memory.c

/* memory.c: Prom routine for acquiring various bits of information
 *           about RAM on the machine, both virtual and physical.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1997 Michael A. Griffith (grif@acm.org)
 */

#include <linux/kernel.h>
#include <linux/init.h>

#include <asm/openprom.h>
#include <asm/sun4prom.h>
#include <asm/oplib.h>

/* This routine, for consistency, returns the ram parameters in the
 * V0 prom memory descriptor format.  I choose this format because I
 * think it was the easiest to work with.  I feel the religious
 * arguments now... ;)  Also, I return the linked lists sorted to
 * prevent paging_init() upset stomach as I have not yet written
 * the pepto-bismol kernel module yet.
 */

struct linux_prom_registers prom_reg_memlist[64];

struct linux_mlist_v0 prom_phys_avail[64];

/* Internal Prom library routine to sort a linux_mlist_v0 memory
 * list.  Used below in initialization.
 */
static void __init
prom_sortmemlist(struct linux_mlist_v0 *thislist)
{
	int swapi = 0;
	int i, mitr, tmpsize;
	char *tmpaddr;
	char *lowest;

	for(i=0; thislist[i].theres_more; i++) {
		lowest = thislist[i].start_adr;
		for(mitr = i+1; thislist[mitr-1].theres_more; mitr++)
			if(thislist[mitr].start_adr < lowest) {
				lowest = thislist[mitr].start_adr;
				swapi = mitr;
			}
		if(lowest == thislist[i].start_adr) continue;
		tmpaddr = thislist[swapi].start_adr;
		tmpsize = thislist[swapi].num_bytes;
		for(mitr = swapi; mitr > i; mitr--) {
			thislist[mitr].start_adr = thislist[mitr-1].start_adr;
			thislist[mitr].num_bytes = thislist[mitr-1].num_bytes;
		}
		thislist[i].start_adr = tmpaddr;
		thislist[i].num_bytes = tmpsize;
	}

	return;
}

/* Initialize the memory lists based upon the prom version. */
void __init prom_meminit(void)
{
	int node = 0;
	unsigned int iter, num_regs;
	struct linux_mlist_v0 *mptr;  /* ptr for traversal */

	switch(prom_vers) {
	case PROM_V0:
		/* Nice, kind of easier to do in this case. */
		for(mptr = (*(romvec->pv_v0mem.v0_available)), iter=0;
		    mptr; mptr=mptr->theres_more, iter++) {
			prom_phys_avail[iter].start_adr = mptr->start_adr;
			prom_phys_avail[iter].num_bytes = mptr->num_bytes;
			prom_phys_avail[iter].theres_more = &prom_phys_avail[iter+1];
		}
		prom_phys_avail[iter-1].theres_more = NULL;
		prom_sortmemlist(prom_phys_avail);
		break;
	case PROM_V2:
	case PROM_V3:
		/* Grrr, have to traverse the prom device tree ;( */
		node = prom_getchild(prom_root_node);
		node = prom_searchsiblings(node, "memory");
		num_regs = prom_getproperty(node, "available",
					    (char *) prom_reg_memlist,
					    sizeof(prom_reg_memlist));
		num_regs = (num_regs/sizeof(struct linux_prom_registers));
		for(iter=0; iter<num_regs; iter++) {
			prom_phys_avail[iter].start_adr =
				(char *) prom_reg_memlist[iter].phys_addr;
			prom_phys_avail[iter].num_bytes =
				(unsigned long) prom_reg_memlist[iter].reg_size;
			prom_phys_avail[iter].theres_more =
				&prom_phys_avail[iter+1];
		}
		prom_phys_avail[iter-1].theres_more = NULL;
		prom_sortmemlist(prom_phys_avail);
		break;

	case PROM_SUN4:
#ifdef CONFIG_SUN4	
		/* how simple :) */
		prom_phys_avail[0].start_adr = NULL;
		prom_phys_avail[0].num_bytes = *(sun4_romvec->memoryavail);
		prom_phys_avail[0].theres_more = NULL;
#endif
		break;

	default:
		break;
	};
}

/* This returns a pointer to our libraries internal v0 format
 * available memory list.
 */
struct linux_mlist_v0 *
prom_meminfo(void)
{
	return prom_phys_avail;
}