drivers/mailbox/mailbox-sti.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * STi Mailbox
   4  *
   5  * Copyright (C) 2015 ST Microelectronics
   6  *
   7  * Author: Lee Jones <lee.jones@linaro.org> for ST Microelectronics
   8  *
   9  * Based on the original driver written by;
  10  *   Alexandre Torgue, Olivier Lebreton and Loic Pallardy
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/io.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mailbox_controller.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/of_device.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23
  24 #include "mailbox.h"
  25
  26 #define STI_MBOX_INST_MAX       4      /* RAM saving: Max supported instances */
  27 #define STI_MBOX_CHAN_MAX       20     /* RAM saving: Max supported channels  */
  28
  29 #define STI_IRQ_VAL_OFFSET      0x04   /* Read interrupt status               */
  30 #define STI_IRQ_SET_OFFSET      0x24   /* Generate a Tx channel interrupt     */
  31 #define STI_IRQ_CLR_OFFSET      0x44   /* Clear pending Rx interrupts         */
  32 #define STI_ENA_VAL_OFFSET      0x64   /* Read enable status                  */
  33 #define STI_ENA_SET_OFFSET      0x84   /* Enable a channel                    */
  34 #define STI_ENA_CLR_OFFSET      0xa4   /* Disable a channel                   */
  35
  36 #define MBOX_BASE(mdev, inst)   ((mdev)->base + ((inst) * 4))
  37
  38 /**
  39  * struct sti_mbox_device - STi Mailbox device data
  40  *
  41  * @dev:        Device to which it is attached
  42  * @mbox:       Representation of a communication channel controller
  43  * @base:       Base address of the register mapping region
  44  * @name:       Name of the mailbox
  45  * @enabled:    Local copy of enabled channels
  46  * @lock:       Mutex protecting enabled status
  47  *
  48  * An IP Mailbox is currently composed of 4 instances
  49  * Each instance is currently composed of 32 channels
  50  * This means that we have 128 channels per Mailbox
  51  * A channel an be used for TX or RX
  52  */
  53 struct sti_mbox_device {
  54         struct device           *dev;
  55         struct mbox_controller  *mbox;
  56         void __iomem            *base;
  57         const char              *name;
  58         u32                     enabled[STI_MBOX_INST_MAX];
  59         spinlock_t              lock;
  60 };
  61
  62 /**
  63  * struct sti_mbox_pdata - STi Mailbox platform specific configuration
  64  *
  65  * @num_inst:   Maximum number of instances in one HW Mailbox
  66  * @num_chan:   Maximum number of channel per instance
  67  */
  68 struct sti_mbox_pdata {
  69         unsigned int            num_inst;
  70         unsigned int            num_chan;
  71 };
  72
  73 /**
  74  * struct sti_channel - STi Mailbox allocated channel information
  75  *
  76  * @mdev:       Pointer to parent Mailbox device
  77  * @instance:   Instance number channel resides in
  78  * @channel:    Channel number pertaining to this container
  79  */
  80 struct sti_channel {
  81         struct sti_mbox_device  *mdev;
  82         unsigned int            instance;
  83         unsigned int            channel;
  84 };
  85
  86 static inline bool sti_mbox_channel_is_enabled(struct mbox_chan *chan)
  87 {
  88         struct sti_channel *chan_info = chan->con_priv;
  89         struct sti_mbox_device *mdev = chan_info->mdev;
  90         unsigned int instance = chan_info->instance;
  91         unsigned int channel = chan_info->channel;
  92
  93         return mdev->enabled[instance] & BIT(channel);
  94 }
  95
  96 static inline
  97 struct mbox_chan *sti_mbox_to_channel(struct mbox_controller *mbox,
  98                                       unsigned int instance,
  99                                       unsigned int channel)
 100 {
 101         struct sti_channel *chan_info;
 102         int i;
 103
 104         for (i = 0; i < mbox->num_chans; i++) {
 105                 chan_info = mbox->chans[i].con_priv;
 106                 if (chan_info &&
 107                     chan_info->instance == instance &&
 108                     chan_info->channel == channel)
 109                         return &mbox->chans[i];
 110         }
 111
 112         dev_err(mbox->dev,
 113                 "Channel not registered: instance: %d channel: %d\n",
 114                 instance, channel);
 115
 116         return NULL;
 117 }
 118
 119 static void sti_mbox_enable_channel(struct mbox_chan *chan)
 120 {
 121         struct sti_channel *chan_info = chan->con_priv;
 122         struct sti_mbox_device *mdev = chan_info->mdev;
 123         unsigned int instance = chan_info->instance;
 124         unsigned int channel = chan_info->channel;
 125         unsigned long flags;
 126         void __iomem *base = MBOX_BASE(mdev, instance);
 127
 128         spin_lock_irqsave(&mdev->lock, flags);
 129         mdev->enabled[instance] |= BIT(channel);
 130         writel_relaxed(BIT(channel), base + STI_ENA_SET_OFFSET);
 131         spin_unlock_irqrestore(&mdev->lock, flags);
 132 }
 133
 134 static void sti_mbox_disable_channel(struct mbox_chan *chan)
 135 {
 136         struct sti_channel *chan_info = chan->con_priv;
 137         struct sti_mbox_device *mdev = chan_info->mdev;
 138         unsigned int instance = chan_info->instance;
 139         unsigned int channel = chan_info->channel;
 140         unsigned long flags;
 141         void __iomem *base = MBOX_BASE(mdev, instance);
 142
 143         spin_lock_irqsave(&mdev->lock, flags);
 144         mdev->enabled[instance] &= ~BIT(channel);
 145         writel_relaxed(BIT(channel), base + STI_ENA_CLR_OFFSET);
 146         spin_unlock_irqrestore(&mdev->lock, flags);
 147 }
 148
 149 static void sti_mbox_clear_irq(struct mbox_chan *chan)
 150 {
 151         struct sti_channel *chan_info = chan->con_priv;
 152         struct sti_mbox_device *mdev = chan_info->mdev;
 153         unsigned int instance = chan_info->instance;
 154         unsigned int channel = chan_info->channel;
 155         void __iomem *base = MBOX_BASE(mdev, instance);
 156
 157         writel_relaxed(BIT(channel), base + STI_IRQ_CLR_OFFSET);
 158 }
 159
 160 static struct mbox_chan *sti_mbox_irq_to_channel(struct sti_mbox_device *mdev,
 161                                                  unsigned int instance)
 162 {
 163         struct mbox_controller *mbox = mdev->mbox;
 164         struct mbox_chan *chan = NULL;
 165         unsigned int channel;
 166         unsigned long bits;
 167         void __iomem *base = MBOX_BASE(mdev, instance);
 168
 169         bits = readl_relaxed(base + STI_IRQ_VAL_OFFSET);
 170         if (!bits)
 171                 /* No IRQs fired in specified instance */
 172                 return NULL;
 173
 174         /* An IRQ has fired, find the associated channel */
 175         for (channel = 0; bits; channel++) {
 176                 if (!test_and_clear_bit(channel, &bits))
 177                         continue;
 178
 179                 chan = sti_mbox_to_channel(mbox, instance, channel);
 180                 if (chan) {
 181                         dev_dbg(mbox->dev,
 182                                 "IRQ fired on instance: %d channel: %d\n",
 183                                 instance, channel);
 184                         break;
 185                 }
 186         }
 187
 188         return chan;
 189 }
 190
 191 static irqreturn_t sti_mbox_thread_handler(int irq, void *data)
 192 {
 193         struct sti_mbox_device *mdev = data;
 194         struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
 195         struct mbox_chan *chan;
 196         unsigned int instance;
 197
 198         for (instance = 0; instance < pdata->num_inst; instance++) {
 199 keep_looking:
 200                 chan = sti_mbox_irq_to_channel(mdev, instance);
 201                 if (!chan)
 202                         continue;
 203
 204                 mbox_chan_received_data(chan, NULL);
 205                 sti_mbox_clear_irq(chan);
 206                 sti_mbox_enable_channel(chan);
 207                 goto keep_looking;
 208         }
 209
 210         return IRQ_HANDLED;
 211 }
 212
 213 static irqreturn_t sti_mbox_irq_handler(int irq, void *data)
 214 {
 215         struct sti_mbox_device *mdev = data;
 216         struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
 217         struct sti_channel *chan_info;
 218         struct mbox_chan *chan;
 219         unsigned int instance;
 220         int ret = IRQ_NONE;
 221
 222         for (instance = 0; instance < pdata->num_inst; instance++) {
 223                 chan = sti_mbox_irq_to_channel(mdev, instance);
 224                 if (!chan)
 225                         continue;
 226                 chan_info = chan->con_priv;
 227
 228                 if (!sti_mbox_channel_is_enabled(chan)) {
 229                         dev_warn(mdev->dev,
 230                                  "Unexpected IRQ: %s\n"
 231                                  "  instance: %d: channel: %d [enabled: %x]\n",
 232                                  mdev->name, chan_info->instance,
 233                                  chan_info->channel, mdev->enabled[instance]);
 234
 235                         /* Only handle IRQ if no other valid IRQs were found */
 236                         if (ret == IRQ_NONE)
 237                                 ret = IRQ_HANDLED;
 238                         continue;
 239                 }
 240
 241                 sti_mbox_disable_channel(chan);
 242                 ret = IRQ_WAKE_THREAD;
 243         }
 244
 245         if (ret == IRQ_NONE)
 246                 dev_err(mdev->dev, "Spurious IRQ - was a channel requested?\n");
 247
 248         return ret;
 249 }
 250
 251 static bool sti_mbox_tx_is_ready(struct mbox_chan *chan)
 252 {
 253         struct sti_channel *chan_info = chan->con_priv;
 254         struct sti_mbox_device *mdev = chan_info->mdev;
 255         unsigned int instance = chan_info->instance;
 256         unsigned int channel = chan_info->channel;
 257         void __iomem *base = MBOX_BASE(mdev, instance);
 258
 259         if (!(readl_relaxed(base + STI_ENA_VAL_OFFSET) & BIT(channel))) {
 260                 dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n",
 261                         mdev->name, instance, channel);
 262                 return false;
 263         }
 264
 265         if (readl_relaxed(base + STI_IRQ_VAL_OFFSET) & BIT(channel)) {
 266                 dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d not ready\n",
 267                         mdev->name, instance, channel);
 268                 return false;
 269         }
 270
 271         return true;
 272 }
 273
 274 static int sti_mbox_send_data(struct mbox_chan *chan, void *data)
 275 {
 276         struct sti_channel *chan_info = chan->con_priv;
 277         struct sti_mbox_device *mdev = chan_info->mdev;
 278         unsigned int instance = chan_info->instance;
 279         unsigned int channel = chan_info->channel;
 280         void __iomem *base = MBOX_BASE(mdev, instance);
 281
 282         /* Send event to co-processor */
 283         writel_relaxed(BIT(channel), base + STI_IRQ_SET_OFFSET);
 284
 285         dev_dbg(mdev->dev,
 286                 "Sent via Mailbox %s: instance: %d channel: %d\n",
 287                 mdev->name, instance, channel);
 288
 289         return 0;
 290 }
 291
 292 static int sti_mbox_startup_chan(struct mbox_chan *chan)
 293 {
 294         sti_mbox_clear_irq(chan);
 295         sti_mbox_enable_channel(chan);
 296
 297         return 0;
 298 }
 299
 300 static void sti_mbox_shutdown_chan(struct mbox_chan *chan)
 301 {
 302         struct sti_channel *chan_info = chan->con_priv;
 303         struct mbox_controller *mbox = chan_info->mdev->mbox;
 304         int i;
 305
 306         for (i = 0; i < mbox->num_chans; i++)
 307                 if (chan == &mbox->chans[i])
 308                         break;
 309
 310         if (mbox->num_chans == i) {
 311                 dev_warn(mbox->dev, "Request to free non-existent channel\n");
 312                 return;
 313         }
 314
 315         /* Reset channel */
 316         sti_mbox_disable_channel(chan);
 317         sti_mbox_clear_irq(chan);
 318         chan->con_priv = NULL;
 319 }
 320
 321 static struct mbox_chan *sti_mbox_xlate(struct mbox_controller *mbox,
 322                                         const struct of_phandle_args *spec)
 323 {
 324         struct sti_mbox_device *mdev = dev_get_drvdata(mbox->dev);
 325         struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
 326         struct sti_channel *chan_info;
 327         struct mbox_chan *chan = NULL;
 328         unsigned int instance  = spec->args[0];
 329         unsigned int channel   = spec->args[1];
 330         int i;
 331
 332         /* Bounds checking */
 333         if (instance >= pdata->num_inst || channel  >= pdata->num_chan) {
 334                 dev_err(mbox->dev,
 335                         "Invalid channel requested instance: %d channel: %d\n",
 336                         instance, channel);
 337                 return ERR_PTR(-EINVAL);
 338         }
 339
 340         for (i = 0; i < mbox->num_chans; i++) {
 341                 chan_info = mbox->chans[i].con_priv;
 342
 343                 /* Is requested channel free? */
 344                 if (chan_info &&
 345                     mbox->dev == chan_info->mdev->dev &&
 346                     instance == chan_info->instance &&
 347                     channel == chan_info->channel) {
 348
 349                         dev_err(mbox->dev, "Channel in use\n");
 350                         return ERR_PTR(-EBUSY);
 351                 }
 352
 353                 /*
 354                  * Find the first free slot, then continue checking
 355                  * to see if requested channel is in use
 356                  */
 357                 if (!chan && !chan_info)
 358                         chan = &mbox->chans[i];
 359         }
 360
 361         if (!chan) {
 362                 dev_err(mbox->dev, "No free channels left\n");
 363                 return ERR_PTR(-EBUSY);
 364         }
 365
 366         chan_info = devm_kzalloc(mbox->dev, sizeof(*chan_info), GFP_KERNEL);
 367         if (!chan_info)
 368                 return ERR_PTR(-ENOMEM);
 369
 370         chan_info->mdev         = mdev;
 371         chan_info->instance     = instance;
 372         chan_info->channel      = channel;
 373
 374         chan->con_priv = chan_info;
 375
 376         dev_info(mbox->dev,
 377                  "Mbox: %s: Created channel: instance: %d channel: %d\n",
 378                  mdev->name, instance, channel);
 379
 380         return chan;
 381 }
 382
 383 static const struct mbox_chan_ops sti_mbox_ops = {
 384         .startup        = sti_mbox_startup_chan,
 385         .shutdown       = sti_mbox_shutdown_chan,
 386         .send_data      = sti_mbox_send_data,
 387         .last_tx_done   = sti_mbox_tx_is_ready,
 388 };
 389
 390 static const struct sti_mbox_pdata mbox_stih407_pdata = {
 391         .num_inst       = 4,
 392         .num_chan       = 32,
 393 };
 394
 395 static const struct of_device_id sti_mailbox_match[] = {
 396         {
 397                 .compatible = "st,stih407-mailbox",
 398                 .data = (void *)&mbox_stih407_pdata
 399         },
 400         { }
 401 };
 402 MODULE_DEVICE_TABLE(of, sti_mailbox_match);
 403
 404 static int sti_mbox_probe(struct platform_device *pdev)
 405 {
 406         const struct of_device_id *match;
 407         struct mbox_controller *mbox;
 408         struct sti_mbox_device *mdev;
 409         struct device_node *np = pdev->dev.of_node;
 410         struct mbox_chan *chans;
 411         int irq;
 412         int ret;
 413
 414         match = of_match_device(sti_mailbox_match, &pdev->dev);
 415         if (!match) {
 416                 dev_err(&pdev->dev, "No configuration found\n");
 417                 return -ENODEV;
 418         }
 419         pdev->dev.platform_data = (struct sti_mbox_pdata *) match->data;
 420
 421         mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
 422         if (!mdev)
 423                 return -ENOMEM;
 424
 425         platform_set_drvdata(pdev, mdev);
 426
 427         mdev->base = devm_platform_ioremap_resource(pdev, 0);
 428         if (IS_ERR(mdev->base))
 429                 return PTR_ERR(mdev->base);
 430
 431         ret = of_property_read_string(np, "mbox-name", &mdev->name);
 432         if (ret)
 433                 mdev->name = np->full_name;
 434
 435         mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
 436         if (!mbox)
 437                 return -ENOMEM;
 438
 439         chans = devm_kcalloc(&pdev->dev,
 440                              STI_MBOX_CHAN_MAX, sizeof(*chans), GFP_KERNEL);
 441         if (!chans)
 442                 return -ENOMEM;
 443
 444         mdev->dev               = &pdev->dev;
 445         mdev->mbox              = mbox;
 446
 447         spin_lock_init(&mdev->lock);
 448
 449         /* STi Mailbox does not have a Tx-Done or Tx-Ready IRQ */
 450         mbox->txdone_irq        = false;
 451         mbox->txdone_poll       = true;
 452         mbox->txpoll_period     = 100;
 453         mbox->ops               = &sti_mbox_ops;
 454         mbox->dev               = mdev->dev;
 455         mbox->of_xlate          = sti_mbox_xlate;
 456         mbox->chans             = chans;
 457         mbox->num_chans         = STI_MBOX_CHAN_MAX;
 458
 459         ret = devm_mbox_controller_register(&pdev->dev, mbox);
 460         if (ret)
 461                 return ret;
 462
 463         /* It's okay for Tx Mailboxes to not supply IRQs */
 464         irq = platform_get_irq(pdev, 0);
 465         if (irq < 0) {
 466                 dev_info(&pdev->dev,
 467                          "%s: Registered Tx only Mailbox\n", mdev->name);
 468                 return 0;
 469         }
 470
 471         ret = devm_request_threaded_irq(&pdev->dev, irq,
 472                                         sti_mbox_irq_handler,
 473                                         sti_mbox_thread_handler,
 474                                         IRQF_ONESHOT, mdev->name, mdev);
 475         if (ret) {
 476                 dev_err(&pdev->dev, "Can't claim IRQ %d\n", irq);
 477                 return -EINVAL;
 478         }
 479
 480         dev_info(&pdev->dev, "%s: Registered Tx/Rx Mailbox\n", mdev->name);
 481
 482         return 0;
 483 }
 484
 485 static struct platform_driver sti_mbox_driver = {
 486         .probe = sti_mbox_probe,
 487         .driver = {
 488                 .name = "sti-mailbox",
 489                 .of_match_table = sti_mailbox_match,
 490         },
 491 };
 492 module_platform_driver(sti_mbox_driver);
 493
 494 MODULE_LICENSE("GPL");
 495 MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller");
 496 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
 497 MODULE_ALIAS("platform:mailbox-sti");