drivers/mailbox/platform_mhu.c

   1 /*
   2  * Copyright (C) 2016 BayLibre SAS.
   3  * Author: Neil Armstrong <narmstrong@baylibre.com>
   4  * Synchronised with arm_mhu.c from :
   5  * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
   6  * Copyright (C) 2015 Linaro Ltd.
   7  * Author: Jassi Brar <jaswinder.singh@linaro.org>
   8  *
   9  * This program is free software: you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation, version 2 of the License.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/interrupt.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/mutex.h>
  22 #include <linux/delay.h>
  23 #include <linux/slab.h>
  24 #include <linux/err.h>
  25 #include <linux/io.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/mailbox_controller.h>
  29
  30 #define INTR_SET_OFS    0x0
  31 #define INTR_STAT_OFS   0x4
  32 #define INTR_CLR_OFS    0x8
  33
  34 #define MHU_SEC_OFFSET  0x0
  35 #define MHU_LP_OFFSET   0xc
  36 #define MHU_HP_OFFSET   0x18
  37 #define TX_REG_OFFSET   0x24
  38
  39 #define MHU_CHANS       3
  40
  41 struct platform_mhu_link {
  42         int irq;
  43         void __iomem *tx_reg;
  44         void __iomem *rx_reg;
  45 };
  46
  47 struct platform_mhu {
  48         void __iomem *base;
  49         struct platform_mhu_link mlink[MHU_CHANS];
  50         struct mbox_chan chan[MHU_CHANS];
  51         struct mbox_controller mbox;
  52 };
  53
  54 static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)
  55 {
  56         struct mbox_chan *chan = p;
  57         struct platform_mhu_link *mlink = chan->con_priv;
  58         u32 val;
  59
  60         val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
  61         if (!val)
  62                 return IRQ_NONE;
  63
  64         mbox_chan_received_data(chan, (void *)&val);
  65
  66         writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
  67
  68         return IRQ_HANDLED;
  69 }
  70
  71 static bool platform_mhu_last_tx_done(struct mbox_chan *chan)
  72 {
  73         struct platform_mhu_link *mlink = chan->con_priv;
  74         u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  75
  76         return (val == 0);
  77 }
  78
  79 static int platform_mhu_send_data(struct mbox_chan *chan, void *data)
  80 {
  81         struct platform_mhu_link *mlink = chan->con_priv;
  82         u32 *arg = data;
  83
  84         writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
  85
  86         return 0;
  87 }
  88
  89 static int platform_mhu_startup(struct mbox_chan *chan)
  90 {
  91         struct platform_mhu_link *mlink = chan->con_priv;
  92         u32 val;
  93         int ret;
  94
  95         val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  96         writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
  97
  98         ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,
  99                           IRQF_SHARED, "platform_mhu_link", chan);
 100         if (ret) {
 101                 dev_err(chan->mbox->dev,
 102                         "Unable to acquire IRQ %d\n", mlink->irq);
 103                 return ret;
 104         }
 105
 106         return 0;
 107 }
 108
 109 static void platform_mhu_shutdown(struct mbox_chan *chan)
 110 {
 111         struct platform_mhu_link *mlink = chan->con_priv;
 112
 113         free_irq(mlink->irq, chan);
 114 }
 115
 116 static const struct mbox_chan_ops platform_mhu_ops = {
 117         .send_data = platform_mhu_send_data,
 118         .startup = platform_mhu_startup,
 119         .shutdown = platform_mhu_shutdown,
 120         .last_tx_done = platform_mhu_last_tx_done,
 121 };
 122
 123 static int platform_mhu_probe(struct platform_device *pdev)
 124 {
 125         int i, err;
 126         struct platform_mhu *mhu;
 127         struct device *dev = &pdev->dev;
 128         struct resource *res;
 129         int platform_mhu_reg[MHU_CHANS] = {
 130                 MHU_SEC_OFFSET, MHU_LP_OFFSET, MHU_HP_OFFSET
 131         };
 132
 133         /* Allocate memory for device */
 134         mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
 135         if (!mhu)
 136                 return -ENOMEM;
 137
 138         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 139         mhu->base = devm_ioremap_resource(dev, res);
 140         if (IS_ERR(mhu->base)) {
 141                 dev_err(dev, "ioremap failed\n");
 142                 return PTR_ERR(mhu->base);
 143         }
 144
 145         for (i = 0; i < MHU_CHANS; i++) {
 146                 mhu->chan[i].con_priv = &mhu->mlink[i];
 147                 mhu->mlink[i].irq = platform_get_irq(pdev, i);
 148                 if (mhu->mlink[i].irq < 0) {
 149                         dev_err(dev, "failed to get irq%d\n", i);
 150                         return mhu->mlink[i].irq;
 151                 }
 152                 mhu->mlink[i].rx_reg = mhu->base + platform_mhu_reg[i];
 153                 mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
 154         }
 155
 156         mhu->mbox.dev = dev;
 157         mhu->mbox.chans = &mhu->chan[0];
 158         mhu->mbox.num_chans = MHU_CHANS;
 159         mhu->mbox.ops = &platform_mhu_ops;
 160         mhu->mbox.txdone_irq = false;
 161         mhu->mbox.txdone_poll = true;
 162         mhu->mbox.txpoll_period = 1;
 163
 164         platform_set_drvdata(pdev, mhu);
 165
 166         err = devm_mbox_controller_register(dev, &mhu->mbox);
 167         if (err) {
 168                 dev_err(dev, "Failed to register mailboxes %d\n", err);
 169                 return err;
 170         }
 171
 172         dev_info(dev, "Platform MHU Mailbox registered\n");
 173         return 0;
 174 }
 175
 176 static const struct of_device_id platform_mhu_dt_ids[] = {
 177         { .compatible = "amlogic,meson-gxbb-mhu", },
 178         { /* sentinel */ },
 179 };
 180 MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);
 181
 182 static struct platform_driver platform_mhu_driver = {
 183         .probe  = platform_mhu_probe,
 184         .driver = {
 185                 .name = "platform-mhu",
 186                 .of_match_table = platform_mhu_dt_ids,
 187         },
 188 };
 189
 190 module_platform_driver(platform_mhu_driver);
 191
 192 MODULE_LICENSE("GPL v2");
 193 MODULE_ALIAS("platform:platform-mhu");
 194 MODULE_DESCRIPTION("Platform MHU Driver");
 195 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");