mirror of
https://github.com/torvalds/linux.git
synced 2024-12-12 06:02:38 +00:00
0256839619
This code looks at urb->transfer_dma, maps the page and takes the data. I am looking for volunteers to contribute architectures other than i386 or to develop an architecure-neutral API for it (or point me that it was done already). Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/*
|
|
* 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"
|
|
|
|
#ifdef __i386__ /* CONFIG_ARCH_I386 does not 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;
|
|
}
|
|
#endif /* __i386__ */
|
|
|
|
#ifndef MON_HAS_UNMAP
|
|
char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
|
|
{
|
|
return 'D';
|
|
}
|
|
#endif
|