diff options
-rw-r--r-- | Documentation/trace/mmiotrace.txt | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/Documentation/trace/mmiotrace.txt b/Documentation/trace/mmiotrace.txt index 162effbfbdec..664e7386d89e 100644 --- a/Documentation/trace/mmiotrace.txt +++ b/Documentation/trace/mmiotrace.txt | |||
@@ -44,7 +44,8 @@ Check for lost events. | |||
44 | Usage | 44 | Usage |
45 | ----- | 45 | ----- |
46 | 46 | ||
47 | Make sure debugfs is mounted to /sys/kernel/debug. If not, (requires root privileges) | 47 | Make sure debugfs is mounted to /sys/kernel/debug. |
48 | If not (requires root privileges): | ||
48 | $ mount -t debugfs debugfs /sys/kernel/debug | 49 | $ mount -t debugfs debugfs /sys/kernel/debug |
49 | 50 | ||
50 | Check that the driver you are about to trace is not loaded. | 51 | Check that the driver you are about to trace is not loaded. |
@@ -91,7 +92,7 @@ $ dmesg > dmesg.txt | |||
91 | $ tar zcf pciid-nick-mmiotrace.tar.gz mydump.txt lspci.txt dmesg.txt | 92 | $ tar zcf pciid-nick-mmiotrace.tar.gz mydump.txt lspci.txt dmesg.txt |
92 | and then send the .tar.gz file. The trace compresses considerably. Replace | 93 | and then send the .tar.gz file. The trace compresses considerably. Replace |
93 | "pciid" and "nick" with the PCI ID or model name of your piece of hardware | 94 | "pciid" and "nick" with the PCI ID or model name of your piece of hardware |
94 | under investigation and your nick name. | 95 | under investigation and your nickname. |
95 | 96 | ||
96 | 97 | ||
97 | How Mmiotrace Works | 98 | How Mmiotrace Works |
@@ -100,7 +101,7 @@ How Mmiotrace Works | |||
100 | Access to hardware IO-memory is gained by mapping addresses from PCI bus by | 101 | Access to hardware IO-memory is gained by mapping addresses from PCI bus by |
101 | calling one of the ioremap_*() functions. Mmiotrace is hooked into the | 102 | calling one of the ioremap_*() functions. Mmiotrace is hooked into the |
102 | __ioremap() function and gets called whenever a mapping is created. Mapping is | 103 | __ioremap() function and gets called whenever a mapping is created. Mapping is |
103 | an event that is recorded into the trace log. Note, that ISA range mappings | 104 | an event that is recorded into the trace log. Note that ISA range mappings |
104 | are not caught, since the mapping always exists and is returned directly. | 105 | are not caught, since the mapping always exists and is returned directly. |
105 | 106 | ||
106 | MMIO accesses are recorded via page faults. Just before __ioremap() returns, | 107 | MMIO accesses are recorded via page faults. Just before __ioremap() returns, |
@@ -122,11 +123,11 @@ Trace Log Format | |||
122 | ---------------- | 123 | ---------------- |
123 | 124 | ||
124 | The raw log is text and easily filtered with e.g. grep and awk. One record is | 125 | The raw log is text and easily filtered with e.g. grep and awk. One record is |
125 | one line in the log. A record starts with a keyword, followed by keyword | 126 | one line in the log. A record starts with a keyword, followed by keyword- |
126 | dependant arguments. Arguments are separated by a space, or continue until the | 127 | dependent arguments. Arguments are separated by a space, or continue until the |
127 | end of line. The format for version 20070824 is as follows: | 128 | end of line. The format for version 20070824 is as follows: |
128 | 129 | ||
129 | Explanation Keyword Space separated arguments | 130 | Explanation Keyword Space-separated arguments |
130 | --------------------------------------------------------------------------- | 131 | --------------------------------------------------------------------------- |
131 | 132 | ||
132 | read event R width, timestamp, map id, physical, value, PC, PID | 133 | read event R width, timestamp, map id, physical, value, PC, PID |
@@ -136,7 +137,7 @@ iounmap event UNMAP timestamp, map id, PC, PID | |||
136 | marker MARK timestamp, text | 137 | marker MARK timestamp, text |
137 | version VERSION the string "20070824" | 138 | version VERSION the string "20070824" |
138 | info for reader LSPCI one line from lspci -v | 139 | info for reader LSPCI one line from lspci -v |
139 | PCI address map PCIDEV space separated /proc/bus/pci/devices data | 140 | PCI address map PCIDEV space-separated /proc/bus/pci/devices data |
140 | unk. opcode UNKNOWN timestamp, map id, physical, data, PC, PID | 141 | unk. opcode UNKNOWN timestamp, map id, physical, data, PC, PID |
141 | 142 | ||
142 | Timestamp is in seconds with decimals. Physical is a PCI bus address, virtual | 143 | Timestamp is in seconds with decimals. Physical is a PCI bus address, virtual |