[PATCH 2/4] PCI: support ARI capability
Support Alternative Routing-ID Interpretation (ARI), which increases the number
of functions that can be supported by a PCIe endpoint. SR-IOV depends on ARI.
PCI-SIG ARI specification can be found at
http://www.pcisig.com/specifications/pciexpress/specifications/ECN-alt-rid-interpretation-070604.pdf
Signed-off-by: Yu Zhao <yu.zhao at intel.com>
Signed-off-by: Eddie Dong <eddie.dong at intel.com>
---
drivers/pci/Kconfig | 7 +++++
drivers/pci/Makefile | 2 +
drivers/pci/ari.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/pci/probe.c | 3 ++
include/linux/pci.h | 29 +++++++++++++++++++
include/linux/pci_regs.h | 14 +++++++++
6 files changed, 125 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index e1ca425..f43cc46 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -50,3 +50,10 @@ config HT_IRQ
This allows native hypertransport devices to use interrupts.
If unsure say Y.
+
+config PCI_ARI
+ bool "PCI ARI support"
+ depends on PCI
+ default n
+ help
+ This enables PCI Alternative Routing-ID Interpretation.
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 7d63f8c..96f2767 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -53,3 +53,5 @@ obj-$(CONFIG_PCI_SYSCALL) += syscall.o
ifeq ($(CONFIG_PCI_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
endif
+
+obj-$(CONFIG_PCI_ARI) += ari.o
diff --git a/drivers/pci/ari.c b/drivers/pci/ari.c
new file mode 100644
index 0000000..e6dae1d
--- /dev/null
+++ b/drivers/pci/ari.c
@@ -0,0 +1,70 @@
+/*
+ * drivers/pci/ari.c
+ *
+ * Copyright (C) 2008 Intel Corporation, Yu Zhao <yu.zhao at intel.com>
+ *
+ * PCI Express Alternative Routing-ID Interpretation capability support.
+ */
+
+#include <linux/pci.h>
+
+#include "pci.h"
+
+/**
+ * pci_ari_enable_fwd - enable ARI forwarding
+ * @dev: PCI device
+ */
+void pci_ari_enable_fwd(struct pci_dev *dev)
+{
+ int pos;
+ u32 cap;
+ u16 ctrl;
+
+ if (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;
+
+ dev->ari_enabled = 1;
+ dev_info(&dev->dev, "ARI forwarding enabled.\n");
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &ctrl);
+ if (ctrl & PCI_EXP_DEVCTL2_ARI)
+ return;
+
+ ctrl |= PCI_EXP_DEVCTL2_ARI;
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, ctrl);
+}
+EXPORT_SYMBOL_GPL(pci_ari_enable_fwd);
+
+/**
+ * pci_ari_next_fn - find next function number
+ * @dev: PCI device
+ *
+ * Returns function number, and 0 if there are no higher numbered
+ * functions; returns negative on failure.
+ */
+int pci_ari_next_fn(struct pci_dev *dev)
+{
+ int pos;
+ u16 cap;
+
+ if (dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
+ return -EINVAL;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
+ if (!pos)
+ return -EIO;
+
+ pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap);
+
+ return PCI_ARI_CAP_NFN(cap);
+}
+EXPORT_SYMBOL_GPL(pci_ari_next_fn);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d030996..e8506fe 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1032,6 +1032,9 @@ int pci_scan_slot(struct pci_bus *bus, i
int func, nr = 0;
int scan_all_fns;
+ if (bus->self)
+ pci_ari_enable_fwd(bus->self);
+
scan_all_fns = pcibios_scan_all_fns(bus, devfn);
for (func = 0; func < 8; func++, devfn++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9ea3a1d..110779a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -214,6 +214,7 @@ #endif
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 on bridge */
unsigned int is_managed:1;
unsigned int is_pcie:1;
pci_dev_flags_t dev_flags;
@@ -1125,5 +1126,33 @@ static inline void pci_mmcfg_early_init(
static inline void pci_mmcfg_late_init(void) { }
#endif
+#ifdef CONFIG_PCI_ARI
+/**
+ * pci_ari_fwd_enabled - query ARI forwarding status
+ * @dev: PCI device
+ *
+ * Returns 1 if ARI forwarding is enabled, and 0 if it's not
+ * enabled; returns negative on failure.
+ */
+static inline int pci_ari_fwd_enabled(struct pci_dev *dev)
+{
+ return dev->ari_enabled;
+}
+extern void pci_ari_enable_fwd(struct pci_dev *dev);
+extern int pci_ari_next_fn(struct pci_dev *dev);
+#else
+static inline int pci_ari_fwd_enabled(struct pci_dev *dev)
+{
+ return -EIO;
+}
+static inline void pci_ari_enable_fwd(struct pci_dev *dev)
+{
+}
+static inline int pci_ari_next_fn(struct pci_dev *dev)
+{
+ return -EIO;
+}
+#endif
+
#endif /* __KERNEL__ */
#endif /* LINUX_PCI_H */
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_PMEIE 0x08 /* PME
#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_ERR 1
#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_ERROR_RETRY 0xC0 /* R
#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 */
--
1.4.2.1
