lkml.org 
[lkml]   [2020]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] dma-contiguous: CMA: give precedence to cmdline
From
Date
Hi Nicolas,

On 10/01/2020 17:19, Nicolas Saenz Julienne wrote:
> Although the device tree might contain a reserved-memory DT node
> dedicated as the default CMA pool, users might want to change CMA's
> parameters using the kernel command line for debugging purposes and
> whatnot. Honor this by bypassing the reserved memory CMA setup, which
> will ultimately end up freeing the memblock and allow the command line
> CMA configuration routine to run.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---
>
> NOTE: Tested this on arm and arm64 with the Raspberry Pi 4.
>
> kernel/dma/contiguous.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index daa4e6eefdde..8bc6f2d670f9 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -302,9 +302,16 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
> phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
> phys_addr_t mask = align - 1;
> unsigned long node = rmem->fdt_node;
> + bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
> struct cma *cma;
> int err;
>
> + if (size_cmdline != -1 && default_cma) {
> + pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
> + rmem->name);
> + return -EBUSY;
> + }
> +
> if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
> of_get_flat_dt_prop(node, "no-map", NULL))
> return -EINVAL;
> @@ -322,7 +329,7 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
> /* Architecture specific contiguous memory fixup. */
> dma_contiguous_early_fixup(rmem->base, rmem->size);
>
> - if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
> + if (default_cma)
> dma_contiguous_set_default(cma);
>
> rmem->ops = &rmem_cma_ops;
>

For what it's worth,

Reviewed-by: Phil Elwell <phil@raspberrypi.org>

Phil

\
 
 \ /
  Last update: 2020-01-10 18:50    [W:0.055 / U:25.648 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site