drivers/soc/microchip/mpfs-sys-controller.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Microchip PolarFire SoC (MPFS) system controller driver
   4  *
   5  * Copyright (c) 2020-2021 Microchip Corporation. All rights reserved.
   6  *
   7  * Author: Conor Dooley <[email protected]>
   8  *
   9  */
  10
  11 #include <linux/slab.h>
  12 #include <linux/kref.h>
  13 #include <linux/module.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/mailbox_client.h>
  17 #include <linux/platform_device.h>
  18 #include <soc/microchip/mpfs.h>
  19
  20 static DEFINE_MUTEX(transaction_lock);
  21
  22 struct mpfs_sys_controller {
  23         struct mbox_client client;
  24         struct mbox_chan *chan;
  25         struct completion c;
  26         struct kref consumers;
  27 };
  28
  29 int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
  30 {
  31         int ret, err;
  32
  33         err = mutex_lock_interruptible(&transaction_lock);
  34         if (err)
  35                 return err;
  36
  37         reinit_completion(&sys_controller->c);
  38
  39         ret = mbox_send_message(sys_controller->chan, msg);
  40         if (ret >= 0) {
  41                 if (wait_for_completion_timeout(&sys_controller->c, HZ)) {
  42                         ret = 0;
  43                 } else {
  44                         ret = -ETIMEDOUT;
  45                         dev_warn(sys_controller->client.dev,
  46                                  "MPFS sys controller transaction timeout\n");
  47                 }
  48         } else {
  49                 dev_err(sys_controller->client.dev,
  50                         "mpfs sys controller transaction returned %d\n", ret);
  51         }
  52
  53         mutex_unlock(&transaction_lock);
  54
  55         return ret;
  56 }
  57 EXPORT_SYMBOL(mpfs_blocking_transaction);
  58
  59 static void rx_callback(struct mbox_client *client, void *msg)
  60 {
  61         struct mpfs_sys_controller *sys_controller =
  62                 container_of(client, struct mpfs_sys_controller, client);
  63
  64         complete(&sys_controller->c);
  65 }
  66
  67 static void mpfs_sys_controller_delete(struct kref *kref)
  68 {
  69         struct mpfs_sys_controller *sys_controller = container_of(kref, struct mpfs_sys_controller,
  70                                                consumers);
  71
  72         mbox_free_channel(sys_controller->chan);
  73         kfree(sys_controller);
  74 }
  75
  76 static void mpfs_sys_controller_put(void *data)
  77 {
  78         struct mpfs_sys_controller *sys_controller = data;
  79
  80         kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
  81 }
  82
  83 static struct platform_device subdevs[] = {
  84         {
  85                 .name           = "mpfs-rng",
  86                 .id             = -1,
  87         },
  88         {
  89                 .name           = "mpfs-generic-service",
  90                 .id             = -1,
  91         }
  92 };
  93
  94 static int mpfs_sys_controller_probe(struct platform_device *pdev)
  95 {
  96         struct device *dev = &pdev->dev;
  97         struct mpfs_sys_controller *sys_controller;
  98         int i, ret;
  99
 100         sys_controller = kzalloc(sizeof(*sys_controller), GFP_KERNEL);
 101         if (!sys_controller)
 102                 return -ENOMEM;
 103
 104         sys_controller->client.dev = dev;
 105         sys_controller->client.rx_callback = rx_callback;
 106         sys_controller->client.tx_block = 1U;
 107
 108         sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
 109         if (IS_ERR(sys_controller->chan)) {
 110                 ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
 111                                     "Failed to get mbox channel\n");
 112                 kfree(sys_controller);
 113                 return ret;
 114         }
 115
 116         init_completion(&sys_controller->c);
 117         kref_init(&sys_controller->consumers);
 118
 119         platform_set_drvdata(pdev, sys_controller);
 120
 121         dev_info(&pdev->dev, "Registered MPFS system controller\n");
 122
 123         for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
 124                 subdevs[i].dev.parent = dev;
 125                 if (platform_device_register(&subdevs[i]))
 126                         dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int mpfs_sys_controller_remove(struct platform_device *pdev)
 133 {
 134         struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
 135
 136         mpfs_sys_controller_put(sys_controller);
 137
 138         return 0;
 139 }
 140
 141 static const struct of_device_id mpfs_sys_controller_of_match[] = {
 142         {.compatible = "microchip,mpfs-sys-controller", },
 143         {},
 144 };
 145 MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
 146
 147 struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
 148 {
 149         const struct of_device_id *match;
 150         struct mpfs_sys_controller *sys_controller;
 151         int ret;
 152
 153         if (!dev->parent)
 154                 goto err_no_device;
 155
 156         match = of_match_node(mpfs_sys_controller_of_match,  dev->parent->of_node);
 157         of_node_put(dev->parent->of_node);
 158         if (!match)
 159                 goto err_no_device;
 160
 161         sys_controller = dev_get_drvdata(dev->parent);
 162         if (!sys_controller)
 163                 goto err_bad_device;
 164
 165         if (!kref_get_unless_zero(&sys_controller->consumers))
 166                 goto err_bad_device;
 167
 168         ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
 169         if (ret)
 170                 return ERR_PTR(ret);
 171
 172         return sys_controller;
 173
 174 err_no_device:
 175         dev_dbg(dev, "Parent device was not an MPFS system controller\n");
 176         return ERR_PTR(-ENODEV);
 177
 178 err_bad_device:
 179         dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
 180         return ERR_PTR(-EPROBE_DEFER);
 181 }
 182 EXPORT_SYMBOL(mpfs_sys_controller_get);
 183
 184 static struct platform_driver mpfs_sys_controller_driver = {
 185         .driver = {
 186                 .name = "mpfs-sys-controller",
 187                 .of_match_table = mpfs_sys_controller_of_match,
 188         },
 189         .probe = mpfs_sys_controller_probe,
 190         .remove = mpfs_sys_controller_remove,
 191 };
 192 module_platform_driver(mpfs_sys_controller_driver);
 193
 194 MODULE_LICENSE("GPL v2");
 195 MODULE_AUTHOR("Conor Dooley <[email protected]>");
 196 MODULE_DESCRIPTION("MPFS system controller driver");