tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * The USB Monitor, inspired by Dave Harding's USBMon.
3 *
4 * mon_dma.c: Library which snoops on DMA areas.
5 *
6 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
7 */
8#include <linux/kernel.h>
9#include <linux/list.h>
10#include <linux/highmem.h>
11#include <asm/page.h>
12
13#include <linux/usb.h> /* Only needed for declarations in usb_mon.h */
14#include "usb_mon.h"
15
16#ifdef __i386__ /* CONFIG_ARCH_I386 does not exit */
17#define MON_HAS_UNMAP 1
18
19#define phys_to_page(phys) pfn_to_page((phys) >> PAGE_SHIFT)
20
21char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
22{
23 struct page *pg;
24 unsigned long flags;
25 unsigned char *map;
26 unsigned char *ptr;
27
28 /*
29 * On i386, a DMA handle is the "physical" address of a page.
30 * In other words, the bus address is equal to physical address.
31 * There is no IOMMU.
32 */
33 pg = phys_to_page(dma_addr);
34
35 /*
36 * We are called from hardware IRQs in case of callbacks.
37 * But we can be called from softirq or process context in case
38 * of submissions. In such case, we need to protect KM_IRQ0.
39 */
40 local_irq_save(flags);
41 map = kmap_atomic(pg, KM_IRQ0);
42 ptr = map + (dma_addr & (PAGE_SIZE-1));
43 memcpy(dst, ptr, len);
44 kunmap_atomic(map, KM_IRQ0);
45 local_irq_restore(flags);
46 return 0;
47}
48#endif /* __i386__ */
49
50#ifndef MON_HAS_UNMAP
51char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
52{
53 return 'D';
54}
55#endif