drivers/fpga/xilinx-pr-decoupler.c

   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
  29 struct xlnx_pr_decoupler_data {
  30         void __iomem *io_base;
  31         struct clk *clk;
  32 };
  33
  34 static 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
  40 static 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
  46 static 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
  65 static 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
  82 static 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
  87 static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
  88         { .compatible = "xlnx,pr-decoupler-1.00", },
  89         { .compatible = "xlnx,pr-decoupler", },
  90         {},
  91 };
  92 MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
  93
  94 static 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
 135 static 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
 147 static 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
 156 module_platform_driver(xlnx_pr_decoupler_driver);
 157
 158 MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
 159 MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
 160 MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
 161 MODULE_LICENSE("GPL v2");