For ITS, MSI functionality consists on building domain stack and
during that process we need to reference to domain stack components
e.g. before we create new DOMAIN_BUS_PCI_MSI domain we need to specify
its DOMAIN_BUS_NEXUS parent domain. In order to manage that process
properly, maintain list which elements contain domain token
(unique for MSI domain stack) and ITS ID: iort_register_domain_token()
and iort_deregister_domain_token(). Then retrieve domain token
any time later with ITS ID being key off: iort_find_domain_token().
With domain token and domain type we are able to find corresponding
IRQ domain.
Since IORT is prepared to describe MSI domain on a per-device basis,
use existing IORT helpers and implement two calls:
1. iort_msi_map_rid() to map MSI RID for a device
2. iort_get_device_domain() to find domain token for a device
Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
---
drivers/acpi/iort.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iort.h | 11 ++++
2 files changed, 180 insertions(+)
diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
index e342bac..496dcf6 100644
--- a/drivers/acpi/iort.c
+++ b/drivers/acpi/iort.c
@@ -22,12 +22,91 @@
#include <linux/kernel.h>
#include <linux/pci.h>
+struct iort_its_msi_chip {
+ struct list_head list;
+ struct fwnode_handle *fw_node;
+ u32 translation_id;
+};
+
typedef acpi_status (*iort_find_node_callback)
(struct acpi_iort_node *node, void *context);
/* Root pointer to the mapped IORT table */
static struct acpi_table_header *iort_table;
+static LIST_HEAD(iort_msi_chip_list);
+static DEFINE_SPINLOCK(iort_msi_chip_lock);
+
+/**
+ * iort_register_domain_token() - register domain token and related ITS ID
+ * to the list from where we can get it back later on.
+ * @trans_id: ITS ID.
+ * @fw_node: Domain token.
+ *
+ * Returns: 0 on success, -ENOMEM if no memory when allocating list element
+ */
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
+{
+ struct iort_its_msi_chip *its_msi_chip;
+
+ its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
+ if (!its_msi_chip)
+ return -ENOMEM;
+
+ its_msi_chip->fw_node = fw_node;
+ its_msi_chip->translation_id = trans_id;
+
+ spin_lock(&iort_msi_chip_lock);
+ list_add(&its_msi_chip->list, &iort_msi_chip_list);
+ spin_unlock(&iort_msi_chip_lock);
+
+ return 0;
+}
+
+/**
+ * iort_deregister_domain_token() - Deregister domain token based on ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: none.
+ */
+void iort_deregister_domain_token(int trans_id)
+{
+ struct iort_its_msi_chip *its_msi_chip, *t;
+
+ spin_lock(&iort_msi_chip_lock);
+ list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
+ if (its_msi_chip->translation_id == trans_id) {
+ list_del(&its_msi_chip->list);
+ kfree(its_msi_chip);
+ break;
+ }
+ }
+ spin_unlock(&iort_msi_chip_lock);
+}
+
+/**
+ * iort_find_domain_token() - Find domain token based on given ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: domain token when find on the list, NULL otherwise
+ */
+struct fwnode_handle *iort_find_domain_token(int trans_id)
+{
+ struct fwnode_handle *fw_node = NULL;
+ struct iort_its_msi_chip *its_msi_chip;
+
+ spin_lock(&iort_msi_chip_lock);
+ list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
+ if (its_msi_chip->translation_id == trans_id) {
+ fw_node = its_msi_chip->fw_node;
+ break;
+ }
+ }
+ spin_unlock(&iort_msi_chip_lock);
+
+ return fw_node;
+}
+
static struct acpi_iort_node *
iort_scan_node(enum acpi_iort_node_type type,
iort_find_node_callback callback, void *context)
@@ -205,6 +284,96 @@ iort_find_dev_node(struct device *dev)
iort_match_node_callback, &pbus->dev);
}
+/**
+ * iort_msi_map_rid() - Map a MSI requester ID for a device
+ * @dev: The device for which the mapping is to be done.
+ * @req_id: The device requester ID.
+ *
+ * Returns: mapped MSI RID on success, input requester ID otherwise
+ */
+u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{
+ struct acpi_iort_node *node;
+ u32 dev_id;
+
+ if (!iort_table)
+ return req_id;
+
+ node = iort_find_dev_node(dev);
+ if (!node) {
+ dev_err(dev, "can't find related IORT node\n");
+ return req_id;
+ }
+
+ iort_node_map_rid(node, req_id, &dev_id, ACPI_IORT_NODE_ITS_GROUP);
+ return dev_id;
+}
+
+/**
+ * iort_dev_find_its_id() - Find the ITS identifier for a device
+ * @dev: The device.
+ * @idx: Index of the ITS identifier list.
+ * @its_id: ITS identifier.
+ *
+ * Returns: 0 on success, appropriate error value otherwise
+ */
+static int
+iort_dev_find_its_id(struct device *dev, u32 req_id, unsigned int idx,
+ int *its_id)
+{
+ struct acpi_iort_its_group *its;
+ struct acpi_iort_node *node;
+
+ node = iort_find_dev_node(dev);
+ if (!node) {
+ dev_err(dev, "can't find related IORT node\n");
+ return -ENXIO;
+ }
+
+ node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP);
+ if (!node) {
+ dev_err(dev, "can't find related ITS node\n");
+ return -ENXIO;
+ }
+
+ /* Move to ITS specific data */
+ its = (struct acpi_iort_its_group *)node->node_data;
+ if (idx > its->its_count) {
+ dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n",
+ idx, its->its_count);
+ return -ENXIO;
+ }
+
+ *its_id = its->identifiers[idx];
+ return 0;
+}
+
+/**
+ * iort_get_device_domain() - Find MSI domain related to a device
+ * @dev: The device.
+ * @req_id: Requester ID for the device.
+ *
+ * Returns: the MSI domain for this device, NULL otherwise
+ */
+struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id)
+{
+ static struct fwnode_handle *handle;
+ int its_id;
+
+ if (!iort_table)
+ return NULL;
+
+ if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
+ return NULL;
+
+ handle = iort_find_domain_token(its_id);
+ if (!handle)
+ return NULL;
+
+ return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
+}
+
void __init iort_table_detect(void)
{
acpi_status status;
diff --git a/include/linux/iort.h b/include/linux/iort.h
index cde6809..d7daba1 100644
--- a/include/linux/iort.h
+++ b/include/linux/iort.h
@@ -20,11 +20,22 @@
#define __IORT_H__
#include <linux/acpi.h>
+#include <linux/fwnode.h>
+#include <linux/irqdomain.h>
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
+void iort_deregister_domain_token(int trans_id);
+struct fwnode_handle *iort_find_domain_token(int trans_id);
#ifdef CONFIG_IORT_TABLE
void iort_table_detect(void);
+u32 iort_msi_map_rid(struct device *dev, u32 req_id);
+struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
#else
static inline void iort_table_detect(void) { }
+static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{ return req_id; }
+static inline struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
#endif
#endif /* __IORT_H__ */
--
1.9.1
--
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