[PATCH v2 3/3] fpga manager: bus driver

[<atull@opensource.altera.com>]

From: Alan Tull <atull@opensource.altera.com>

Support programming the fpga from device tree overlays.

This patch adds one exported function to the core
(fpga-mgr.c): of_fpga_mgr_dev_lookup
  Get pointer to fpga manager struct given a phandle.

This code is dependent on Pantelis Antoniou's current work
on Device Tree overlays, a method of dynamically altering
the kernel's live Device Tree.  The rest of the patchset was
tested with recent for-next, but this 'bus driver' patch was
tested with Pantelis's and Grant Likely's stuff that is in git
(his git repo https://github.com/pantoniou/linux-beagle-track-mainline
 v3.17-rc2-115-gbc778b8 == dt-ng/bbb) plus some dtc fixups
for compiling overlays.

Here's a simple example. Start with:
  * the altera-gpio driver built in to the kernel but not in the
    device tree.
  * raw fpga image at /lib/firmware/soc_system.rbf
  * Load appropriate device tree overlay in configfs by doing
    $ mkdir /config/device-tree/overlays/1
    $ echo socfpga_overlay.dtbo > /config/device-tree/overlays/1/path
  * This results in the FPGA getting programmed and the altera
    gpio driver getting probed.
  * To remove/clear FPGA image by putting the FPGA in reset,
    remove device tree overlay by doing:
    $ rmdir /config/device-tree/overlays/1

Device tree overlay looks like this:
/dts-v1/;
/plugin/;
/ {
	fragment@0 {
		target-path="/soc";
		__overlay__ {
			#address-cells = <1>;
	                #size-cells = <1>;

			bridge@0xff200000 {
				compatible = "fpga-mgr-bus", "simple-bus";
				reg = <0xff200000 0x200000>;
				clocks = <0x2 0x2>;
				clock-names = "h2f_lw_axi_clock", "f2h_sdram0_clock";
				#address-cells = <0x2>;
				#size-cells = <0x1>;
				ranges = <0x1 0x10040 0xff210040 0x20>;

				fpgamgr = <&hps_0_fpgamgr>;
				fpga-firmware = "soc_system.rbf";

				gpio@0x100010040 {
					compatible = "altr,pio-14.0", "altr,pio-1.0";
					reg = <0x1 0x10040 0x20>;
					clocks = <0x2>;
					altr,gpio-bank-width = <0x4>;
					resetvalue = <0x0>;
					#gpio-cells = <0x2>;
					gpio-controller;
					linux,phandle = <0x2d>;
				};
			};
		};
	};
};

Signed-off-by: Alan Tull <atull@opensource.altera.com>

v2: simplify of_fpga_mgr_dev_lookup to return NULL on failure
    move suspend/resume to fpga-mgr.c core
    support 'rmdir' to remove overlay
---
 drivers/fpga/Kconfig     |    7 +++
 drivers/fpga/Makefile    |    1 +
 drivers/fpga/bus.c       |  124 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/fpga/fpga-mgr.c  |   23 +++++++++
 include/linux/fpga-mgr.h |    2 +
 5 files changed, 157 insertions(+)
 create mode 100644 drivers/fpga/bus.c

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index e775b17..2bd6c83 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -18,4 +18,11 @@ config FPGA_MGR_SYSFS
 	help
 	  FPGA Manager SysFS interface.
 
+config FPGA_MGR_BUS
+	bool "FPGA Manager Bus"
+	depends on FPGA
+	help
+	  FPGA Manager Bus interface.  Allows loading FPGA images
+	  from Device Tree or from other drivers.
+
 endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index c8a676f..e39911f 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -6,5 +6,6 @@ fpga-mgr-core-y += fpga-mgr.o
 
 # Core FPGA Manager Framework
 obj-$(CONFIG_FPGA)			+= fpga-mgr-core.o
+obj-$(CONFIG_FPGA_MGR_BUS)		+= bus.o
 
 # FPGA Manager Drivers
diff --git a/drivers/fpga/bus.c b/drivers/fpga/bus.c
new file mode 100644
index 0000000..999346e
--- /dev/null
+++ b/drivers/fpga/bus.c
@@ -0,0 +1,124 @@
+/*
+ * FPGA Manager Bus Driver
+ *
+ *  Copyright (C) 2013-2014 Altera Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/completion.h>
+#include <linux/fs.h>
+#include <linux/fpga-mgr.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+struct fpga_mgr_bus_priv {
+	struct device *dev;
+	struct device_node *np;
+	struct fpga_manager *mgr;
+	const char *path;
+};
+
+static int fpga_mgr_bus_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	struct fpga_mgr_bus_priv *priv;
+	const char *path;
+	struct fpga_manager *mgr;
+	int ret = 0;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* Find the FPGA Manager to associate with */
+	mgr = of_fpga_mgr_dev_lookup(np, "fpgamgr");
+	if (!mgr) {
+		dev_err(mgr->dev, "%s could not find fpga mgr\n", __func__);
+		return -ENODEV;
+	}
+
+	/* Find the FPGA image on the firmware path */
+	of_property_read_string(np, "fpga-firmware", &path);
+
+	ret = fpga_mgr_firmware_write(mgr, path);
+	if (ret != 0) {
+		dev_err(mgr->dev, "%s fpga mgr write failure\n", __func__);
+		return -EIO;
+	}
+
+	priv->dev = dev;
+	priv->np = np;
+	priv->mgr = mgr;
+	priv->path = path;
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+/* Called when the Device Tree overlay is removed */
+static int fpga_mgr_bus_remove(struct platform_device *pdev)
+{
+	struct fpga_mgr_bus_priv *priv = platform_get_drvdata(pdev);
+	struct fpga_manager *mgr = priv->mgr;
+
+	return fpga_mgr_reset(mgr);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id fpga_mgr_bus_of_match[] = {
+	{ .compatible = "fpga-mgr-bus", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, fpga_mgr_bus_of_match);
+#endif
+
+static struct platform_driver fpga_mgr_bus_driver = {
+	.probe = fpga_mgr_bus_probe,
+	.remove = fpga_mgr_bus_remove,
+	.driver = {
+		.name	= "fpga_manager_bus",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(fpga_mgr_bus_of_match),
+	},
+};
+
+static int __init fpga_mgr_bus_init(void)
+{
+	return platform_driver_register(&fpga_mgr_bus_driver);
+}
+
+static void __exit fpga_mgr_bus_exit(void)
+{
+	platform_driver_unregister(&fpga_mgr_bus_driver);
+}
+
+module_init(fpga_mgr_bus_init);
+module_exit(fpga_mgr_bus_exit);
+
+MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
+MODULE_DESCRIPTION("Altera FPGA Manager Bus");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
index 0c7236a..fed13a6 100644
--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c
@@ -350,6 +350,29 @@ const struct attribute_group *fpga_mgr_groups[] = {
 #define fpga_mgr_groups NULL
 #endif /* CONFIG_FPGA_MGR_SYSFS */
 
+/* Find the fpga manager that is pointed to by a phandle */
+struct fpga_manager *of_fpga_mgr_dev_lookup(struct device_node *node,
+					    const char *mgr_property)
+{
+	struct fpga_manager *mgr;
+	struct device_node *mgr_node;
+
+	mgr_node = of_parse_phandle(node, mgr_property, 0);
+	if (!mgr_node)
+		return NULL;
+
+	list_for_each_entry(mgr, &fpga_manager_list, list)
+		if (mgr_node == mgr->np) {
+			of_node_put(mgr_node);
+			return mgr;
+		}
+
+	of_node_put(mgr_node);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(of_fpga_mgr_dev_lookup);
+
 static int fpga_mgr_suspend(struct device *dev)
 {
 	struct fpga_manager *mgr = dev_get_drvdata(dev);
diff --git a/include/linux/fpga-mgr.h b/include/linux/fpga-mgr.h
index 97c7e0b..abf2699 100644
--- a/include/linux/fpga-mgr.h
+++ b/include/linux/fpga-mgr.h
@@ -110,6 +110,8 @@ int fpga_mgr_register(struct platform_device *pdev,
 		      struct fpga_manager_ops *mops,
 		      const char *name, void *priv);
 void fpga_mgr_remove(struct platform_device *pdev);
+struct fpga_manager *of_fpga_mgr_dev_lookup(struct device_node *node,
+					    const char *mgr_property);
 
 #endif /* CONFIG_FPGA */
 #endif /*_LINUX_FPGA_MGR_H */
-- 
1.7.9.5