drivers/mailbox/mailbox-altera.c

   1 /*
   2  * Copyright Altera Corporation (C) 2013-2014. All rights reserved
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/device.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/io.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mailbox_controller.h>
  22 #include <linux/module.h>
  23 #include <linux/of.h>
  24 #include <linux/platform_device.h>
  25
  26 #define DRIVER_NAME     "altera-mailbox"
  27
  28 #define MAILBOX_CMD_REG                 0x00
  29 #define MAILBOX_PTR_REG                 0x04
  30 #define MAILBOX_STS_REG                 0x08
  31 #define MAILBOX_INTMASK_REG             0x0C
  32
  33 #define INT_PENDING_MSK                 0x1
  34 #define INT_SPACE_MSK                   0x2
  35
  36 #define STS_PENDING_MSK                 0x1
  37 #define STS_FULL_MSK                    0x2
  38 #define STS_FULL_OFT                    0x1
  39
  40 #define MBOX_PENDING(status)    (((status) & STS_PENDING_MSK))
  41 #define MBOX_FULL(status)       (((status) & STS_FULL_MSK) >> STS_FULL_OFT)
  42
  43 enum altera_mbox_msg {
  44         MBOX_CMD = 0,
  45         MBOX_PTR,
  46 };
  47
  48 #define MBOX_POLLING_MS         5       /* polling interval 5ms */
  49
  50 struct altera_mbox {
  51         bool is_sender;         /* 1-sender, 0-receiver */
  52         bool intr_mode;
  53         int irq;
  54         void __iomem *mbox_base;
  55         struct device *dev;
  56         struct mbox_controller controller;
  57
  58         /* If the controller supports only RX polling mode */
  59         struct timer_list rxpoll_timer;
  60 };
  61
  62 static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
  63 {
  64         if (!chan || !chan->con_priv)
  65                 return NULL;
  66
  67         return (struct altera_mbox *)chan->con_priv;
  68 }
  69
  70 static inline int altera_mbox_full(struct altera_mbox *mbox)
  71 {
  72         u32 status;
  73
  74         status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
  75         return MBOX_FULL(status);
  76 }
  77
  78 static inline int altera_mbox_pending(struct altera_mbox *mbox)
  79 {
  80         u32 status;
  81
  82         status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
  83         return MBOX_PENDING(status);
  84 }
  85
  86 static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
  87 {
  88         u32 mask;
  89
  90         mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
  91         if (enable)
  92                 mask |= INT_PENDING_MSK;
  93         else
  94                 mask &= ~INT_PENDING_MSK;
  95         writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
  96 }
  97
  98 static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
  99 {
 100         u32 mask;
 101
 102         mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
 103         if (enable)
 104                 mask |= INT_SPACE_MSK;
 105         else
 106                 mask &= ~INT_SPACE_MSK;
 107         writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
 108 }
 109
 110 static bool altera_mbox_is_sender(struct altera_mbox *mbox)
 111 {
 112         u32 reg;
 113         /* Write a magic number to PTR register and read back this register.
 114          * This register is read-write if it is a sender.
 115          */
 116         #define MBOX_MAGIC      0xA5A5AA55
 117         writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
 118         reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
 119         if (reg == MBOX_MAGIC) {
 120                 /* Clear to 0 */
 121                 writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
 122                 return true;
 123         }
 124         return false;
 125 }
 126
 127 static void altera_mbox_rx_data(struct mbox_chan *chan)
 128 {
 129         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 130         u32 data[2];
 131
 132         if (altera_mbox_pending(mbox)) {
 133                 data[MBOX_PTR] =
 134                         readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
 135                 data[MBOX_CMD] =
 136                         readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
 137                 mbox_chan_received_data(chan, (void *)data);
 138         }
 139 }
 140
 141 static void altera_mbox_poll_rx(unsigned long data)
 142 {
 143         struct mbox_chan *chan = (struct mbox_chan *)data;
 144         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 145
 146         altera_mbox_rx_data(chan);
 147
 148         mod_timer(&mbox->rxpoll_timer,
 149                   jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
 150 }
 151
 152 static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
 153 {
 154         struct mbox_chan *chan = (struct mbox_chan *)p;
 155         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 156
 157         altera_mbox_tx_intmask(mbox, false);
 158         mbox_chan_txdone(chan, 0);
 159
 160         return IRQ_HANDLED;
 161 }
 162
 163 static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
 164 {
 165         struct mbox_chan *chan = (struct mbox_chan *)p;
 166
 167         altera_mbox_rx_data(chan);
 168         return IRQ_HANDLED;
 169 }
 170
 171 static int altera_mbox_startup_sender(struct mbox_chan *chan)
 172 {
 173         int ret;
 174         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 175
 176         if (mbox->intr_mode) {
 177                 ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
 178                                   DRIVER_NAME, chan);
 179                 if (unlikely(ret)) {
 180                         dev_err(mbox->dev,
 181                                 "failed to register mailbox interrupt:%d\n",
 182                                 ret);
 183                         return ret;
 184                 }
 185         }
 186
 187         return 0;
 188 }
 189
 190 static int altera_mbox_startup_receiver(struct mbox_chan *chan)
 191 {
 192         int ret;
 193         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 194
 195         if (mbox->intr_mode) {
 196                 ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
 197                                   DRIVER_NAME, chan);
 198                 if (unlikely(ret)) {
 199                         mbox->intr_mode = false;
 200                         goto polling; /* use polling if failed */
 201                 }
 202
 203                 altera_mbox_rx_intmask(mbox, true);
 204                 return 0;
 205         }
 206
 207 polling:
 208         /* Setup polling timer */
 209         setup_timer(&mbox->rxpoll_timer, altera_mbox_poll_rx,
 210                     (unsigned long)chan);
 211         mod_timer(&mbox->rxpoll_timer,
 212                   jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
 213
 214         return 0;
 215 }
 216
 217 static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
 218 {
 219         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 220         u32 *udata = (u32 *)data;
 221
 222         if (!mbox || !data)
 223                 return -EINVAL;
 224         if (!mbox->is_sender) {
 225                 dev_warn(mbox->dev,
 226                          "failed to send. This is receiver mailbox.\n");
 227                 return -EINVAL;
 228         }
 229
 230         if (altera_mbox_full(mbox))
 231                 return -EBUSY;
 232
 233         /* Enable interrupt before send */
 234         if (mbox->intr_mode)
 235                 altera_mbox_tx_intmask(mbox, true);
 236
 237         /* Pointer register must write before command register */
 238         writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
 239         writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);
 240
 241         return 0;
 242 }
 243
 244 static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
 245 {
 246         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 247
 248         /* Return false if mailbox is full */
 249         return altera_mbox_full(mbox) ? false : true;
 250 }
 251
 252 static bool altera_mbox_peek_data(struct mbox_chan *chan)
 253 {
 254         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 255
 256         return altera_mbox_pending(mbox) ? true : false;
 257 }
 258
 259 static int altera_mbox_startup(struct mbox_chan *chan)
 260 {
 261         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 262         int ret = 0;
 263
 264         if (!mbox)
 265                 return -EINVAL;
 266
 267         if (mbox->is_sender)
 268                 ret = altera_mbox_startup_sender(chan);
 269         else
 270                 ret = altera_mbox_startup_receiver(chan);
 271
 272         return ret;
 273 }
 274
 275 static void altera_mbox_shutdown(struct mbox_chan *chan)
 276 {
 277         struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 278
 279         if (mbox->intr_mode) {
 280                 /* Unmask all interrupt masks */
 281                 writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
 282                 free_irq(mbox->irq, chan);
 283         } else if (!mbox->is_sender) {
 284                 del_timer_sync(&mbox->rxpoll_timer);
 285         }
 286 }
 287
 288 static const struct mbox_chan_ops altera_mbox_ops = {
 289         .send_data = altera_mbox_send_data,
 290         .startup = altera_mbox_startup,
 291         .shutdown = altera_mbox_shutdown,
 292         .last_tx_done = altera_mbox_last_tx_done,
 293         .peek_data = altera_mbox_peek_data,
 294 };
 295
 296 static int altera_mbox_probe(struct platform_device *pdev)
 297 {
 298         struct altera_mbox *mbox;
 299         struct resource *regs;
 300         struct mbox_chan *chans;
 301         int ret;
 302
 303         mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox),
 304                             GFP_KERNEL);
 305         if (!mbox)
 306                 return -ENOMEM;
 307
 308         /* Allocated one channel */
 309         chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
 310         if (!chans)
 311                 return -ENOMEM;
 312
 313         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 314
 315         mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
 316         if (IS_ERR(mbox->mbox_base))
 317                 return PTR_ERR(mbox->mbox_base);
 318
 319         /* Check is it a sender or receiver? */
 320         mbox->is_sender = altera_mbox_is_sender(mbox);
 321
 322         mbox->irq = platform_get_irq(pdev, 0);
 323         if (mbox->irq >= 0)
 324                 mbox->intr_mode = true;
 325
 326         mbox->dev = &pdev->dev;
 327
 328         /* Hardware supports only one channel. */
 329         chans[0].con_priv = mbox;
 330         mbox->controller.dev = mbox->dev;
 331         mbox->controller.num_chans = 1;
 332         mbox->controller.chans = chans;
 333         mbox->controller.ops = &altera_mbox_ops;
 334
 335         if (mbox->is_sender) {
 336                 if (mbox->intr_mode) {
 337                         mbox->controller.txdone_irq = true;
 338                 } else {
 339                         mbox->controller.txdone_poll = true;
 340                         mbox->controller.txpoll_period = MBOX_POLLING_MS;
 341                 }
 342         }
 343
 344         ret = mbox_controller_register(&mbox->controller);
 345         if (ret) {
 346                 dev_err(&pdev->dev, "Register mailbox failed\n");
 347                 goto err;
 348         }
 349
 350         platform_set_drvdata(pdev, mbox);
 351 err:
 352         return ret;
 353 }
 354
 355 static int altera_mbox_remove(struct platform_device *pdev)
 356 {
 357         struct altera_mbox *mbox = platform_get_drvdata(pdev);
 358
 359         if (!mbox)
 360                 return -EINVAL;
 361
 362         mbox_controller_unregister(&mbox->controller);
 363
 364         return 0;
 365 }
 366
 367 static const struct of_device_id altera_mbox_match[] = {
 368         { .compatible = "altr,mailbox-1.0" },
 369         { /* Sentinel */ }
 370 };
 371
 372 MODULE_DEVICE_TABLE(of, altera_mbox_match);
 373
 374 static struct platform_driver altera_mbox_driver = {
 375         .probe  = altera_mbox_probe,
 376         .remove = altera_mbox_remove,
 377         .driver = {
 378                 .name   = DRIVER_NAME,
 379                 .of_match_table = altera_mbox_match,
 380         },
 381 };
 382
 383 module_platform_driver(altera_mbox_driver);
 384
 385 MODULE_LICENSE("GPL v2");
 386 MODULE_DESCRIPTION("Altera mailbox specific functions");
 387 MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
 388 MODULE_ALIAS("platform:altera-mailbox");