fpga: Add support for Xilinx DFX AXI Shutdown manager

This patch adds support for Xilinx Dynamic Function eXchange(DFX) AXI
shutdown manager IP. It can be used to safely handling the AXI traffic
on a Reconfigurable Partition when it is undergoing dynamic reconfiguration
and there by preventing system deadlock that may occur if AXI transactions
are interrupted during reconfiguration.

PR-Decoupler and AXI shutdown manager are completely different IPs.
But both the IP registers are compatible and also both belong to the
same sub-system (fpga-bridge).So using same driver for both IP's.

Signed-off-by: Nava kishore Manne <[e-mail]>
Reviewed-by: Tom Rix <[e-mail]>
Signed-off-by: Moritz Fischer <[e-mail]>

drivers/fpga/Kconfig

···
 	depends on FPGA_BRIDGE
 	depends on HAS_IOMEM
 	help
-	  Say Y to enable drivers for Xilinx LogiCORE PR Decoupler.
+	  Say Y to enable drivers for Xilinx LogiCORE PR Decoupler
+	  or Xilinx Dynamic Function eXchnage AIX Shutdown Manager.
 	  The PR Decoupler exists in the FPGA fabric to isolate one
 	  region of the FPGA from the busses while that region is
 	  being reprogrammed during partial reconfig.
+	  The Dynamic Function eXchange AXI shutdown manager prevents
+	  AXI traffic from passing through the bridge. The controller
+	  safely handles AXI4MM and AXI4-Lite interfaces on a
+	  Reconfigurable Partition when it is undergoing dynamic
+	  reconfiguration, preventing the system deadlock that can
+	  occur if AXI transactions are interrupted by DFX.
 
 config FPGA_REGION
 	tristate "FPGA Region"

drivers/fpga/xilinx-pr-decoupler.c

···
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2017, National Instruments Corp.
- * Copyright (c) 2017, Xilix Inc
+ * Copyright (c) 2017, Xilinx Inc
  *
  * FPGA Bridge Driver for the Xilinx LogiCORE Partial Reconfiguration
  * Decoupler IP Core.
···
 #define CTRL_CMD_COUPLE		0
 #define CTRL_OFFSET		0
 
+struct xlnx_config_data {
+	const char *name;
+};
+
 struct xlnx_pr_decoupler_data {
+	const struct xlnx_config_data *ipconfig;
 	void __iomem *io_base;
 	struct clk *clk;
 };
···
 	.enable_show = xlnx_pr_decoupler_enable_show,
 };
 
+static const struct xlnx_config_data decoupler_config = {
+	.name = "Xilinx PR Decoupler",
+};
+
+static const struct xlnx_config_data shutdown_config = {
+	.name = "Xilinx DFX AXI Shutdown Manager",
+};
+
 static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
-	{ .compatible = "xlnx,pr-decoupler-1.00", },
-	{ .compatible = "xlnx,pr-decoupler", },
+	{ .compatible = "xlnx,pr-decoupler-1.00", .data = &decoupler_config },
+	{ .compatible = "xlnx,pr-decoupler", .data = &decoupler_config },
+	{ .compatible = "xlnx,dfx-axi-shutdown-manager-1.00",
+					.data = &shutdown_config },
+	{ .compatible = "xlnx,dfx-axi-shutdown-manager",
+					.data = &shutdown_config },
 	{},
 };
 MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 
 static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct xlnx_pr_decoupler_data *priv;
 	struct fpga_bridge *br;
 	int err;
···
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
+
+	if (np) {
+		const struct of_device_id *match;
+
+		match = of_match_node(xlnx_pr_decoupler_of_match, np);
+		if (match && match->data)
+			priv->ipconfig = match->data;
+	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->io_base = devm_ioremap_resource(&pdev->dev, res);
···
 
 	clk_disable(priv->clk);
 
-	br = devm_fpga_bridge_create(&pdev->dev, "Xilinx PR Decoupler",
+	br = devm_fpga_bridge_create(&pdev->dev, priv->ipconfig->name,
 				     &xlnx_pr_decoupler_br_ops, priv);
 	if (!br) {
 		err = -ENOMEM;
···
 
 	err = fpga_bridge_register(br);
 	if (err) {
-		dev_err(&pdev->dev, "unable to register Xilinx PR Decoupler");
+		dev_err(&pdev->dev, "unable to register %s",
+			priv->ipconfig->name);
 		goto err_clk;
 	}