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Subject[PATCH v3 2/4] of/irq: Add new function of_msi_map_rid()
Date
From: David Daney <david.daney@cavium.com>

The device tree property "msi-map" specifies how to create the PCI
requester id used in some MSI controllers. Add a new function
of_msi_map_rid() that finds the msi-map property and applies its
translation to a given requester id.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: David Daney <david.daney@cavium.com>
---
drivers/of/irq.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_irq.h | 7 +++++
2 files changed, 91 insertions(+)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 55317fa..c90bd4e 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -598,3 +598,87 @@ void of_msi_configure(struct device *dev, struct device_node *np)
d = irq_find_host(msi_np);
dev_set_msi_domain(dev, d);
}
+
+/**
+ * of_msi_map_rid - Map a MSI requester ID for a device.
+ * @dev: device for which the mapping is to be done.
+ * @msi_np: device node of the expected msi controller.
+ * @rid_in: unmapped MSI requester ID for the device.
+ *
+ * Walk up the device hierarchy looking for devices with a "msi-map"
+ * property. If found, apply the mapping to @rid_in.
+ *
+ * Returns the mapped MSI requester ID.
+ */
+u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in)
+{
+ struct device *parent_dev;
+ struct device_node *msi_controller_node;
+ u32 map_mask, masked_rid, rid_base, msi_base, rid_len, phandle;
+ int msi_map_len;
+ bool matched;
+ u32 rid_out = rid_in;
+ const __be32 *msi_map = NULL;
+
+ /*
+ * Walk up the device parent links looking for one with a
+ * "msi-map" property.
+ */
+ for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) {
+ if (!parent_dev->of_node)
+ continue;
+
+ msi_map = of_get_property(parent_dev->of_node,
+ "msi-map", &msi_map_len);
+ if (!msi_map)
+ continue;
+
+ if (msi_map_len % (4 * sizeof(__be32))) {
+ dev_err(parent_dev, "Error: Bad msi-map length: %d\n",
+ msi_map_len);
+ return rid_out;
+ }
+ /* We have a good parent_dev and msi_map, let's use them. */
+ break;
+ }
+ if (!msi_map)
+ return rid_out;
+
+ /* The default is to select all bits. */
+ map_mask = 0xffffffff;
+
+ /*
+ * Can be overridden by "msi-map-mask" property. If
+ * of_property_read_u32() fails, the default is used.
+ */
+ of_property_read_u32(parent_dev->of_node, "msi-map-mask", &map_mask);
+
+ masked_rid = map_mask & rid_in;
+ matched = false;
+ while (!matched && msi_map_len >= 4 * sizeof(__be32)) {
+ rid_base = be32_to_cpup(msi_map + 0);
+ phandle = be32_to_cpup(msi_map + 1);
+ msi_base = be32_to_cpup(msi_map + 2);
+ rid_len = be32_to_cpup(msi_map + 3);
+
+ msi_controller_node = of_find_node_by_phandle(phandle);
+
+ matched = masked_rid >= rid_base &&
+ masked_rid < rid_base + rid_len &&
+ msi_np == msi_controller_node;
+
+ of_node_put(msi_controller_node);
+ msi_map_len -= 4 * sizeof(__be32);
+ msi_map += 4;
+ }
+ if (!matched)
+ return rid_out;
+
+ rid_out = masked_rid + msi_base;
+ dev_dbg(dev,
+ "msi-map at: %s, using mask %08x, rid-base: %08x, msi-base: %08x, length: %08x, rid: %08x -> %08x\n",
+ dev_name(parent_dev), map_mask, rid_base, msi_base,
+ rid_len, rid_in, rid_out);
+
+ return rid_out;
+}
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index 4bcbd58..8cd9334 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -75,6 +75,7 @@ static inline int of_irq_to_resource_table(struct device_node *dev,
extern unsigned int irq_of_parse_and_map(struct device_node *node, int index);
extern struct device_node *of_irq_find_parent(struct device_node *child);
extern void of_msi_configure(struct device *dev, struct device_node *np);
+u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in);

#else /* !CONFIG_OF */
static inline unsigned int irq_of_parse_and_map(struct device_node *dev,
@@ -87,6 +88,12 @@ static inline void *of_irq_find_parent(struct device_node *child)
{
return NULL;
}
+
+static inline u32 of_msi_map_rid(struct device *dev,
+ struct device_node *msi_np, u32 rid_in)
+{
+ return rid_in;
+}
#endif /* !CONFIG_OF */

#endif /* __OF_IRQ_H */
--
1.9.1


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