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@semihalf.com Acked-by: Rafael J. Wysocki rjw@rjwysocki.net Reviewed-by: Hanjun Guo hanjun.guo@linaro.org --- drivers/acpi/arm64/iort.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi_iort.h | 12 ++++ 2 files changed, 164 insertions(+)
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 3eaeb66..c669fdab 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -22,6 +22,12 @@ #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);
@@ -31,6 +37,76 @@ 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) @@ -202,6 +278,82 @@ static struct acpi_iort_node *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; + + node = iort_find_dev_node(dev); + if (!node) + 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) + return -ENXIO; + + node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP); + if (!node) + 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) +{ + struct fwnode_handle *handle; + int its_id; + + 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 acpi_iort_init(void) { acpi_status status; diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h index fcacaf7..0e32dac 100644 --- a/include/linux/acpi_iort.h +++ b/include/linux/acpi_iort.h @@ -20,11 +20,23 @@ #define __ACPI_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_ACPI_IORT void acpi_iort_init(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 acpi_iort_init(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 /* __ACPI_IORT_H__ */