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 acquire 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 const 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 = 1; 152 153 amba_set_drvdata(adev, 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, "ARM MHU Mailbox registered\n"); 162 return 0; 163 } 164 165 static struct amba_id mhu_ids[] = { 166 { 167 .id = 0x1bb098, 168 .mask = 0xffffff, 169 }, 170 { 0, 0 }, 171 }; 172 MODULE_DEVICE_TABLE(amba, mhu_ids); 173 174 static struct amba_driver arm_mhu_driver = { 175 .drv = { 176 .name = "mhu", 177 }, 178 .id_table = mhu_ids, 179 .probe = mhu_probe, 180 }; 181 module_amba_driver(arm_mhu_driver); 182 183 MODULE_LICENSE("GPL v2"); 184 MODULE_DESCRIPTION("ARM MHU Driver"); 185 MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>"); 186