1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd. 4 * Copyright (C) 2015 Linaro Ltd. 5 * Author: Jassi Brar <jaswinder.singh@linaro.org> 6 */ 7 8 #include <linux/amba/bus.h> 9 #include <linux/device.h> 10 #include <linux/err.h> 11 #include <linux/interrupt.h> 12 #include <linux/io.h> 13 #include <linux/mailbox_controller.h> 14 #include <linux/module.h> 15 16 #define INTR_STAT_OFS 0x0 17 #define INTR_SET_OFS 0x8 18 #define INTR_CLR_OFS 0x10 19 20 #define MHU_LP_OFFSET 0x0 21 #define MHU_HP_OFFSET 0x20 22 #define MHU_SEC_OFFSET 0x200 23 #define TX_REG_OFFSET 0x100 24 25 #define MHU_CHANS 3 26 27 struct mhu_link { 28 unsigned irq; 29 void __iomem *tx_reg; 30 void __iomem *rx_reg; 31 }; 32 33 struct arm_mhu { 34 void __iomem *base; 35 struct mhu_link mlink[MHU_CHANS]; 36 struct mbox_chan chan[MHU_CHANS]; 37 struct mbox_controller mbox; 38 }; 39 40 static irqreturn_t mhu_rx_interrupt(int irq, void *p) 41 { 42 struct mbox_chan *chan = p; 43 struct mhu_link *mlink = chan->con_priv; 44 u32 val; 45 46 val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS); 47 if (!val) 48 return IRQ_NONE; 49 50 mbox_chan_received_data(chan, (void *)&val); 51 52 writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS); 53 54 return IRQ_HANDLED; 55 } 56 57 static bool mhu_last_tx_done(struct mbox_chan *chan) 58 { 59 struct mhu_link *mlink = chan->con_priv; 60 u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS); 61 62 return (val == 0); 63 } 64 65 static int mhu_send_data(struct mbox_chan *chan, void *data) 66 { 67 struct mhu_link *mlink = chan->con_priv; 68 u32 *arg = data; 69 70 writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS); 71 72 return 0; 73 } 74 75 static int mhu_startup(struct mbox_chan *chan) 76 { 77 struct mhu_link *mlink = chan->con_priv; 78 u32 val; 79 int ret; 80 81 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS); 82 writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS); 83 84 ret = request_irq(mlink->irq, mhu_rx_interrupt, 85 IRQF_SHARED, "mhu_link", chan); 86 if (ret) { 87 dev_err(chan->mbox->dev, 88 "Unable to acquire IRQ %d\n", mlink->irq); 89 return ret; 90 } 91 92 return 0; 93 } 94 95 static void mhu_shutdown(struct mbox_chan *chan) 96 { 97 struct mhu_link *mlink = chan->con_priv; 98 99 free_irq(mlink->irq, chan); 100 } 101 102 static const struct mbox_chan_ops mhu_ops = { 103 .send_data = mhu_send_data, 104 .startup = mhu_startup, 105 .shutdown = mhu_shutdown, 106 .last_tx_done = mhu_last_tx_done, 107 }; 108 109 static int mhu_probe(struct amba_device *adev, const struct amba_id *id) 110 { 111 int i, err; 112 struct arm_mhu *mhu; 113 struct device *dev = &adev->dev; 114 int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET}; 115 116 if (!of_device_is_compatible(dev->of_node, "arm,mhu")) 117 return -ENODEV; 118 119 /* Allocate memory for device */ 120 mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL); 121 if (!mhu) 122 return -ENOMEM; 123 124 mhu->base = devm_ioremap_resource(dev, &adev->res); 125 if (IS_ERR(mhu->base)) 126 return PTR_ERR(mhu->base); 127 128 for (i = 0; i < MHU_CHANS; i++) { 129 mhu->chan[i].con_priv = &mhu->mlink[i]; 130 mhu->mlink[i].irq = adev->irq[i]; 131 mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i]; 132 mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET; 133 } 134 135 mhu->mbox.dev = dev; 136 mhu->mbox.chans = &mhu->chan[0]; 137 mhu->mbox.num_chans = MHU_CHANS; 138 mhu->mbox.ops = &mhu_ops; 139 mhu->mbox.txdone_irq = false; 140 mhu->mbox.txdone_poll = true; 141 mhu->mbox.txpoll_period = 1; 142 143 amba_set_drvdata(adev, mhu); 144 145 err = devm_mbox_controller_register(dev, &mhu->mbox); 146 if (err) { 147 dev_err(dev, "Failed to register mailboxes %d\n", err); 148 return err; 149 } 150 151 dev_info(dev, "ARM MHU Mailbox registered\n"); 152 return 0; 153 } 154 155 static struct amba_id mhu_ids[] = { 156 { 157 .id = 0x1bb098, 158 .mask = 0xffffff, 159 }, 160 { 0, 0 }, 161 }; 162 MODULE_DEVICE_TABLE(amba, mhu_ids); 163 164 static struct amba_driver arm_mhu_driver = { 165 .drv = { 166 .name = "mhu", 167 }, 168 .id_table = mhu_ids, 169 .probe = mhu_probe, 170 }; 171 module_amba_driver(arm_mhu_driver); 172 173 MODULE_LICENSE("GPL v2"); 174 MODULE_DESCRIPTION("ARM MHU Driver"); 175 MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>"); 176