drivers/fpga/xilinx-pr-decoupler.c

   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
  21 struct xlnx_pr_decoupler_data {
  22         void __iomem *io_base;
  23         struct clk *clk;
  24 };
  25
  26 static 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
  32 static 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
  38 static 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
  57 static 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
  74 static 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
  79 static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
  80         { .compatible = "xlnx,pr-decoupler-1.00", },
  81         { .compatible = "xlnx,pr-decoupler", },
  82         {},
  83 };
  84 MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
  85
  86 static 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
 134 err_clk:
 135         clk_unprepare(priv->clk);
 136
 137         return err;
 138 }
 139
 140 static 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
 152 static 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
 161 module_platform_driver(xlnx_pr_decoupler_driver);
 162
 163 MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
 164 MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
 165 MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
 166 MODULE_LICENSE("GPL v2");