Messages in this thread |  | | Subject | Re: [PATCH] dma-contiguous: CMA: give precedence to cmdline | From | Phil Elwell <> | Date | Fri, 10 Jan 2020 17:36:30 +0000 |
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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
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