Commit | Line | Data |
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02568396 PZ |
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 | ||
5b1c674d PZ |
16 | /* |
17 | * PC-compatibles, are, fortunately, sufficiently cache-coherent for this. | |
18 | */ | |
19 | #if defined(__i386__) || defined(__x86_64__) /* CONFIG_ARCH_I386 doesn't exit */ | |
02568396 PZ |
20 | #define MON_HAS_UNMAP 1 |
21 | ||
22 | #define phys_to_page(phys) pfn_to_page((phys) >> PAGE_SHIFT) | |
23 | ||
24 | char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len) | |
25 | { | |
26 | struct page *pg; | |
27 | unsigned long flags; | |
28 | unsigned char *map; | |
29 | unsigned char *ptr; | |
30 | ||
31 | /* | |
32 | * On i386, a DMA handle is the "physical" address of a page. | |
33 | * In other words, the bus address is equal to physical address. | |
34 | * There is no IOMMU. | |
35 | */ | |
36 | pg = phys_to_page(dma_addr); | |
37 | ||
38 | /* | |
39 | * We are called from hardware IRQs in case of callbacks. | |
40 | * But we can be called from softirq or process context in case | |
41 | * of submissions. In such case, we need to protect KM_IRQ0. | |
42 | */ | |
43 | local_irq_save(flags); | |
44 | map = kmap_atomic(pg, KM_IRQ0); | |
45 | ptr = map + (dma_addr & (PAGE_SIZE-1)); | |
46 | memcpy(dst, ptr, len); | |
47 | kunmap_atomic(map, KM_IRQ0); | |
48 | local_irq_restore(flags); | |
49 | return 0; | |
50 | } | |
51 | #endif /* __i386__ */ | |
52 | ||
53 | #ifndef MON_HAS_UNMAP | |
54 | char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len) | |
55 | { | |
56 | return 'D'; | |
57 | } | |
58 | #endif |