Re: [PATCH v3 2/6] libfdt: Add iterator over properties

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

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On Wed, Jul 20, 2016 at 04:20:40PM +0200, Maxime Ripard wrote:
> Implement a macro based on fdt_first_property_offset and
> fdt_next_property_offset that provides a convenience to iterate over all
> the properties of a given node.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> Acked-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
>  libfdt/libfdt.h            | 26 +++++++++++++
>  tests/.gitignore           |  1 +
>  tests/Makefile.tests       |  1 +
>  tests/property_iterate.c   | 97 ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/property_iterate.dts | 24 ++++++++++++
>  tests/run_tests.sh         |  3 ++
>  6 files changed, 152 insertions(+)
>  create mode 100644 tests/property_iterate.c
>  create mode 100644 tests/property_iterate.dts
> 
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 70ec39c7104c..cb2f080c81d4 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -457,6 +457,32 @@ int fdt_first_property_offset(const void *fdt, int nodeoffset);
>   */
>  int fdt_next_property_offset(const void *fdt, int offset);
>  
> +/**
> + * fdt_for_each_property - iterate over all properties of a node

Name here doesn't match the actual macro name.

> + * @property_offset:	property offset (int)

Note (int, lvalue).

> + * @fdt:		FDT blob (const void *)
> + * @node:		node offset (int)
> + *
> + * This is actually a wrapper around a for loop and would be used like so:
> + *
> + *	fdt_for_each_property(property, fdt, node) {
> + *		if ((property < 0) && (property != -FDT_ERR_NOT_FOUND)) {
> + *			Error handling
> + *		}

Error handling needs to go after the for block.

> + *
> + *		Use property
> + *		...
> + *	}
> + *
> + * Note that this is implemented as a macro and property is used as
> + * iterator in the loop. The node variable can be constant or even a
> + * literal.
> + */
> +#define fdt_for_each_property_offset(property, fdt, node)	\
> +	for (property = fdt_first_property_offset(fdt, node);	\
> +	     property >= 0;					\
> +	     property = fdt_next_property_offset(fdt, property))
> +
>  /**
>   * fdt_get_property_by_offset - retrieve the property at a given offset
>   * @fdt: pointer to the device tree blob
> diff --git a/tests/.gitignore b/tests/.gitignore
> index e4532da30bf5..fa4616ba28c2 100644
> --- a/tests/.gitignore
> +++ b/tests/.gitignore
> @@ -40,6 +40,7 @@ tmp.*
>  /path_offset
>  /path_offset_aliases
>  /phandle_format
> +/property_iterate
>  /propname_escapes
>  /references
>  /root_node
> diff --git a/tests/Makefile.tests b/tests/Makefile.tests
> index f7c3a4b00ead..196518c83eda 100644
> --- a/tests/Makefile.tests
> +++ b/tests/Makefile.tests
> @@ -23,6 +23,7 @@ LIB_TESTS_L = get_mem_rsv \
>  	add_subnode_with_nops path_offset_aliases \
>  	utilfdt_test \
>  	integer-expressions \
> +	property_iterate \
>  	subnode_iterate
>  LIB_TESTS = $(LIB_TESTS_L:%=$(TESTS_PREFIX)%)
>  
> diff --git a/tests/property_iterate.c b/tests/property_iterate.c
> new file mode 100644
> index 000000000000..0f3959cb8c22
> --- /dev/null
> +++ b/tests/property_iterate.c
> @@ -0,0 +1,97 @@
> +/*
> + * libfdt - Flat Device Tree manipulation
> + *	Tests that fdt_next_subnode() works as expected
> + *
> + * Copyright (C) 2013 Google, Inc
> + *
> + * Copyright (C) 2007 David Gibson, IBM Corporation.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public License
> + * as published by the Free Software Foundation; either version 2.1 of
> + * the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdint.h>
> +
> +#include <libfdt.h>
> +
> +#include "tests.h"
> +#include "testdata.h"
> +
> +static void test_node(void *fdt, int parent_offset)
> +{
> +	fdt32_t properties;
> +	const fdt32_t *prop;
> +	int offset, property;
> +	int count;
> +	int len;
> +
> +	/*
> +	 * This property indicates the number of properties in our
> +	 * test node to expect
> +	 */
> +	prop = fdt_getprop(fdt, parent_offset, "test-properties", &len);
> +	if (!prop || len != sizeof(fdt32_t)) {
> +		FAIL("Missing/invalid test-properties property at '%s'",
> +		     fdt_get_name(fdt, parent_offset, NULL));
> +	}
> +	properties = cpu_to_fdt32(*prop);
> +
> +	count = 0;
> +	offset = fdt_first_subnode(fdt, parent_offset);
> +	if (offset < 0)
> +		FAIL("Missing test node\n");
> +
> +	fdt_for_each_property_offset(property, fdt, offset)
> +		count++;
> +
> +	if (count != properties) {
> +		FAIL("Node '%s': Expected %d properties, got %d\n",
> +		     fdt_get_name(fdt, parent_offset, NULL), properties,
> +		     count);
> +	}
> +}
> +
> +static void check_fdt_next_subnode(void *fdt)
> +{
> +	int offset;
> +	int count = 0;
> +
> +	fdt_for_each_subnode(offset, fdt, 0) {
> +		test_node(fdt, offset);
> +		count++;
> +	}
> +
> +	if (count != 2)
> +		FAIL("Expected %d tests, got %d\n", 2, count);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	void *fdt;
> +
> +	test_init(argc, argv);
> +	if (argc != 2)
> +		CONFIG("Usage: %s <dtb file>", argv[0]);
> +
> +	fdt = load_blob(argv[1]);
> +	if (!fdt)
> +		FAIL("No device tree available");
> +
> +	check_fdt_next_subnode(fdt);
> +
> +	PASS();
> +}
> diff --git a/tests/property_iterate.dts b/tests/property_iterate.dts
> new file mode 100644
> index 000000000000..2ed677e7e6ea
> --- /dev/null
> +++ b/tests/property_iterate.dts
> @@ -0,0 +1,24 @@
> +/dts-v1/;
> +
> +/ {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	test1 {
> +		test-properties = <3>;
> +
> +		test {
> +			linux,phandle = <0x1>;
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +		};
> +	};
> +
> +	test2 {
> +		test-properties = <0>;
> +
> +		test {
> +		};
> +	};
> +};
> +
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index 7eb9b3d33108..6a2662b2abaf 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -269,6 +269,9 @@ libfdt_tests () {
>      run_dtc_test -I dts -O dtb -o subnode_iterate.dtb subnode_iterate.dts
>      run_test subnode_iterate subnode_iterate.dtb
>  
> +    run_dtc_test -I dts -O dtb -o property_iterate.dtb property_iterate.dts
> +    run_test property_iterate property_iterate.dtb
> +
>      # Tests for behaviour on various sorts of corrupted trees
>      run_test truncated_property
>  

-- 
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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