This patch causes pcs_parse_pinconf() to return an error when no
pinctrl_map is added. The current behavior is to return 0 when
!PCS_HAS_PINCONF or !nconfs. Thus pcs_parse_one_pinctrl_entry()
incorrectly assumes that a map was added and sets num_maps = 2.
Analysis:
=========
The function pcs_parse_one_pinctrl_entry() calls pcs_parse_pinconf()
if PCS_HAS_PINCONF is enabled. The function pcs_parse_pinconf()
returns 0 to indicate there was no error and num_maps is then set to 2:
980 static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs,
981 struct device_node *np,
982 struct pinctrl_map **map,
983 unsigned *num_maps,
984 const char **pgnames)
985 {
<snip>
1053 (*map)->type = PIN_MAP_TYPE_MUX_GROUP;
1054 (*map)->data.mux.group = np->name;
1055 (*map)->data.mux.function = np->name;
1056
1057 if (PCS_HAS_PINCONF && function) {
1058 res = pcs_parse_pinconf(pcs, np, function, map);
1059 if (res)
1060 goto free_pingroups;
1061 *num_maps = 2;
1062 } else {
1063 *num_maps = 1;
1064 }
However, pcs_parse_pinconf() will also return 0 if !PCS_HAS_PINCONF or
!nconfs. I believe these conditions should indicate that no map was
added by returning non-zero. Otherwise pcs_parse_one_pinctrl_entry()
will set num_maps = 2 even though no maps were successfully added, as
it does not reach "m++" on line 940:
895 static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
896 struct pcs_function *func,
897 struct pinctrl_map **map)
898
899 {
900 struct pinctrl_map *m = *map;
<snip>
917 /* If pinconf isn't supported, don't parse properties in below. */
918 if (!PCS_HAS_PINCONF)
919 return 0;
920
921 /* cacluate how much properties are supported in current node */
922 for (i = 0; i < ARRAY_SIZE(prop2); i++) {
923 if (of_find_property(np, prop2[i].name, NULL))
924 nconfs++;
925 }
926 for (i = 0; i < ARRAY_SIZE(prop4); i++) {
927 if (of_find_property(np, prop4[i].name, NULL))
928 nconfs++;
929 }
930 if (!nconfs)
919 return 0;
932
933 func->conf = devm_kcalloc(pcs->dev,
934 nconfs, sizeof(struct pcs_conf_vals),
935 GFP_KERNEL);
936 if (!func->conf)
937 return -ENOMEM;
938 func->nconfs = nconfs;
939 conf = &(func->conf[0]);
940 m++;
This situtation will cause a boot failure [0] on the BeagleBone Black
(AM3358) when am33xx_pinmux node in arch/arm/boot/dts/am33xx-l4.dtsi
has compatible = "pinconf-single" instead of "pinctrl-single".
The patch fixes this issue by returning -ENOSUPP when !PCS_HAS_PINCONF
or !nconfs, so that pcs_parse_one_pinctrl_entry() will know that no
map was added.
[0] https://lore.kernel.org/linux-omap/20200529175544.GA3766151@x1/
Signed-off-by: Drew Fustini <[email protected]>
---
drivers/pinctrl/pinctrl-single.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 1e0614daee9b..18a02cd0c701 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -916,7 +916,7 @@ static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
/* If pinconf isn't supported, don't parse properties in below. */
if (!PCS_HAS_PINCONF)
- return 0;
+ return -ENOTSUPP; /* do not return 0 as no map added */
/* cacluate how much properties are supported in current node */
for (i = 0; i < ARRAY_SIZE(prop2); i++) {
@@ -928,7 +928,7 @@ static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
nconfs++;
}
if (!nconfs)
- return 0;
+ return -ENOTSUPP; /* do not return 0 as no map added */
func->conf = devm_kcalloc(pcs->dev,
nconfs, sizeof(struct pcs_conf_vals),
--
2.25.1
* Drew Fustini <[email protected]> [200531 20:42]:
> This patch causes pcs_parse_pinconf() to return an error when no
> pinctrl_map is added. The current behavior is to return 0 when
> !PCS_HAS_PINCONF or !nconfs. Thus pcs_parse_one_pinctrl_entry()
> incorrectly assumes that a map was added and sets num_maps = 2.
Looks OK to me, would be good to wait for Haojian to test this one.
Regards,
Tony
On Mon, Jun 01, 2020 at 09:18:51AM -0700, Tony Lindgren wrote:
> * Drew Fustini <[email protected]> [200531 20:42]:
> > This patch causes pcs_parse_pinconf() to return an error when no
> > pinctrl_map is added. The current behavior is to return 0 when
> > !PCS_HAS_PINCONF or !nconfs. Thus pcs_parse_one_pinctrl_entry()
> > incorrectly assumes that a map was added and sets num_maps = 2.
>
> Looks OK to me, would be good to wait for Haojian to test this one.
>
> Regards,
>
> Tony
Yes, I would like to get input as I don't have the other platforms using
"pinconf,single":
$ git grep 'compatible = "pinconf-single"' arch/
arch/arm/boot/dts/am33xx-l4.dtsi: compatible = "pinconf-single";
arch/arm/boot/dts/hi3620.dtsi: compatible = "pinconf-single";
arch/arm/boot/dts/pxa3xx.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/broadcom/stingray/stingray-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hi3798cv200.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hi6220.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hi6220.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey960-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey960-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey960-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey960-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey960-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey970-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey970-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey970-pinctrl.dtsi: compatible = "pinconf-single";
arch/arm64/boot/dts/hisilicon/hikey970-pinctrl.dtsi: compatible = "pinconf-single";
NOTE: the arch/arm/boot/dts/am33xx-l4.dtsi was patched by me from
"pinctrl-single" to "pinconf-single. But, I think for upstream
submission I would need to move that to one of the beaglebone specific
dts files like am335x-bone-common.dtsi.
I believe this pinctrl-single.c patch fixes a flaw in return logic and
is useful regardless of whether beaglebone adopts "pinconf,single".
However, I would very much like to get input from others in case my
analysis is too narrow.
Thanks,
Drew
On 5/31/20 15:41, Drew Fustini wrote:
> This patch causes pcs_parse_pinconf() to return an error when no
> pinctrl_map is added. The current behavior is to return 0 when
> !PCS_HAS_PINCONF or !nconfs. Thus pcs_parse_one_pinctrl_entry()
> incorrectly assumes that a map was added and sets num_maps = 2.
>
> Analysis:
> =========
> The function pcs_parse_one_pinctrl_entry() calls pcs_parse_pinconf()
> if PCS_HAS_PINCONF is enabled. The function pcs_parse_pinconf()
> returns 0 to indicate there was no error and num_maps is then set to 2:
>
> 980 static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs,
> 981 struct device_node *np,
> 982 struct pinctrl_map **map,
> 983 unsigned *num_maps,
> 984 const char **pgnames)
> 985 {
> <snip>
> 1053 (*map)->type = PIN_MAP_TYPE_MUX_GROUP;
> 1054 (*map)->data.mux.group = np->name;
> 1055 (*map)->data.mux.function = np->name;
> 1056
> 1057 if (PCS_HAS_PINCONF && function) {
> 1058 res = pcs_parse_pinconf(pcs, np, function, map);
> 1059 if (res)
> 1060 goto free_pingroups;
> 1061 *num_maps = 2;
> 1062 } else {
> 1063 *num_maps = 1;
> 1064 }
>
> However, pcs_parse_pinconf() will also return 0 if !PCS_HAS_PINCONF or
> !nconfs. I believe these conditions should indicate that no map was
> added by returning non-zero. Otherwise pcs_parse_one_pinctrl_entry()
> will set num_maps = 2 even though no maps were successfully added, as
> it does not reach "m++" on line 940:
>
> 895 static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
> 896 struct pcs_function *func,
> 897 struct pinctrl_map **map)
> 898
> 899 {
> 900 struct pinctrl_map *m = *map;
> <snip>
> 917 /* If pinconf isn't supported, don't parse properties in below. */
> 918 if (!PCS_HAS_PINCONF)
> 919 return 0;
> 920
> 921 /* cacluate how much properties are supported in current node */
> 922 for (i = 0; i < ARRAY_SIZE(prop2); i++) {
> 923 if (of_find_property(np, prop2[i].name, NULL))
> 924 nconfs++;
> 925 }
> 926 for (i = 0; i < ARRAY_SIZE(prop4); i++) {
> 927 if (of_find_property(np, prop4[i].name, NULL))
> 928 nconfs++;
> 929 }
> 930 if (!nconfs)
> 919 return 0;
> 932
> 933 func->conf = devm_kcalloc(pcs->dev,
> 934 nconfs, sizeof(struct pcs_conf_vals),
> 935 GFP_KERNEL);
> 936 if (!func->conf)
> 937 return -ENOMEM;
> 938 func->nconfs = nconfs;
> 939 conf = &(func->conf[0]);
> 940 m++;
>
> This situtation will cause a boot failure [0] on the BeagleBone Black
> (AM3358) when am33xx_pinmux node in arch/arm/boot/dts/am33xx-l4.dtsi
> has compatible = "pinconf-single" instead of "pinctrl-single".
>
> The patch fixes this issue by returning -ENOSUPP when !PCS_HAS_PINCONF
> or !nconfs, so that pcs_parse_one_pinctrl_entry() will know that no
> map was added.
>
> [0] https://lore.kernel.org/linux-omap/20200529175544.GA3766151@x1/
>
Maybe add this Fixes tag here:
Fixes: 9dddb4df90d1 ("pinctrl: single: support generic pinconf")
--
Gustavo
> Signed-off-by: Drew Fustini <[email protected]>
> ---
> drivers/pinctrl/pinctrl-single.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
> index 1e0614daee9b..18a02cd0c701 100644
> --- a/drivers/pinctrl/pinctrl-single.c
> +++ b/drivers/pinctrl/pinctrl-single.c
> @@ -916,7 +916,7 @@ static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
>
> /* If pinconf isn't supported, don't parse properties in below. */
> if (!PCS_HAS_PINCONF)
> - return 0;
> + return -ENOTSUPP; /* do not return 0 as no map added */
>
> /* cacluate how much properties are supported in current node */
> for (i = 0; i < ARRAY_SIZE(prop2); i++) {
> @@ -928,7 +928,7 @@ static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
> nconfs++;
> }
> if (!nconfs)
> - return 0;
> + return -ENOTSUPP; /* do not return 0 as no map added */
>
> func->conf = devm_kcalloc(pcs->dev,
> nconfs, sizeof(struct pcs_conf_vals),
>