Commit e8d9d1f5 authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Grant Likely
Browse files

drivers: of: add initialization code for static reserved memory 



This patch adds support for static (defined by 'reg' property) reserved
memory regions declared in device tree.

Memory blocks can be reliably reserved only during early boot. This must
happen before the whole memory management subsystem is initialized,
because we need to ensure that the given contiguous blocks are not yet
allocated by kernel. Also it must happen before kernel mappings for the
whole low memory are created, to ensure that there will be no mappings
(for reserved blocks). Typically, all this happens before device tree
structures are unflattened, so we need to get reserved memory layout
directly from fdt.

Based on previous code provided by Josh Cartwright <joshc@codeaurora.org>

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
parent f08ad1de

drivers/of/fdt.c

+131 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_fdt.h>

#include <linux/sizes.h>

#include <linux/string.h>

#include <linux/errno.h>

#include <linux/slab.h>
@@ -439,6 +440,118 @@ struct boot_param_header *initial_boot_params; 


#ifdef CONFIG_OF_EARLY_FLATTREE



/**

 * res_mem_reserve_reg() - reserve all memory described in 'reg' property

 */

static int __init __reserved_mem_reserve_reg(unsigned long node,

					     const char *uname)

{

	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);

	phys_addr_t base, size;

	unsigned long len;

	__be32 *prop;

	int nomap;



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

	if (!prop)

		return -ENOENT;



	if (len && len % t_len != 0) {

		pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",

		       uname);

		return -EINVAL;

	}



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



	while (len >= t_len) {

		base = dt_mem_next_cell(dt_root_addr_cells, &prop);

		size = dt_mem_next_cell(dt_root_size_cells, &prop);



		if (base && size &&

		    early_init_dt_reserve_memory_arch(base, size, nomap) == 0)

			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n",

				uname, &base, (unsigned long)size / SZ_1M);

		else

			pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %ld MiB\n",

				uname, &base, (unsigned long)size / SZ_1M);



		len -= t_len;

	}

	return 0;

}



/**

 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided

 * in /reserved-memory matches the values supported by the current implementation,

 * also check if ranges property has been provided

 */

static int __reserved_mem_check_root(unsigned long node)

{

	__be32 *prop;



	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);

	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)

		return -EINVAL;



	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);

	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)

		return -EINVAL;



	prop = of_get_flat_dt_prop(node, "ranges", NULL);

	if (!prop)

		return -EINVAL;

	return 0;

}



/**

 * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory

 */

static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,

					  int depth, void *data)

{

	static int found;

	const char *status;



	if (!found && depth == 1 && strcmp(uname, "reserved-memory") == 0) {

		if (__reserved_mem_check_root(node) != 0) {

			pr_err("Reserved memory: unsupported node format, ignoring\n");

			/* break scan */

			return 1;

		}

		found = 1;

		/* scan next node */

		return 0;

	} else if (!found) {

		/* scan next node */

		return 0;

	} else if (found && depth < 2) {

		/* scanning of /reserved-memory has been finished */

		return 1;

	}



	status = of_get_flat_dt_prop(node, "status", NULL);

	if (status && strcmp(status, "okay") != 0 && strcmp(status, "ok") != 0)

		return 0;



	__reserved_mem_reserve_reg(node, uname);



	/* scan next node */

	return 0;

}



/**

 * early_init_fdt_scan_reserved_mem() - create reserved memory regions

 *

 * This function grabs memory from early allocator for device exclusive use

 * defined in device tree structures. It should be called by arch specific code

 * once the early allocator (i.e. memblock) has been fully activated.

 */

void __init early_init_fdt_scan_reserved_mem(void)

{

	of_scan_flat_dt(__fdt_scan_reserved_mem, NULL);

}



/**

 * of_scan_flat_dt - scan flattened tree blob and call callback on each.

 * @it: callback function
@@ -856,6 +969,16 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size) 
	memblock_add(base, size);

}



int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,

					phys_addr_t size, bool nomap)

{

	if (memblock_is_region_reserved(base, size))

		return -EBUSY;

	if (nomap)

		return memblock_remove(base, size);

	return memblock_reserve(base, size);

}



/*

 * called from unflatten_device_tree() to bootstrap devicetree itself

 * Architectures can override this definition if memblock isn't used
@@ -864,6 +987,14 @@ void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align) 
{

	return __va(memblock_alloc(size, align));

}

#else

int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,

					phys_addr_t size, bool nomap)

{

	pr_err("Reserved memory not supported, ignoring range 0x%llx - 0x%llx%s\n",

		  base, size, nomap ? " (nomap)" : "");

	return -ENOSYS;

}

#endif



bool __init early_init_dt_scan(void *params)

include/linux/of_fdt.h

+4 −0
Original line number Diff line number Diff line
@@ -98,7 +98,10 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname, 
				     int depth, void *data);

extern int early_init_dt_scan_memory(unsigned long node, const char *uname,

				     int depth, void *data);

extern void early_init_fdt_scan_reserved_mem(void);

extern void early_init_dt_add_memory_arch(u64 base, u64 size);

extern int early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size,

					     bool no_map);

extern void * early_init_dt_alloc_memory_arch(u64 size, u64 align);

extern u64 dt_mem_next_cell(int s, __be32 **cellp);
@@ -118,6 +121,7 @@ extern void unflatten_and_copy_device_tree(void); 
extern void early_init_devtree(void *);

extern void early_get_first_memblock_info(void *, phys_addr_t *);

#else /* CONFIG_OF_FLATTREE */

static inline void early_init_fdt_scan_reserved_mem(void) {}

static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }

static inline void unflatten_device_tree(void) {}

static inline void unflatten_and_copy_device_tree(void) {}

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