1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2017, National Instruments Corp.
  4 * Copyright (c) 2017, Xilix Inc
  5 *
  6 * FPGA Bridge Driver for the Xilinx LogiCORE Partial Reconfiguration
  7 * Decoupler IP Core.
  8 */
  9
 10#include <linux/clk.h>
 11#include <linux/io.h>
 12#include <linux/kernel.h>
 13#include <linux/of_device.h>
 14#include <linux/module.h>
 15#include <linux/fpga/fpga-bridge.h>
 16
 17#define CTRL_CMD_DECOUPLE	BIT(0)
 18#define CTRL_CMD_COUPLE		0
 19#define CTRL_OFFSET		0
 20
 21struct xlnx_pr_decoupler_data {
 22	void __iomem *io_base;
 23	struct clk *clk;
 24};
 25
 26static inline void xlnx_pr_decoupler_write(struct xlnx_pr_decoupler_data *d,
 27					   u32 offset, u32 val)
 28{
 29	writel(val, d->io_base + offset);
 30}
 31
 32static inline u32 xlnx_pr_decouple_read(const struct xlnx_pr_decoupler_data *d,
 33					u32 offset)
 34{
 35	return readl(d->io_base + offset);
 36}
 37
 38static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
 39{
 40	int err;
 41	struct xlnx_pr_decoupler_data *priv = bridge->priv;
 42
 43	err = clk_enable(priv->clk);
 44	if (err)
 45		return err;
 46
 47	if (enable)
 48		xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_COUPLE);
 49	else
 50		xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_DECOUPLE);
 51
 52	clk_disable(priv->clk);
 53
 54	return 0;
 55}
 56
 57static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
 58{
 59	const struct xlnx_pr_decoupler_data *priv = bridge->priv;
 60	u32 status;
 61	int err;
 62
 63	err = clk_enable(priv->clk);
 64	if (err)
 65		return err;
 66
 67	status = readl(priv->io_base);
 68
 69	clk_disable(priv->clk);
 70
 71	return !status;
 72}
 73
 74static const struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
 75	.enable_set = xlnx_pr_decoupler_enable_set,
 76	.enable_show = xlnx_pr_decoupler_enable_show,
 77};
 78
 79static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
 80	{ .compatible = "xlnx,pr-decoupler-1.00", },
 81	{ .compatible = "xlnx,pr-decoupler", },
 82	{},
 83};
 84MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 85
 86static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 87{
 88	struct xlnx_pr_decoupler_data *priv;
 89	struct fpga_bridge *br;
 90	int err;
 91	struct resource *res;
 92
 93	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 94	if (!priv)
 95		return -ENOMEM;
 96
 97	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 98	priv->io_base = devm_ioremap_resource(&pdev->dev, res);
 99	if (IS_ERR(priv->io_base))
100		return PTR_ERR(priv->io_base);
101
102	priv->clk = devm_clk_get(&pdev->dev, "aclk");
103	if (IS_ERR(priv->clk)) {
104		if (PTR_ERR(priv->clk) != -EPROBE_DEFER)
105			dev_err(&pdev->dev, "input clock not found\n");
106		return PTR_ERR(priv->clk);
107	}
108
109	err = clk_prepare_enable(priv->clk);
110	if (err) {
111		dev_err(&pdev->dev, "unable to enable clock\n");
112		return err;
113	}
114
115	clk_disable(priv->clk);
116
117	br = devm_fpga_bridge_create(&pdev->dev, "Xilinx PR Decoupler",
118				     &xlnx_pr_decoupler_br_ops, priv);
119	if (!br) {
120		err = -ENOMEM;
121		goto err_clk;
122	}
123
124	platform_set_drvdata(pdev, br);
125
126	err = fpga_bridge_register(br);
127	if (err) {
128		dev_err(&pdev->dev, "unable to register Xilinx PR Decoupler");
129		goto err_clk;
130	}
131
132	return 0;
133
134err_clk:
135	clk_unprepare(priv->clk);
136
137	return err;
138}
139
140static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
141{
142	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
143	struct xlnx_pr_decoupler_data *p = bridge->priv;
144
145	fpga_bridge_unregister(bridge);
146
147	clk_unprepare(p->clk);
148
149	return 0;
150}
151
152static struct platform_driver xlnx_pr_decoupler_driver = {
153	.probe = xlnx_pr_decoupler_probe,
154	.remove = xlnx_pr_decoupler_remove,
155	.driver = {
156		.name = "xlnx_pr_decoupler",
157		.of_match_table = of_match_ptr(xlnx_pr_decoupler_of_match),
158	},
159};
160
161module_platform_driver(xlnx_pr_decoupler_driver);
162
163MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
164MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
165MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
166MODULE_LICENSE("GPL v2");