path: root/arch/sparc/kernel/mdesc.c

/* mdesc.c: Sun4V machine description handling.
 *
 * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/memblock.h>
#include <linux/log2.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/bootmem.h>

#include <asm/cpudata.h>
#include <asm/hypervisor.h>
#include <asm/mdesc.h>
#include <asm/prom.h>
#include <asm/oplib.h>
#include <asm/smp.h>

/* Unlike the OBP device tree, the machine description is a full-on
 * DAG.  An arbitrary number of ARCs are possible from one
 * node to other nodes and thus we can't use the OBP device_node
 * data structure to represent these nodes inside of the kernel.
 *
 * Actually, it isn't even a DAG, because there are back pointers
 * which create cycles in the graph.
 *
 * mdesc_hdr and mdesc_elem describe the layout of the data structure
 * we get from the Hypervisor.
 */
struct mdesc_hdr {
	u32	version; /* Transport version */
	u32	node_sz; /* node block size */
	u32	name_sz; /* name block size */
	u32	data_sz; /* data block size */
} __attribute__((aligned(16)));

struct mdesc_elem {
	u8	tag;
#define MD_LIST_END	0x00
#define MD_NODE		0x4e
#define MD_NODE_END	0x45
#define MD_NOOP		0x20
#define MD_PROP_ARC	0x61
#define MD_PROP_VAL	0x76
#define MD_PROP_STR	0x73
#define MD_PROP_DATA	0x64
	u8	name_len;
	u16	resv;
	u32	name_offset;
	union {
		struct {
			u32	data_len;
			u32	data_offset;
		} data;
		u64	val;
	} d;
};

struct mdesc_mem_ops {
	struct mdesc_handle *(*alloc)(unsigned int mdesc_size);
	void (*free)(struct mdesc_handle *handle);
};

struct mdesc_handle {
	struct list_head	list;
	struct mdesc_mem_ops	*mops;
	void			*self_base;
	atomic_t		refcnt;
	unsigned int		handle_size;
	struct mdesc_hdr	mdesc;
};

static void mdesc_handle_init(struct mdesc_handle *hp,
			      unsigned int handle_size,
			      void *base)
{
	BUG_ON(((unsigned long)&hp->mdesc) & (16UL - 1));

	memset(hp, 0, handle_size);
	INIT_LIST_HEAD(&hp->list);
	hp->self_base = base;
	atomic_set(&hp->refcnt, 1);
	hp->handle_size = handle_size;
}

static struct mdesc_handle * __init mdesc_memblock_alloc(unsigned int mdesc_size)
{
	unsigned int handle_size, alloc_size;
	struct mdesc_handle *hp;
	unsigned long paddr;

	handle_size = (sizeof(struct mdesc_handle) -
		       sizeof(struct mdesc_hdr) +
		       mdesc_size);
	alloc_size = PAGE_ALIGN(handle_size);

	paddr = memblock_alloc(alloc_size, PAGE_SIZE);

	hp = NULL;
	if (paddr) {
		hp = __va(paddr);
		mdesc_handle_init(hp, handle_size, hp);
	}
	return hp;
}

static void mdesc_memblock_free(struct mdesc_handle *hp)
{
	unsigned int alloc_size;
	unsigned long start;

	BUG_ON(atomic_read(&hp->refcnt) != 0);
	BUG_ON(!list_empty(&hp->list));

	alloc_size = PAGE_ALIGN(hp->handle_size);
	start = __pa(hp);
	free_bootmem_late(start, alloc_size);
}

static struct mdesc_mem_ops memblock_mdesc_ops = {
	.alloc = mdesc_memblock_alloc,
	.free  = mdesc_memblock_free,
};

static struct mdesc_handle *mdesc_kmalloc(unsigned int mdesc_size)
{
	unsigned int handle_size;
	void *base;

	handle_size = (sizeof(struct mdesc_handle) -
		       sizeof(struct mdesc_hdr) +
		       mdesc_size);

	base = kmalloc(handle_size + 15, GFP_KERNEL | __GFP_NOFAIL);
	if (base) {
		struct mdesc_handle *hp;
		unsigned long addr;

		addr = (unsigned long)base;
		addr = (addr + 15UL) & ~15UL;
		hp = (struct mdesc_handle *) addr;

		mdesc_handle_init(hp, handle_size, base);
		return hp;
	}

	return NULL;
}

static void mdesc_kfree(struct mdesc_handle *hp)
{
	BUG_ON(atomic_read(&hp->refcnt) != 0);
	BUG_ON(!list_empty(&hp->list));

	kfree(hp->self_base);
}

static struct mdesc_mem_ops kmalloc_mdesc_memops = {
	.alloc = mdesc_kmalloc,
	.free  = mdesc_kfree,
};

static struct mdesc_handle *mdesc_alloc(unsigned int mdesc_size,
					struct mdesc_mem_ops *mops)
{
	struct mdesc_handle *hp = mops->alloc(mdesc_size);

	if (hp)
		hp->mops = mops;

	return hp;
}

static void mdesc_free(struct mdesc_handle *hp)