[PATCH 02/10] staging: fsl-mc: Added generic MSI support for FSL-MC devices

[J. German Rivera]

Created an MSI domain for the fsl-mc bus-- including functions
to create a domain, find a domain, alloc/free domain irqs, and
bus specific overrides for domain and irq_chip ops.

Signed-off-by: J. German Rivera <German.Rivera@xxxxxxxxxxxxx>
---
 drivers/staging/fsl-mc/bus/Kconfig          |   1 +
 drivers/staging/fsl-mc/bus/Makefile         |   1 +
 drivers/staging/fsl-mc/bus/mc-msi.c         | 278 ++++++++++++++++++++++++++++
 drivers/staging/fsl-mc/include/mc-private.h |  17 ++
 drivers/staging/fsl-mc/include/mc.h         |  17 ++
 5 files changed, 314 insertions(+)
 create mode 100644 drivers/staging/fsl-mc/bus/mc-msi.c

diff --git a/drivers/staging/fsl-mc/bus/Kconfig b/drivers/staging/fsl-mc/bus/Kconfig
index 0d779d9..c498ac6 100644
--- a/drivers/staging/fsl-mc/bus/Kconfig
+++ b/drivers/staging/fsl-mc/bus/Kconfig
@@ -9,6 +9,7 @@
 config FSL_MC_BUS
 	tristate "Freescale Management Complex (MC) bus driver"
 	depends on OF && ARM64
+	select GENERIC_MSI_IRQ_DOMAIN
 	help
 	  Driver to enable the bus infrastructure for the Freescale
           QorIQ Management Complex (fsl-mc). The fsl-mc is a hardware
diff --git a/drivers/staging/fsl-mc/bus/Makefile b/drivers/staging/fsl-mc/bus/Makefile
index 25433a9..a5f2ba4 100644
--- a/drivers/staging/fsl-mc/bus/Makefile
+++ b/drivers/staging/fsl-mc/bus/Makefile
@@ -13,5 +13,6 @@ mc-bus-driver-objs := mc-bus.o \
 		      dpmng.o \
 		      dprc-driver.o \
 		      mc-allocator.o \
+		      mc-msi.o \
 		      dpmcp.o \
 		      dpbp.o
diff --git a/drivers/staging/fsl-mc/bus/mc-msi.c b/drivers/staging/fsl-mc/bus/mc-msi.c
new file mode 100644
index 0000000..dfe8016
--- /dev/null
+++ b/drivers/staging/fsl-mc/bus/mc-msi.c
@@ -0,0 +1,278 @@
+/*
+ * Freescale Management Complex (MC) bus driver MSI support
+ *
+ * Copyright (C) 2015 Freescale Semiconductor, Inc.
+ * Author: German Rivera <German.Rivera@xxxxxxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include "../include/mc-private.h"
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/irqchip/arm-gic-v3.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include "../include/mc-sys.h"
+#include "dprc-cmd.h"
+
+static void fsl_mc_msi_set_desc(msi_alloc_info_t *arg,
+				struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = (irq_hw_number_t)desc->msi_attrib.entry_nr;
+}
+
+static void fsl_mc_msi_update_dom_ops(struct msi_domain_info *info)
+{
+	struct msi_domain_ops *ops = info->ops;
+
+	if (WARN_ON(!ops))
+		return;
+
+	if (!ops->set_desc)
+		ops->set_desc = fsl_mc_msi_set_desc;
+}
+
+static void __fsl_mc_msi_write_msg(struct fsl_mc_device *mc_bus_dev,
+				   struct fsl_mc_device_irq *mc_dev_irq)
+{
+	int error;
+	struct fsl_mc_device *owner_mc_dev = mc_dev_irq->mc_dev;
+	struct msi_desc *msi_desc = mc_dev_irq->msi_desc;
+	struct dprc_irq_cfg irq_cfg;
+
+	/*
+	 * msi_desc->msg.address is 0x0 when this function is invoked in
+	 * the free_irq() code path. In this case, for the MC, we don't
+	 * really need to "unprogram" the MSI, so we just return.
+	 */
+	if (msi_desc->msg.address_lo == 0x0 && msi_desc->msg.address_hi == 0x0)
+		return;
+
+	if (WARN_ON(!owner_mc_dev))
+		return;
+
+	irq_cfg.paddr = ((u64)msi_desc->msg.address_hi << 32) |
+			msi_desc->msg.address_lo;
+	irq_cfg.val = msi_desc->msg.data;
+	irq_cfg.user_irq_id = msi_desc->irq;
+
+	/*
+	 * DPRCs and other objects use different commands to set up IRQs,
+	 * so we have to differentiate them here.
+	 */
+	if (owner_mc_dev == mc_bus_dev) {
+		/*
+		 * IRQ is for the mc_bus_dev's DPRC itself
+		 */
+		error = dprc_set_irq(mc_bus_dev->mc_io,
+				     MC_CMD_FLAG_INTR_DIS | MC_CMD_FLAG_PRI,
+				     mc_bus_dev->mc_handle,
+				     mc_dev_irq->dev_irq_index,
+				     &irq_cfg);
+		if (error < 0) {
+			dev_err(&owner_mc_dev->dev,
+				"dprc_set_irq() failed: %d\n", error);
+		}
+	} else {
+		error = dprc_set_obj_irq(mc_bus_dev->mc_io,
+					 MC_CMD_FLAG_INTR_DIS | MC_CMD_FLAG_PRI,
+					 mc_bus_dev->mc_handle,
+					 owner_mc_dev->obj_desc.type,
+					 owner_mc_dev->obj_desc.id,
+					 mc_dev_irq->dev_irq_index,
+					 &irq_cfg);
+		if (error < 0) {
+			dev_err(&owner_mc_dev->dev,
+				"dprc_obj_set_irq() failed: %d\n", error);
+		}
+	}
+}
+
+/*
+ * NOTE: This function is invoked with interrupts disabled
+ */
+static void fsl_mc_msi_write_msg(struct irq_data *irq_data,
+				 struct msi_msg *msg)
+{
+	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
+	struct fsl_mc_device *mc_bus_dev = to_fsl_mc_device(msi_desc->dev);
+	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
+	struct fsl_mc_device_irq *mc_dev_irq =
+		&mc_bus->irq_resources[msi_desc->msi_attrib.entry_nr];
+
+	WARN_ON(mc_dev_irq->msi_desc != msi_desc);
+	msi_desc->msg = *msg;
+
+	/*
+	 * Program the MSI (paddr, value) pair in the device:
+	 */
+	__fsl_mc_msi_write_msg(mc_bus_dev, mc_dev_irq);
+}
+
+static void fsl_mc_msi_update_chip_ops(struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	if (WARN_ON((!chip)))
+		return;
+
+	if (!chip->irq_write_msi_msg)
+		chip->irq_write_msi_msg = fsl_mc_msi_write_msg;
+}
+
+/**
+ * fsl_mc_msi_create_irq_domain - Create a fsl-mc MSI interrupt domain
+ * @np:		Optional device-tree node of the interrupt controller
+ * @info:	MSI domain info
+ * @parent:	Parent irq domain
+ *
+ * Updates the domain and chip ops and creates a fsl-mc MSI
+ * interrupt domain.
+ *
+ * Returns:
+ * A domain pointer or NULL in case of failure.
+ */
+struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
+						struct msi_domain_info *info,
+						struct irq_domain *parent)
+{
+	struct irq_domain *domain;
+
+	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
+		fsl_mc_msi_update_dom_ops(info);
+	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
+		fsl_mc_msi_update_chip_ops(info);
+
+	domain = msi_create_irq_domain(fwnode, info, parent);
+	if (domain)
+		domain->bus_token = DOMAIN_BUS_FSL_MC_MSI;
+
+	return domain;
+}
+
+int fsl_mc_find_msi_domain(struct device_node *mc_of_node,
+			   struct irq_domain **mc_msi_domain)
+{
+	struct device_node *msi_parent_node;
+	struct irq_domain *msi_domain;
+
+	msi_parent_node = of_parse_phandle(mc_of_node, "msi-parent", 0);
+	if (!msi_parent_node) {
+		pr_err("msi-parent phandle missing for %s\n",
+		       mc_of_node->full_name);
+		return -ENOENT;
+	}
+
+	/*
+	 * Look up the fsl-mc MSI domain:
+	 */
+	msi_domain = irq_find_matching_host(msi_parent_node,
+					    DOMAIN_BUS_FSL_MC_MSI);
+	if (!msi_domain) {
+		pr_err("Unable to find fsl-mc MSI domain for %s\n",
+		       mc_of_node->full_name);
+
+		return -ENOENT;
+	}
+
+	*mc_msi_domain = msi_domain;
+	return 0;
+}
+
+static void fsl_mc_msi_free_descs(struct device *dev)
+{
+	struct msi_desc *desc, *tmp;
+
+	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
+		list_del(&desc->list);
+		free_msi_entry(desc);
+	}
+}
+
+static int fsl_mc_msi_alloc_descs(struct device *dev, unsigned int irq_count)
+
+{
+	unsigned int i;
+	int error;
+	struct msi_desc *msi_desc;
+
+	for (i = 0; i < irq_count; i++) {
+		msi_desc = alloc_msi_entry(dev);
+		if (!msi_desc) {
+			dev_err(dev, "Failed to allocate msi entry\n");
+			error = -ENOMEM;
+			goto cleanup_msi_descs;
+		}
+
+		msi_desc->msi_attrib.is_msix = 1;
+		msi_desc->msi_attrib.is_64 = 1;
+		msi_desc->msi_attrib.entry_nr = i;
+		msi_desc->nvec_used = 1;
+		INIT_LIST_HEAD(&msi_desc->list);
+		list_add_tail(&msi_desc->list, dev_to_msi_list(dev));
+	}
+
+	return 0;
+
+cleanup_msi_descs:
+	fsl_mc_msi_free_descs(dev);
+	return error;
+}
+
+int fsl_mc_msi_domain_alloc_irqs(struct device *dev,
+				 unsigned int irq_count)
+{
+	struct irq_domain *msi_domain;
+	int error;
+
+	if (WARN_ON(!list_empty(dev_to_msi_list(dev))))
+		return -EINVAL;
+
+	error = fsl_mc_msi_alloc_descs(dev, irq_count);
+	if (error < 0)
+		return error;
+
+	msi_domain = dev_get_msi_domain(dev);
+	if (WARN_ON(!msi_domain)) {
+		error = -EINVAL;
+		goto cleanup_msi_descs;
+	}
+
+	/*
+	 * NOTE: Calling this function will trigger the invocation of the
+	 * its_fsl_mc_msi_prepare() callback
+	 */
+	error = msi_domain_alloc_irqs(msi_domain, dev, irq_count);
+
+	if (error) {
+		dev_err(dev, "Failed to allocate IRQs\n");
+		goto cleanup_msi_descs;
+	}
+
+	return 0;
+
+cleanup_msi_descs:
+	fsl_mc_msi_free_descs(dev);
+	return error;
+}
+
+void fsl_mc_msi_domain_free_irqs(struct device *dev)
+{
+	struct irq_domain *msi_domain;
+
+	msi_domain = dev_get_msi_domain(dev);
+	if (WARN_ON(!msi_domain))
+		return;
+
+	msi_domain_free_irqs(msi_domain, dev);
+
+	if (WARN_ON(list_empty(dev_to_msi_list(dev))))
+		return;
+
+	fsl_mc_msi_free_descs(dev);
+}
diff --git a/drivers/staging/fsl-mc/include/mc-private.h b/drivers/staging/fsl-mc/include/mc-private.h
index 2c4cc79..3dabd003 100644
--- a/drivers/staging/fsl-mc/include/mc-private.h
+++ b/drivers/staging/fsl-mc/include/mc-private.h
@@ -26,6 +26,9 @@
 	 strcmp(_obj_type, "dpmcp") == 0 || \
 	 strcmp(_obj_type, "dpcon") == 0)
 
+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
@@ -79,11 +82,13 @@ struct fsl_mc_resource_pool {
  * @resource_pools: array of resource pools (one pool per resource type)
  * for this MC bus. These resources represent allocatable entities
  * from the physical DPRC.
+ * @irq_resources: Pointer to array of IRQ objects for the IRQ pool
  * @scan_mutex: Serializes bus scanning
  */
 struct fsl_mc_bus {
 	struct fsl_mc_device mc_dev;
 	struct fsl_mc_resource_pool resource_pools[FSL_MC_NUM_POOL_TYPES];
+	struct fsl_mc_device_irq *irq_resources;
 	struct mutex scan_mutex;    /* serializes bus scanning */
 };
 
@@ -116,4 +121,16 @@ int __must_check fsl_mc_resource_allocate(struct fsl_mc_bus *mc_bus,
 
 void fsl_mc_resource_free(struct fsl_mc_resource *resource);
 
+struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
+						struct msi_domain_info *info,
+						struct irq_domain *parent);
+
+int fsl_mc_find_msi_domain(struct device_node *mc_of_node,
+			   struct irq_domain **mc_msi_domain);
+
+int fsl_mc_msi_domain_alloc_irqs(struct device *dev,
+				 unsigned int irq_count);
+
+void fsl_mc_msi_domain_free_irqs(struct device *dev);
+
 #endif /* _FSL_MC_PRIVATE_H_ */
diff --git a/drivers/staging/fsl-mc/include/mc.h b/drivers/staging/fsl-mc/include/mc.h
index a933291..1c1d6ae 100644
--- a/drivers/staging/fsl-mc/include/mc.h
+++ b/drivers/staging/fsl-mc/include/mc.h
@@ -104,6 +104,23 @@ struct fsl_mc_resource {
 };
 
 /**
+ * struct fsl_mc_device_irq - MC object device message-based interrupt
+ * @msi_desc: pointer to MSI descriptor allocated by fsl_mc_msi_alloc_descs()
+ * @mc_dev: MC object device that owns this interrupt
+ * @dev_irq_index: device-relative IRQ index
+ * @resource: MC generic resource associated with the interrupt
+ */
+struct fsl_mc_device_irq {
+	struct msi_desc *msi_desc;
+	struct fsl_mc_device *mc_dev;
+	u8 dev_irq_index;
+	struct fsl_mc_resource resource;
+};
+
+#define to_fsl_mc_irq(_mc_resource) \
+	container_of(_mc_resource, struct fsl_mc_device_irq, resource)
+
+/**
  * Bit masks for a MC object device (struct fsl_mc_device) flags
  */
 #define FSL_MC_IS_DPRC	0x0001
-- 
2.3.3

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