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/mod_devicetable.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mailbox_controller.h>
  22
  23 #define INTR_SET_OFS    0x0
  24 #define INTR_STAT_OFS   0x4
  25 #define INTR_CLR_OFS    0x8
  26
  27 #define MHU_SEC_OFFSET  0x0
  28 #define MHU_LP_OFFSET   0xc
  29 #define MHU_HP_OFFSET   0x18
  30 #define TX_REG_OFFSET   0x24
  31
  32 #define MHU_CHANS       3
  33
  34 struct platform_mhu_link {
  35         int irq;
  36         void __iomem *tx_reg;
  37         void __iomem *rx_reg;
  38 };
  39
  40 struct platform_mhu {
  41         void __iomem *base;
  42         struct platform_mhu_link mlink[MHU_CHANS];
  43         struct mbox_chan chan[MHU_CHANS];
  44         struct mbox_controller mbox;
  45 };
  46
  47 static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)
  48 {
  49         struct mbox_chan *chan = p;
  50         struct platform_mhu_link *mlink = chan->con_priv;
  51         u32 val;
  52
  53         val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
  54         if (!val)
  55                 return IRQ_NONE;
  56
  57         mbox_chan_received_data(chan, (void *)&val);
  58
  59         writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
  60
  61         return IRQ_HANDLED;
  62 }
  63
  64 static bool platform_mhu_last_tx_done(struct mbox_chan *chan)
  65 {
  66         struct platform_mhu_link *mlink = chan->con_priv;
  67         u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  68
  69         return (val == 0);
  70 }
  71
  72 static int platform_mhu_send_data(struct mbox_chan *chan, void *data)
  73 {
  74         struct platform_mhu_link *mlink = chan->con_priv;
  75         u32 *arg = data;
  76
  77         writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
  78
  79         return 0;
  80 }
  81
  82 static int platform_mhu_startup(struct mbox_chan *chan)
  83 {
  84         struct platform_mhu_link *mlink = chan->con_priv;
  85         u32 val;
  86         int ret;
  87
  88         val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
  89         writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
  90
  91         ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,
  92                           IRQF_SHARED, "platform_mhu_link", chan);
  93         if (ret) {
  94                 dev_err(chan->mbox->dev,
  95                         "Unable to acquire IRQ %d\n", mlink->irq);
  96                 return ret;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static void platform_mhu_shutdown(struct mbox_chan *chan)
 103 {
 104         struct platform_mhu_link *mlink = chan->con_priv;
 105
 106         free_irq(mlink->irq, chan);
 107 }
 108
 109 static const struct mbox_chan_ops platform_mhu_ops = {
 110         .send_data = platform_mhu_send_data,
 111         .startup = platform_mhu_startup,
 112         .shutdown = platform_mhu_shutdown,
 113         .last_tx_done = platform_mhu_last_tx_done,
 114 };
 115
 116 static int platform_mhu_probe(struct platform_device *pdev)
 117 {
 118         int i, err;
 119         struct platform_mhu *mhu;
 120         struct device *dev = &pdev->dev;
 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         mhu->base = devm_platform_ioremap_resource(pdev, 0);
 131         if (IS_ERR(mhu->base)) {
 132                 dev_err(dev, "ioremap failed\n");
 133                 return PTR_ERR(mhu->base);
 134         }
 135
 136         for (i = 0; i < MHU_CHANS; i++) {
 137                 mhu->chan[i].con_priv = &mhu->mlink[i];
 138                 mhu->mlink[i].irq = platform_get_irq(pdev, i);
 139                 if (mhu->mlink[i].irq < 0)
 140                         return mhu->mlink[i].irq;
 141                 mhu->mlink[i].rx_reg = mhu->base + platform_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 = &platform_mhu_ops;
 149         mhu->mbox.txdone_irq = false;
 150         mhu->mbox.txdone_poll = true;
 151         mhu->mbox.txpoll_period = 1;
 152
 153         platform_set_drvdata(pdev, mhu);
 154
 155         err = devm_mbox_controller_register(dev, &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, "Platform MHU Mailbox registered\n");
 162         return 0;
 163 }
 164
 165 static const struct of_device_id platform_mhu_dt_ids[] = {
 166         { .compatible = "amlogic,meson-gxbb-mhu", },
 167         { /* sentinel */ },
 168 };
 169 MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);
 170
 171 static struct platform_driver platform_mhu_driver = {
 172         .probe  = platform_mhu_probe,
 173         .driver = {
 174                 .name = "platform-mhu",
 175                 .of_match_table = platform_mhu_dt_ids,
 176         },
 177 };
 178
 179 module_platform_driver(platform_mhu_driver);
 180
 181 MODULE_LICENSE("GPL v2");
 182 MODULE_ALIAS("platform:platform-mhu");
 183 MODULE_DESCRIPTION("Platform MHU Driver");
 184 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");