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/ipc.h>
  12 #include <linux/firmware/imx/sci.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irq.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mailbox_client.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/platform_device.h>
  21
  22 #define SCU_MU_CHAN_NUM         8
  23 #define MAX_RX_TIMEOUT          (msecs_to_jiffies(30))
  24
  25 struct imx_sc_chan {
  26         struct imx_sc_ipc *sc_ipc;
  27
  28         struct mbox_client cl;
  29         struct mbox_chan *ch;
  30         int idx;
  31         struct completion tx_done;
  32 };
  33
  34 struct imx_sc_ipc {
  35         /* SCU uses 4 Tx and 4 Rx channels */
  36         struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
  37         struct device *dev;
  38         struct mutex lock;
  39         struct completion done;
  40         bool fast_ipc;
  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         int i;
 119
 120         if (!sc_ipc->msg) {
 121                 dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
 122                                 sc_chan->idx, *data);
 123                 return;
 124         }
 125
 126         if (sc_ipc->fast_ipc) {
 127                 hdr = msg;
 128                 sc_ipc->rx_size = hdr->size;
 129                 sc_ipc->msg[0] = *data++;
 130
 131                 for (i = 1; i < sc_ipc->rx_size; i++)
 132                         sc_ipc->msg[i] = *data++;
 133
 134                 complete(&sc_ipc->done);
 135
 136                 return;
 137         }
 138
 139         if (sc_chan->idx == 0) {
 140                 hdr = msg;
 141                 sc_ipc->rx_size = hdr->size;
 142                 dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
 143                 if (sc_ipc->rx_size > 4)
 144                         dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
 145                                  sc_ipc->rx_size);
 146         }
 147
 148         sc_ipc->msg[sc_chan->idx] = *data;
 149         sc_ipc->count++;
 150
 151         dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
 152                 sc_ipc->count, *data);
 153
 154         if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
 155                 complete(&sc_ipc->done);
 156 }
 157
 158 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 159 {
 160         struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
 161         struct imx_sc_chan *sc_chan;
 162         u32 *data = msg;
 163         int ret;
 164         int size;
 165         int i;
 166
 167         /* Check size */
 168         if (hdr.size > IMX_SC_RPC_MAX_MSG)
 169                 return -EINVAL;
 170
 171         dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
 172                 hdr.func, hdr.size);
 173
 174         size = sc_ipc->fast_ipc ? 1 : hdr.size;
 175         for (i = 0; i < size; i++) {
 176                 sc_chan = &sc_ipc->chans[i % 4];
 177
 178                 /*
 179                  * SCU requires that all messages words are written
 180                  * sequentially but linux MU driver implements multiple
 181                  * independent channels for each register so ordering between
 182                  * different channels must be ensured by SCU API interface.
 183                  *
 184                  * Wait for tx_done before every send to ensure that no
 185                  * queueing happens at the mailbox channel level.
 186                  */
 187                 if (!sc_ipc->fast_ipc) {
 188                         wait_for_completion(&sc_chan->tx_done);
 189                         reinit_completion(&sc_chan->tx_done);
 190                 }
 191
 192                 ret = mbox_send_message(sc_chan->ch, &data[i]);
 193                 if (ret < 0)
 194                         return ret;
 195         }
 196
 197         return 0;
 198 }
 199
 200 /*
 201  * RPC command/response
 202  */
 203 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 204 {
 205         uint8_t saved_svc, saved_func;
 206         struct imx_sc_rpc_msg *hdr;
 207         int ret;
 208
 209         if (WARN_ON(!sc_ipc || !msg))
 210                 return -EINVAL;
 211
 212         mutex_lock(&sc_ipc->lock);
 213         reinit_completion(&sc_ipc->done);
 214
 215         if (have_resp) {
 216                 sc_ipc->msg = msg;
 217                 saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
 218                 saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
 219         }
 220         sc_ipc->count = 0;
 221         ret = imx_scu_ipc_write(sc_ipc, msg);
 222         if (ret < 0) {
 223                 dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
 224                 goto out;
 225         }
 226
 227         if (have_resp) {
 228                 if (!wait_for_completion_timeout(&sc_ipc->done,
 229                                                  MAX_RX_TIMEOUT)) {
 230                         dev_err(sc_ipc->dev, "RPC send msg timeout\n");
 231                         mutex_unlock(&sc_ipc->lock);
 232                         return -ETIMEDOUT;
 233                 }
 234
 235                 /* response status is stored in hdr->func field */
 236                 hdr = msg;
 237                 ret = hdr->func;
 238                 /*
 239                  * Some special SCU firmware APIs do NOT have return value
 240                  * in hdr->func, but they do have response data, those special
 241                  * APIs are defined as void function in SCU firmware, so they
 242                  * should be treated as return success always.
 243                  */
 244                 if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
 245                         (saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
 246                          saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
 247                         ret = 0;
 248         }
 249
 250 out:
 251         sc_ipc->msg = NULL;
 252         mutex_unlock(&sc_ipc->lock);
 253
 254         dev_dbg(sc_ipc->dev, "RPC SVC done\n");
 255
 256         return imx_sc_to_linux_errno(ret);
 257 }
 258 EXPORT_SYMBOL(imx_scu_call_rpc);
 259
 260 static int imx_scu_probe(struct platform_device *pdev)
 261 {
 262         struct device *dev = &pdev->dev;
 263         struct imx_sc_ipc *sc_ipc;
 264         struct imx_sc_chan *sc_chan;
 265         struct mbox_client *cl;
 266         char *chan_name;
 267         struct of_phandle_args args;
 268         int num_channel;
 269         int ret;
 270         int i;
 271
 272         sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
 273         if (!sc_ipc)
 274                 return -ENOMEM;
 275
 276         ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
 277                                          "#mbox-cells", 0, &args);
 278         if (ret)
 279                 return ret;
 280
 281         sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");
 282
 283         num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
 284         for (i = 0; i < num_channel; i++) {
 285                 if (i < num_channel / 2)
 286                         chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
 287                 else
 288                         chan_name = kasprintf(GFP_KERNEL, "rx%d",
 289                                               i - num_channel / 2);
 290
 291                 if (!chan_name)
 292                         return -ENOMEM;
 293
 294                 sc_chan = &sc_ipc->chans[i];
 295                 cl = &sc_chan->cl;
 296                 cl->dev = dev;
 297                 cl->tx_block = false;
 298                 cl->knows_txdone = true;
 299                 cl->rx_callback = imx_scu_rx_callback;
 300
 301                 if (!sc_ipc->fast_ipc) {
 302                         /* Initial tx_done completion as "done" */
 303                         cl->tx_done = imx_scu_tx_done;
 304                         init_completion(&sc_chan->tx_done);
 305                         complete(&sc_chan->tx_done);
 306                 }
 307
 308                 sc_chan->sc_ipc = sc_ipc;
 309                 sc_chan->idx = i % (num_channel / 2);
 310                 sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
 311                 if (IS_ERR(sc_chan->ch)) {
 312                         ret = PTR_ERR(sc_chan->ch);
 313                         if (ret != -EPROBE_DEFER)
 314                                 dev_err(dev, "Failed to request mbox chan %s ret %d\n",
 315                                         chan_name, ret);
 316                         kfree(chan_name);
 317                         return ret;
 318                 }
 319
 320                 dev_dbg(dev, "request mbox chan %s\n", chan_name);
 321                 /* chan_name is not used anymore by framework */
 322                 kfree(chan_name);
 323         }
 324
 325         sc_ipc->dev = dev;
 326         mutex_init(&sc_ipc->lock);
 327         init_completion(&sc_ipc->done);
 328
 329         imx_sc_ipc_handle = sc_ipc;
 330
 331         ret = imx_scu_soc_init(dev);
 332         if (ret)
 333                 dev_warn(dev, "failed to initialize SoC info: %d\n", ret);
 334
 335         ret = imx_scu_enable_general_irq_channel(dev);
 336         if (ret)
 337                 dev_warn(dev,
 338                         "failed to enable general irq channel: %d\n", ret);
 339
 340         dev_info(dev, "NXP i.MX SCU Initialized\n");
 341
 342         return devm_of_platform_populate(dev);
 343 }
 344
 345 static const struct of_device_id imx_scu_match[] = {
 346         { .compatible = "fsl,imx-scu", },
 347         { /* Sentinel */ }
 348 };
 349
 350 static struct platform_driver imx_scu_driver = {
 351         .driver = {
 352                 .name = "imx-scu",
 353                 .of_match_table = imx_scu_match,
 354         },
 355         .probe = imx_scu_probe,
 356 };
 357 builtin_platform_driver(imx_scu_driver);
 358
 359 MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
 360 MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
 361 MODULE_LICENSE("GPL v2");