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authorPete Zaitcev <zaitcev@redhat.com>2005-08-15 16:53:57 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2005-09-08 16:28:36 -0700
commit0256839619d9b1e933cafc83e7f0deaad4216465 (patch)
treeafadd5815781a99e06ebb537d8ac677d307c09fe /drivers/usb/mon/mon_dma.c
parentd0384200f6b608e77fb5ddf7dfae1bf0e42c1c6e (diff)
[PATCH] usbmon in 2.6.13: peeking into DMA areas
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>
Diffstat (limited to 'drivers/usb/mon/mon_dma.c')
-rw-r--r--drivers/usb/mon/mon_dma.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/usb/mon/mon_dma.c b/drivers/usb/mon/mon_dma.c
new file mode 100644
index 00000000000..0a1367b760a
--- /dev/null
+++ b/drivers/usb/mon/mon_dma.c
@@ -0,0 +1,55 @@
+/*
+ * 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