removes important resource protection;
- it doesn’t address the root cause.
The real issue is likely that:
- resources should be released on stop but aren’t;
- or the mapping should happen once during probe, not on every start.
Better alterntives:
1. move the devm_ioremap_resource_wc() to probe() and keep it mapped for
the device lifetime. This is the typical pattern for remoteproc drivers.
2. use non-devm versions in start/stop callbacks:
/* In start callback */
cpu_addr = ioremap_wc(res.start, resource_size(&res));
/* In stop callback */
iounmap(cpu_addr);
My vote goes for option 1.
+ if (!cpu_addr) {
dev_err(dev, "failed to map memory %pR\n", &res);
- return PTR_ERR(cpu_addr);
+ return -ENOMEM;
}
/* Register memory region */
