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/jiffies.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/mailbox_client.h>
  18 #include <linux/platform_device.h>
  19 #include <soc/microchip/mpfs.h>
  20
  21 /*
  22  * This timeout must be long, as some services (example: image authentication)
  23  * take significant time to complete
  24  */
  25 #define MPFS_SYS_CTRL_TIMEOUT_MS 30000
  26
  27 static DEFINE_MUTEX(transaction_lock);
  28
  29 struct mpfs_sys_controller {
  30         struct mbox_client client;
  31         struct mbox_chan *chan;
  32         struct completion c;
  33         struct kref consumers;
  34 };
  35
  36 int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
  37 {
  38         unsigned long timeout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
  39         int ret;
  40
  41         ret = mutex_lock_interruptible(&transaction_lock);
  42         if (ret)
  43                 return ret;
  44
  45         reinit_completion(&sys_controller->c);
  46
  47         ret = mbox_send_message(sys_controller->chan, msg);
  48         if (ret < 0) {
  49                 dev_warn(sys_controller->client.dev, "MPFS sys controller service timeout\n");
  50                 goto out;
  51         }
  52
  53         /*
  54          * Unfortunately, the system controller will only deliver an interrupt
  55          * if a service succeeds. mbox_send_message() will block until the busy
  56          * flag is gone. If the busy flag is gone but no interrupt has arrived
  57          * to trigger the rx callback then the service can be deemed to have
  58          * failed.
  59          * The caller can then interrogate msg::response::resp_status to
  60          * determine the cause of the failure.
  61          * mbox_send_message() returns positive integers in the success path, so
  62          * ret needs to be cleared if we do get an interrupt.
  63          */
  64         if (!wait_for_completion_timeout(&sys_controller->c, timeout)) {
  65                 ret = -EBADMSG;
  66                 dev_warn(sys_controller->client.dev, "MPFS sys controller service failed\n");
  67         } else {
  68                 ret = 0;
  69         }
  70
  71 out:
  72         mutex_unlock(&transaction_lock);
  73
  74         return ret;
  75 }
  76 EXPORT_SYMBOL(mpfs_blocking_transaction);
  77
  78 static void mpfs_sys_controller_rx_callback(struct mbox_client *client, void *msg)
  79 {
  80         struct mpfs_sys_controller *sys_controller =
  81                 container_of(client, struct mpfs_sys_controller, client);
  82
  83         complete(&sys_controller->c);
  84 }
  85
  86 static void mpfs_sys_controller_delete(struct kref *kref)
  87 {
  88         struct mpfs_sys_controller *sys_controller =
  89                 container_of(kref, struct mpfs_sys_controller, consumers);
  90
  91         mbox_free_channel(sys_controller->chan);
  92         kfree(sys_controller);
  93 }
  94
  95 static void mpfs_sys_controller_put(void *data)
  96 {
  97         struct mpfs_sys_controller *sys_controller = data;
  98
  99         kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
 100 }
 101
 102 static struct platform_device subdevs[] = {
 103         {
 104                 .name           = "mpfs-rng",
 105                 .id             = -1,
 106         },
 107         {
 108                 .name           = "mpfs-generic-service",
 109                 .id             = -1,
 110         }
 111 };
 112
 113 static int mpfs_sys_controller_probe(struct platform_device *pdev)
 114 {
 115         struct device *dev = &pdev->dev;
 116         struct mpfs_sys_controller *sys_controller;
 117         int i, ret;
 118
 119         sys_controller = kzalloc(sizeof(*sys_controller), GFP_KERNEL);
 120         if (!sys_controller)
 121                 return -ENOMEM;
 122
 123         sys_controller->client.dev = dev;
 124         sys_controller->client.rx_callback = mpfs_sys_controller_rx_callback;
 125         sys_controller->client.tx_block = 1U;
 126         sys_controller->client.tx_tout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
 127
 128         sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
 129         if (IS_ERR(sys_controller->chan)) {
 130                 ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
 131                                     "Failed to get mbox channel\n");
 132                 kfree(sys_controller);
 133                 return ret;
 134         }
 135
 136         init_completion(&sys_controller->c);
 137         kref_init(&sys_controller->consumers);
 138
 139         platform_set_drvdata(pdev, sys_controller);
 140
 141         dev_info(&pdev->dev, "Registered MPFS system controller\n");
 142
 143         for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
 144                 subdevs[i].dev.parent = dev;
 145                 if (platform_device_register(&subdevs[i]))
 146                         dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
 147         }
 148
 149         return 0;
 150 }
 151
 152 static int mpfs_sys_controller_remove(struct platform_device *pdev)
 153 {
 154         struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
 155
 156         mpfs_sys_controller_put(sys_controller);
 157
 158         return 0;
 159 }
 160
 161 static const struct of_device_id mpfs_sys_controller_of_match[] = {
 162         {.compatible = "microchip,mpfs-sys-controller", },
 163         {},
 164 };
 165 MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
 166
 167 struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
 168 {
 169         const struct of_device_id *match;
 170         struct mpfs_sys_controller *sys_controller;
 171         int ret;
 172
 173         if (!dev->parent)
 174                 goto err_no_device;
 175
 176         match = of_match_node(mpfs_sys_controller_of_match,  dev->parent->of_node);
 177         of_node_put(dev->parent->of_node);
 178         if (!match)
 179                 goto err_no_device;
 180
 181         sys_controller = dev_get_drvdata(dev->parent);
 182         if (!sys_controller)
 183                 goto err_bad_device;
 184
 185         if (!kref_get_unless_zero(&sys_controller->consumers))
 186                 goto err_bad_device;
 187
 188         ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
 189         if (ret)
 190                 return ERR_PTR(ret);
 191
 192         return sys_controller;
 193
 194 err_no_device:
 195         dev_dbg(dev, "Parent device was not an MPFS system controller\n");
 196         return ERR_PTR(-ENODEV);
 197
 198 err_bad_device:
 199         dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
 200         return ERR_PTR(-EPROBE_DEFER);
 201 }
 202 EXPORT_SYMBOL(mpfs_sys_controller_get);
 203
 204 static struct platform_driver mpfs_sys_controller_driver = {
 205         .driver = {
 206                 .name = "mpfs-sys-controller",
 207                 .of_match_table = mpfs_sys_controller_of_match,
 208         },
 209         .probe = mpfs_sys_controller_probe,
 210         .remove = mpfs_sys_controller_remove,
 211 };
 212 module_platform_driver(mpfs_sys_controller_driver);
 213
 214 MODULE_LICENSE("GPL v2");
 215 MODULE_AUTHOR("Conor Dooley <[email protected]>");
 216 MODULE_DESCRIPTION("MPFS system controller driver");