Re: [PATCH v4 04/10] of: irq: add helper to remap interrupts to another irqdomain

[Lina Iyer <ilina@codeaurora.org>]

I observed an issue with return value being set to 0, when a match is
not found in the irqdomain-map.

On Wed, Mar 13 2019 at 15:20 -0600, Lina Iyer wrote:
>From: Stephen Boyd <swboyd@chromium.org>
>
>Sometimes interrupts are routed from an interrupt controller to another
>in no specific order. Having these in the drivers makes it difficult to
>maintain when the same drivers supports multiple variants with different
>mapping. Also, specifying them in DT makes little sense with a bunch of
>numbers like -
>	<0, 13>, <5, 32>,
>
>It makes more sense when we can have the parent handle along with
>interrupt specifiers for the incoming interrupt as well as that of the
>outgoing interrupt like -
>	<22 0 &intc 36 0>,
>	<24 0 &intc 37 0>,
>	<26 0 &intc 38 0>,
>
>And the interrupt specifiers can be interpreted using these optional
>properties -
>	irqdomain-map-mask = <0xff 0>;
>	irqdomain-map-pass-thru = <0 0xff>;
>
>The irqdomain-map-mask reads the input interrupt specifier to parse the
>incoming interrupt port. The format of the output port is specified with
>the irqdomain-map-pass-thru property.
>
>Let's add a helper function to parse this from DT and match a struct
>irq_fwspec using the input interrupt specifier from the irqdomain-map
>and the valid bits specified in the irqdomain-map-mask and copy the
>output interrupt specifier from the map to irq_fwspec per the mask in
>irqdomain-map-pass-thru property for the matched interrupt.
>
>Signed-off-by: Stephen Boyd <swboyd@chromium.org>
>Signed-off-by: Lina Iyer <ilina@codeaurora.org>
>---
>Changes in v4:
>	- Fix commit text spelling and verbosity
>---
> drivers/of/irq.c       | 125 +++++++++++++++++++++++++++++++++++++++++
> include/linux/of_irq.h |   1 +
> 2 files changed, 126 insertions(+)
>
>diff --git a/drivers/of/irq.c b/drivers/of/irq.c
>index e1f6f392a4c0..a1534f947ed4 100644
>--- a/drivers/of/irq.c
>+++ b/drivers/of/irq.c
>@@ -273,6 +273,131 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
> }
> EXPORT_SYMBOL_GPL(of_irq_parse_raw);
>
>+int of_irq_domain_map(const struct irq_fwspec *in, struct irq_fwspec *out)
>+{
>+	char *stem_name;
>+	char *cells_name, *map_name = NULL, *mask_name = NULL;
>+	char *pass_name = NULL;
>+	struct device_node *cur, *new = NULL;
>+	const __be32 *map, *mask, *pass;
>+	static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
>+	static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
>+	__be32 initial_match_array[MAX_PHANDLE_ARGS];
>+	const __be32 *match_array = initial_match_array;
>+	int i, ret, map_len, match;
>+	u32 in_size, out_size;
>+
>+	stem_name = "";
>+	cells_name = "#interrupt-cells";
>+
>+	ret = -ENOMEM;
>+	map_name = kasprintf(GFP_KERNEL, "irqdomain%s-map", stem_name);
>+	if (!map_name)
>+		goto free;
>+
>+	mask_name = kasprintf(GFP_KERNEL, "irqdomain%s-map-mask", stem_name);
>+	if (!mask_name)
>+		goto free;
>+
>+	pass_name = kasprintf(GFP_KERNEL, "irqdomain%s-map-pass-thru", stem_name);
>+	if (!pass_name)
>+		goto free;
>+
>+	/* Get the #interrupt-cells property */
>+	cur = to_of_node(in->fwnode);
>+	ret = of_property_read_u32(cur, cells_name, &in_size);
>+	if (ret < 0)
>+		goto put;
>+
>+	/* Precalculate the match array - this simplifies match loop */
>+	for (i = 0; i < in_size; i++)
>+		initial_match_array[i] = cpu_to_be32(in->param[i]);
>+
>+	ret = -EINVAL;
This value...
>+	/* Get the irqdomain-map property */
>+	map = of_get_property(cur, map_name, &map_len);
>+	if (!map) {
>+		ret = 0;
>+		goto free;
>+	}
>+	map_len /= sizeof(u32);
>+
>+	/* Get the irqdomain-map-mask property (optional) */
>+	mask = of_get_property(cur, mask_name, NULL);
>+	if (!mask)
>+		mask = dummy_mask;
>+	/* Iterate through irqdomain-map property */
>+	match = 0;
>+	while (map_len > (in_size + 1) && !match) {
>+		/* Compare specifiers */
>+		match = 1;
>+		for (i = 0; i < in_size; i++, map_len--)
>+			match &= !((match_array[i] ^ *map++) & mask[i]);
>+
>+		of_node_put(new);
>+		new = of_find_node_by_phandle(be32_to_cpup(map));
>+		map++;
>+		map_len--;
>+
>+		/* Check if not found */
>+		if (!new)
>+			goto put;
>+
>+		if (!of_device_is_available(new))
>+			match = 0;
>+
>+		ret = of_property_read_u32(new, cells_name, &out_size);
Gets overwritten by this, and set to 0.
>+		if (ret)
>+			goto put;
>+
>+		/* Check for malformed properties */
>+		if (WARN_ON(out_size > MAX_PHANDLE_ARGS))
>+			goto put;
>+		if (map_len < out_size)
>+			goto put;
>+
>+		/* Move forward by new node's #interrupt-cells amount */
>+		map += out_size;
>+		map_len -= out_size;
>+	}
>+	if (match) {
If  match is not found, then ret remains 0.

>+		/* Get the irqdomain-map-pass-thru property (optional) */
>+		pass = of_get_property(cur, pass_name, NULL);
>+		if (!pass)
>+			pass = dummy_pass;
>+
>+		/*
>+		 * Successfully parsed a irqdomain-map translation; copy new
>+		 * specifier into the out structure, keeping the
>+		 * bits specified in irqdomain-map-pass-thru.
>+		 */
>+		match_array = map - out_size;
>+		for (i = 0; i < out_size; i++) {
>+			__be32 val = *(map - out_size + i);
>+
>+			out->param[i] = in->param[i];
>+			if (i < in_size) {
>+				val &= ~pass[i];
>+				val |= cpu_to_be32(out->param[i]) & pass[i];
>+			}
>+
>+			out->param[i] = be32_to_cpu(val);
>+		}
>+		out->param_count = in_size = out_size;
>+		out->fwnode = of_node_to_fwnode(new);
>+	}
>+put:
>+	of_node_put(cur);
>+	of_node_put(new);
>+free:
>+	kfree(mask_name);
>+	kfree(map_name);
>+	kfree(pass_name);
>+
>+	return ret;
>+}
>+EXPORT_SYMBOL(of_irq_domain_map);
>+
> /**
>  * of_irq_parse_one - Resolve an interrupt for a device
>  * @device: the device whose interrupt is to be resolved
>diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
>index 1214cabb2247..86342502a62a 100644
>--- a/include/linux/of_irq.h
>+++ b/include/linux/of_irq.h
>@@ -32,6 +32,7 @@ static inline int of_irq_parse_oldworld(struct device_node *device, int index,
> }
> #endif /* CONFIG_PPC32 && CONFIG_PPC_PMAC */
>
>+extern int of_irq_domain_map(const struct irq_fwspec *in, struct irq_fwspec *out);
> extern int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq);
> extern int of_irq_parse_one(struct device_node *device, int index,
> 			  struct of_phandle_args *out_irq);
>--
>The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>a Linux Foundation Collaborative Project
>
--8<---
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 2653abfaf09d..e12f27403b3a 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -361,32 +361,36 @@ int of_irq_domain_map(const struct irq_fwspec *in, struct irq_fwspec *out)
                map += out_size;
                map_len -= out_size;
        }
-       if (match) {
-               /* Get the irqdomain-map-pass-thru property (optional) */
-               pass = of_get_property(cur, pass_name, NULL);
-               if (!pass)
-                       pass = dummy_pass;

-               /*
-                * Successfully parsed a irqdomain-map translation; copy new
-                * specifier into the out structure, keeping the
-                * bits specified in irqdomain-map-pass-thru.
-                */
-               match_array = map - out_size;
-               for (i = 0; i < out_size; i++) {
-                       __be32 val = *(map - out_size + i);
-
-                       out->param[i] = in->param[i];
-                       if (i < in_size) {
-                               val &= ~pass[i];
-                               val |= cpu_to_be32(out->param[i]) & pass[i];
-                       }
+       if (!match) {
+               ret = -EINVAL;
+               goto put;
+       }

-                       out->param[i] = be32_to_cpu(val);
+       /* Get the irqdomain-map-pass-thru property (optional) */
+       pass = of_get_property(cur, pass_name, NULL);
+       if (!pass)
+               pass = dummy_pass;
+
+       /*
+        * Successfully parsed a irqdomain-map translation; copy new
+        * specifier into the out structure, keeping the
+        * bits specified in irqdomain-map-pass-thru.
+        */
+       match_array = map - out_size;
+       for (i = 0; i < out_size; i++) {
+               __be32 val = *(map - out_size + i);
+
+               out->param[i] = in->param[i];
+               if (i < in_size) {
+                       val &= ~pass[i];
+                       val |= cpu_to_be32(out->param[i]) & pass[i];
                }
-               out->param_count = in_size = out_size;
-               out->fwnode = of_node_to_fwnode(new);
+
+               out->param[i] = be32_to_cpu(val);
        }
+       out->param_count = in_size = out_size;
+       out->fwnode = of_node_to_fwnode(new);
 put:
        of_node_put(cur);
        of_node_put(new);