On Thu, Aug 31, 2017 at 04:42:00AM -0600, Simon Glass wrote:
> Extend the Properties class with some functions to read a single integer
> property. Add a new getprop_obj() function to return a Property object
> instead of the raw data.
>
> This suggested approach can be extended to handle other types, as well as
> arrays.
>
> Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
Sorry again I've taken so long to respond.
This way of doing it really seems awkward to me. You're introducing a
clunky variant getter just to wrap the bytearray in an object,
essentially just to get conversion methods.
It seems to be simpler to just have as_cell() and whatnot as plain
functions that go straight from bytestring/bytearray to an int or
whatever.
Longer term, I did have an idea that might resolve the
propery-as-object or property-as-bytestring conundrum a bit more
satisfactorily. But, I'm not entirely sure how you'd go about
implementing it with swig in the picture: it should be possible in
(modern) Python to make a Property object that's a sub-class of the
(byte)string type. That way it can be used directly as though it were
a bytestring, but you can also add properties to do extra stuff.
[Which raises a minor detail, most of the functions which return
bytearray()s now should probably be returning strings - there doesn't
seem to be a reason to return a mutable object]
> ---
>
> Changes in v2: None
>
> pylibfdt/libfdt.i | 35 +++++++++++++++++++++++++++++++++++
> tests/pylibfdt_tests.py | 12 ++++++++++++
> tests/run_tests.sh | 1 +
> tests/test_props.dts | 11 +++++++++++
> 4 files changed, 59 insertions(+)
> create mode 100644 tests/test_props.dts
>
> diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
> index f8e3a2c..4d60f90 100644
> --- a/pylibfdt/libfdt.i
> +++ b/pylibfdt/libfdt.i
> @@ -376,6 +376,26 @@ class Fdt:
> return pdata
> return bytearray(pdata[0])
>
> + def getprop_obj(self, nodeoffset, prop_name, quiet=()):
> + """Get a property from a node as a Property object
> +
> + Args:
> + nodeoffset: Node offset containing property to get
> + prop_name: Name of property to get
> + quiet: Errors to ignore (empty to raise on all errors)
> +
> + Returns:
> + Property object, or None if not found
> +
> + Raises:
> + FdtError if any error occurs (e.g. the property is not found)
> + """
> + pdata = check_err_null(fdt_getprop(self._fdt, nodeoffset, prop_name),
> + quiet)
> + if isinstance(pdata, (int)):
> + return None
> + return Property(prop_name, bytearray(pdata[0]))
> +
> def get_phandle(self, nodeoffset):
> """Get the phandle of a node
>
> @@ -432,6 +452,21 @@ class Property:
> def __init__(self, name, value):
> self.name = name
> self.value = value
> +
> + def to_cell(self, fmt):
> + return struct.unpack('>' + fmt, self.value)[0]
> +
> + def to_uint32(self):
> + return self.to_cell('L')
> +
> + def to_int32(self):
> + return self.to_cell('l')
> +
> + def to_uint64(self):
> + return self.to_cell('Q')
> +
> + def to_int64(self):
> + return self.to_cell('q')
> %}
>
> %rename(fdt_property) fdt_property_func;
> diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
> index 0ec0f38..fc5210b 100644
> --- a/tests/pylibfdt_tests.py
> +++ b/tests/pylibfdt_tests.py
> @@ -89,6 +89,7 @@ class PyLibfdtTests(unittest.TestCase):
> def setUp(self):
> """Read in the device tree we use for testing"""
> self.fdt = _ReadFdt('test_tree1.dtb')
> + self.fdt2 = _ReadFdt('test_props.dtb')
>
> def GetPropList(self, node_path):
> """Read a list of properties from a node
> @@ -330,6 +331,17 @@ class PyLibfdtTests(unittest.TestCase):
> node2 = self.fdt.path_offset('/subnode@2/subsubnode@0')
> self.assertEquals(node2, self.fdt.node_offset_by_phandle(0x2001))
>
> + def get_prop(self, name):
> + return self.fdt2.getprop_obj(0, name)
> +
> + def testGetIntProperties(self):
> + """Test that we can access properties as integers"""
> + self.assertEquals(0xdeadbeef, self.get_prop("prop-hex32").to_uint32())
> + self.assertEquals(123, self.get_prop("prop-uint32").to_uint32())
> + self.assertEquals(-2, self.get_prop("prop-int32").to_int32())
> + self.assertEquals(9223372036854775807,
> + self.get_prop("prop-uint64").to_uint64())
> + self.assertEquals(-2, self.get_prop("prop-int64").to_int64())
>
> if __name__ == "__main__":
> unittest.main()
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index fa7b2f7..441e773 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -809,6 +809,7 @@ fdtoverlay_tests() {
> }
>
> pylibfdt_tests () {
> + run_dtc_test -I dts -O dtb -o test_props.dtb test_props.dts
> TMP=/tmp/tests.stderr.$$
> python pylibfdt_tests.py -v 2> $TMP
>
> diff --git a/tests/test_props.dts b/tests/test_props.dts
> new file mode 100644
> index 0000000..7e59bd1
> --- /dev/null
> +++ b/tests/test_props.dts
> @@ -0,0 +1,11 @@
> +/dts-v1/;
> +
> +/ {
> + compatible = "test_props";
> + prop-hex32 = <0xdeadbeef>;
> + prop-uint32 = <123>;
> + prop-int32 = <0xfffffffe>;
> + prop-hex64 = /bits/ 64 <0xdeadbeef01abcdef>;
> + prop-uint64 = /bits/ 64 <9223372036854775807>;
> + prop-int64 = /bits/ 64 <0xfffffffffffffffe>;
> +};
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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