linux/drivers/mailbox/hi3660-mailbox.c
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   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (c) 2017-2018 Hisilicon Limited.
   3// Copyright (c) 2017-2018 Linaro Limited.
   4
   5#include <linux/bitops.h>
   6#include <linux/delay.h>
   7#include <linux/device.h>
   8#include <linux/err.h>
   9#include <linux/interrupt.h>
  10#include <linux/io.h>
  11#include <linux/iopoll.h>
  12#include <linux/mailbox_controller.h>
  13#include <linux/module.h>
  14#include <linux/platform_device.h>
  15#include <linux/slab.h>
  16
  17#include "mailbox.h"
  18
  19#define MBOX_CHAN_MAX                   32
  20
  21#define MBOX_RX                         0x0
  22#define MBOX_TX                         0x1
  23
  24#define MBOX_BASE(mbox, ch)             ((mbox)->base + ((ch) * 0x40))
  25#define MBOX_SRC_REG                    0x00
  26#define MBOX_DST_REG                    0x04
  27#define MBOX_DCLR_REG                   0x08
  28#define MBOX_DSTAT_REG                  0x0c
  29#define MBOX_MODE_REG                   0x10
  30#define MBOX_IMASK_REG                  0x14
  31#define MBOX_ICLR_REG                   0x18
  32#define MBOX_SEND_REG                   0x1c
  33#define MBOX_DATA_REG                   0x20
  34
  35#define MBOX_IPC_LOCK_REG               0xa00
  36#define MBOX_IPC_UNLOCK                 0x1acce551
  37
  38#define MBOX_AUTOMATIC_ACK              1
  39
  40#define MBOX_STATE_IDLE                 BIT(4)
  41#define MBOX_STATE_READY                BIT(5)
  42#define MBOX_STATE_ACK                  BIT(7)
  43
  44#define MBOX_MSG_LEN                    8
  45
  46/**
  47 * Hi3660 mailbox channel information
  48 *
  49 * A channel can be used for TX or RX, it can trigger remote
  50 * processor interrupt to notify remote processor and can receive
  51 * interrupt if has incoming message.
  52 *
  53 * @dst_irq:    Interrupt vector for remote processor
  54 * @ack_irq:    Interrupt vector for local processor
  55 */
  56struct hi3660_chan_info {
  57        unsigned int dst_irq;
  58        unsigned int ack_irq;
  59};
  60
  61/**
  62 * Hi3660 mailbox controller data
  63 *
  64 * Mailbox controller includes 32 channels and can allocate
  65 * channel for message transferring.
  66 *
  67 * @dev:        Device to which it is attached
  68 * @base:       Base address of the register mapping region
  69 * @chan:       Representation of channels in mailbox controller
  70 * @mchan:      Representation of channel info
  71 * @controller: Representation of a communication channel controller
  72 */
  73struct hi3660_mbox {
  74        struct device *dev;
  75        void __iomem *base;
  76        struct mbox_chan chan[MBOX_CHAN_MAX];
  77        struct hi3660_chan_info mchan[MBOX_CHAN_MAX];
  78        struct mbox_controller controller;
  79};
  80
  81static struct hi3660_mbox *to_hi3660_mbox(struct mbox_controller *mbox)
  82{
  83        return container_of(mbox, struct hi3660_mbox, controller);
  84}
  85
  86static int hi3660_mbox_check_state(struct mbox_chan *chan)
  87{
  88        unsigned long ch = (unsigned long)chan->con_priv;
  89        struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
  90        struct hi3660_chan_info *mchan = &mbox->mchan[ch];
  91        void __iomem *base = MBOX_BASE(mbox, ch);
  92        unsigned long val;
  93        unsigned int ret;
  94
  95        /* Mailbox is ready to use */
  96        if (readl(base + MBOX_MODE_REG) & MBOX_STATE_READY)
  97                return 0;
  98
  99        /* Wait for acknowledge from remote */
 100        ret = readx_poll_timeout_atomic(readl, base + MBOX_MODE_REG,
 101                        val, (val & MBOX_STATE_ACK), 1000, 300000);
 102        if (ret) {
 103                dev_err(mbox->dev, "%s: timeout for receiving ack\n", __func__);
 104                return ret;
 105        }
 106
 107        /* clear ack state, mailbox will get back to ready state */
 108        writel(BIT(mchan->ack_irq), base + MBOX_ICLR_REG);
 109
 110        return 0;
 111}
 112
 113static int hi3660_mbox_unlock(struct mbox_chan *chan)
 114{
 115        struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
 116        unsigned int val, retry = 3;
 117
 118        do {
 119                writel(MBOX_IPC_UNLOCK, mbox->base + MBOX_IPC_LOCK_REG);
 120
 121                val = readl(mbox->base + MBOX_IPC_LOCK_REG);
 122                if (!val)
 123                        break;
 124
 125                udelay(10);
 126        } while (retry--);
 127
 128        if (val)
 129                dev_err(mbox->dev, "%s: failed to unlock mailbox\n", __func__);
 130
 131        return (!val) ? 0 : -ETIMEDOUT;
 132}
 133
 134static int hi3660_mbox_acquire_channel(struct mbox_chan *chan)
 135{
 136        unsigned long ch = (unsigned long)chan->con_priv;
 137        struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
 138        struct hi3660_chan_info *mchan = &mbox->mchan[ch];
 139        void __iomem *base = MBOX_BASE(mbox, ch);
 140        unsigned int val, retry;
 141
 142        for (retry = 10; retry; retry--) {
 143                /* Check if channel is in idle state */
 144                if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE) {
 145                        writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
 146
 147                        /* Check ack bit has been set successfully */
 148                        val = readl(base + MBOX_SRC_REG);
 149                        if (val & BIT(mchan->ack_irq))
 150                                break;
 151                }
 152        }
 153
 154        if (!retry)
 155                dev_err(mbox->dev, "%s: failed to acquire channel\n", __func__);
 156
 157        return retry ? 0 : -ETIMEDOUT;
 158}
 159
 160static int hi3660_mbox_startup(struct mbox_chan *chan)
 161{
 162        int ret;
 163
 164        ret = hi3660_mbox_unlock(chan);
 165        if (ret)
 166                return ret;
 167
 168        ret = hi3660_mbox_acquire_channel(chan);
 169        if (ret)
 170                return ret;
 171
 172        return 0;
 173}
 174
 175static int hi3660_mbox_send_data(struct mbox_chan *chan, void *msg)
 176{
 177        unsigned long ch = (unsigned long)chan->con_priv;
 178        struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
 179        struct hi3660_chan_info *mchan = &mbox->mchan[ch];
 180        void __iomem *base = MBOX_BASE(mbox, ch);
 181        u32 *buf = msg;
 182        unsigned int i;
 183        int ret;
 184
 185        ret = hi3660_mbox_check_state(chan);
 186        if (ret)
 187                return ret;
 188
 189        /* Clear mask for destination interrupt */
 190        writel_relaxed(~BIT(mchan->dst_irq), base + MBOX_IMASK_REG);
 191
 192        /* Config destination for interrupt vector */
 193        writel_relaxed(BIT(mchan->dst_irq), base + MBOX_DST_REG);
 194
 195        /* Automatic acknowledge mode */
 196        writel_relaxed(MBOX_AUTOMATIC_ACK, base + MBOX_MODE_REG);
 197
 198        /* Fill message data */
 199        for (i = 0; i < MBOX_MSG_LEN; i++)
 200                writel_relaxed(buf[i], base + MBOX_DATA_REG + i * 4);
 201
 202        /* Trigger data transferring */
 203        writel(BIT(mchan->ack_irq), base + MBOX_SEND_REG);
 204        return 0;
 205}
 206
 207static const struct mbox_chan_ops hi3660_mbox_ops = {
 208        .startup        = hi3660_mbox_startup,
 209        .send_data      = hi3660_mbox_send_data,
 210};
 211
 212static struct mbox_chan *hi3660_mbox_xlate(struct mbox_controller *controller,
 213                                           const struct of_phandle_args *spec)
 214{
 215        struct hi3660_mbox *mbox = to_hi3660_mbox(controller);
 216        struct hi3660_chan_info *mchan;
 217        unsigned int ch = spec->args[0];
 218
 219        if (ch >= MBOX_CHAN_MAX) {
 220                dev_err(mbox->dev, "Invalid channel idx %d\n", ch);
 221                return ERR_PTR(-EINVAL);
 222        }
 223
 224        mchan = &mbox->mchan[ch];
 225        mchan->dst_irq = spec->args[1];
 226        mchan->ack_irq = spec->args[2];
 227
 228        return &mbox->chan[ch];
 229}
 230
 231static const struct of_device_id hi3660_mbox_of_match[] = {
 232        { .compatible = "hisilicon,hi3660-mbox", },
 233        {},
 234};
 235
 236MODULE_DEVICE_TABLE(of, hi3660_mbox_of_match);
 237
 238static int hi3660_mbox_probe(struct platform_device *pdev)
 239{
 240        struct device *dev = &pdev->dev;
 241        struct hi3660_mbox *mbox;
 242        struct mbox_chan *chan;
 243        struct resource *res;
 244        unsigned long ch;
 245        int err;
 246
 247        mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
 248        if (!mbox)
 249                return -ENOMEM;
 250
 251        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 252        mbox->base = devm_ioremap_resource(dev, res);
 253        if (IS_ERR(mbox->base))
 254                return PTR_ERR(mbox->base);
 255
 256        mbox->dev = dev;
 257        mbox->controller.dev = dev;
 258        mbox->controller.chans = mbox->chan;
 259        mbox->controller.num_chans = MBOX_CHAN_MAX;
 260        mbox->controller.ops = &hi3660_mbox_ops;
 261        mbox->controller.of_xlate = hi3660_mbox_xlate;
 262
 263        /* Initialize mailbox channel data */
 264        chan = mbox->chan;
 265        for (ch = 0; ch < MBOX_CHAN_MAX; ch++)
 266                chan[ch].con_priv = (void *)ch;
 267
 268        err = devm_mbox_controller_register(dev, &mbox->controller);
 269        if (err) {
 270                dev_err(dev, "Failed to register mailbox %d\n", err);
 271                return err;
 272        }
 273
 274        platform_set_drvdata(pdev, mbox);
 275        dev_info(dev, "Mailbox enabled\n");
 276        return 0;
 277}
 278
 279static struct platform_driver hi3660_mbox_driver = {
 280        .probe  = hi3660_mbox_probe,
 281        .driver = {
 282                .name = "hi3660-mbox",
 283                .of_match_table = hi3660_mbox_of_match,
 284        },
 285};
 286
 287static int __init hi3660_mbox_init(void)
 288{
 289        return platform_driver_register(&hi3660_mbox_driver);
 290}
 291core_initcall(hi3660_mbox_init);
 292
 293static void __exit hi3660_mbox_exit(void)
 294{
 295        platform_driver_unregister(&hi3660_mbox_driver);
 296}
 297module_exit(hi3660_mbox_exit);
 298
 299MODULE_LICENSE("GPL");
 300MODULE_DESCRIPTION("Hisilicon Hi3660 Mailbox Controller");
 301MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
 302