staging: fsl-mc: Extended MC bus allocator to include IRQs

All the IRQs for DPAA2 objects in the same DPRC must use
the ICID of that DPRC, as their device Id in the GIC-ITS.
Thus, all these IRQs must share the same ITT table in the GIC.
As a result, a pool of IRQs with the same device Id must be
preallocated per DPRC (fsl-mc bus instance). So, the fsl-mc
bus object allocator is extended to also provide services
to allocate IRQs to DPAA2 devices, from their parent fsl-mc bus
IRQ pool.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fsl-mc/bus/mc-allocator.c

@@ -15,6 +15,7 @@
 #include "../include/dpcon-cmd.h"
 #include "dpmcp-cmd.h"
 #include "dpmcp.h"
+#include <linux/msi.h>
 
 /**
  * fsl_mc_resource_pool_add_device - add allocatable device to a resource
@@ -160,6 +161,7 @@ static const char *const fsl_mc_pool_type_strings[] = {
 	[FSL_MC_POOL_DPMCP] = "dpmcp",
 	[FSL_MC_POOL_DPBP] = "dpbp",
 	[FSL_MC_POOL_DPCON] = "dpcon",
+	[FSL_MC_POOL_IRQ] = "irq",
 };
 
 static int __must_check object_type_to_pool_type(const char *object_type,
@@ -465,6 +467,203 @@ void fsl_mc_object_free(struct fsl_mc_device *mc_adev)
 }
 EXPORT_SYMBOL_GPL(fsl_mc_object_free);
 
+/*
+ * Initialize the interrupt pool associated with a MC bus.
+ * It allocates a block of IRQs from the GIC-ITS
+ */
+int fsl_mc_populate_irq_pool(struct fsl_mc_bus *mc_bus,
+			     unsigned int irq_count)
+{
+	unsigned int i;
+	struct msi_desc *msi_desc;
+	struct fsl_mc_device_irq *irq_resources;
+	struct fsl_mc_device_irq *mc_dev_irq;
+	int error;
+	struct fsl_mc_device *mc_bus_dev = &mc_bus->mc_dev;
+	struct fsl_mc_resource_pool *res_pool =
+			&mc_bus->resource_pools[FSL_MC_POOL_IRQ];
+
+	if (WARN_ON(irq_count == 0 ||
+		    irq_count > FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS))
+		return -EINVAL;
+
+	error = fsl_mc_msi_domain_alloc_irqs(&mc_bus_dev->dev, irq_count);
+	if (error < 0)
+		return error;
+
+	irq_resources = devm_kzalloc(&mc_bus_dev->dev,
+				     sizeof(*irq_resources) * irq_count,
+				     GFP_KERNEL);
+	if (!irq_resources) {
+		error = -ENOMEM;
+		goto cleanup_msi_irqs;
+	}
+
+	for (i = 0; i < irq_count; i++) {
+		mc_dev_irq = &irq_resources[i];
+
+		/*
+		 * NOTE: This mc_dev_irq's MSI addr/value pair will be set
+		 * by the fsl_mc_msi_write_msg() callback
+		 */
+		mc_dev_irq->resource.type = res_pool->type;
+		mc_dev_irq->resource.data = mc_dev_irq;
+		mc_dev_irq->resource.parent_pool = res_pool;
+		INIT_LIST_HEAD(&mc_dev_irq->resource.node);
+		list_add_tail(&mc_dev_irq->resource.node, &res_pool->free_list);
+	}
+
+	for_each_msi_entry(msi_desc, &mc_bus_dev->dev) {
+		mc_dev_irq = &irq_resources[msi_desc->fsl_mc.msi_index];
+		mc_dev_irq->msi_desc = msi_desc;
+		mc_dev_irq->resource.id = msi_desc->irq;
+	}
+
+	res_pool->max_count = irq_count;
+	res_pool->free_count = irq_count;
+	mc_bus->irq_resources = irq_resources;
+	return 0;
+
+cleanup_msi_irqs:
+	fsl_mc_msi_domain_free_irqs(&mc_bus_dev->dev);
+	return error;
+}
+EXPORT_SYMBOL_GPL(fsl_mc_populate_irq_pool);
+
+/**
+ * Teardown the interrupt pool associated with an MC bus.
+ * It frees the IRQs that were allocated to the pool, back to the GIC-ITS.
+ */
+void fsl_mc_cleanup_irq_pool(struct fsl_mc_bus *mc_bus)
+{
+	struct fsl_mc_device *mc_bus_dev = &mc_bus->mc_dev;
+	struct fsl_mc_resource_pool *res_pool =
+			&mc_bus->resource_pools[FSL_MC_POOL_IRQ];
+
+	if (WARN_ON(!mc_bus->irq_resources))
+		return;
+
+	if (WARN_ON(res_pool->max_count == 0))
+		return;
+
+	if (WARN_ON(res_pool->free_count != res_pool->max_count))
+		return;
+
+	INIT_LIST_HEAD(&res_pool->free_list);
+	res_pool->max_count = 0;
+	res_pool->free_count = 0;
+	mc_bus->irq_resources = NULL;
+	fsl_mc_msi_domain_free_irqs(&mc_bus_dev->dev);
+}
+EXPORT_SYMBOL_GPL(fsl_mc_cleanup_irq_pool);
+
+/**
+ * It allocates the IRQs required by a given MC object device. The
+ * IRQs are allocated from the interrupt pool associated with the
+ * MC bus that contains the device, if the device is not a DPRC device.
+ * Otherwise, the IRQs are allocated from the interrupt pool associated
+ * with the MC bus that represents the DPRC device itself.
+ */
+int __must_check fsl_mc_allocate_irqs(struct fsl_mc_device *mc_dev)
+{
+	int i;
+	int irq_count;
+	int res_allocated_count = 0;
+	int error = -EINVAL;
+	struct fsl_mc_device_irq **irqs = NULL;
+	struct fsl_mc_bus *mc_bus;
+	struct fsl_mc_resource_pool *res_pool;
+
+	if (WARN_ON(mc_dev->irqs))
+		return -EINVAL;
+
+	irq_count = mc_dev->obj_desc.irq_count;
+	if (WARN_ON(irq_count == 0))
+		return -EINVAL;
+
+	if (strcmp(mc_dev->obj_desc.type, "dprc") == 0)
+		mc_bus = to_fsl_mc_bus(mc_dev);
+	else
+		mc_bus = to_fsl_mc_bus(to_fsl_mc_device(mc_dev->dev.parent));
+
+	if (WARN_ON(!mc_bus->irq_resources))
+		return -EINVAL;
+
+	res_pool = &mc_bus->resource_pools[FSL_MC_POOL_IRQ];
+	if (res_pool->free_count < irq_count) {
+		dev_err(&mc_dev->dev,
+			"Not able to allocate %u irqs for device\n", irq_count);
+		return -ENOSPC;
+	}
+
+	irqs = devm_kzalloc(&mc_dev->dev, irq_count * sizeof(irqs[0]),
+			    GFP_KERNEL);
+	if (!irqs)
+		return -ENOMEM;
+
+	for (i = 0; i < irq_count; i++) {
+		struct fsl_mc_resource *resource;
+
+		error = fsl_mc_resource_allocate(mc_bus, FSL_MC_POOL_IRQ,
+						 &resource);
+		if (error < 0)
+			goto error_resource_alloc;
+
+		irqs[i] = to_fsl_mc_irq(resource);
+		res_allocated_count++;
+
+		WARN_ON(irqs[i]->mc_dev);
+		irqs[i]->mc_dev = mc_dev;
+		irqs[i]->dev_irq_index = i;
+	}
+
+	mc_dev->irqs = irqs;
+	return 0;
+
+error_resource_alloc:
+	for (i = 0; i < res_allocated_count; i++) {
+		irqs[i]->mc_dev = NULL;
+		fsl_mc_resource_free(&irqs[i]->resource);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(fsl_mc_allocate_irqs);
+
+/*
+ * It frees the IRQs that were allocated for a MC object device, by
+ * returning them to the corresponding interrupt pool.
+ */
+void fsl_mc_free_irqs(struct fsl_mc_device *mc_dev)
+{
+	int i;
+	int irq_count;
+	struct fsl_mc_bus *mc_bus;
+	struct fsl_mc_device_irq **irqs = mc_dev->irqs;
+
+	if (WARN_ON(!irqs))
+		return;
+
+	irq_count = mc_dev->obj_desc.irq_count;
+
+	if (strcmp(mc_dev->obj_desc.type, "dprc") == 0)
+		mc_bus = to_fsl_mc_bus(mc_dev);
+	else
+		mc_bus = to_fsl_mc_bus(to_fsl_mc_device(mc_dev->dev.parent));
+
+	if (WARN_ON(!mc_bus->irq_resources))
+		return;
+
+	for (i = 0; i < irq_count; i++) {
+		WARN_ON(!irqs[i]->mc_dev);
+		irqs[i]->mc_dev = NULL;
+		fsl_mc_resource_free(&irqs[i]->resource);
+	}
+
+	mc_dev->irqs = NULL;
+}
+EXPORT_SYMBOL_GPL(fsl_mc_free_irqs);
+
 /**
  * fsl_mc_allocator_probe - callback invoked when an allocatable device is
  * being added to the system

drivers/staging/fsl-mc/include/mc-private.h

@@ -29,6 +29,16 @@
 struct irq_domain;
 struct msi_domain_info;
 
+/**
+ * Maximum number of total IRQs that can be pre-allocated for an MC bus'
+ * IRQ pool
+ */
+#define FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS	256
+
+struct device_node;
+struct irq_domain;
+struct msi_domain_info;
+
 /**
  * struct fsl_mc - Private data of a "fsl,qoriq-mc" platform device
  * @root_mc_bus_dev: MC object device representing the root DPRC
@@ -137,4 +147,9 @@ int __init its_fsl_mc_msi_init(void);
 
 void its_fsl_mc_msi_cleanup(void);
 
+int fsl_mc_populate_irq_pool(struct fsl_mc_bus *mc_bus,
+			     unsigned int irq_count);
+
+void fsl_mc_cleanup_irq_pool(struct fsl_mc_bus *mc_bus);
+
 #endif /* _FSL_MC_PRIVATE_H_ */

drivers/staging/fsl-mc/include/mc.h

@@ -14,12 +14,14 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 #include <linux/list.h>
+#include <linux/interrupt.h>
 #include "../include/dprc.h"
 
 #define FSL_MC_VENDOR_FREESCALE	0x1957
 
 struct fsl_mc_device;
 struct fsl_mc_io;
+struct fsl_mc_bus;
 
 /**
  * struct fsl_mc_driver - MC object device driver object
@@ -75,6 +77,7 @@ enum fsl_mc_pool_type {
 	FSL_MC_POOL_DPMCP = 0x0,    /* corresponds to "dpmcp" in the MC */
 	FSL_MC_POOL_DPBP,	    /* corresponds to "dpbp" in the MC */
 	FSL_MC_POOL_DPCON,	    /* corresponds to "dpcon" in the MC */
+	FSL_MC_POOL_IRQ,
 
 	/*
 	 * NOTE: New resource pool types must be added before this entry
@@ -141,6 +144,7 @@ struct fsl_mc_device_irq {
  * NULL if none.
  * @obj_desc: MC description of the DPAA device
  * @regions: pointer to array of MMIO region entries
+ * @irqs: pointer to array of pointers to interrupts allocated to this device
  * @resource: generic resource associated with this MC object device, if any.
  *
  * Generic device object for MC object devices that are "attached" to a
@@ -172,6 +176,7 @@ struct fsl_mc_device {
 	struct fsl_mc_io *mc_io;
 	struct dprc_obj_desc obj_desc;
 	struct resource *regions;
+	struct fsl_mc_device_irq **irqs;
 	struct fsl_mc_resource *resource;
 };
 
@@ -215,6 +220,10 @@ int __must_check fsl_mc_object_allocate(struct fsl_mc_device *mc_dev,
 
 void fsl_mc_object_free(struct fsl_mc_device *mc_adev);
 
+int __must_check fsl_mc_allocate_irqs(struct fsl_mc_device *mc_dev);
+
+void fsl_mc_free_irqs(struct fsl_mc_device *mc_dev);
+
 extern struct bus_type fsl_mc_bus_type;
 
 #endif /* _FSL_MC_H_ */