[PATCH] genirq: msi: refactor the msi_ops

The current msi_ops are short sighted in a number of ways, this patch attempts
to fix the glaring deficiences.

- Report in msi_ops if a 64bit address is needed in the msi message, so we
  can fail 32bit only msi structures.

- Send and receive a full struct msi_msg in both setup and target.  This is
  a little cleaner and allows for architectures that need to modify the data
  to retarget the msi interrupt to a different cpu.

- In target pass in the full cpu mask instead of just the first cpu in case
  we can make use of the full cpu mask.

- Operate in terms of irqs and not vectors, currently there is still a 1-1
  relationship but on architectures other than ia64 I expect this will change.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/linux/pci.h b/include/linux/pci.h
index b9bb6c46e05..2aabe90f1cd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -617,6 +617,68 @@ extern int pci_enable_msix(struct pci_dev* dev,
         struct msix_entry *entries, int nvec);
 extern void pci_disable_msix(struct pci_dev *dev);
 extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
+
+/*
+ * MSI operation vector.  Used by the msi core code (drivers/pci/msi.c)
+ * to abstract platform-specific tasks relating to MSI address generation
+ * and resource management.
+ */
+struct msi_ops {
+        int needs_64bit_address;
+        /**
+         * setup - generate an MSI bus address and data for a given vector
+         * @pdev: PCI device context (in)
+         * @irq: irq allocated by the msi core (in)
+         * @msg: PCI bus address and data for msi message (out)
+         *
+         * Description: The setup op is used to generate a PCI bus addres and
+         * data which the msi core will program into the card MSI capability
+         * registers.  The setup routine is responsible for picking an initial
+         * cpu to target the MSI at.  The setup routine is responsible for
+         * examining pdev to determine the MSI capabilities of the card and
+         * generating a suitable address/data.  The setup routine is
+         * responsible for allocating and tracking any system resources it
+         * needs to route the MSI to the cpu it picks, and for associating
+         * those resources with the passed in vector.
+         *
+         * Returns 0 if the MSI address/data was successfully setup.
+         **/
+
+        int     (*setup)    (struct pci_dev *pdev, unsigned int irq,
+                             struct msi_msg *msg);
+
+        /**
+         * teardown - release resources allocated by setup
+         * @vector: vector context for resources (in)
+         *
+         * Description:  The teardown op is used to release any resources
+         * that were allocated in the setup routine associated with the passed
+         * in vector.
+         **/
+
+        void    (*teardown) (unsigned int irq);
+
+        /**
+         * target - retarget an MSI at a different cpu
+         * @vector: vector context for resources (in)
+         * @cpu:  new cpu to direct vector at (in)
+         * @addr_hi: new value of PCI bus upper 32 bits (in/out)
+         * @addr_lo: new value of PCI bus lower 32 bits (in/out)
+         *
+         * Description:  The target op is used to redirect an MSI vector
+         * at a different cpu.  addr_hi/addr_lo coming in are the existing
+         * values that the MSI core has programmed into the card.  The
+         * target code is responsible for freeing any resources (if any)
+         * associated with the old address, and generating a new PCI bus
+         * addr_hi/addr_lo that will redirect the vector at the indicated cpu.
+         **/
+
+        void    (*target)   (unsigned int irq, cpumask_t cpumask,
+                             struct msi_msg *msg);
+};
+
+extern int msi_register(struct msi_ops *ops);
+
 #endif
 
 extern void pci_block_user_cfg_access(struct pci_dev *dev);