[PATCH v2 6/7] platform-msi: Allow creation of a MSI-based stacked irq domain
Marc Zyngier
marc.zyngier at arm.com
Mon Nov 23 00:26:07 PST 2015
We almost have all the needed bits requiredable to create a irq domain
on top of a MSI domain.
For this, we enable a few things:
- the virq is stored in the msi_desc
- device, msi_alloc_info and domain-specific data
are stored in the platform_priv_data structure
- we introduce a new API for platform-msi:
/* Create a MSI-based domain */
struct irq_domain *
platform_msi_create_device_domain(struct device *dev,
unsigned int nvec,
irq_write_msi_msg_t write_msi_msg,
const struct irq_domain_ops *ops,
void *host_data);
/* Allocate MSIs in an MSI domain */
int platform_msi_domain_alloc(struct irq_domain *domain,
unsigned int virq,
unsigned int nr_irqs);
/* Free MSIs from an MSI domain */
void platform_msi_domain_free(struct irq_domain *domain,
unsigned int virq,
unsigned int nvec);
/* Obtain the host data passed to platform_msi_create_device_domain */
void *platform_msi_get_host_data(struct irq_domain *domain);
platform_msi_create_device_domain() is a hybrid of irqdomain creation
and interrupt allocation, creating a domain backed by the MSIs associated
to a device. IRQs can then be allocated in that domain using
platform_msi_domain_alloc().
This now allows a wired irq to MSI bridge to be created.
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
drivers/base/platform-msi.c | 130 +++++++++++++++++++++++++++++++++++++++++++-
include/linux/msi.h | 12 ++++
2 files changed, 140 insertions(+), 2 deletions(-)
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 44b8c0d..a203896 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -32,6 +32,9 @@
* and the callback to write the MSI message.
*/
struct platform_msi_priv_data {
+ struct device *dev;
+ void *host_data;
+ msi_alloc_info_t arg;
irq_write_msi_msg_t write_msg;
int devid;
};
@@ -124,8 +127,9 @@ static void platform_msi_free_descs(struct device *dev, int base, int nvec)
}
}
-static int platform_msi_alloc_descs(struct device *dev, int nvec,
- struct platform_msi_priv_data *data)
+static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
+ int nvec,
+ struct platform_msi_priv_data *data)
{
struct msi_desc *desc;
@@ -145,6 +149,7 @@ static int platform_msi_alloc_descs(struct device *dev, int nvec,
desc->platform.msi_priv_data = data;
desc->platform.msi_index = base + i;
desc->nvec_used = 1;
+ desc->irq = virq ? virq + i : 0;
list_add_tail(&desc->list, dev_to_msi_list(dev));
}
@@ -159,6 +164,13 @@ static int platform_msi_alloc_descs(struct device *dev, int nvec,
return 0;
}
+static int platform_msi_alloc_descs(struct device *dev, int nvec,
+ struct platform_msi_priv_data *data)
+
+{
+ return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
+}
+
/**
* platform_msi_create_irq_domain - Create a platform MSI interrupt domain
* @fwnode: Optional fwnode of the interrupt controller
@@ -225,6 +237,7 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
}
datap->write_msg = write_msi_msg;
+ datap->dev = dev;
return datap;
}
@@ -288,3 +301,116 @@ void platform_msi_domain_free_irqs(struct device *dev)
msi_domain_free_irqs(dev->msi_domain, dev);
platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
}
+
+/**
+ * platform_msi_get_host_data - Query the private data associated with
+ * a platform-msi domain
+ * @domain: The platform-msi domain
+ *
+ * Returns the private data provided when calling
+ * platform_msi_create_device_domain.
+ */
+void *platform_msi_get_host_data(struct irq_domain *domain)
+{
+ struct platform_msi_priv_data *data = domain->host_data;
+ return data->host_data;
+}
+
+/**
+ * platform_msi_create_device_domain - Create a platform-msi domain
+ *
+ * @dev: The device generating the MSIs
+ * @nvec: The number of MSIs that need to be allocated
+ * @write_msi_msg: Callback to write an interrupt message for @dev
+ * @ops: The hierarchy domain operations to use
+ * @host_data: Private data associated to this domain
+ *
+ * Returns an irqdomain for @nvec interrupts
+ */
+struct irq_domain *
+platform_msi_create_device_domain(struct device *dev,
+ unsigned int nvec,
+ irq_write_msi_msg_t write_msi_msg,
+ const struct irq_domain_ops *ops,
+ void *host_data)
+{
+ struct platform_msi_priv_data *data;
+ struct irq_domain *domain;
+ int err;
+
+ data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
+ if (IS_ERR(data))
+ return NULL;
+
+ data->host_data = host_data;
+ domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
+ of_node_to_fwnode(dev->of_node),
+ ops, data);
+ if (!domain)
+ goto free_priv;
+
+ err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
+ if (err)
+ goto free_domain;
+
+ return domain;
+
+free_domain:
+ irq_domain_remove(domain);
+free_priv:
+ platform_msi_free_priv_data(data);
+ return NULL;
+}
+
+/**
+ * platform_msi_domain_free - Free interrupts associated with a platform-msi
+ * domain
+ *
+ * @domain: The platform-msi domain
+ * @virq: The base irq from which to perform the free operation
+ * @nvec: How many interrupts to free from @virq
+ */
+void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
+ unsigned int nvec)
+{
+ struct platform_msi_priv_data *data = domain->host_data;
+ struct msi_desc *desc;
+ for_each_msi_entry(desc, data->dev) {
+ if (WARN_ON(!desc->irq || desc->nvec_used != 1))
+ return;
+ if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
+ continue;
+
+ irq_domain_free_irqs_common(domain, desc->irq, 1);
+ }
+}
+
+/**
+ * platform_msi_domain_alloc - Allocate interrupts associated with
+ * a platform-msi domain
+ *
+ * @domain: The platform-msi domain
+ * @virq: The base irq from which to perform the allocate operation
+ * @nvec: How many interrupts to free from @virq
+ *
+ * Return 0 on success, or an error code on failure. Must be called
+ * with irq_domain_mutex held (which can only be done as part of a
+ * top-level interrupt allocation).
+ */
+int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs)
+{
+ struct platform_msi_priv_data *data = domain->host_data;
+ int err;
+
+ err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
+ if (err)
+ return err;
+
+ err = msi_domain_populate_irqs(domain->parent, data->dev,
+ virq, nr_irqs, &data->arg);
+ if (err)
+ platform_msi_domain_free(domain, virq, nr_irqs);
+
+ return err;
+}
diff --git a/include/linux/msi.h b/include/linux/msi.h
index cee102b..1c6342a 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -174,6 +174,7 @@ struct msi_controller {
#include <asm/msi.h>
struct irq_domain;
+struct irq_domain_ops;
struct irq_chip;
struct device_node;
struct fwnode_handle;
@@ -285,6 +286,17 @@ int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
int nvec, msi_alloc_info_t *args);
int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
int virq, int nvec, msi_alloc_info_t *args);
+struct irq_domain *
+platform_msi_create_device_domain(struct device *dev,
+ unsigned int nvec,
+ irq_write_msi_msg_t write_msi_msg,
+ const struct irq_domain_ops *ops,
+ void *host_data);
+int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs);
+void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
+ unsigned int nvec);
+void *platform_msi_get_host_data(struct irq_domain *domain);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
--
2.1.4
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