/* * Copyright (C) 2010,2015 Broadcom * Copyright (C) 2013-2014 Lubomir Rintel * Copyright (C) 2013 Craig McGeachie * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This device provides a mechanism for writing to the mailboxes, * that are shared between the ARM and the VideoCore processor * * Parts of the driver are based on: * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/ * linux.git * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/ * mailbox/bcm2835-ipc.c * - documentation available on the following web site: * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface */ #include <linux/device.h> #include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/kernel.h> #include <linux/mailbox_controller.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/of_irq.h> #include <linux/platform_device.h> #include <linux/spinlock.h> /* Mailboxes */ #define ARM_0_MAIL0 0x00 #define ARM_0_MAIL1 0x20 /* * Mailbox registers. We basically only support mailbox 0 & 1. We * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about * the placement of memory barriers. */ #define MAIL0_RD (ARM_0_MAIL0 + 0x00) #define MAIL0_POL (ARM_0_MAIL0 + 0x10) #define MAIL0_STA (ARM_0_MAIL0 + 0x18) #define MAIL0_CNF (ARM_0_MAIL0 + 0x1C) #define MAIL1_WRT (ARM_0_MAIL1 + 0x00) #define MAIL1_STA (ARM_0_MAIL1 + 0x18) /* Status register: FIFO state. */ #define ARM_MS_FULL BIT(31) #define ARM_MS_EMPTY BIT(30) /* Configuration register: Enable interrupts. */ #define ARM_MC_IHAVEDATAIRQEN BIT(0) struct bcm2835_mbox { void __iomem *regs; spinlock_t lock; struct mbox_controller controller; }; static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link) { return container_of(link->mbox, struct bcm2835_mbox, controller); } static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id) { struct bcm2835_mbox *mbox = dev_id; struct device *dev = mbox->controller.dev; struct mbox_chan *link = &mbox->controller.chans[0]; while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) { u32 msg = readl(mbox->regs + MAIL0_RD); dev_dbg(dev, "Reply 0x%08X\n", msg); mbox_chan_received_data(link, &msg); } return IRQ_HANDLED; } static int bcm2835_send_data(struct mbox_chan *link, void *data) { struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); u32 msg = *(u32 *)data; spin_lock(&mbox->lock); writel(msg, mbox->regs + MAIL1_WRT); dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg); spin_unlock(&mbox->lock); return 0; } static int bcm2835_startup(struct mbox_chan *link) { struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); /* Enable the interrupt on data reception */ writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF); return 0; } static void bcm2835_shutdown(struct mbox_chan *link) { struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); writel(0, mbox->regs + MAIL0_CNF); } static bool bcm2835_last_tx_done(struct mbox_chan *link) { struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); bool ret; spin_lock(&mbox->lock); ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL); spin_unlock(&mbox->lock); return ret; } static const struct mbox_chan_ops bcm2835_mbox_chan_ops = { .send_data = bcm2835_send_data, .startup = bcm2835_startup, .shutdown = bcm2835_shutdown, .last_tx_done = bcm2835_last_tx_done }; static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox, const struct of_phandle_args *sp) { if (sp->args_count != 0) return NULL; return &mbox->chans[0]; } static int bcm2835_mbox_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; int ret = 0; struct resource *iomem; struct bcm2835_mbox *mbox; mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); if (mbox == NULL) return -ENOMEM; spin_lock_init(&mbox->lock); ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0), bcm2835_mbox_irq, 0, dev_name(dev), mbox); if (ret) { dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n", ret); return -ENODEV; } iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0); mbox->regs = devm_ioremap_resource(&pdev->dev, iomem); if (IS_ERR(mbox->regs)) { ret = PTR_ERR(mbox->regs); dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret); return ret; } mbox->controller.txdone_poll = true; mbox->controller.txpoll_period = 5; mbox->controller.ops = &bcm2835_mbox_chan_ops; mbox->controller.of_xlate = &bcm2835_mbox_index_xlate; mbox->controller.dev = dev; mbox->controller.num_chans = 1; mbox->controller.chans = devm_kzalloc(dev, sizeof(*mbox->controller.chans), GFP_KERNEL); if (!mbox->controller.chans) return -ENOMEM; ret = mbox_controller_register(&mbox->controller); if (ret) return ret; platform_set_drvdata(pdev, mbox); dev_info(dev, "mailbox enabled\n"); return ret; } static int bcm2835_mbox_remove(struct platform_device *pdev) { struct bcm2835_mbox *mbox = platform_get_drvdata(pdev); mbox_controller_unregister(&mbox->controller); return 0; } static const struct of_device_id bcm2835_mbox_of_match[] = { { .compatible = "brcm,bcm2835-mbox", }, {}, }; MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match); static struct platform_driver bcm2835_mbox_driver = { .driver = { .name = "bcm2835-mbox", .of_match_table = bcm2835_mbox_of_match, }, .probe = bcm2835_mbox_probe, .remove = bcm2835_mbox_remove, }; module_platform_driver(bcm2835_mbox_driver); MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); MODULE_DESCRIPTION("BCM2835 mailbox IPC driver"); MODULE_LICENSE("GPL v2");