[PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[Niklas Söderlund]

All lines in data-lanes and clock-lanes properties must be unique.
Instead of drivers checking for this add it to the generic parser.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 drivers/media/v4l2-core/v4l2-of.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
index 93b33681776c..1042db6bb996 100644
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -32,12 +32,19 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
 	prop = of_find_property(node, "data-lanes", NULL);
 	if (prop) {
 		const __be32 *lane = NULL;
-		unsigned int i;
+		unsigned int i, n;
 
 		for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
 			lane = of_prop_next_u32(prop, lane, &v);
 			if (!lane)
 				break;
+			for (n = 0; n < i; n++) {
+				if (bus->data_lanes[n] == v) {
+					pr_warn("%s: duplicated lane %u in data-lanes\n",
+						node->full_name, v);
+					return -EINVAL;
+				}
+			}
 			bus->data_lanes[i] = v;
 		}
 		bus->num_data_lanes = i;
@@ -63,6 +70,15 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
 	}
 
 	if (!of_property_read_u32(node, "clock-lanes", &v)) {
+		unsigned int n;
+
+		for (n = 0; n < bus->num_data_lanes; n++) {
+			if (bus->data_lanes[n] == v) {
+				pr_warn("%s: duplicated lane %u in clock-lanes\n",
+					node->full_name, v);
+				return -EINVAL;
+			}
+		}
 		bus->clock_lane = v;
 		have_clk_lane = true;
 	}
-- 
2.11.0

Re: [PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[Geert Uytterhoeven]

Hi Niklas,

On Thu, Jan 26, 2017 at 2:12 PM, Niklas Söderlund
<niklas.soderlund+renesas@ragnatech.se> wrote:
> diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
> index 93b33681776c..1042db6bb996 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -32,12 +32,19 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>         prop = of_find_property(node, "data-lanes", NULL);
>         if (prop) {
>                 const __be32 *lane = NULL;
> -               unsigned int i;
> +               unsigned int i, n;

Not "j"?

>                 for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
>                         lane = of_prop_next_u32(prop, lane, &v);
>                         if (!lane)
>                                 break;
> +                       for (n = 0; n < i; n++) {

I'm not used seeing for loops with an index named "n", and limit named "i" ;-)

> +                               if (bus->data_lanes[n] == v) {
> +                                       pr_warn("%s: duplicated lane %u in data-lanes\n",
> +                                               node->full_name, v);
> +                                       return -EINVAL;
> +                               }
> +                       }
>                         bus->data_lanes[i] = v;
>                 }
>                 bus->num_data_lanes = i;
> @@ -63,6 +70,15 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>         }
>
>         if (!of_property_read_u32(node, "clock-lanes", &v)) {
> +               unsigned int n;

Likewise.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[Sakari Ailus]

Hi Niklas,

On Thu, Jan 26, 2017 at 02:12:59PM +0100, Niklas Söderlund wrote:
> All lines in data-lanes and clock-lanes properties must be unique.
> Instead of drivers checking for this add it to the generic parser.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  drivers/media/v4l2-core/v4l2-of.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
> index 93b33681776c..1042db6bb996 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -32,12 +32,19 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>  	prop = of_find_property(node, "data-lanes", NULL);
>  	if (prop) {
>  		const __be32 *lane = NULL;
> -		unsigned int i;
> +		unsigned int i, n;
>  
>  		for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
>  			lane = of_prop_next_u32(prop, lane, &v);
>  			if (!lane)
>  				break;
> +			for (n = 0; n < i; n++) {
> +				if (bus->data_lanes[n] == v) {
> +					pr_warn("%s: duplicated lane %u in data-lanes\n",
> +						node->full_name, v);
> +					return -EINVAL;
> +				}
> +			}

In some cases it's just the number of lanes that matter, not their order, as
the hardware cannot reorder them. I might still just print a warning but not
return an error. Same below.

Although then hardware that actually can reorder the lanes might have issues
if such a bug exists in DTB. Presumably the DTB would have been tested at
some point though.

>  			bus->data_lanes[i] = v;
>  		}
>  		bus->num_data_lanes = i;
> @@ -63,6 +70,15 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>  	}
>  
>  	if (!of_property_read_u32(node, "clock-lanes", &v)) {
> +		unsigned int n;
> +
> +		for (n = 0; n < bus->num_data_lanes; n++) {
> +			if (bus->data_lanes[n] == v) {
> +				pr_warn("%s: duplicated lane %u in clock-lanes\n",
> +					node->full_name, v);
> +				return -EINVAL;
> +			}
> +		}
>  		bus->clock_lane = v;
>  		have_clk_lane = true;
>  	}

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi	XMPP: sailus@retiisi.org.uk

Re: [PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[Sakari Ailus]

Hi Niklas,

On Thu, Jan 26, 2017 at 02:12:59PM +0100, Niklas S�derlund wrote:
> All lines in data-lanes and clock-lanes properties must be unique.
> Instead of drivers checking for this add it to the generic parser.
> 
> Signed-off-by: Niklas S�derlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  drivers/media/v4l2-core/v4l2-of.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
> index 93b33681776c..1042db6bb996 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -32,12 +32,19 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>  	prop = of_find_property(node, "data-lanes", NULL);
>  	if (prop) {
>  		const __be32 *lane = NULL;
> -		unsigned int i;
> +		unsigned int i, n;
>  
>  		for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
>  			lane = of_prop_next_u32(prop, lane, &v);
>  			if (!lane)
>  				break;
> +			for (n = 0; n < i; n++) {
> +				if (bus->data_lanes[n] == v) {
> +					pr_warn("%s: duplicated lane %u in data-lanes\n",
> +						node->full_name, v);
> +					return -EINVAL;
> +				}
> +			}

In some cases it's just the number of lanes that matter, not their order, as
the hardware cannot reorder them. I might still just print a warning but not
return an error. Same below.

Although then hardware that actually can reorder the lanes might have issues
if such a bug exists in DTB. Presumably the DTB would have been tested at
some point though.

>  			bus->data_lanes[i] = v;
>  		}
>  		bus->num_data_lanes = i;
> @@ -63,6 +70,15 @@ static int v4l2_of_parse_csi_bus(const struct device_node *node,
>  	}
>  
>  	if (!of_property_read_u32(node, "clock-lanes", &v)) {
> +		unsigned int n;
> +
> +		for (n = 0; n < bus->num_data_lanes; n++) {
> +			if (bus->data_lanes[n] == v) {
> +				pr_warn("%s: duplicated lane %u in clock-lanes\n",
> +					node->full_name, v);
> +				return -EINVAL;
> +			}
> +		}
>  		bus->clock_lane = v;
>  		have_clk_lane = true;
>  	}

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi	XMPP: sailus@retiisi.org.uk

Re: [PATCH] v4l: of: check for unique lanes in data-lanes and clock-lanes

[Laurent Pinchart]

Hi Niklas,

Thank you for the patch.

On Thursday 26 Jan 2017 14:12:59 Niklas Söderlund wrote:
> All lines in data-lanes and clock-lanes properties must be unique.
> Instead of drivers checking for this add it to the generic parser.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  drivers/media/v4l2-core/v4l2-of.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-of.c
> b/drivers/media/v4l2-core/v4l2-of.c index 93b33681776c..1042db6bb996 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -32,12 +32,19 @@ static int v4l2_of_parse_csi_bus(const struct
> device_node *node, prop = of_find_property(node, "data-lanes", NULL);
>  	if (prop) {
>  		const __be32 *lane = NULL;
> -		unsigned int i;
> +		unsigned int i, n;
> 
>  		for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
>  			lane = of_prop_next_u32(prop, lane, &v);
>  			if (!lane)
>  				break;
> +			for (n = 0; n < i; n++) {
> +				if (bus->data_lanes[n] == v) {
> +					pr_warn("%s: duplicated lane %u in 
data-lanes\n",
> +						node->full_name, v);
> +					return -EINVAL;
> +				}

If you used a bitmask to store the already used lanes you could avoid the 
nested loops.

Apart from that,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +			}
>  			bus->data_lanes[i] = v;
>  		}
>  		bus->num_data_lanes = i;
> @@ -63,6 +70,15 @@ static int v4l2_of_parse_csi_bus(const struct device_node
> *node, }
> 
>  	if (!of_property_read_u32(node, "clock-lanes", &v)) {
> +		unsigned int n;
> +
> +		for (n = 0; n < bus->num_data_lanes; n++) {
> +			if (bus->data_lanes[n] == v) {
> +				pr_warn("%s: duplicated lane %u in clock-
lanes\n",
> +					node->full_name, v);
> +				return -EINVAL;
> +			}
> +		}
>  		bus->clock_lane = v;
>  		have_clk_lane = true;
>  	}

-- 
Regards,

Laurent Pinchart