of: restore old handling of cells_name=NULL in of_*_phandle_with_args()
Before commit e42ee61017f5 ("of: Let of_for_each_phandle fallback to
non-negative cell_count") the iterator functions calling
of_for_each_phandle assumed a cell count of 0 if cells_name was NULL.
This corner case was missed when implementing the fallback logic in
e42ee61017f5 and resulted in an endless loop.
Restore the old behaviour of of_count_phandle_with_args() and
of_parse_phandle_with_args() and add a check to
of_phandle_iterator_init() to prevent a similar failure as a safety
precaution. of_parse_phandle_with_args_map() doesn't need a similar fix
as cells_name isn't NULL there.
Affected drivers are:
- drivers/base/power/domain.c
- drivers/base/power/domain.c
- drivers/clk/ti/clk-dra7-atl.c
- drivers/hwmon/ibmpowernv.c
- drivers/i2c/muxes/i2c-demux-pinctrl.c
- drivers/iommu/mtk_iommu.c
- drivers/net/ethernet/freescale/fman/mac.c
- drivers/opp/of.c
- drivers/perf/arm_dsu_pmu.c
- drivers/regulator/of_regulator.c
- drivers/remoteproc/imx_rproc.c
- drivers/soc/rockchip/pm_domains.c
- sound/soc/fsl/imx-audmix.c
- sound/soc/fsl/imx-audmix.c
- sound/soc/meson/axg-card.c
- sound/soc/samsung/tm2_wm5110.c
- sound/soc/samsung/tm2_wm5110.c
Thanks to Geert Uytterhoeven for reporting the issue, Peter Rosin for
helping pinpoint the actual problem and the testers for confirming this
fix.
Fixes: e42ee61017f5 ("of: Let of_for_each_phandle fallback to non-negative cell_count")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 2f25d2d..1d667eb 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1286,6 +1286,13 @@
memset(it, 0, sizeof(*it));
+ /*
+ * one of cell_count or cells_name must be provided to determine the
+ * argument length.
+ */
+ if (cell_count < 0 && !cells_name)
+ return -EINVAL;
+
list = of_get_property(np, list_name, &size);
if (!list)
return -ENOENT;
@@ -1512,10 +1519,17 @@
const char *cells_name, int index,
struct of_phandle_args *out_args)
{
+ int cell_count = -1;
+
if (index < 0)
return -EINVAL;
- return __of_parse_phandle_with_args(np, list_name, cells_name, -1,
- index, out_args);
+
+ /* If cells_name is NULL we assume a cell count of 0 */
+ if (!cells_name)
+ cell_count = 0;
+
+ return __of_parse_phandle_with_args(np, list_name, cells_name,
+ cell_count, index, out_args);
}
EXPORT_SYMBOL(of_parse_phandle_with_args);
@@ -1765,6 +1779,23 @@
struct of_phandle_iterator it;
int rc, cur_index = 0;
+ /*
+ * If cells_name is NULL we assume a cell count of 0. This makes
+ * counting the phandles trivial as each 32bit word in the list is a
+ * phandle and no arguments are to consider. So we don't iterate through
+ * the list but just use the length to determine the phandle count.
+ */
+ if (!cells_name) {
+ const __be32 *list;
+ int size;
+
+ list = of_get_property(np, list_name, &size);
+ if (!list)
+ return -ENOENT;
+
+ return size / sizeof(*list);
+ }
+
rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
if (rc)
return rc;
