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of/address: Add of_range_count() helper 

Some users need a count of the number of ranges entries before
iterating over the entries. Typically this is for allocating some data
structure based on the size. Add a helper, of_range_count(), to get the
count. The helper must be called with an struct of_range_parser
initialized by of_range_parser_init().

Link: https://lore.kernel.org/r/20230328-dt-address-helpers-v1-4-e2456c3e77ab@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Rob Herring 2023-03-28 15:15:59 -05:00
parent 3d5089c426
commit b50c788a56
2 changed files with 22 additions and 1 deletions
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7
drivers/of/unittest.c
View File

@ -1014,7 +1014,7 @@ static void __init of_unittest_bus_ranges(void)
struct of_range range;
struct of_range_parser parser;
struct resource res;
int ret, i = 0;
int ret, count, i = 0;
np = of_find_node_by_path("/testcase-data/address-tests");
if (!np) {
@ -1040,6 +1040,11 @@ static void __init of_unittest_bus_ranges(void)
"of_range_to_resource wrong resource start address on node %pOF res=%pR\n",
np, &res);
count = of_range_count(&parser);
unittest(count == 2,
"of_range_count wrong size on node %pOF count=%d\n",
np, count);
/*
* Get the "ranges" from the device tree
*/

16
include/linux/of_address.h
View File

@ -35,6 +35,22 @@ struct of_pci_range {
for (; of_pci_range_parser_one(parser, range);)
#define for_each_of_range for_each_of_pci_range
/*
* of_range_count - Get the number of "ranges" or "dma-ranges" entries
* @parser: Parser state initialized by of_range_parser_init()
*
* Returns the number of entries or 0 if none.
*
* Note that calling this within or after the for_each_of_range() iterator will
* be inaccurate giving the number of entries remaining.
*/
static inline int of_range_count(const struct of_range_parser *parser)
{
if (!parser || !parser->node || !parser->range || parser->range == parser->end)
return 0;
return (parser->end - parser->range) / (parser->na + parser->pna + parser->ns);
}
/* Translate a DMA address from device space to CPU space */
extern u64 of_translate_dma_address(struct device_node *dev,
const __be32 *in_addr);