LXR linux/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
  25struct 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
  34struct 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 */
  51enum 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
  67static 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
  82static struct imx_sc_ipc *imx_sc_ipc_handle;
  83
  84static 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 */
  94int 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}
 102EXPORT_SYMBOL(imx_scu_get_handle);
 103
 104/* Callback called when the word of a message is ack-ed, eg read by SCU */
 105static 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
 112static 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
 158static 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 */
 203int 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
 250out:
 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}
 258EXPORT_SYMBOL(imx_scu_call_rpc);
 259
 260static 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
 345static const struct of_device_id imx_scu_match[] = {
 346        { .compatible = "fsl,imx-scu", },
 347        { /* Sentinel */ }
 348};
 349
 350static 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};
 357builtin_platform_driver(imx_scu_driver);
 358
 359MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
 360MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
 361MODULE_LICENSE("GPL v2");
 362