1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2010,2015 Broadcom 4 * Copyright (C) 2013-2014 Lubomir Rintel 5 * Copyright (C) 2013 Craig McGeachie 6 * 7 * Parts of the driver are based on: 8 * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was 9 * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/ 10 * linux.git 11 * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at 12 * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/ 13 * mailbox/bcm2835-ipc.c 14 * - documentation available on the following web site: 15 * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface 16 */ 17 18 #include <linux/device.h> 19 #include <linux/dma-mapping.h> 20 #include <linux/err.h> 21 #include <linux/interrupt.h> 22 #include <linux/irq.h> 23 #include <linux/kernel.h> 24 #include <linux/mailbox_controller.h> 25 #include <linux/module.h> 26 #include <linux/of_address.h> 27 #include <linux/of_irq.h> 28 #include <linux/platform_device.h> 29 #include <linux/spinlock.h> 30 31 /* Mailboxes */ 32 #define ARM_0_MAIL0 0x00 33 #define ARM_0_MAIL1 0x20 34 35 /* 36 * Mailbox registers. We basically only support mailbox 0 & 1. We 37 * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See 38 * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about 39 * the placement of memory barriers. 40 */ 41 #define MAIL0_RD (ARM_0_MAIL0 + 0x00) 42 #define MAIL0_POL (ARM_0_MAIL0 + 0x10) 43 #define MAIL0_STA (ARM_0_MAIL0 + 0x18) 44 #define MAIL0_CNF (ARM_0_MAIL0 + 0x1C) 45 #define MAIL1_WRT (ARM_0_MAIL1 + 0x00) 46 #define MAIL1_STA (ARM_0_MAIL1 + 0x18) 47 48 /* Status register: FIFO state. */ 49 #define ARM_MS_FULL BIT(31) 50 #define ARM_MS_EMPTY BIT(30) 51 52 /* Configuration register: Enable interrupts. */ 53 #define ARM_MC_IHAVEDATAIRQEN BIT(0) 54 55 struct bcm2835_mbox { 56 void __iomem *regs; 57 spinlock_t lock; 58 struct mbox_controller controller; 59 }; 60 61 static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link) 62 { 63 return container_of(link->mbox, struct bcm2835_mbox, controller); 64 } 65 66 static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id) 67 { 68 struct bcm2835_mbox *mbox = dev_id; 69 struct device *dev = mbox->controller.dev; 70 struct mbox_chan *link = &mbox->controller.chans[0]; 71 72 while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) { 73 u32 msg = readl(mbox->regs + MAIL0_RD); 74 dev_dbg(dev, "Reply 0x%08X\n", msg); 75 mbox_chan_received_data(link, &msg); 76 } 77 return IRQ_HANDLED; 78 } 79 80 static int bcm2835_send_data(struct mbox_chan *link, void *data) 81 { 82 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); 83 u32 msg = *(u32 *)data; 84 85 spin_lock(&mbox->lock); 86 writel(msg, mbox->regs + MAIL1_WRT); 87 dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg); 88 spin_unlock(&mbox->lock); 89 return 0; 90 } 91 92 static int bcm2835_startup(struct mbox_chan *link) 93 { 94 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); 95 96 /* Enable the interrupt on data reception */ 97 writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF); 98 99 return 0; 100 } 101 102 static void bcm2835_shutdown(struct mbox_chan *link) 103 { 104 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); 105 106 writel(0, mbox->regs + MAIL0_CNF); 107 } 108 109 static bool bcm2835_last_tx_done(struct mbox_chan *link) 110 { 111 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); 112 bool ret; 113 114 spin_lock(&mbox->lock); 115 ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL); 116 spin_unlock(&mbox->lock); 117 return ret; 118 } 119 120 static const struct mbox_chan_ops bcm2835_mbox_chan_ops = { 121 .send_data = bcm2835_send_data, 122 .startup = bcm2835_startup, 123 .shutdown = bcm2835_shutdown, 124 .last_tx_done = bcm2835_last_tx_done 125 }; 126 127 static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox, 128 const struct of_phandle_args *sp) 129 { 130 if (sp->args_count != 0) 131 return ERR_PTR(-EINVAL); 132 133 return &mbox->chans[0]; 134 } 135 136 static int bcm2835_mbox_probe(struct platform_device *pdev) 137 { 138 struct device *dev = &pdev->dev; 139 int ret = 0; 140 struct bcm2835_mbox *mbox; 141 142 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); 143 if (mbox == NULL) 144 return -ENOMEM; 145 spin_lock_init(&mbox->lock); 146 147 ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0), 148 bcm2835_mbox_irq, 0, dev_name(dev), mbox); 149 if (ret) { 150 dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n", 151 ret); 152 return -ENODEV; 153 } 154 155 mbox->regs = devm_platform_ioremap_resource(pdev, 0); 156 if (IS_ERR(mbox->regs)) { 157 ret = PTR_ERR(mbox->regs); 158 return ret; 159 } 160 161 mbox->controller.txdone_poll = true; 162 mbox->controller.txpoll_period = 5; 163 mbox->controller.ops = &bcm2835_mbox_chan_ops; 164 mbox->controller.of_xlate = &bcm2835_mbox_index_xlate; 165 mbox->controller.dev = dev; 166 mbox->controller.num_chans = 1; 167 mbox->controller.chans = devm_kzalloc(dev, 168 sizeof(*mbox->controller.chans), GFP_KERNEL); 169 if (!mbox->controller.chans) 170 return -ENOMEM; 171 172 ret = devm_mbox_controller_register(dev, &mbox->controller); 173 if (ret) 174 return ret; 175 176 platform_set_drvdata(pdev, mbox); 177 dev_info(dev, "mailbox enabled\n"); 178 179 return ret; 180 } 181 182 static const struct of_device_id bcm2835_mbox_of_match[] = { 183 { .compatible = "brcm,bcm2835-mbox", }, 184 {}, 185 }; 186 MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match); 187 188 static struct platform_driver bcm2835_mbox_driver = { 189 .driver = { 190 .name = "bcm2835-mbox", 191 .of_match_table = bcm2835_mbox_of_match, 192 }, 193 .probe = bcm2835_mbox_probe, 194 }; 195 module_platform_driver(bcm2835_mbox_driver); 196 197 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); 198 MODULE_DESCRIPTION("BCM2835 mailbox IPC driver"); 199 MODULE_LICENSE("GPL v2"); 200