drivers/mailbox/platform_mhu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2016 BayLibre SAS.
   4  * Author: Neil Armstrong <narmstrong@baylibre.com>
   5  * Synchronised with arm_mhu.c from :
   6  * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
   7  * Copyright (C) 2015 Linaro Ltd.
   8  * Author: Jassi Brar <jaswinder.singh@linaro.org>
   9  */
  10
  11 #include <linux/interrupt.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/mutex.h>
  14 #include <linux/delay.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/mailbox_controller.h>
  21
  22 #define INTR_SET_OFS    0x0
  23 #define INTR_STAT_OFS   0x4
  24 #define INTR_CLR_OFS    0x8
  25
  26 #define MHU_SEC_OFFSET  0x0
  27 #define MHU_LP_OFFSET   0xc
  28 #define MHU_HP_OFFSET   0x18
  29 #define TX_REG_OFFSET   0x24
  30
  31 #define MHU_CHANS       3
  32
  33 struct platform_mhu_link {
  34         int irq;
  35         void __iomem *tx_reg;
  36         void __iomem *rx_reg;
  37 };
  38
  39 struct platform_mhu {
  40         void __iomem *base;
  41         struct platform_mhu_link mlink[MHU_CHANS];
  42         struct mbox_chan chan[MHU_CHANS];
  43         struct mbox_controller mbox;
  44 };
  45
  46 static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)
  47 {
  48         struct mbox_chan *chan = p;
  49         struct platform_mhu_link *mlink = chan->con_priv;
  50         u32 val;
  51
  52         val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
  53         if (!val)
  54                 return IRQ_NONE;
  55
  56         mbox_chan_received_data(chan, (void *)&val);
  57
  58         writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
  59
  60         return IRQ_HANDLED;
  61 }
  62
  63 static bool platform_mhu_last_tx_done(struct mbox_chan *chan)
  64 {
  65         struct platform_mhu_link *mlink = chan->con_priv;
  66         u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  67
  68         return (val == 0);
  69 }
  70
  71 static int platform_mhu_send_data(struct mbox_chan *chan, void *data)
  72 {
  73         struct platform_mhu_link *mlink = chan->con_priv;
  74         u32 *arg = data;
  75
  76         writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
  77
  78         return 0;
  79 }
  80
  81 static int platform_mhu_startup(struct mbox_chan *chan)
  82 {
  83         struct platform_mhu_link *mlink = chan->con_priv;
  84         u32 val;
  85         int ret;
  86
  87         val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  88         writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
  89
  90         ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,
  91                           IRQF_SHARED, "platform_mhu_link", chan);
  92         if (ret) {
  93                 dev_err(chan->mbox->dev,
  94                         "Unable to acquire IRQ %d\n", mlink->irq);
  95                 return ret;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static void platform_mhu_shutdown(struct mbox_chan *chan)
 102 {
 103         struct platform_mhu_link *mlink = chan->con_priv;
 104
 105         free_irq(mlink->irq, chan);
 106 }
 107
 108 static const struct mbox_chan_ops platform_mhu_ops = {
 109         .send_data = platform_mhu_send_data,
 110         .startup = platform_mhu_startup,
 111         .shutdown = platform_mhu_shutdown,
 112         .last_tx_done = platform_mhu_last_tx_done,
 113 };
 114
 115 static int platform_mhu_probe(struct platform_device *pdev)
 116 {
 117         int i, err;
 118         struct platform_mhu *mhu;
 119         struct device *dev = &pdev->dev;
 120         struct resource *res;
 121         int platform_mhu_reg[MHU_CHANS] = {
 122                 MHU_SEC_OFFSET, MHU_LP_OFFSET, MHU_HP_OFFSET
 123         };
 124
 125         /* Allocate memory for device */
 126         mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
 127         if (!mhu)
 128                 return -ENOMEM;
 129
 130         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 131         mhu->base = devm_ioremap_resource(dev, res);
 132         if (IS_ERR(mhu->base)) {
 133                 dev_err(dev, "ioremap failed\n");
 134                 return PTR_ERR(mhu->base);
 135         }
 136
 137         for (i = 0; i < MHU_CHANS; i++) {
 138                 mhu->chan[i].con_priv = &mhu->mlink[i];
 139                 mhu->mlink[i].irq = platform_get_irq(pdev, i);
 140                 if (mhu->mlink[i].irq < 0) {
 141                         dev_err(dev, "failed to get irq%d\n", i);
 142                         return mhu->mlink[i].irq;
 143                 }
 144                 mhu->mlink[i].rx_reg = mhu->base + platform_mhu_reg[i];
 145                 mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
 146         }
 147
 148         mhu->mbox.dev = dev;
 149         mhu->mbox.chans = &mhu->chan[0];
 150         mhu->mbox.num_chans = MHU_CHANS;
 151         mhu->mbox.ops = &platform_mhu_ops;
 152         mhu->mbox.txdone_irq = false;
 153         mhu->mbox.txdone_poll = true;
 154         mhu->mbox.txpoll_period = 1;
 155
 156         platform_set_drvdata(pdev, mhu);
 157
 158         err = devm_mbox_controller_register(dev, &mhu->mbox);
 159         if (err) {
 160                 dev_err(dev, "Failed to register mailboxes %d\n", err);
 161                 return err;
 162         }
 163
 164         dev_info(dev, "Platform MHU Mailbox registered\n");
 165         return 0;
 166 }
 167
 168 static const struct of_device_id platform_mhu_dt_ids[] = {
 169         { .compatible = "amlogic,meson-gxbb-mhu", },
 170         { /* sentinel */ },
 171 };
 172 MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);
 173
 174 static struct platform_driver platform_mhu_driver = {
 175         .probe  = platform_mhu_probe,
 176         .driver = {
 177                 .name = "platform-mhu",
 178                 .of_match_table = platform_mhu_dt_ids,
 179         },
 180 };
 181
 182 module_platform_driver(platform_mhu_driver);
 183
 184 MODULE_LICENSE("GPL v2");
 185 MODULE_ALIAS("platform:platform-mhu");
 186 MODULE_DESCRIPTION("Platform MHU Driver");
 187 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");