drivers/firmware/imx/imx-scu.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2018 NXP
   4  *  Author: Dong Aisheng <aisheng.dong@nxp.com>
   5  *
   6  * Implementation of the SCU IPC functions using MUs (client side).
   7  *
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/firmware/imx/types.h>
  12 #include <linux/firmware/imx/ipc.h>
  13 #include <linux/firmware/imx/sci.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mailbox_client.h>
  18 #include <linux/module.h>
  19 #include <linux/mutex.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/platform_device.h>
  22
  23 #define SCU_MU_CHAN_NUM         8
  24 #define MAX_RX_TIMEOUT          (msecs_to_jiffies(30))
  25
  26 struct imx_sc_chan {
  27         struct imx_sc_ipc *sc_ipc;
  28
  29         struct mbox_client cl;
  30         struct mbox_chan *ch;
  31         int idx;
  32         struct completion tx_done;
  33 };
  34
  35 struct imx_sc_ipc {
  36         /* SCU uses 4 Tx and 4 Rx channels */
  37         struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
  38         struct device *dev;
  39         struct mutex lock;
  40         struct completion done;
  41
  42         /* temporarily store the SCU msg */
  43         u32 *msg;
  44         u8 rx_size;
  45         u8 count;
  46 };
  47
  48 /*
  49  * This type is used to indicate error response for most functions.
  50  */
  51 enum imx_sc_error_codes {
  52         IMX_SC_ERR_NONE = 0,    /* Success */
  53         IMX_SC_ERR_VERSION = 1, /* Incompatible API version */
  54         IMX_SC_ERR_CONFIG = 2,  /* Configuration error */
  55         IMX_SC_ERR_PARM = 3,    /* Bad parameter */
  56         IMX_SC_ERR_NOACCESS = 4,        /* Permission error (no access) */
  57         IMX_SC_ERR_LOCKED = 5,  /* Permission error (locked) */
  58         IMX_SC_ERR_UNAVAILABLE = 6,     /* Unavailable (out of resources) */
  59         IMX_SC_ERR_NOTFOUND = 7,        /* Not found */
  60         IMX_SC_ERR_NOPOWER = 8, /* No power */
  61         IMX_SC_ERR_IPC = 9,             /* Generic IPC error */
  62         IMX_SC_ERR_BUSY = 10,   /* Resource is currently busy/active */
  63         IMX_SC_ERR_FAIL = 11,   /* General I/O failure */
  64         IMX_SC_ERR_LAST
  65 };
  66
  67 static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
  68         0,       /* IMX_SC_ERR_NONE */
  69         -EINVAL, /* IMX_SC_ERR_VERSION */
  70         -EINVAL, /* IMX_SC_ERR_CONFIG */
  71         -EINVAL, /* IMX_SC_ERR_PARM */
  72         -EACCES, /* IMX_SC_ERR_NOACCESS */
  73         -EACCES, /* IMX_SC_ERR_LOCKED */
  74         -ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
  75         -EEXIST, /* IMX_SC_ERR_NOTFOUND */
  76         -EPERM,  /* IMX_SC_ERR_NOPOWER */
  77         -EPIPE,  /* IMX_SC_ERR_IPC */
  78         -EBUSY,  /* IMX_SC_ERR_BUSY */
  79         -EIO,    /* IMX_SC_ERR_FAIL */
  80 };
  81
  82 static struct imx_sc_ipc *imx_sc_ipc_handle;
  83
  84 static inline int imx_sc_to_linux_errno(int errno)
  85 {
  86         if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
  87                 return imx_sc_linux_errmap[errno];
  88         return -EIO;
  89 }
  90
  91 /*
  92  * Get the default handle used by SCU
  93  */
  94 int imx_scu_get_handle(struct imx_sc_ipc **ipc)
  95 {
  96         if (!imx_sc_ipc_handle)
  97                 return -EPROBE_DEFER;
  98
  99         *ipc = imx_sc_ipc_handle;
 100         return 0;
 101 }
 102 EXPORT_SYMBOL(imx_scu_get_handle);
 103
 104 /* Callback called when the word of a message is ack-ed, eg read by SCU */
 105 static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
 106 {
 107         struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
 108
 109         complete(&sc_chan->tx_done);
 110 }
 111
 112 static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 113 {
 114         struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
 115         struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
 116         struct imx_sc_rpc_msg *hdr;
 117         u32 *data = msg;
 118
 119         if (!sc_ipc->msg) {
 120                 dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
 121                                 sc_chan->idx, *data);
 122                 return;
 123         }
 124
 125         if (sc_chan->idx == 0) {
 126                 hdr = msg;
 127                 sc_ipc->rx_size = hdr->size;
 128                 dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
 129                 if (sc_ipc->rx_size > 4)
 130                         dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
 131                                  sc_ipc->rx_size);
 132         }
 133
 134         sc_ipc->msg[sc_chan->idx] = *data;
 135         sc_ipc->count++;
 136
 137         dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
 138                 sc_ipc->count, *data);
 139
 140         if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
 141                 complete(&sc_ipc->done);
 142 }
 143
 144 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 145 {
 146         struct imx_sc_rpc_msg *hdr = msg;
 147         struct imx_sc_chan *sc_chan;
 148         u32 *data = msg;
 149         int ret;
 150         int i;
 151
 152         /* Check size */
 153         if (hdr->size > IMX_SC_RPC_MAX_MSG)
 154                 return -EINVAL;
 155
 156         dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr->svc,
 157                 hdr->func, hdr->size);
 158
 159         for (i = 0; i < hdr->size; i++) {
 160                 sc_chan = &sc_ipc->chans[i % 4];
 161
 162                 /*
 163                  * SCU requires that all messages words are written
 164                  * sequentially but linux MU driver implements multiple
 165                  * independent channels for each register so ordering between
 166                  * different channels must be ensured by SCU API interface.
 167                  *
 168                  * Wait for tx_done before every send to ensure that no
 169                  * queueing happens at the mailbox channel level.
 170                  */
 171                 wait_for_completion(&sc_chan->tx_done);
 172                 reinit_completion(&sc_chan->tx_done);
 173
 174                 ret = mbox_send_message(sc_chan->ch, &data[i]);
 175                 if (ret < 0)
 176                         return ret;
 177         }
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * RPC command/response
 184  */
 185 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 186 {
 187         uint8_t saved_svc, saved_func;
 188         struct imx_sc_rpc_msg *hdr;
 189         int ret;
 190
 191         if (WARN_ON(!sc_ipc || !msg))
 192                 return -EINVAL;
 193
 194         mutex_lock(&sc_ipc->lock);
 195         reinit_completion(&sc_ipc->done);
 196
 197         if (have_resp) {
 198                 sc_ipc->msg = msg;
 199                 saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
 200                 saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
 201         }
 202         sc_ipc->count = 0;
 203         ret = imx_scu_ipc_write(sc_ipc, msg);
 204         if (ret < 0) {
 205                 dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
 206                 goto out;
 207         }
 208
 209         if (have_resp) {
 210                 if (!wait_for_completion_timeout(&sc_ipc->done,
 211                                                  MAX_RX_TIMEOUT)) {
 212                         dev_err(sc_ipc->dev, "RPC send msg timeout\n");
 213                         mutex_unlock(&sc_ipc->lock);
 214                         return -ETIMEDOUT;
 215                 }
 216
 217                 /* response status is stored in hdr->func field */
 218                 hdr = msg;
 219                 ret = hdr->func;
 220                 /*
 221                  * Some special SCU firmware APIs do NOT have return value
 222                  * in hdr->func, but they do have response data, those special
 223                  * APIs are defined as void function in SCU firmware, so they
 224                  * should be treated as return success always.
 225                  */
 226                 if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
 227                         (saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
 228                          saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
 229                         ret = 0;
 230         }
 231
 232 out:
 233         sc_ipc->msg = NULL;
 234         mutex_unlock(&sc_ipc->lock);
 235
 236         dev_dbg(sc_ipc->dev, "RPC SVC done\n");
 237
 238         return imx_sc_to_linux_errno(ret);
 239 }
 240 EXPORT_SYMBOL(imx_scu_call_rpc);
 241
 242 static int imx_scu_probe(struct platform_device *pdev)
 243 {
 244         struct device *dev = &pdev->dev;
 245         struct imx_sc_ipc *sc_ipc;
 246         struct imx_sc_chan *sc_chan;
 247         struct mbox_client *cl;
 248         char *chan_name;
 249         int ret;
 250         int i;
 251
 252         sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
 253         if (!sc_ipc)
 254                 return -ENOMEM;
 255
 256         for (i = 0; i < SCU_MU_CHAN_NUM; i++) {
 257                 if (i < 4)
 258                         chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
 259                 else
 260                         chan_name = kasprintf(GFP_KERNEL, "rx%d", i - 4);
 261
 262                 if (!chan_name)
 263                         return -ENOMEM;
 264
 265                 sc_chan = &sc_ipc->chans[i];
 266                 cl = &sc_chan->cl;
 267                 cl->dev = dev;
 268                 cl->tx_block = false;
 269                 cl->knows_txdone = true;
 270                 cl->rx_callback = imx_scu_rx_callback;
 271
 272                 /* Initial tx_done completion as "done" */
 273                 cl->tx_done = imx_scu_tx_done;
 274                 init_completion(&sc_chan->tx_done);
 275                 complete(&sc_chan->tx_done);
 276
 277                 sc_chan->sc_ipc = sc_ipc;
 278                 sc_chan->idx = i % 4;
 279                 sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
 280                 if (IS_ERR(sc_chan->ch)) {
 281                         ret = PTR_ERR(sc_chan->ch);
 282                         if (ret != -EPROBE_DEFER)
 283                                 dev_err(dev, "Failed to request mbox chan %s ret %d\n",
 284                                         chan_name, ret);
 285                         return ret;
 286                 }
 287
 288                 dev_dbg(dev, "request mbox chan %s\n", chan_name);
 289                 /* chan_name is not used anymore by framework */
 290                 kfree(chan_name);
 291         }
 292
 293         sc_ipc->dev = dev;
 294         mutex_init(&sc_ipc->lock);
 295         init_completion(&sc_ipc->done);
 296
 297         imx_sc_ipc_handle = sc_ipc;
 298
 299         ret = imx_scu_enable_general_irq_channel(dev);
 300         if (ret)
 301                 dev_warn(dev,
 302                         "failed to enable general irq channel: %d\n", ret);
 303
 304         dev_info(dev, "NXP i.MX SCU Initialized\n");
 305
 306         return devm_of_platform_populate(dev);
 307 }
 308
 309 static const struct of_device_id imx_scu_match[] = {
 310         { .compatible = "fsl,imx-scu", },
 311         { /* Sentinel */ }
 312 };
 313
 314 static struct platform_driver imx_scu_driver = {
 315         .driver = {
 316                 .name = "imx-scu",
 317                 .of_match_table = imx_scu_match,
 318         },
 319         .probe = imx_scu_probe,
 320 };
 321 builtin_platform_driver(imx_scu_driver);
 322
 323 MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
 324 MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
 325 MODULE_LICENSE("GPL v2");