cxl: Enable CAPP recovery

Turning snoops on is the last step in CAPP recovery. Sapphire is expected to
have reinitialized the PHB and done the previous recovery steps.

Add mode argument to opal call to do this. Driver can turn snoops off although
it does not currently.
Signed-off-by: Ryan Grimm <grimm@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/opal.h

@@ -595,6 +595,14 @@ enum {
 	OPAL_PHB3_NUM_PEST_REGS = 256
 };
 
+/* CAPI modes for PHB */
+enum {
+	OPAL_PHB_CAPI_MODE_PCIE         = 0,
+	OPAL_PHB_CAPI_MODE_CAPI         = 1,
+	OPAL_PHB_CAPI_MODE_SNOOP_OFF    = 2,
+	OPAL_PHB_CAPI_MODE_SNOOP_ON     = 3,
+};
+
 struct OpalIoPhbErrorCommon {
 	__be32 version;
 	__be32 ioType;

arch/powerpc/include/asm/pnv-pci.h

@@ -13,7 +13,7 @@
 #include <linux/pci.h>
 #include <misc/cxl.h>
 
-int pnv_phb_to_cxl(struct pci_dev *dev);
+int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode);
 int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 			   unsigned int virq);
 int pnv_cxl_alloc_hwirqs(struct pci_dev *dev, int num);

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -1468,7 +1468,7 @@ struct device_node *pnv_pci_to_phb_node(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pnv_pci_to_phb_node);
 
-int pnv_phb_to_cxl(struct pci_dev *dev)
+int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode)
 {
 	struct pci_controller *hose = pci_bus_to_host(dev->bus);
 	struct pnv_phb *phb = hose->private_data;
@@ -1481,13 +1481,13 @@ int pnv_phb_to_cxl(struct pci_dev *dev)
 
 	pe_info(pe, "Switching PHB to CXL\n");
 
-	rc = opal_pci_set_phb_cxl_mode(phb->opal_id, 1, pe->pe_number);
+	rc = opal_pci_set_phb_cxl_mode(phb->opal_id, mode, pe->pe_number);
 	if (rc)
 		dev_err(&dev->dev, "opal_pci_set_phb_cxl_mode failed: %i\n", rc);
 
 	return rc;
 }
-EXPORT_SYMBOL(pnv_phb_to_cxl);
+EXPORT_SYMBOL(pnv_phb_to_cxl_mode);
 
 /* Find PHB for cxl dev and allocate MSI hwirqs?
  * Returns the absolute hardware IRQ number

drivers/misc/cxl/pci.c

@@ -926,9 +926,15 @@ static struct cxl *cxl_init_adapter(struct pci_dev *dev)
 	if ((rc = init_implementation_adapter_regs(adapter, dev)))
 		goto err3;
 
-	if ((rc = pnv_phb_to_cxl(dev)))
+	if ((rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_CAPI)))
 		goto err3;
 
+	/* If recovery happened, the last step is to turn on snooping.
+	 * In the non-recovery case this has no effect */
+	if ((rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON))) {
+		goto err3;
+	}
+
 	if ((rc = cxl_register_psl_err_irq(adapter)))
 		goto err3;