Commit 0fd17e59 authored by Oreoluwa Babatunde's avatar Oreoluwa Babatunde Committed by Marek Szyprowski
Browse files

of: reserved_mem: Allow reserved_mem framework detect "cma=" kernel param 



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.

Signed-off-by: default avatarOreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
Tested-by: default avatarJoy Zou <joy.zou@nxp.com>
Acked-by: default avatarRob Herring (Arm) <robh@kernel.org>
Fixes: 8a6e02d0 ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Fixes: 2c223f72 ("of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()")
Link: https://lore.kernel.org/r/20251210002027.1171519-1-oreoluwa.babatunde@oss.qualcomm.com


[mszyprow: rebased onto v6.19-rc1, added fixes tags, added a stub for
 cma_skip_dt_default_reserved_mem() if no CONFIG_DMA_CMA is set]
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent c6ccd098

drivers/of/of_reserved_mem.c

+17 −2
Original line number Diff line number Diff line
@@ -157,13 +157,19 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, 
	phys_addr_t base, size;

	int i, len;

	const __be32 *prop;

	bool nomap;

	bool nomap, default_cma;



	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);

	if (!prop)

		return -ENOENT;



	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);



	if (default_cma && cma_skip_dt_default_reserved_mem()) {

		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");

		return -EINVAL;

	}



	for (i = 0; i < len; i++) {

		u64 b, s;
@@ -248,10 +254,13 @@ void __init fdt_scan_reserved_mem_reg_nodes(void) 


	fdt_for_each_subnode(child, fdt, node) {

		const char *uname;

		bool default_cma = of_get_flat_dt_prop(child, "linux,cma-default", NULL);

		u64 b, s;



		if (!of_fdt_device_is_available(fdt, child))

			continue;

		if (default_cma && cma_skip_dt_default_reserved_mem())

			continue;



		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))

			continue;
@@ -389,7 +398,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam 
	phys_addr_t base = 0, align = 0, size;

	int i, len;

	const __be32 *prop;

	bool nomap;

	bool nomap, default_cma;

	int ret;



	prop = of_get_flat_dt_prop(node, "size", &len);
@@ -413,6 +422,12 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam 
	}



	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);



	if (default_cma && cma_skip_dt_default_reserved_mem()) {

		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");

		return -EINVAL;

	}



	/* Need adjust the alignment to satisfy the CMA requirement */

	if (IS_ENABLED(CONFIG_CMA)

include/linux/cma.h

+9 −0
Original line number Diff line number Diff line
@@ -57,6 +57,15 @@ extern bool cma_intersects(struct cma *cma, unsigned long start, unsigned long e 


extern void cma_reserve_pages_on_error(struct cma *cma);



#ifdef CONFIG_DMA_CMA

extern bool cma_skip_dt_default_reserved_mem(void);

#else

static inline bool cma_skip_dt_default_reserved_mem(void)

{

	return false;

}

#endif



#ifdef CONFIG_CMA

struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp);

bool cma_free_folio(struct cma *cma, const struct folio *folio);

kernel/dma/contiguous.c

+10 −6
Original line number Diff line number Diff line
@@ -91,6 +91,16 @@ static int __init early_cma(char *p) 
}

early_param("cma", early_cma);



/*

 * cma_skip_dt_default_reserved_mem - This is called from the

 * reserved_mem framework to detect if the default cma region is being

 * set by the "cma=" kernel parameter.

 */

bool __init cma_skip_dt_default_reserved_mem(void)

{

	return size_cmdline != -1;

}



#ifdef CONFIG_DMA_NUMA_CMA



static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
@@ -470,12 +480,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem) 
	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;