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, Xilinx 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/module.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/property.h>
  17 #include <linux/fpga/fpga-bridge.h>
  18
  19 #define CTRL_CMD_DECOUPLE       BIT(0)
  20 #define CTRL_CMD_COUPLE         0
  21 #define CTRL_OFFSET             0
  22
  23 struct xlnx_config_data {
  24         const char *name;
  25 };
  26
  27 struct xlnx_pr_decoupler_data {
  28         const struct xlnx_config_data *ipconfig;
  29         void __iomem *io_base;
  30         struct clk *clk;
  31 };
  32
  33 static inline void xlnx_pr_decoupler_write(struct xlnx_pr_decoupler_data *d,
  34                                            u32 offset, u32 val)
  35 {
  36         writel(val, d->io_base + offset);
  37 }
  38
  39 static inline u32 xlnx_pr_decouple_read(const struct xlnx_pr_decoupler_data *d,
  40                                         u32 offset)
  41 {
  42         return readl(d->io_base + offset);
  43 }
  44
  45 static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
  46 {
  47         int err;
  48         struct xlnx_pr_decoupler_data *priv = bridge->priv;
  49
  50         err = clk_enable(priv->clk);
  51         if (err)
  52                 return err;
  53
  54         if (enable)
  55                 xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_COUPLE);
  56         else
  57                 xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_DECOUPLE);
  58
  59         clk_disable(priv->clk);
  60
  61         return 0;
  62 }
  63
  64 static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
  65 {
  66         const struct xlnx_pr_decoupler_data *priv = bridge->priv;
  67         u32 status;
  68         int err;
  69
  70         err = clk_enable(priv->clk);
  71         if (err)
  72                 return err;
  73
  74         status = xlnx_pr_decouple_read(priv, CTRL_OFFSET);
  75
  76         clk_disable(priv->clk);
  77
  78         return !status;
  79 }
  80
  81 static const struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
  82         .enable_set = xlnx_pr_decoupler_enable_set,
  83         .enable_show = xlnx_pr_decoupler_enable_show,
  84 };
  85
  86 static const struct xlnx_config_data decoupler_config = {
  87         .name = "Xilinx PR Decoupler",
  88 };
  89
  90 static const struct xlnx_config_data shutdown_config = {
  91         .name = "Xilinx DFX AXI Shutdown Manager",
  92 };
  93
  94 static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
  95         { .compatible = "xlnx,pr-decoupler-1.00", .data = &decoupler_config },
  96         { .compatible = "xlnx,pr-decoupler", .data = &decoupler_config },
  97         { .compatible = "xlnx,dfx-axi-shutdown-manager-1.00",
  98                                         .data = &shutdown_config },
  99         { .compatible = "xlnx,dfx-axi-shutdown-manager",
 100                                         .data = &shutdown_config },
 101         {},
 102 };
 103 MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 104
 105 static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 106 {
 107         struct xlnx_pr_decoupler_data *priv;
 108         struct fpga_bridge *br;
 109         int err;
 110
 111         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 112         if (!priv)
 113                 return -ENOMEM;
 114
 115         priv->ipconfig = device_get_match_data(&pdev->dev);
 116
 117         priv->io_base = devm_platform_ioremap_resource(pdev, 0);
 118         if (IS_ERR(priv->io_base))
 119                 return PTR_ERR(priv->io_base);
 120
 121         priv->clk = devm_clk_get(&pdev->dev, "aclk");
 122         if (IS_ERR(priv->clk))
 123                 return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
 124                                      "input clock not found\n");
 125
 126         err = clk_prepare_enable(priv->clk);
 127         if (err) {
 128                 dev_err(&pdev->dev, "unable to enable clock\n");
 129                 return err;
 130         }
 131
 132         clk_disable(priv->clk);
 133
 134         br = fpga_bridge_register(&pdev->dev, priv->ipconfig->name,
 135                                   &xlnx_pr_decoupler_br_ops, priv);
 136         if (IS_ERR(br)) {
 137                 err = PTR_ERR(br);
 138                 dev_err(&pdev->dev, "unable to register %s",
 139                         priv->ipconfig->name);
 140                 goto err_clk;
 141         }
 142
 143         platform_set_drvdata(pdev, br);
 144
 145         return 0;
 146
 147 err_clk:
 148         clk_unprepare(priv->clk);
 149
 150         return err;
 151 }
 152
 153 static void xlnx_pr_decoupler_remove(struct platform_device *pdev)
 154 {
 155         struct fpga_bridge *bridge = platform_get_drvdata(pdev);
 156         struct xlnx_pr_decoupler_data *p = bridge->priv;
 157
 158         fpga_bridge_unregister(bridge);
 159
 160         clk_unprepare(p->clk);
 161 }
 162
 163 static struct platform_driver xlnx_pr_decoupler_driver = {
 164         .probe = xlnx_pr_decoupler_probe,
 165         .remove = xlnx_pr_decoupler_remove,
 166         .driver = {
 167                 .name = "xlnx_pr_decoupler",
 168                 .of_match_table = xlnx_pr_decoupler_of_match,
 169         },
 170 };
 171
 172 module_platform_driver(xlnx_pr_decoupler_driver);
 173
 174 MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
 175 MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
 176 MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
 177 MODULE_LICENSE("GPL v2");