usb_parse_data(9f)

1usb_parse_data(9F)       Kernel Functions for Drivers       usb_parse_data(9F)
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NAME

6       usb_parse_data  -  Tokenize  and align the bytes of raw variable-format
7       data
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SYNOPSIS

10       #include <sys/usb/usba.h>
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14       size_t usb_parse_data(char *format, uchar_t *data,
15            size_t datalen, void *structure, size_t structlen);
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INTERFACE LEVEL

19       Solaris DDI specific (Solaris DDI)
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PARAMETERS

22       format       Null terminated string describing the format of  the  data
23                    structure  for  general-purpose byte swapping. The letters
24                    "c," "s," "l," and "L" represent 1, 2, 4 and 8 byte  quan‐
25                    tities,  respectively.  A  descriptor  that  consists of a
26                    short and two bytes would be described by "scc." A  number
27                    preceding  a letter serves as a multiplier of that letter.
28                    A format equivalent to "scc" is "s2c."
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31       data         Raw descriptor data to parse.
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34       datalen      Length, in bytes, of the raw descriptor data buffer.
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37       structure    Destination data buffer where parsed data is returned.
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40       structlen    Length, in bytes, of the destination data  buffer.  Parsed
41                    result length will not exceed this value.
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DESCRIPTION

45       The  usb_parse_data  function  parses  data  such  as a variable-format
46       class- or vendor-specific descriptor. The function also  tokenizes  and
47       aligns  the bytes of raw descriptor data into fields of a variable-for‐
48       mat descriptor.
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51       While the USBA framework can parse the endpoint, interface,  configura‐
52       tion,  and string descriptors defined by the USB 2.0 specification, the
53       format of class- or vendor-specific descriptors  cannot  be  explicitly
54       defined  by  the  specification and will be unique for each. The format
55       argument defines how to parse such a descriptor.
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58       While the USB specification defines bit ordering as little-endian, this
59       routine  (like  the entire API), converts the data to the endianness of
60       the host.
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63       The structlen parameter defines the size of the destination  data  buf‐
64       fer.  Data  is truncated to this size if the destination data buffer is
65       too small.
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RETURN VALUES

68       On success: Returns the size (in bytes) of the parsed data result.
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71       On failure: Returns 0. (Same as USB_PARSE_ERROR).
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CONTEXT

74       May be called from user, kernel or interrupt context.
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EXAMPLES

77           /*
78            * Parse raw descriptor data in buf, putting result into ret_descr.
79            * ret_buf_len holds the size of ret_descr buf;  routine returns
80            * number of resulting bytes.
81            *
82            * Descriptor being parsed has 2 chars, followed by one short,
83            * 3 chars and one more short.
84            */
85           size_t size_of_returned_descr;
86           xxx_descr_t ret_descr;
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88            size_of_returned_descr = usb_parse_data("ccscccs",
89               buf, sizeof(buf), (void *)ret_descr, (sizeof)xxx_descr_t));
90           if (size_of_returned_descr < (sizeof (xxx_descr_t))) {
91                    /* Data truncated. */
92           }
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94           or:
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96           size_of_returned_descr = usb_parse_data("2cs3cs",
97               buf, sizeof(buf), (void *)ret_descr, (sizeof)xxx_descr_t));
98           if (size_of_returned_descr < (sizeof (xxx_descr_t))) {
99                   /* Data truncated. */
100           }
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ATTRIBUTES

104       See attributes(5) for descriptions of the following attributes:
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109       ┌─────────────────────────────┬─────────────────────────────┐
110       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
111       ├─────────────────────────────┼─────────────────────────────┤
112       │Architecture                 │PCI-based systems            │
113       ├─────────────────────────────┼─────────────────────────────┤
114       │Interface stability          │Committed                    │
115       ├─────────────────────────────┼─────────────────────────────┤
116       │Availability                 │SUNWusb                      │
117       └─────────────────────────────┴─────────────────────────────┘
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