1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/cdx/cdx_msi.c b/drivers/cdx/cdx_msi.c
new file mode 100644
index 000000000000..e55f1716cfcb
--- /dev/null
+++ b/drivers/cdx/cdx_msi.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD CDX bus driver MSI support
+ *
+ * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/cdx/cdx_bus.h>
+
+#include "cdx.h"
+
+static void cdx_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 cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
+
+	/* We would not operate on msg here rather we wait for irq_bus_sync_unlock()
+	 * to be called from preemptible task context.
+	 */
+	msi_desc->msg = *msg;
+	cdx_dev->msi_write_pending = true;
+}
+
+static void cdx_msi_write_irq_lock(struct irq_data *irq_data)
+{
+	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
+	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
+
+	mutex_lock(&cdx_dev->irqchip_lock);
+}
+
+static void cdx_msi_write_irq_unlock(struct irq_data *irq_data)
+{
+	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
+	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
+	struct cdx_controller *cdx = cdx_dev->cdx;
+	struct cdx_device_config dev_config;
+
+	if (!cdx_dev->msi_write_pending) {
+		mutex_unlock(&cdx_dev->irqchip_lock);
+		return;
+	}
+
+	cdx_dev->msi_write_pending = false;
+	mutex_unlock(&cdx_dev->irqchip_lock);
+
+	dev_config.msi.msi_index = msi_desc->msi_index;
+	dev_config.msi.data = msi_desc->msg.data;
+	dev_config.msi.addr = ((u64)(msi_desc->msg.address_hi) << 32) | msi_desc->msg.address_lo;
+
+	/*
+	 * dev_configure() is a controller callback which can interact with
+	 * Firmware or other entities, and can sleep, so invoke this function
+	 * outside of the mutex held region.
+	 */
+	dev_config.type = CDX_DEV_MSI_CONF;
+	if (cdx->ops->dev_configure)
+		cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config);
+}
+
+int cdx_enable_msi(struct cdx_device *cdx_dev)
+{
+	struct cdx_controller *cdx = cdx_dev->cdx;
+	struct cdx_device_config dev_config;
+
+	dev_config.type = CDX_DEV_MSI_ENABLE;
+	dev_config.msi_enable = true;
+	if (cdx->ops->dev_configure) {
+		return cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num,
+					       &dev_config);
+	}
+
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(cdx_enable_msi);
+
+void cdx_disable_msi(struct cdx_device *cdx_dev)
+{
+	struct cdx_controller *cdx = cdx_dev->cdx;
+	struct cdx_device_config dev_config;
+
+	dev_config.type = CDX_DEV_MSI_ENABLE;
+	dev_config.msi_enable = false;
+	if (cdx->ops->dev_configure)
+		cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config);
+}
+EXPORT_SYMBOL_GPL(cdx_disable_msi);
+
+static struct irq_chip cdx_msi_irq_chip = {
+	.name			= "CDX-MSI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= msi_domain_set_affinity,
+	.irq_write_msi_msg	= cdx_msi_write_msg,
+	.irq_bus_lock		= cdx_msi_write_irq_lock,
+	.irq_bus_sync_unlock	= cdx_msi_write_irq_unlock
+};
+
+/* Convert an msi_desc to a unique identifier within the domain. */
+static irq_hw_number_t cdx_domain_calc_hwirq(struct cdx_device *dev,
+					     struct msi_desc *desc)
+{
+	return ((irq_hw_number_t)dev->msi_dev_id << 10) | desc->msi_index;
+}
+
+static void cdx_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = cdx_domain_calc_hwirq(to_cdx_device(desc->dev), desc);
+}
+
+static int cdx_msi_prepare(struct irq_domain *msi_domain,
+			   struct device *dev,
+			   int nvec, msi_alloc_info_t *info)
+{
+	struct cdx_device *cdx_dev = to_cdx_device(dev);
+	struct device *parent = cdx_dev->cdx->dev;
+	struct msi_domain_info *msi_info;
+	u32 dev_id;
+	int ret;
+
+	/* Retrieve device ID from requestor ID using parent device */
+	ret = of_map_id(parent->of_node, cdx_dev->msi_dev_id, "msi-map", "msi-map-mask",
+			NULL, &dev_id);
+	if (ret) {
+		dev_err(dev, "of_map_id failed for MSI: %d\n", ret);
+		return ret;
+	}
+
+#ifdef GENERIC_MSI_DOMAIN_OPS
+	/* Set the device Id to be passed to the GIC-ITS */
+	info->scratchpad[0].ul = dev_id;
+#endif
+
+	msi_info = msi_get_domain_info(msi_domain->parent);
+
+	return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info);
+}
+
+static struct msi_domain_ops cdx_msi_ops = {
+	.msi_prepare	= cdx_msi_prepare,
+	.set_desc	= cdx_msi_set_desc
+};
+
+static struct msi_domain_info cdx_msi_domain_info = {
+	.ops	= &cdx_msi_ops,
+	.chip	= &cdx_msi_irq_chip,
+	.flags	= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		  MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS
+};
+
+struct irq_domain *cdx_msi_domain_init(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct fwnode_handle *fwnode_handle;
+	struct irq_domain *cdx_msi_domain;
+	struct device_node *parent_node;
+	struct irq_domain *parent;
+
+	fwnode_handle = of_node_to_fwnode(np);
+
+	parent_node = of_parse_phandle(np, "msi-map", 1);
+	if (!parent_node) {
+		dev_err(dev, "msi-map not present on cdx controller\n");
+		return NULL;
+	}
+
+	parent = irq_find_matching_fwnode(of_node_to_fwnode(parent_node), DOMAIN_BUS_NEXUS);
+	if (!parent || !msi_get_domain_info(parent)) {
+		dev_err(dev, "unable to locate ITS domain\n");
+		return NULL;
+	}
+
+	cdx_msi_domain = msi_create_irq_domain(fwnode_handle, &cdx_msi_domain_info, parent);
+	if (!cdx_msi_domain) {
+		dev_err(dev, "unable to create CDX-MSI domain\n");
+		return NULL;
+	}
+
+	dev_dbg(dev, "CDX-MSI domain created\n");
+
+	return cdx_msi_domain;
+}
+EXPORT_SYMBOL_NS_GPL(cdx_msi_domain_init, CDX_BUS_CONTROLLER);