AHCI: Support multiple MSIs

Take advantage of multiple MSIs implementation on x86 - on
systems with IRQ remapping AHCI ports not only get assigned
separate MSI vectors - but also separate IRQs. As result,
interrupts generated by different ports could be serviced on
different CPUs rather than on a single one.

In cases when number of allocated MSIs is less than requested
the Sharing Last MSI mode does not get used, no matter
implemented in hardware or not. Instead, the driver assumes the
advantage of multiple MSIs is negated and falls back to the
single MSI mode as if MRSM bit was set (some Intel chips
implement this strategy anyway - MRSM bit gets set even if the
number of allocated MSIs exceeds the number of implemented ports).

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/15bf7ee314dd55f21ec7d2a01c47613cd8190a7c.1353324359.git.agordeev@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 9be471200a07..b830e6c9fe49 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -231,6 +231,7 @@ enum {
         AHCI_HFLAG_DELAY_ENGINE         = (1 << 15), /* do not start engine on
                                                         port start (wait until
                                                         error-handling stage) */
+        AHCI_HFLAG_MULTI_MSI            = (1 << 16), /* multiple PCI MSIs */
 
         /* ap->flags bits */
 
@@ -297,6 +298,8 @@ struct ahci_port_priv {
         unsigned int            ncq_saw_d2h:1;
         unsigned int            ncq_saw_dmas:1;
         unsigned int            ncq_saw_sdb:1;
+        u32                     intr_status;    /* interrupts to handle */
+        spinlock_t              lock;           /* protects parent ata_port */
         u32                     intr_mask;      /* interrupts to enable */
         bool                    fbs_supported;  /* set iff FBS is supported */
         bool                    fbs_enabled;    /* set iff FBS is enabled */
@@ -359,7 +362,10 @@ void ahci_set_em_messages(struct ahci_host_priv *hpriv,
                           struct ata_port_info *pi);
 int ahci_reset_em(struct ata_host *host);
 irqreturn_t ahci_interrupt(int irq, void *dev_instance);
+irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
+irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
 void ahci_print_info(struct ata_host *host, const char *scc_s);
+int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis);
 
 static inline void __iomem *__ahci_port_base(struct ata_host *host,
                                              unsigned int port_no)