[PATCH] cxl: add device ID for Mellanox ConnectX-4

[Andrew Donnellan <andrew.donnellan@au1.ibm.com>]

Currently the cxl driver attempts to bind to any class 1200 (processing
accelerator) device, and only works out whether it's actually a CAPI card
later on. This doesn't really break anything (if it's not a CAPI card,
we'll abort very quickly), but ideally we'd like to remove this and be
explicit about the cards we support.

For CAPI-capable FPGA devices, we currently use a regular PCI_DEVICE entry
in the ID table to match the vendor and device ID. However, in the case of
some bi-modal devices, such as the Mellanox ConnectX-4, this may not be
sufficient. The CX-4 uses the same vendor and device ID whether in regular
PCIe mode or in CAPI mode, and one of its functions in PCIe mode has a CAPI
VSEC, so cxl would incorrectly try to initialise it as if it's already in
CAPI mode.

For this case, add a PCI_DEVICE_ACCEL macro which also checks the class
number, and add a device ID for the Mellanox CX-4 in CAPI mode. Don't
remove the generic class entry just yet - we'll remove it eventually after
we're certain that no end users are depending on it.

Suggested-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
---
 drivers/misc/cxl/pci.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index d152e2d..cc66ee2 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -118,13 +118,29 @@
 #define   AFUD_EB_LEN(val)		EXTRACT_PPC_BITS(val, 8, 63)
 #define AFUD_READ_EB_OFF(afu)		AFUD_READ(afu, 0x48)
 
+/*
+ * Matches a given PCI vendor ID and device ID, but only for class 12
+ * (processing accelerators). Useful for bi-modal cards, such as the
+ * Mellanox ConnectX-4, which keep the same vendor/device ID
+ * post-mode-switch.
+ */
+#define PCI_DEVICE_ACCEL(vend, dev) \
+	.vendor = (vend), .device = (dev), \
+	.subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID, \
+	.class = 0x120000, .class_mask = 0xff0000
+
 static const struct pci_device_id cxl_pci_tbl[] = {
+	/* FPGA devices */
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0477), },
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x044b), },
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x04cf), },
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0601), },
-	{ PCI_DEVICE_CLASS(0x120000, ~0), },
 
+	/* Mellanox ConnectX-4 */
+	{ PCI_DEVICE_ACCEL(PCI_VENDOR_ID_MELLANOX, 0x1013), },
+
+	/* Generic match for class 120000 devices, will be removed eventually */
+	{ PCI_DEVICE_CLASS(0x120000, ~0), },
 	{ }
 };
 MODULE_DEVICE_TABLE(pci, cxl_pci_tbl);
-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited