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 /*
17 * PC-compatibles, are, fortunately, sufficiently cache-coherent for this.
18 */
19 #if defined(__i386__) || defined(__x86_64__) /* CONFIG_ARCH_I386 doesn't exit */
20 #define MON_HAS_UNMAP 1
21
22 #define phys_to_page(phys) pfn_to_page((phys) >> PAGE_SHIFT)
23
mon_dmapeek(unsigned char * dst,dma_addr_t dma_addr,int len)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
mon_dmapeek_vec(const struct mon_reader_bin * rp,unsigned int offset,dma_addr_t dma_addr,unsigned int length)52 void mon_dmapeek_vec(const struct mon_reader_bin *rp,
53 unsigned int offset, dma_addr_t dma_addr, unsigned int length)
54 {
55 unsigned long flags;
56 unsigned int step_len;
57 struct page *pg;
58 unsigned char *map;
59 unsigned long page_off, page_len;
60
61 local_irq_save(flags);
62 while (length) {
63 /* compute number of bytes we are going to copy in this page */
64 step_len = length;
65 page_off = dma_addr & (PAGE_SIZE-1);
66 page_len = PAGE_SIZE - page_off;
67 if (page_len < step_len)
68 step_len = page_len;
69
70 /* copy data and advance pointers */
71 pg = phys_to_page(dma_addr);
72 map = kmap_atomic(pg, KM_IRQ0);
73 offset = mon_copy_to_buff(rp, offset, map + page_off, step_len);
74 kunmap_atomic(map, KM_IRQ0);
75 dma_addr += step_len;
76 length -= step_len;
77 }
78 local_irq_restore(flags);
79 }
80
81 #endif /* __i386__ */
82
83 #ifndef MON_HAS_UNMAP
mon_dmapeek(unsigned char * dst,dma_addr_t dma_addr,int len)84 char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
85 {
86 return 'D';
87 }
88
mon_dmapeek_vec(const struct mon_reader_bin * rp,unsigned int offset,dma_addr_t dma_addr,unsigned int length)89 void mon_dmapeek_vec(const struct mon_reader_bin *rp,
90 unsigned int offset, dma_addr_t dma_addr, unsigned int length)
91 {
92 ;
93 }
94
95 #endif /* MON_HAS_UNMAP */
96