CXL and AER drivers need the ability to identify CXL devices and CXL port
devices.
First, add set_pcie_cxl() with logic checking for CXL Flexbus DVSEC
presence. The CXL Flexbus DVSEC presence is used because it is required
for all the CXL PCIe devices.[1]
Add boolean 'struct pci_dev::is_cxl' with the purpose to cache the CXL
Flexbus presence.
Add pcie_is_cxl() as a macro to return 'struct pci_dev::is_cxl',
Add pcie_is_cxl_port() to check if a device is a CXL root port, CXL
upstream switch port, or CXL downstream switch port. Also, verify the
CXL extensions DVSEC for port is present.[1]
[1] CXL 3.1 Spec, 8.1.1 PCIe Designated Vendor-Specific Extended
Capability (DVSEC) ID Assignment, Table 8-2
Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
---
drivers/pci/pci.c | 14 ++++++++++++++
drivers/pci/probe.c | 10 ++++++++++
include/linux/pci.h | 4 ++++
include/uapi/linux/pci_regs.h | 3 ++-
4 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7d85c04fbba2..c1b243aec61c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5034,6 +5034,20 @@ static u16 cxl_port_dvsec(struct pci_dev *dev)
PCI_DVSEC_CXL_PORT);
}
+bool pcie_is_cxl_port(struct pci_dev *dev)
+{
+ if (!pcie_is_cxl(dev))
+ return false;
+
+ if ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
+ (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
+ (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM))
+ return false;
+
+ return cxl_port_dvsec(dev);
+}
+EXPORT_SYMBOL_GPL(pcie_is_cxl_port);
+
static bool cxl_sbr_masked(struct pci_dev *dev)
{
u16 dvsec, reg;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4f68414c3086..9324eb345f11 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1631,6 +1631,14 @@ static void set_pcie_thunderbolt(struct pci_dev *dev)
dev->is_thunderbolt = 1;
}
+static void set_pcie_cxl(struct pci_dev *dev)
+{
+ u16 dvsec = pci_find_dvsec_capability(dev, PCI_VENDOR_ID_CXL,
+ PCI_DVSEC_CXL_FLEXBUS);
+ if (dvsec)
+ dev->is_cxl = 1;
+}
+
static void set_pcie_untrusted(struct pci_dev *dev)
{
struct pci_dev *parent;
@@ -1945,6 +1953,8 @@ int pci_setup_device(struct pci_dev *dev)
/* Need to have dev->cfg_size ready */
set_pcie_thunderbolt(dev);
+ set_pcie_cxl(dev);
+
set_pcie_untrusted(dev);
/* "Unknown power state" */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 106ac83e3a7b..d3b1af9fb273 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -443,6 +443,7 @@ struct pci_dev {
unsigned int is_hotplug_bridge:1;
unsigned int shpc_managed:1; /* SHPC owned by shpchp */
unsigned int is_thunderbolt:1; /* Thunderbolt controller */
+ unsigned int is_cxl:1; /* CXL alternate protocol */
/*
* Devices marked being untrusted are the ones that can potentially
* execute DMA attacks and similar. They are typically connected
@@ -743,6 +744,9 @@ static inline bool pci_is_vga(struct pci_dev *pdev)
return false;
}
+#define pcie_is_cxl(dev) (dev->is_cxl)
+bool pcie_is_cxl_port(struct pci_dev *dev);
+
#define for_each_pci_bridge(dev, bus) \
list_for_each_entry(dev, &bus->devices, bus_list) \
if (!pci_is_bridge(dev)) {} else
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 12323b3334a9..5df6c74963c5 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -1186,9 +1186,10 @@
#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL 0x00ff0000
#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX 0xff000000
-/* Compute Express Link (CXL r3.1, sec 8.1.5) */
+/* Compute Express Link (CXL r3.1, sec 8.1) */
#define PCI_DVSEC_CXL_PORT 3
#define PCI_DVSEC_CXL_PORT_CTL 0x0c
#define PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR 0x00000001
+#define PCI_DVSEC_CXL_FLEXBUS 7
#endif /* LINUX_PCI_REGS_H */
--
2.34.1
