drivers/mailbox/arm_mhu.c

   1 /*
   2  * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
   3  * Copyright (C) 2015 Linaro Ltd.
   4  * Author: Jassi Brar <jaswinder.singh@linaro.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/interrupt.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/mutex.h>
  19 #include <linux/delay.h>
  20 #include <linux/slab.h>
  21 #include <linux/err.h>
  22 #include <linux/io.h>
  23 #include <linux/module.h>
  24 #include <linux/amba/bus.h>
  25 #include <linux/mailbox_controller.h>
  26
  27 #define INTR_STAT_OFS   0x0
  28 #define INTR_SET_OFS    0x8
  29 #define INTR_CLR_OFS    0x10
  30
  31 #define MHU_LP_OFFSET   0x0
  32 #define MHU_HP_OFFSET   0x20
  33 #define MHU_SEC_OFFSET  0x200
  34 #define TX_REG_OFFSET   0x100
  35
  36 #define MHU_CHANS       3
  37
  38 struct mhu_link {
  39         unsigned irq;
  40         void __iomem *tx_reg;
  41         void __iomem *rx_reg;
  42 };
  43
  44 struct arm_mhu {
  45         void __iomem *base;
  46         struct mhu_link mlink[MHU_CHANS];
  47         struct mbox_chan chan[MHU_CHANS];
  48         struct mbox_controller mbox;
  49 };
  50
  51 static irqreturn_t mhu_rx_interrupt(int irq, void *p)
  52 {
  53         struct mbox_chan *chan = p;
  54         struct mhu_link *mlink = chan->con_priv;
  55         u32 val;
  56
  57         val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
  58         if (!val)
  59                 return IRQ_NONE;
  60
  61         mbox_chan_received_data(chan, (void *)&val);
  62
  63         writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
  64
  65         return IRQ_HANDLED;
  66 }
  67
  68 static bool mhu_last_tx_done(struct mbox_chan *chan)
  69 {
  70         struct mhu_link *mlink = chan->con_priv;
  71         u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  72
  73         return (val == 0);
  74 }
  75
  76 static int mhu_send_data(struct mbox_chan *chan, void *data)
  77 {
  78         struct mhu_link *mlink = chan->con_priv;
  79         u32 *arg = data;
  80
  81         writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
  82
  83         return 0;
  84 }
  85
  86 static int mhu_startup(struct mbox_chan *chan)
  87 {
  88         struct mhu_link *mlink = chan->con_priv;
  89         u32 val;
  90         int ret;
  91
  92         val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  93         writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
  94
  95         ret = request_irq(mlink->irq, mhu_rx_interrupt,
  96                           IRQF_SHARED, "mhu_link", chan);
  97         if (ret) {
  98                 dev_err(chan->mbox->dev,
  99                         "Unable to aquire IRQ %d\n", mlink->irq);
 100                 return ret;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static void mhu_shutdown(struct mbox_chan *chan)
 107 {
 108         struct mhu_link *mlink = chan->con_priv;
 109
 110         free_irq(mlink->irq, chan);
 111 }
 112
 113 static struct mbox_chan_ops mhu_ops = {
 114         .send_data = mhu_send_data,
 115         .startup = mhu_startup,
 116         .shutdown = mhu_shutdown,
 117         .last_tx_done = mhu_last_tx_done,
 118 };
 119
 120 static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
 121 {
 122         int i, err;
 123         struct arm_mhu *mhu;
 124         struct device *dev = &adev->dev;
 125         int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};
 126
 127         /* Allocate memory for device */
 128         mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
 129         if (!mhu)
 130                 return -ENOMEM;
 131
 132         mhu->base = devm_ioremap_resource(dev, &adev->res);
 133         if (IS_ERR(mhu->base)) {
 134                 dev_err(dev, "ioremap failed\n");
 135                 return PTR_ERR(mhu->base);
 136         }
 137
 138         for (i = 0; i < MHU_CHANS; i++) {
 139                 mhu->chan[i].con_priv = &mhu->mlink[i];
 140                 mhu->mlink[i].irq = adev->irq[i];
 141                 mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
 142                 mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
 143         }
 144
 145         mhu->mbox.dev = dev;
 146         mhu->mbox.chans = &mhu->chan[0];
 147         mhu->mbox.num_chans = MHU_CHANS;
 148         mhu->mbox.ops = &mhu_ops;
 149         mhu->mbox.txdone_irq = false;
 150         mhu->mbox.txdone_poll = true;
 151         mhu->mbox.txpoll_period = 10;
 152
 153         amba_set_drvdata(adev, mhu);
 154
 155         err = mbox_controller_register(&mhu->mbox);
 156         if (err) {
 157                 dev_err(dev, "Failed to register mailboxes %d\n", err);
 158                 return err;
 159         }
 160
 161         dev_info(dev, "ARM MHU Mailbox registered\n");
 162         return 0;
 163 }
 164
 165 static int mhu_remove(struct amba_device *adev)
 166 {
 167         struct arm_mhu *mhu = amba_get_drvdata(adev);
 168
 169         mbox_controller_unregister(&mhu->mbox);
 170
 171         return 0;
 172 }
 173
 174 static struct amba_id mhu_ids[] = {
 175         {
 176                 .id     = 0x1bb098,
 177                 .mask   = 0xffffff,
 178         },
 179         { 0, 0 },
 180 };
 181 MODULE_DEVICE_TABLE(amba, mhu_ids);
 182
 183 static struct amba_driver arm_mhu_driver = {
 184         .drv = {
 185                 .name   = "mhu",
 186         },
 187         .id_table       = mhu_ids,
 188         .probe          = mhu_probe,
 189         .remove         = mhu_remove,
 190 };
 191 module_amba_driver(arm_mhu_driver);
 192
 193 MODULE_LICENSE("GPL v2");
 194 MODULE_DESCRIPTION("ARM MHU Driver");
 195 MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");