diff options
Diffstat (limited to 'drivers/mailbox/bcm2835-mailbox.c')
| -rw-r--r-- | drivers/mailbox/bcm2835-mailbox.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/mailbox/bcm2835-mailbox.c b/drivers/mailbox/bcm2835-mailbox.c new file mode 100644 index 000000000..e92bbc533 --- /dev/null +++ b/drivers/mailbox/bcm2835-mailbox.c @@ -0,0 +1,216 @@ +/* + * 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 ERR_PTR(-EINVAL); + + 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"); |