From 8db02d8b4089fa8098a170738e8ae7939aa8ae7a Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 8 Oct 2015 15:10:48 -0700 Subject: [PATCH] of/irq: Add new function of_msi_map_rid() 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 Acked-by: Rob Herring Signed-off-by: David Daney Signed-off-by: Marc Zyngier --- 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 55317fa9c9dc..c90bd4ec3183 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 4bcbd586a672..8cd9334e5731 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 */ -- 2.20.1