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authorLogan Gunthorpe <logang@deltatee.com>2019-05-24 01:30:56 +0300
committerJon Mason <jdmason@kudzu.us>2019-06-13 16:02:33 +0300
commit26b3a37b928457ba2cd98eaf6d7b0feca5a30fa6 (patch)
tree828a124eb32052fd1603bb77f072a4b3fab1d27a /include/linux/ntb.h
parentd217e07b32a6750e44f529e0218898c024b2c637 (diff)
downloadlinux-26b3a37b928457ba2cd98eaf6d7b0feca5a30fa6.tar.xz
NTB: Introduce MSI library
The NTB MSI library allows passing MSI interrupts across a memory window. This offers similar functionality to doorbells or messages except will often have much better latency and the client can potentially use significantly more remote interrupts than typical hardware provides for doorbells. (Which can be important in high-multiport setups.) The library utilizes one memory window per peer and uses the highest index memory windows. Before any ntb_msi function may be used, the user must call ntb_msi_init(). It may then setup and tear down the memory windows when the link state changes using ntb_msi_setup_mws() and ntb_msi_clear_mws(). The peer which receives the interrupt must call ntb_msim_request_irq() to assign the interrupt handler (this function is functionally similar to devm_request_irq()) and the returned descriptor must be transferred to the peer which can use it to trigger the interrupt. The triggering peer, once having received the descriptor, can trigger the interrupt by calling ntb_msi_peer_trigger(). Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Allen Hubbe <allenbh@gmail.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
Diffstat (limited to 'include/linux/ntb.h')
-rw-r--r--include/linux/ntb.h73
1 files changed, 73 insertions, 0 deletions
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index bed421b9579b..8c13538aeffe 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -58,9 +58,11 @@
#include <linux/completion.h>
#include <linux/device.h>
+#include <linux/interrupt.h>
struct ntb_client;
struct ntb_dev;
+struct ntb_msi;
struct pci_dev;
/**
@@ -426,6 +428,10 @@ struct ntb_dev {
spinlock_t ctx_lock;
/* block unregister until device is fully released */
struct completion released;
+
+#ifdef CONFIG_NTB_MSI
+ struct ntb_msi *msi;
+#endif
};
#define dev_ntb(__dev) container_of((__dev), struct ntb_dev, dev)
@@ -1627,4 +1633,71 @@ static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
return ntb_mw_count(ntb, pidx) - ret - 1;
}
+struct ntb_msi_desc {
+ u32 addr_offset;
+ u32 data;
+};
+
+#ifdef CONFIG_NTB_MSI
+
+int ntb_msi_init(struct ntb_dev *ntb, void (*desc_changed)(void *ctx));
+int ntb_msi_setup_mws(struct ntb_dev *ntb);
+void ntb_msi_clear_mws(struct ntb_dev *ntb);
+int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
+ irq_handler_t thread_fn,
+ const char *name, void *dev_id,
+ struct ntb_msi_desc *msi_desc);
+void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id);
+int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
+ struct ntb_msi_desc *desc);
+int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
+ struct ntb_msi_desc *desc,
+ phys_addr_t *msi_addr);
+
+#else /* not CONFIG_NTB_MSI */
+
+static inline int ntb_msi_init(struct ntb_dev *ntb,
+ void (*desc_changed)(void *ctx))
+{
+ return -EOPNOTSUPP;
+}
+static inline int ntb_msi_setup_mws(struct ntb_dev *ntb)
+{
+ return -EOPNOTSUPP;
+}
+static inline void ntb_msi_clear_mws(struct ntb_dev *ntb) {}
+static inline int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb,
+ irq_handler_t handler,
+ irq_handler_t thread_fn,
+ const char *name, void *dev_id,
+ struct ntb_msi_desc *msi_desc)
+{
+ return -EOPNOTSUPP;
+}
+static inline void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq,
+ void *dev_id) {}
+static inline int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
+ struct ntb_msi_desc *desc)
+{
+ return -EOPNOTSUPP;
+}
+static inline int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
+ struct ntb_msi_desc *desc,
+ phys_addr_t *msi_addr)
+{
+ return -EOPNOTSUPP;
+
+}
+
+#endif /* CONFIG_NTB_MSI */
+
+static inline int ntbm_msi_request_irq(struct ntb_dev *ntb,
+ irq_handler_t handler,
+ const char *name, void *dev_id,
+ struct ntb_msi_desc *msi_desc)
+{
+ return ntbm_msi_request_threaded_irq(ntb, handler, NULL, name,
+ dev_id, msi_desc);
+}
+
#endif