1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
new file mode 100644
index 000000000..12b044151
--- /dev/null
+++ b/drivers/base/platform-msi.c
@@ -0,0 +1,351 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MSI framework for platform devices
+ *
+ * Copyright (C) 2015 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/slab.h>
+
+#define DEV_ID_SHIFT	21
+#define MAX_DEV_MSIS	(1 << (32 - DEV_ID_SHIFT))
+
+/*
+ * Internal data structure containing a (made up, but unique) devid
+ * 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;
+};
+
+/* The devid allocator */
+static DEFINE_IDA(platform_msi_devid_ida);
+
+#ifdef GENERIC_MSI_DOMAIN_OPS
+/*
+ * Convert an msi_desc to a globaly unique identifier (per-device
+ * devid + msi_desc position in the msi_list).
+ */
+static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
+{
+	u32 devid = desc->dev->msi.data->platform_data->devid;
+
+	return (devid << (32 - DEV_ID_SHIFT)) | desc->msi_index;
+}
+
+static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = platform_msi_calc_hwirq(desc);
+}
+
+static int platform_msi_init(struct irq_domain *domain,
+			     struct msi_domain_info *info,
+			     unsigned int virq, irq_hw_number_t hwirq,
+			     msi_alloc_info_t *arg)
+{
+	return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					     info->chip, info->chip_data);
+}
+
+static void platform_msi_set_proxy_dev(msi_alloc_info_t *arg)
+{
+	arg->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
+}
+#else
+#define platform_msi_set_desc		NULL
+#define platform_msi_init		NULL
+#define platform_msi_set_proxy_dev(x)	do {} while(0)
+#endif
+
+static void platform_msi_update_dom_ops(struct msi_domain_info *info)
+{
+	struct msi_domain_ops *ops = info->ops;
+
+	BUG_ON(!ops);
+
+	if (ops->msi_init == NULL)
+		ops->msi_init = platform_msi_init;
+	if (ops->set_desc == NULL)
+		ops->set_desc = platform_msi_set_desc;
+}
+
+static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct msi_desc *desc = irq_data_get_msi_desc(data);
+
+	desc->dev->msi.data->platform_data->write_msg(desc, msg);
+}
+
+static void platform_msi_update_chip_ops(struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	BUG_ON(!chip);
+	if (!chip->irq_mask)
+		chip->irq_mask = irq_chip_mask_parent;
+	if (!chip->irq_unmask)
+		chip->irq_unmask = irq_chip_unmask_parent;
+	if (!chip->irq_eoi)
+		chip->irq_eoi = irq_chip_eoi_parent;
+	if (!chip->irq_set_affinity)
+		chip->irq_set_affinity = msi_domain_set_affinity;
+	if (!chip->irq_write_msi_msg)
+		chip->irq_write_msi_msg = platform_msi_write_msg;
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		    !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
+}
+
+/**
+ * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
+ * @fwnode:		Optional fwnode of the interrupt controller
+ * @info:	MSI domain info
+ * @parent:	Parent irq domain
+ *
+ * Updates the domain and chip ops and creates a platform MSI
+ * interrupt domain.
+ *
+ * Returns:
+ * A domain pointer or NULL in case of failure.
+ */
+struct irq_domain *platform_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)
+		platform_msi_update_dom_ops(info);
+	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
+		platform_msi_update_chip_ops(info);
+	info->flags |= MSI_FLAG_DEV_SYSFS | MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS |
+		       MSI_FLAG_FREE_MSI_DESCS;
+
+	domain = msi_create_irq_domain(fwnode, info, parent);
+	if (domain)
+		irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(platform_msi_create_irq_domain);
+
+static int platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
+					irq_write_msi_msg_t write_msi_msg)
+{
+	struct platform_msi_priv_data *datap;
+	int err;
+
+	/*
+	 * Limit the number of interrupts to 2048 per device. Should we
+	 * need to bump this up, DEV_ID_SHIFT should be adjusted
+	 * accordingly (which would impact the max number of MSI
+	 * capable devices).
+	 */
+	if (!dev->msi.domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
+		return -EINVAL;
+
+	if (dev->msi.domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
+		dev_err(dev, "Incompatible msi_domain, giving up\n");
+		return -EINVAL;
+	}
+
+	err = msi_setup_device_data(dev);
+	if (err)
+		return err;
+
+	/* Already initialized? */
+	if (dev->msi.data->platform_data)
+		return -EBUSY;
+
+	datap = kzalloc(sizeof(*datap), GFP_KERNEL);
+	if (!datap)
+		return -ENOMEM;
+
+	datap->devid = ida_simple_get(&platform_msi_devid_ida,
+				      0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
+	if (datap->devid < 0) {
+		err = datap->devid;
+		kfree(datap);
+		return err;
+	}
+
+	datap->write_msg = write_msi_msg;
+	datap->dev = dev;
+	dev->msi.data->platform_data = datap;
+	return 0;
+}
+
+static void platform_msi_free_priv_data(struct device *dev)
+{
+	struct platform_msi_priv_data *data = dev->msi.data->platform_data;
+
+	dev->msi.data->platform_data = NULL;
+	ida_simple_remove(&platform_msi_devid_ida, data->devid);
+	kfree(data);
+}
+
+/**
+ * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
+ * @dev:		The device for which to allocate interrupts
+ * @nvec:		The number of interrupts to allocate
+ * @write_msi_msg:	Callback to write an interrupt message for @dev
+ *
+ * Returns:
+ * Zero for success, or an error code in case of failure
+ */
+int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
+				   irq_write_msi_msg_t write_msi_msg)
+{
+	int err;
+
+	err = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
+	if (err)
+		return err;
+
+	err = msi_domain_alloc_irqs(dev->msi.domain, dev, nvec);
+	if (err)
+		platform_msi_free_priv_data(dev);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
+
+/**
+ * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
+ * @dev:	The device for which to free interrupts
+ */
+void platform_msi_domain_free_irqs(struct device *dev)
+{
+	msi_domain_free_irqs(dev->msi.domain, dev);
+	platform_msi_free_priv_data(dev);
+}
+EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
+
+/**
+ * platform_msi_get_host_data - Query the private data associated with
+ *                              a platform-msi domain
+ * @domain:	The platform-msi domain
+ *
+ * Return: 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;
+}
+
+static struct lock_class_key platform_device_msi_lock_class;
+
+/**
+ * __platform_msi_create_device_domain - Create a platform-msi device domain
+ *
+ * @dev:		The device generating the MSIs
+ * @nvec:		The number of MSIs that need to be allocated
+ * @is_tree:		flag to indicate tree hierarchy
+ * @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
+ *
+ * Return: An irqdomain for @nvec interrupts on success, NULL in case of error.
+ *
+ * This is for interrupt domains which stack on a platform-msi domain
+ * created by platform_msi_create_irq_domain(). @dev->msi.domain points to
+ * that platform-msi domain which is the parent for the new domain.
+ */
+struct irq_domain *
+__platform_msi_create_device_domain(struct device *dev,
+				    unsigned int nvec,
+				    bool is_tree,
+				    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;
+
+	err = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
+	if (err)
+		return NULL;
+
+	/*
+	 * Use a separate lock class for the MSI descriptor mutex on
+	 * platform MSI device domains because the descriptor mutex nests
+	 * into the domain mutex. See alloc/free below.
+	 */
+	lockdep_set_class(&dev->msi.data->mutex, &platform_device_msi_lock_class);
+
+	data = dev->msi.data->platform_data;
+	data->host_data = host_data;
+	domain = irq_domain_create_hierarchy(dev->msi.domain, 0,
+					     is_tree ? 0 : nvec,
+					     dev->fwnode, ops, data);
+	if (!domain)
+		goto free_priv;
+
+	platform_msi_set_proxy_dev(&data->arg);
+	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(dev);
+	return NULL;
+}
+
+/**
+ * platform_msi_device_domain_free - Free interrupts associated with a platform-msi
+ *				     device domain
+ *
+ * @domain:	The platform-msi device domain
+ * @virq:	The base irq from which to perform the free operation
+ * @nr_irqs:	How many interrupts to free from @virq
+ */
+void platform_msi_device_domain_free(struct irq_domain *domain, unsigned int virq,
+				     unsigned int nr_irqs)
+{
+	struct platform_msi_priv_data *data = domain->host_data;
+
+	msi_lock_descs(data->dev);
+	irq_domain_free_irqs_common(domain, virq, nr_irqs);
+	msi_free_msi_descs_range(data->dev, MSI_DESC_ALL, virq, virq + nr_irqs - 1);
+	msi_unlock_descs(data->dev);
+}
+
+/**
+ * platform_msi_device_domain_alloc - Allocate interrupts associated with
+ *				      a platform-msi device domain
+ *
+ * @domain:	The platform-msi device domain
+ * @virq:	The base irq from which to perform the allocate operation
+ * @nr_irqs:	How many interrupts to allocate 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_device_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				     unsigned int nr_irqs)
+{
+	struct platform_msi_priv_data *data = domain->host_data;
+	struct device *dev = data->dev;
+
+	return msi_domain_populate_irqs(domain->parent, dev, virq, nr_irqs, &data->arg);
+}