cxl: Set the PBCQ Tunnel BAR register when enabling capi mode

philippe56 · mpe · commit 401dca8cbd14 · 2018-05-15T21:29:53.000+10:00
Skiboot used to set the default Tunnel BAR register value when capi mode was enabled. This approach was ok for the cxl driver, but prevented other drivers from choosing different values. Skiboot versions > 5.11 will not set the default value any longer. This patch modifies the cxl driver to set/reset the Tunnel BAR register when entering/exiting the cxl mode, with pnv_pci_set_tunnel_bar(). That should work with old skiboot (since we are re-writing the value already set) and new skiboot. mpe: The tunnel support was only merged into Linux recently, in commit d6a90bb ("powerpc/powernv: Enable tunneled operations") (v4.17-rc1), so with new skiboot kernels between that commit and this will not work correctly. Fixes: d6a90bb ("powerpc/powernv: Enable tunneled operations") Signed-off-by: Philippe Bergheaud <felix@linux.ibm.com> Reviewed-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
@@ -1742,6 +1742,10 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev)
 	/* Required for devices using CAPP DMA mode, harmless for others */
 	pci_set_master(dev);
 
+	if (cxl_is_power9())
+		if (pnv_pci_set_tunnel_bar(dev, 0x00020000E0000000ull, 1))
+			dev_info(&dev->dev, "Tunneled operations unsupported\n");
+
 	if ((rc = pnv_phb_to_cxl_mode(dev, adapter->native->sl_ops->capi_mode)))
 		goto err;
 
@@ -1768,6 +1772,9 @@ static void cxl_deconfigure_adapter(struct cxl *adapter)
 {
 	struct pci_dev *pdev = to_pci_dev(adapter->dev.parent);
 
+	if (cxl_is_power9())
+		pnv_pci_set_tunnel_bar(pdev, 0x00020000E0000000ull, 0);
+
 	cxl_native_release_psl_err_irq(adapter);
 	cxl_unmap_adapter_regs(adapter);
 
