From: Sunil Goutham <sgout...@cavium.com>

This patch adds generic support for MSI-X interrupts to the SATA PCI
driver. Only single interrupt support is implemented. Thus, per-port
interrupts can not yet be enabled.

The driver now checks the device for the existence of MSI-X and tries
to enable the interrupt. Otherwise, if a device is not MSI-X capable,
the initialization is skipped and MSI or intx interrupts are
configured.

This patch also enables AHCI for Cavium Thunder SoCs that uses MSI-X.

Signed-off-by: Sunil Goutham <sgout...@cavium.com>
Signed-off-by: Robert Richter <rrich...@cavium.com>
---
 arch/arm64/Kconfig |  1 +
 drivers/ata/ahci.c | 40 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ac9afde76dea..55970474d3ae 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -145,6 +145,7 @@ config ARCH_THUNDER
        bool "Cavium Inc. Thunder SoC Family"
        help
          This enables support for Cavium's Thunder Family of SoCs.
+       select SATA_AHCI
 
 config ARCH_VEXPRESS
        bool "ARMv8 software model (Versatile Express)"
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5f039f191067..8e43ccb72c95 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -52,6 +52,7 @@
 
 enum {
        AHCI_PCI_BAR_STA2X11    = 0,
+       AHCI_PCI_BAR_CAVIUM     = 0,
        AHCI_PCI_BAR_ENMOTUS    = 2,
        AHCI_PCI_BAR_STANDARD   = 5,
 };
@@ -483,6 +484,9 @@ static const struct pci_device_id ahci_pci_tbl[] = {
        /* Enmotus */
        { PCI_DEVICE(0x1c44, 0x8000), board_ahci },
 
+       /* Cavium */
+       { PCI_DEVICE(0x177d, 0xa01c), .driver_data = board_ahci },
+
        /* Generic, PCI class code for AHCI */
        { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
          PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff, board_ahci },
@@ -1188,11 +1192,43 @@ static inline void ahci_gtf_filter_workaround(struct 
ata_host *host)
 {}
 #endif
 
+static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports,
+                         struct ahci_host_priv *hpriv)
+{
+       int rc, nvec;
+       struct msix_entry entry = {};
+
+       /* check if msix is supported */
+       nvec = pci_msix_vec_count(pdev);
+       if (nvec <= 0)
+               return 0;
+
+       /* per-port msix interrupts are not supported */
+       if (n_ports > 1 && nvec >= n_ports)
+               return -ENOSYS;
+
+       /* only enable the first entry (entry.entry = 0) */
+       rc = pci_enable_msix_exact(pdev, &entry, 1);
+       if (rc < 0)
+               return rc;
+
+       pdev->irq = entry.vector;
+
+       return 1;
+}
+
 static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
                                struct ahci_host_priv *hpriv)
 {
        int rc, nvec;
 
+       nvec = ahci_init_msix(pdev, n_ports, hpriv);
+       if (nvec > 0)
+               return nvec;
+
+       if (nvec && nvec != -ENOSYS)
+               dev_err(&pdev->dev, "failed to enable MSI-X: %d", nvec);
+
        if (hpriv->flags & AHCI_HFLAG_NO_MSI)
                goto intx;
 
@@ -1271,11 +1307,13 @@ static int ahci_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
                dev_info(&pdev->dev,
                         "PDC42819 can only drive SATA devices with this 
driver\n");
 
-       /* Both Connext and Enmotus devices use non-standard BARs */
+       /* Some devices use non-standard BARs */
        if (pdev->vendor == PCI_VENDOR_ID_STMICRO && pdev->device == 0xCC06)
                ahci_pci_bar = AHCI_PCI_BAR_STA2X11;
        else if (pdev->vendor == 0x1c44 && pdev->device == 0x8000)
                ahci_pci_bar = AHCI_PCI_BAR_ENMOTUS;
+       else if (pdev->vendor == 0x177d && pdev->device == 0xa01c)
+               ahci_pci_bar = AHCI_PCI_BAR_CAVIUM;
 
        /*
         * The JMicron chip 361/363 contains one SATA controller and one
-- 
2.1.3

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