Messages in this thread |  | | Date | Tue, 9 Dec 2025 09:27:20 -0600 | | From | Rob Herring <> | | Subject | Re: [RFC PATCH] remoteproc: imx_dsp_rproc: Fix multiple start/stop commands |
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On Tue, Dec 09, 2025 at 04:04:25PM +0200, 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
So unlike Marek's case, the first time works. Can you confirm your region is fixed address?
> 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 <daniel.baluta@nxp.com> > --- > 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));
Best case this is reusing the same mapping and we just have unnecessary ioremap and iounmap calls and devm entries. Worst case, we get a new virtual mapping every time. IIRC, arm32 will reuse existing mapping, but arm64 does not. But that's 10+ years ago I looked into it.
Seems like devres is not the right lifetime. This should be just ioremap_wc() instead.
Rob
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