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Subject[PATCH 3/6 v3] PCI: support ARI capability
Add Alternative Routing-ID Interpretation (ARI) support.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Alex Chiang <achiang@hp.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>

---
drivers/pci/pci.c | 31 +++++++++++++++++++++++++++++++
drivers/pci/pci.h | 12 ++++++++++++
drivers/pci/probe.c | 3 +++
include/linux/pci.h | 1 +
include/linux/pci_regs.h | 14 ++++++++++++++
5 files changed, 61 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 400d3b3..fe9efc4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1260,6 +1260,37 @@ void pci_pm_init(struct pci_dev *dev)
}
}

+/**
+ * pci_ari_init - turn on ARI forwarding if it's supported
+ * @dev: the PCI device
+ */
+void pci_ari_init(struct pci_dev *dev)
+{
+ int pos;
+ u32 cap;
+ u16 ctrl;
+
+ if (!dev->is_pcie || (dev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ dev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return;
+
+ pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP2, &cap);
+
+ if (!(cap & PCI_EXP_DEVCAP2_ARI))
+ return;
+
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &ctrl);
+ ctrl |= PCI_EXP_DEVCTL2_ARI;
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, ctrl);
+
+ dev->ari_enabled = 1;
+ dev_info(&dev->dev, "ARI forwarding enabled.\n");
+}
+
int
pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
{
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9f0fa0e..593b415 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -165,5 +165,17 @@ extern struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
extern int pci_resource_alignment(struct pci_dev *dev, int resno);
extern int pci_resource_bar(struct pci_dev *dev, int resno,
enum pci_bar_type *type);
+extern void pci_ari_init(struct pci_dev *dev);
+/**
+ * pci_ari_fwd_enabled - query ARI forwarding status
+ * @dev: the PCI device
+ *
+ * Returns 1 if ARI forwarding is enabled, or 0 if not enabled;
+ * returns negative on failure.
+ */
+static inline int pci_ari_enabled(struct pci_dev *dev)
+{
+ return dev->ari_enabled;
+}

#endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b9f759d..06b9a75 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1019,6 +1019,9 @@ static void pci_init_capabilities(struct pci_dev *dev)

/* Vital Product Data */
pci_vpd_pci22_init(dev);
+
+ /* Alternative Routing-ID Forwarding */
+ pci_ari_init(dev);
}

void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a0d6381..497d639 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -237,6 +237,7 @@ struct pci_dev {
unsigned int broken_parity_status:1; /* Device generates false positive parity */
unsigned int msi_enabled:1;
unsigned int msix_enabled:1;
+ unsigned int ari_enabled:1; /* ARI forwarding */
unsigned int is_managed:1;
unsigned int is_pcie:1;
pci_dev_flags_t dev_flags;
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index 450684f..eb6686b 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -419,6 +419,10 @@
#define PCI_EXP_RTCTL_CRSSVE 0x10 /* CRS Software Visibility Enable */
#define PCI_EXP_RTCAP 30 /* Root Capabilities */
#define PCI_EXP_RTSTA 32 /* Root Status */
+#define PCI_EXP_DEVCAP2 36 /* Device Capabilities 2 */
+#define PCI_EXP_DEVCAP2_ARI 0x20 /* Alternative Routing-ID */
+#define PCI_EXP_DEVCTL2 40 /* Device Control 2 */
+#define PCI_EXP_DEVCTL2_ARI 0x20 /* Alternative Routing-ID */

/* Extended Capabilities (PCI-X 2.0 and Express) */
#define PCI_EXT_CAP_ID(header) (header & 0x0000ffff)
@@ -429,6 +433,7 @@
#define PCI_EXT_CAP_ID_VC 2
#define PCI_EXT_CAP_ID_DSN 3
#define PCI_EXT_CAP_ID_PWR 4
+#define PCI_EXT_CAP_ID_ARI 14

/* Advanced Error Reporting */
#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
@@ -536,5 +541,14 @@
#define HT_CAPTYPE_GEN3 0xD0 /* Generation 3 hypertransport configuration */
#define HT_CAPTYPE_PM 0xE0 /* Hypertransport powermanagement configuration */

+/* Alternative Routing-ID Interpretation */
+#define PCI_ARI_CAP 0x04 /* ARI Capability Register */
+#define PCI_ARI_CAP_MFVC 0x0001 /* MFVC Function Groups Capability */
+#define PCI_ARI_CAP_ACS 0x0002 /* ACS Function Groups Capability */
+#define PCI_ARI_CAP_NFN(x) (((x) >> 8) & 0xff) /* Next Function Number */
+#define PCI_ARI_CTRL 0x06 /* ARI Control Register */
+#define PCI_ARI_CTRL_MFVC 0x0001 /* MFVC Function Groups Enable */
+#define PCI_ARI_CTRL_ACS 0x0002 /* ACS Function Groups Enable */
+#define PCI_ARI_CTRL_FG(x) (((x) >> 4) & 7) /* Function Group */

#endif /* LINUX_PCI_REGS_H */
--
1.5.6.4


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