ioport.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

/* $Id: ioport.c,v 1.45 2001/10/30 04:54:21 davem Exp $
 * ioport.c:  Simple io mapping allocator.
 *
 * Copyright (C) 1995 David S. Miller ([e-mail])
 * Copyright (C) 1995 Miguel de Icaza ([e-mail])
 *
 * 1996: sparc_free_io, 1999: ioremap()/iounmap() by Pete Zaitcev.
 *
 * 2000/01/29
 * <rth> zait: as long as pci_alloc_consistent produces something addressable, 
 *	things are ok.
 * <zaitcev> rth: no, it is relevant, because get_free_pages returns you a
 *	pointer into the big page mapping
 * <rth> zait: so what?
 * <rth> zait: remap_it_my_way(virt_to_phys(get_free_page()))
 * <zaitcev> Hmm
 * <zaitcev> Suppose I did this remap_it_my_way(virt_to_phys(get_free_page())).
 *	So far so good.
 * <zaitcev> Now, driver calls pci_free_consistent(with result of
 *	remap_it_my_way()).
 * <zaitcev> How do you find the address to pass to free_pages()?
 * <rth> zait: walk the page tables?  It's only two or three level after all.
 * <rth> zait: you have to walk them anyway to remove the mapping.
 * <zaitcev> Hmm
 * <zaitcev> Sounds reasonable
 */

#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/pci.h>		/* struct pci_dev */
#include <linux/proc_fs.h>

#include <asm/io.h>
#include <asm/vaddrs.h>
#include <asm/oplib.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>

#define mmu_inval_dma_area(p, l)	/* Anton pulled it out for 2.4.0-xx */

struct resource *_sparc_find_resource(struct resource *r, unsigned long);

static void *_sparc_ioremap(struct resource *res, u32 bus, u32 pa, int sz);
static void *_sparc_alloc_io(unsigned int busno, unsigned long phys,
    unsigned long size, char *name);
static void _sparc_free_io(struct resource *res);

/* This points to the next to use virtual memory for DVMA mappings */
static struct resource _sparc_dvma = {
	"sparc_dvma", DVMA_VADDR, DVMA_END - 1
};
/* This points to the start of I/O mappings, cluable from outside. */
/*ext*/ struct resource sparc_iomap = {
	"sparc_iomap", IOBASE_VADDR, IOBASE_END - 1
};

/*
 * BTFIXUP would do as well but it seems overkill for the case.
 */
static void (*_sparc_mapioaddr)(unsigned long pa, unsigned long va,
    int bus, int ro);
static void (*_sparc_unmapioaddr)(unsigned long va);

/*
 * Our mini-allocator...
 * Boy this is gross! We need it because we must map I/O for
 * timers and interrupt controller before the kmalloc is available.
 */

#define XNMLN  15
#define XNRES  10	/* SS-10 uses 8 */

struct xresource {
	struct resource xres;	/* Must be first */
	int xflag;		/* 1 == used */
	char xname[XNMLN+1];
};

static struct xresource xresv[XNRES];

static struct xresource *xres_alloc(void) {
	struct xresource *xrp;
	int n;

	xrp = xresv;
	for (n = 0; n < XNRES; n++) {
		if (xrp->xflag == 0) {
			xrp->xflag = 1;
			return xrp;
		}
		xrp++;
	}
	return NULL;
}

static void xres_free(struct xresource *xrp) {
	xrp->xflag = 0;
}

/*
 * These are typically used in PCI drivers
 * which are trying to be cross-platform.
 *
 * Bus type is always zero on IIep.
 */
void *ioremap(unsigned long offset, unsigned long size)
{
	char name[14];

	sprintf(name, "phys_%08x", (u32)offset);
	return _sparc_alloc_io(0, offset, size, name);
}

/*
 * Comlimentary to ioremap().
 */
void iounmap(void *virtual)
{
	unsigned long vaddr = (unsigned long) virtual & PAGE_MASK;
	struct resource *res;

	if ((res = _sparc_find_resource(&sparc_iomap, vaddr)) == NULL) {
		printk("free_io/iounmap: cannot free %lx\n", vaddr);
		return;
	}
	_sparc_free_io(res);

	if ((char *)res >= (char*)xresv && (char *)res < (char *)&xresv[XNRES]) {
		xres_free((struct xresource *)res);
	} else {
		kfree(res);
	}
}

/*
 */
unsigned long sbus_ioremap(struct resource *phyres, unsigned long offset,
    unsigned long size, char *name)
{
	return (unsigned long) _sparc_alloc_io(phyres->flags & 0xF,
	    phyres->start + offset, size, name);
}

/*
 */
void sbus_iounmap(unsigned long addr, unsigned long size)
{
	iounmap((void *)addr);
}

/*
 * Meat of mapping
 */
static void *_sparc_alloc_io(unsigned int busno, unsigned long phys,
    unsigned long size, char *name)
{
	static int printed_full = 0;
	struct xresource *xres;
	struct resource *res;
	char *tack;
	int tlen;
	void *va;	/* P3 diag */

	if (name == NULL) name = "???";

	if ((xres = xres_alloc()) != 0) {
		tack = xres->xname;
		res = &xres->xres;
	} else {
		if (!printed_full) {
			printk("ioremap: done with statics, switching to malloc\n");
			printed_full = 1;
		}
		tlen = strlen(name);
		tack = kmalloc(sizeof (struct resource) + tlen + 1, GFP_KERNEL);
		if (tack == NULL) return NULL;
		memset(tack, 0, sizeof(struct resource));
		res = (struct resource *) tack;
		tack += sizeof (struct resource);
	}

	strncpy(tack, name, XNMLN);
	tack[XNMLN] = 0;
	res->name = tack;

	va = _sparc_ioremap(res, busno, phys, size);
	/* printk("ioremap(0x%x:%08lx[0x%lx])=%p\n", busno, phys, size, va); */ /* P3 diag */
	return va;
}

/*
 */
static void *
_sparc_ioremap(struct resource *res, u32 bus, u32 pa, int sz)
{
	unsigned long offset = ((unsigned long) pa) & (~PAGE_MASK);
	unsigned long va;
	unsigned int psz;

	if (allocate_resource(&sparc_iomap, res,
	    (offset + sz + PAGE_SIZE-1) & PAGE_MASK,
	    sparc_iomap.start, sparc_iomap.end, PAGE_SIZE, NULL, NULL) != 0) {
		/* Usually we cannot see printks in this case. */
		prom_printf("alloc_io_res(%s): cannot occupy\n",
		    (res->name != NULL)? res->name: "???");
		prom_halt();
	}

	va = res->start;
	pa &= PAGE_MASK;
	for (psz = res->end - res->start + 1; psz != 0; psz -= PAGE_SIZE) {
		(*_sparc_mapioaddr)(pa, va, bus, 0);
		va += PAGE_SIZE;
		pa += PAGE_SIZE;
	}

	/*
	 * XXX Playing with implementation details here.
	 * On sparc64 Ebus has resources with precise boundaries.
	 * We share drivers with sparc64. Too clever drivers use
	 * start of a resource instead of a base address.
	 *
	 * XXX-2 This may be not valid anymore, clean when
	 * interface to sbus_ioremap() is resolved.
	 */
	res->start += offset;
	res->end = res->start + sz - 1;		/* not strictly necessary.. */

	return (void *) res->start;
}

/*
 * Comlimentary to _sparc_ioremap().
 */
static void _sparc_free_io(struct resource *res)
{
	unsigned long plen;

	plen = res->end - res->start + 1;
	plen = (plen + PAGE_SIZE-1) & PAGE_MASK;
	while (plen != 0) {
		plen -= PAGE_SIZE;
		(*_sparc_unmapioaddr)(res->start + plen);
	}

	release_resource(res);
}

#ifdef CONFIG_SBUS

void sbus_set_sbus64(struct sbus_dev *sdev, int x) {
	printk("sbus_set_sbus64: unsupported\n");
}

/*
 * Allocate a chunk of memory suitable for DMA.
 * Typically devices use them for control blocks.
 * CPU may access them without any explicit flushing.
 *
 * XXX Some clever people know that sdev is not used and supply NULL. Watch.
 */
void *sbus_alloc_consistent(struct sbus_dev *sdev, long len, u32 *dma_addrp)
{
	unsigned long len_total = (len + PAGE_SIZE-1) & PAGE_MASK;
	unsigned long va;
	struct resource *res;
	int order;

	/* XXX why are some lenghts signed, others unsigned? */
	if (len <= 0) {
		return NULL;
	}
	/* XXX So what is maxphys for us and how do drivers know it? */
	if (len > 256*1024) {			/* __get_free_pages() limit */
		return NULL;
	}

	order = get_order(len_total);
	va = __get_free_pages(GFP_KERNEL, order);
	if (va == 0) {
		/*
		 * printk here may be flooding... Consider removal XXX.
		 */
		printk("sbus_alloc_consistent: no %ld pages\n", len_total>>PAGE_SHIFT);
		return NULL;
	}

	if ((res = kmalloc(sizeof(struct resource), GFP_KERNEL)) == NULL) {
		free_pages(va, order);
		printk("sbus_alloc_consistent: no core\n");
		return NULL;
	}
	memset((char*)res, 0, sizeof(struct resource));

	if (allocate_resource(&_sparc_dvma, res, len_total,
	    _sparc_dvma.start, _sparc_dvma.end, PAGE_SIZE, NULL, NULL) != 0) {
		printk("sbus_alloc_consistent: cannot occupy 0x%lx", len_total);
		free_pages(va, order);
		kfree(res);
		return NULL;
	}

	mmu_map_dma_area(va, res->start, len_total);

	*dma_addrp = res->start;
	return (void *)res->start;
}

void sbus_free_consistent(struct sbus_dev *sdev, long n, void *p, u32 ba)
{
	struct resource *res;
	unsigned long pgp;

	if ((res = _sparc_find_resource(&_sparc_dvma,
	    (unsigned long)p)) == NULL) {
		printk("sbus_free_consistent: cannot free %p\n", p);
		return;
	}

	if (((unsigned long)p & (PAGE_SIZE-1)) != 0) {
		printk("sbus_free_consistent: unaligned va %p\n", p);
		return;
	}

	n = (n + PAGE_SIZE-1) & PAGE_MASK;
	if ((res->end-res->start)+1 != n) {
		printk("sbus_free_consistent: region 0x%lx asked 0x%lx\n",
		    (long)((res->end-res->start)+1), n);
		return;
	}

	release_resource(res);
	kfree(res);

	/* mmu_inval_dma_area(va, n); */ /* it's consistent, isn't it */
	pgp = (unsigned long) phys_to_virt(mmu_translate_dvma(ba));
	mmu_unmap_dma_area(ba, n);

	free_pages(pgp, get_order(n));
}

/*
 * Map a chunk of memory so that devices can see it.
 * CPU view of this memory may be inconsistent with
 * a device view and explicit flushing is necessary.
 */
u32 sbus_map_single(struct sbus_dev *sdev, void *va, long len, int direction)
{
#if 0 /* This is the version that abuses consistent space */
	unsigned long len_total = (len + PAGE_SIZE-1) & PAGE_MASK;
	struct resource *res;

	/* XXX why are some lenghts signed, others unsigned? */
	if (len <= 0) {
		return 0;
	}
	/* XXX So what is maxphys for us and how do drivers know it? */
	if (len > 256*1024) {			/* __get_free_pages() limit */
		return 0;
	}

	if ((res = kmalloc(sizeof(struct resource), GFP_KERNEL)) == NULL) {
		printk("sbus_map_single: no core\n");
		return 0;
	}
	memset((char*)res, 0, sizeof(struct resource));
	res->name = va; /* XXX */

	if (allocate_resource(&_sparc_dvma, res, len_total,
	    _sparc_dvma.start, _sparc_dvma.end, PAGE_SIZE) != 0) {
		printk("sbus_map_single: cannot occupy 0x%lx", len);
		kfree(res);
		return 0;
	}

	mmu_map_dma_area(va, res->start, len_total);
	mmu_flush_dma_area((unsigned long)va, len_total); /* in all contexts? */

	return res->start;
#endif
#if 1 /* "trampoline" version */
	/* XXX why are some lenghts signed, others unsigned? */
	if (len <= 0) {
		return 0;
	}
	/* XXX So what is maxphys for us and how do drivers know it? */
	if (len > 256*1024) {			/* __get_free_pages() limit */