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/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_config_data {
  22         const char *name;
  23 };
  24
  25 struct xlnx_pr_decoupler_data {
  26         const struct xlnx_config_data *ipconfig;
  27         void __iomem *io_base;
  28         struct clk *clk;
  29 };
  30
  31 static inline void xlnx_pr_decoupler_write(struct xlnx_pr_decoupler_data *d,
  32                                            u32 offset, u32 val)
  33 {
  34         writel(val, d->io_base + offset);
  35 }
  36
  37 static inline u32 xlnx_pr_decouple_read(const struct xlnx_pr_decoupler_data *d,
  38                                         u32 offset)
  39 {
  40         return readl(d->io_base + offset);
  41 }
  42
  43 static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
  44 {
  45         int err;
  46         struct xlnx_pr_decoupler_data *priv = bridge->priv;
  47
  48         err = clk_enable(priv->clk);
  49         if (err)
  50                 return err;
  51
  52         if (enable)
  53                 xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_COUPLE);
  54         else
  55                 xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_DECOUPLE);
  56
  57         clk_disable(priv->clk);
  58
  59         return 0;
  60 }
  61
  62 static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
  63 {
  64         const struct xlnx_pr_decoupler_data *priv = bridge->priv;
  65         u32 status;
  66         int err;
  67
  68         err = clk_enable(priv->clk);
  69         if (err)
  70                 return err;
  71
  72         status = readl(priv->io_base);
  73
  74         clk_disable(priv->clk);
  75
  76         return !status;
  77 }
  78
  79 static const struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
  80         .enable_set = xlnx_pr_decoupler_enable_set,
  81         .enable_show = xlnx_pr_decoupler_enable_show,
  82 };
  83
  84 #ifdef CONFIG_OF
  85 static const struct xlnx_config_data decoupler_config = {
  86         .name = "Xilinx PR Decoupler",
  87 };
  88
  89 static const struct xlnx_config_data shutdown_config = {
  90         .name = "Xilinx DFX AXI Shutdown Manager",
  91 };
  92
  93 static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
  94         { .compatible = "xlnx,pr-decoupler-1.00", .data = &decoupler_config },
  95         { .compatible = "xlnx,pr-decoupler", .data = &decoupler_config },
  96         { .compatible = "xlnx,dfx-axi-shutdown-manager-1.00",
  97                                         .data = &shutdown_config },
  98         { .compatible = "xlnx,dfx-axi-shutdown-manager",
  99                                         .data = &shutdown_config },
 100         {},
 101 };
 102 MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 103 #endif
 104
 105 static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 106 {
 107         struct device_node *np = pdev->dev.of_node;
 108         struct xlnx_pr_decoupler_data *priv;
 109         struct fpga_bridge *br;
 110         int err;
 111         struct resource *res;
 112
 113         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 114         if (!priv)
 115                 return -ENOMEM;
 116
 117         if (np) {
 118                 const struct of_device_id *match;
 119
 120                 match = of_match_node(xlnx_pr_decoupler_of_match, np);
 121                 if (match && match->data)
 122                         priv->ipconfig = match->data;
 123         }
 124
 125         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 126         priv->io_base = devm_ioremap_resource(&pdev->dev, res);
 127         if (IS_ERR(priv->io_base))
 128                 return PTR_ERR(priv->io_base);
 129
 130         priv->clk = devm_clk_get(&pdev->dev, "aclk");
 131         if (IS_ERR(priv->clk))
 132                 return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
 133                                      "input clock not found\n");
 134
 135         err = clk_prepare_enable(priv->clk);
 136         if (err) {
 137                 dev_err(&pdev->dev, "unable to enable clock\n");
 138                 return err;
 139         }
 140
 141         clk_disable(priv->clk);
 142
 143         br = fpga_bridge_register(&pdev->dev, priv->ipconfig->name,
 144                                   &xlnx_pr_decoupler_br_ops, priv);
 145         if (IS_ERR(br)) {
 146                 err = PTR_ERR(br);
 147                 dev_err(&pdev->dev, "unable to register %s",
 148                         priv->ipconfig->name);
 149                 goto err_clk;
 150         }
 151
 152         platform_set_drvdata(pdev, br);
 153
 154         return 0;
 155
 156 err_clk:
 157         clk_unprepare(priv->clk);
 158
 159         return err;
 160 }
 161
 162 static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
 163 {
 164         struct fpga_bridge *bridge = platform_get_drvdata(pdev);
 165         struct xlnx_pr_decoupler_data *p = bridge->priv;
 166
 167         fpga_bridge_unregister(bridge);
 168
 169         clk_unprepare(p->clk);
 170
 171         return 0;
 172 }
 173
 174 static struct platform_driver xlnx_pr_decoupler_driver = {
 175         .probe = xlnx_pr_decoupler_probe,
 176         .remove = xlnx_pr_decoupler_remove,
 177         .driver = {
 178                 .name = "xlnx_pr_decoupler",
 179                 .of_match_table = of_match_ptr(xlnx_pr_decoupler_of_match),
 180         },
 181 };
 182
 183 module_platform_driver(xlnx_pr_decoupler_driver);
 184
 185 MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
 186 MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
 187 MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
 188 MODULE_LICENSE("GPL v2");