mon_dma.c
2.36 KB
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/*
* The USB Monitor, inspired by Dave Harding's USBMon.
*
* mon_dma.c: Library which snoops on DMA areas.
*
* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <asm/page.h>
#include <linux/usb.h> /* Only needed for declarations in usb_mon.h */
#include "usb_mon.h"
/*
* PC-compatibles, are, fortunately, sufficiently cache-coherent for this.
*/
#if defined(__i386__) || defined(__x86_64__) /* CONFIG_ARCH_I386 doesn't exit */
#define MON_HAS_UNMAP 1
#define phys_to_page(phys) pfn_to_page((phys) >> PAGE_SHIFT)
char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
{
struct page *pg;
unsigned long flags;
unsigned char *map;
unsigned char *ptr;
/*
* On i386, a DMA handle is the "physical" address of a page.
* In other words, the bus address is equal to physical address.
* There is no IOMMU.
*/
pg = phys_to_page(dma_addr);
/*
* We are called from hardware IRQs in case of callbacks.
* But we can be called from softirq or process context in case
* of submissions. In such case, we need to protect KM_IRQ0.
*/
local_irq_save(flags);
map = kmap_atomic(pg, KM_IRQ0);
ptr = map + (dma_addr & (PAGE_SIZE-1));
memcpy(dst, ptr, len);
kunmap_atomic(map, KM_IRQ0);
local_irq_restore(flags);
return 0;
}
void mon_dmapeek_vec(const struct mon_reader_bin *rp,
unsigned int offset, dma_addr_t dma_addr, unsigned int length)
{
unsigned long flags;
unsigned int step_len;
struct page *pg;
unsigned char *map;
unsigned long page_off, page_len;
local_irq_save(flags);
while (length) {
/* compute number of bytes we are going to copy in this page */
step_len = length;
page_off = dma_addr & (PAGE_SIZE-1);
page_len = PAGE_SIZE - page_off;
if (page_len < step_len)
step_len = page_len;
/* copy data and advance pointers */
pg = phys_to_page(dma_addr);
map = kmap_atomic(pg, KM_IRQ0);
offset = mon_copy_to_buff(rp, offset, map + page_off, step_len);
kunmap_atomic(map, KM_IRQ0);
dma_addr += step_len;
length -= step_len;
}
local_irq_restore(flags);
}
#endif /* __i386__ */
#ifndef MON_HAS_UNMAP
char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
{
return 'D';
}
void mon_dmapeek_vec(const struct mon_reader_bin *rp,
unsigned int offset, dma_addr_t dma_addr, unsigned int length)
{
;
}
#endif /* MON_HAS_UNMAP */