root/drivers/firmware/imx/imx-scu.c

DEFINITIONS

1. imx_sc_to_linux_errno
2. imx_scu_get_handle
3. imx_scu_tx_done
4. imx_scu_rx_callback
5. imx_scu_ipc_write
6. imx_scu_call_rpc
7. imx_scu_probe

   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         bool fast_ipc;
  42 
  43         /* temporarily store the SCU msg */
  44         u32 *msg;
  45         u8 rx_size;
  46         u8 count;
  47 };
  48 
  49 /*
  50  * This type is used to indicate error response for most functions.
  51  */
  52 enum imx_sc_error_codes {
  53         IMX_SC_ERR_NONE = 0,    /* Success */
  54         IMX_SC_ERR_VERSION = 1, /* Incompatible API version */
  55         IMX_SC_ERR_CONFIG = 2,  /* Configuration error */
  56         IMX_SC_ERR_PARM = 3,    /* Bad parameter */
  57         IMX_SC_ERR_NOACCESS = 4,        /* Permission error (no access) */
  58         IMX_SC_ERR_LOCKED = 5,  /* Permission error (locked) */
  59         IMX_SC_ERR_UNAVAILABLE = 6,     /* Unavailable (out of resources) */
  60         IMX_SC_ERR_NOTFOUND = 7,        /* Not found */
  61         IMX_SC_ERR_NOPOWER = 8, /* No power */
  62         IMX_SC_ERR_IPC = 9,             /* Generic IPC error */
  63         IMX_SC_ERR_BUSY = 10,   /* Resource is currently busy/active */
  64         IMX_SC_ERR_FAIL = 11,   /* General I/O failure */
  65         IMX_SC_ERR_LAST
  66 };
  67 
  68 static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
  69         0,       /* IMX_SC_ERR_NONE */
  70         -EINVAL, /* IMX_SC_ERR_VERSION */
  71         -EINVAL, /* IMX_SC_ERR_CONFIG */
  72         -EINVAL, /* IMX_SC_ERR_PARM */
  73         -EACCES, /* IMX_SC_ERR_NOACCESS */
  74         -EACCES, /* IMX_SC_ERR_LOCKED */
  75         -ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
  76         -EEXIST, /* IMX_SC_ERR_NOTFOUND */
  77         -EPERM,  /* IMX_SC_ERR_NOPOWER */
  78         -EPIPE,  /* IMX_SC_ERR_IPC */
  79         -EBUSY,  /* IMX_SC_ERR_BUSY */
  80         -EIO,    /* IMX_SC_ERR_FAIL */
  81 };
  82 
  83 static struct imx_sc_ipc *imx_sc_ipc_handle;
  84 
  85 static inline int imx_sc_to_linux_errno(int errno)
  86 {
  87         if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
  88                 return imx_sc_linux_errmap[errno];
  89         return -EIO;
  90 }
  91 
  92 /*
  93  * Get the default handle used by SCU
  94  */
  95 int imx_scu_get_handle(struct imx_sc_ipc **ipc)
  96 {
  97         if (!imx_sc_ipc_handle)
  98                 return -EPROBE_DEFER;
  99 
 100         *ipc = imx_sc_ipc_handle;
 101         return 0;
 102 }
 103 EXPORT_SYMBOL(imx_scu_get_handle);
 104 
 105 /* Callback called when the word of a message is ack-ed, eg read by SCU */
 106 static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
 107 {
 108         struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
 109 
 110         complete(&sc_chan->tx_done);
 111 }
 112 
 113 static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 114 {
 115         struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
 116         struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
 117         struct imx_sc_rpc_msg *hdr;
 118         u32 *data = msg;
 119         int i;
 120 
 121         if (!sc_ipc->msg) {
 122                 dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
 123                                 sc_chan->idx, *data);
 124                 return;
 125         }
 126 
 127         if (sc_ipc->fast_ipc) {
 128                 hdr = msg;
 129                 sc_ipc->rx_size = hdr->size;
 130                 sc_ipc->msg[0] = *data++;
 131 
 132                 for (i = 1; i < sc_ipc->rx_size; i++)
 133                         sc_ipc->msg[i] = *data++;
 134 
 135                 complete(&sc_ipc->done);
 136 
 137                 return;
 138         }
 139 
 140         if (sc_chan->idx == 0) {
 141                 hdr = msg;
 142                 sc_ipc->rx_size = hdr->size;
 143                 dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
 144                 if (sc_ipc->rx_size > 4)
 145                         dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
 146                                  sc_ipc->rx_size);
 147         }
 148 
 149         sc_ipc->msg[sc_chan->idx] = *data;
 150         sc_ipc->count++;
 151 
 152         dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
 153                 sc_ipc->count, *data);
 154 
 155         if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
 156                 complete(&sc_ipc->done);
 157 }
 158 
 159 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 160 {
 161         struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
 162         struct imx_sc_chan *sc_chan;
 163         u32 *data = msg;
 164         int ret;
 165         int size;
 166         int i;
 167 
 168         /* Check size */
 169         if (hdr.size > IMX_SC_RPC_MAX_MSG)
 170                 return -EINVAL;
 171 
 172         dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
 173                 hdr.func, hdr.size);
 174 
 175         size = sc_ipc->fast_ipc ? 1 : hdr.size;
 176         for (i = 0; i < size; i++) {
 177                 sc_chan = &sc_ipc->chans[i % 4];
 178 
 179                 /*
 180                  * SCU requires that all messages words are written
 181                  * sequentially but linux MU driver implements multiple
 182                  * independent channels for each register so ordering between
 183                  * different channels must be ensured by SCU API interface.
 184                  *
 185                  * Wait for tx_done before every send to ensure that no
 186                  * queueing happens at the mailbox channel level.
 187                  */
 188                 if (!sc_ipc->fast_ipc) {
 189                         wait_for_completion(&sc_chan->tx_done);
 190                         reinit_completion(&sc_chan->tx_done);
 191                 }
 192 
 193                 ret = mbox_send_message(sc_chan->ch, &data[i]);
 194                 if (ret < 0)
 195                         return ret;
 196         }
 197 
 198         return 0;
 199 }
 200 
 201 /*
 202  * RPC command/response
 203  */
 204 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 205 {
 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         sc_ipc->count = 0;
 218         ret = imx_scu_ipc_write(sc_ipc, msg);
 219         if (ret < 0) {
 220                 dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
 221                 goto out;
 222         }
 223 
 224         if (have_resp) {
 225                 if (!wait_for_completion_timeout(&sc_ipc->done,
 226                                                  MAX_RX_TIMEOUT)) {
 227                         dev_err(sc_ipc->dev, "RPC send msg timeout\n");
 228                         mutex_unlock(&sc_ipc->lock);
 229                         return -ETIMEDOUT;
 230                 }
 231 
 232                 /* response status is stored in hdr->func field */
 233                 hdr = msg;
 234                 ret = hdr->func;
 235         }
 236 
 237 out:
 238         sc_ipc->msg = NULL;
 239         mutex_unlock(&sc_ipc->lock);
 240 
 241         dev_dbg(sc_ipc->dev, "RPC SVC done\n");
 242 
 243         return imx_sc_to_linux_errno(ret);
 244 }
 245 EXPORT_SYMBOL(imx_scu_call_rpc);
 246 
 247 static int imx_scu_probe(struct platform_device *pdev)
 248 {
 249         struct device *dev = &pdev->dev;
 250         struct imx_sc_ipc *sc_ipc;
 251         struct imx_sc_chan *sc_chan;
 252         struct mbox_client *cl;
 253         char *chan_name;
 254         struct of_phandle_args args;
 255         int num_channel;
 256         int ret;
 257         int i;
 258 
 259         sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
 260         if (!sc_ipc)
 261                 return -ENOMEM;
 262 
 263         ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
 264                                          "#mbox-cells", 0, &args);
 265         if (ret)
 266                 return ret;
 267 
 268         sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");
 269 
 270         num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
 271         for (i = 0; i < num_channel; i++) {
 272                 if (i < num_channel / 2)
 273                         chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
 274                 else
 275                         chan_name = kasprintf(GFP_KERNEL, "rx%d",
 276                                               i - num_channel / 2);
 277 
 278                 if (!chan_name)
 279                         return -ENOMEM;
 280 
 281                 sc_chan = &sc_ipc->chans[i];
 282                 cl = &sc_chan->cl;
 283                 cl->dev = dev;
 284                 cl->tx_block = false;
 285                 cl->knows_txdone = true;
 286                 cl->rx_callback = imx_scu_rx_callback;
 287 
 288                 if (!sc_ipc->fast_ipc) {
 289                         /* Initial tx_done completion as "done" */
 290                         cl->tx_done = imx_scu_tx_done;
 291                         init_completion(&sc_chan->tx_done);
 292                         complete(&sc_chan->tx_done);
 293                 }
 294 
 295                 sc_chan->sc_ipc = sc_ipc;
 296                 sc_chan->idx = i % (num_channel / 2);
 297                 sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
 298                 if (IS_ERR(sc_chan->ch)) {
 299                         ret = PTR_ERR(sc_chan->ch);
 300                         if (ret != -EPROBE_DEFER)
 301                                 dev_err(dev, "Failed to request mbox chan %s ret %d\n",
 302                                         chan_name, ret);
 303                         return ret;
 304                 }
 305 
 306                 dev_dbg(dev, "request mbox chan %s\n", chan_name);
 307                 /* chan_name is not used anymore by framework */
 308                 kfree(chan_name);
 309         }
 310 
 311         sc_ipc->dev = dev;
 312         mutex_init(&sc_ipc->lock);
 313         init_completion(&sc_ipc->done);
 314 
 315         imx_sc_ipc_handle = sc_ipc;
 316 
 317         ret = imx_scu_enable_general_irq_channel(dev);
 318         if (ret)
 319                 dev_warn(dev,
 320                         "failed to enable general irq channel: %d\n", ret);
 321 
 322         dev_info(dev, "NXP i.MX SCU Initialized\n");
 323 
 324         return devm_of_platform_populate(dev);
 325 }
 326 
 327 static const struct of_device_id imx_scu_match[] = {
 328         { .compatible = "fsl,imx-scu", },
 329         { /* Sentinel */ }
 330 };
 331 
 332 static struct platform_driver imx_scu_driver = {
 333         .driver = {
 334                 .name = "imx-scu",
 335                 .of_match_table = imx_scu_match,
 336         },
 337         .probe = imx_scu_probe,
 338 };
 339 builtin_platform_driver(imx_scu_driver);
 340 
 341 MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
 342 MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
 343 MODULE_LICENSE("GPL v2");