1/*
  2 * Copyright (c) 2017, National Instruments Corp.
  3 * Copyright (c) 2017, Xilix Inc
  4 *
  5 * FPGA Bridge Driver for the Xilinx LogiCORE Partial Reconfiguration
  6 * Decoupler IP Core.
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License as published by
 10 * the Free Software Foundation; version 2 of the License.
 11 *
 12 * This program is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 15 * GNU General Public License for more details.
 16 */
 17
 18#include <linux/clk.h>
 19#include <linux/io.h>
 20#include <linux/kernel.h>
 21#include <linux/of_device.h>
 22#include <linux/module.h>
 23#include <linux/fpga/fpga-bridge.h>
 24
 25#define CTRL_CMD_DECOUPLE	BIT(0)
 26#define CTRL_CMD_COUPLE		0
 27#define CTRL_OFFSET		0
 28
 29struct xlnx_pr_decoupler_data {
 30	void __iomem *io_base;
 31	struct clk *clk;
 32};
 33
 34static inline void xlnx_pr_decoupler_write(struct xlnx_pr_decoupler_data *d,
 35					   u32 offset, u32 val)
 36{
 37	writel(val, d->io_base + offset);
 38}
 39
 40static inline u32 xlnx_pr_decouple_read(const struct xlnx_pr_decoupler_data *d,
 41					u32 offset)
 42{
 43	return readl(d->io_base + offset);
 44}
 45
 46static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
 47{
 48	int err;
 49	struct xlnx_pr_decoupler_data *priv = bridge->priv;
 50
 51	err = clk_enable(priv->clk);
 52	if (err)
 53		return err;
 54
 55	if (enable)
 56		xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_COUPLE);
 57	else
 58		xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_DECOUPLE);
 59
 60	clk_disable(priv->clk);
 61
 62	return 0;
 63}
 64
 65static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
 66{
 67	const struct xlnx_pr_decoupler_data *priv = bridge->priv;
 68	u32 status;
 69	int err;
 70
 71	err = clk_enable(priv->clk);
 72	if (err)
 73		return err;
 74
 75	status = readl(priv->io_base);
 76
 77	clk_disable(priv->clk);
 78
 79	return !status;
 80}
 81
 82static const struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
 83	.enable_set = xlnx_pr_decoupler_enable_set,
 84	.enable_show = xlnx_pr_decoupler_enable_show,
 85};
 86
 87static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
 88	{ .compatible = "xlnx,pr-decoupler-1.00", },
 89	{ .compatible = "xlnx,pr-decoupler", },
 90	{},
 91};
 92MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 93
 94static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 95{
 96	struct xlnx_pr_decoupler_data *priv;
 97	int err;
 98	struct resource *res;
 99
100	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
101	if (!priv)
102		return -ENOMEM;
103
104	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105	priv->io_base = devm_ioremap_resource(&pdev->dev, res);
106	if (IS_ERR(priv->io_base))
107		return PTR_ERR(priv->io_base);
108
109	priv->clk = devm_clk_get(&pdev->dev, "aclk");
110	if (IS_ERR(priv->clk)) {
111		dev_err(&pdev->dev, "input clock not found\n");
112		return PTR_ERR(priv->clk);
113	}
114
115	err = clk_prepare_enable(priv->clk);
116	if (err) {
117		dev_err(&pdev->dev, "unable to enable clock\n");
118		return err;
119	}
120
121	clk_disable(priv->clk);
122
123	err = fpga_bridge_register(&pdev->dev, "Xilinx PR Decoupler",
124				   &xlnx_pr_decoupler_br_ops, priv);
125
126	if (err) {
127		dev_err(&pdev->dev, "unable to register Xilinx PR Decoupler");
128		clk_unprepare(priv->clk);
129		return err;
130	}
131
132	return 0;
133}
134
135static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
136{
137	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
138	struct xlnx_pr_decoupler_data *p = bridge->priv;
139
140	fpga_bridge_unregister(&pdev->dev);
141
142	clk_unprepare(p->clk);
143
144	return 0;
145}
146
147static struct platform_driver xlnx_pr_decoupler_driver = {
148	.probe = xlnx_pr_decoupler_probe,
149	.remove = xlnx_pr_decoupler_remove,
150	.driver = {
151		.name = "xlnx_pr_decoupler",
152		.of_match_table = of_match_ptr(xlnx_pr_decoupler_of_match),
153	},
154};
155
156module_platform_driver(xlnx_pr_decoupler_driver);
157
158MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
159MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
160MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
161MODULE_LICENSE("GPL v2");