Re: [PATCH] of: reserved_mem: Allow reserved_mem framework detect "cma=" kernel param

[Joy Zou]

On Tue, Dec 09, 2025 at 04:20:27PM -0800, Oreoluwa Babatunde wrote:
> When initializing the default cma region, the "cma=" kernel parameter
> takes priority over a DT defined linux,cma-default region. Hence, give
> the reserved_mem framework the ability to detect this so that the DT
> defined cma region can skip initialization accordingly.
> 
Hi Oreoluwa,
  Have tested i.MX6ULL 9x9, i.MX6ULL 14x14, i.MX6SLL EVK and i.MX7D
SABRE-SD boards.
  Before this patch, i.MX6ULL 9x9 failed to allocate CMA memory when using
"cma=" kernel parameter. After applying the patch, CMA allocation works
correctly on all tested platforms.

Tested-by: Joy Zou <joy.zou@xxxxxxx>

BR
Joy Zou
> Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@xxxxxxxxxxxxxxxx>
> ---
>  drivers/of/of_reserved_mem.c | 19 +++++++++++++++++--
>  include/linux/cma.h          |  1 +
>  kernel/dma/contiguous.c      | 16 ++++++++++------
>  3 files changed, 28 insertions(+), 8 deletions(-)
> 2.34.1