From: Lubomir Rintel <lkundrak@xxxxx> Implement BCM2835 mailbox support as a device registered with the general purpose mailbox framework. Implementation based on commits by Lubomir Rintel [1], Suman Anna and Jassi Brar [2] on which to base the implementation. [1] http://lists.infradead.org/pipermail/linux-rpi-kernel/2013-April/000528.html [2] http://lists.infradead.org/pipermail/linux-rpi-kernel/2013-May/000546.html Signed-off-by: Lubomir Rintel <lkundrak@xxxxx> Signed-off-by: Craig McGeachie <slapdau@xxxxxxxxxxxx> Signed-off-by: Suman Anna <s-anna@xxxxxx> Signed-off-by: Jassi Brar <jassisinghbrar@xxxxxxxxx> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx> Cc: Jassi Brar <jassisinghbrar@xxxxxxxxx> Acked-by: Lee Jones <lee.jones@xxxxxxxxxx> --- v2: Squashed Craig's work for review, carried over to new version of Mailbox framework (changes by Lubomir) v3: Fix multi-line comment style. Refer to the documentation by filename. Only declare one MODULE_AUTHOR. Alphabetize includes. Drop some excessive dev_dbg()s (changes by anholt). v4: Use the new bcm2835_peripheral_read_workaround(), drop the unnecessary wmb()s, make the messages be a pointer to u32, rather than u32-cast-as-pointer, fold in small static functions, drop extra error messages, clean up sizeof() arg for malloc, disable interrupts on unload. drivers/mailbox/Kconfig | 8 ++ drivers/mailbox/Makefile | 2 + drivers/mailbox/bcm2835-mailbox.c | 259 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 269 insertions(+) create mode 100644 drivers/mailbox/bcm2835-mailbox.c diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index 84325f2..2873a03 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -51,4 +51,12 @@ config ALTERA_MBOX An implementation of the Altera Mailbox soft core. It is used to send message between processors. Say Y here if you want to use the Altera mailbox support. + +config BCM2835_MBOX + tristate "BCM2835 Mailbox" + depends on ARCH_BCM2835 + help + An implementation of the BCM2385 Mailbox. It is used to invoke + the services of the Videocore. Say Y here if you want to use the + BCM2835 Mailbox. endif diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index 2e79231..7feb8da 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -9,3 +9,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o obj-$(CONFIG_PCC) += pcc.o obj-$(CONFIG_ALTERA_MBOX) += mailbox-altera.o + +obj-$(CONFIG_BCM2835_MBOX) += bcm2835-mailbox.o diff --git a/drivers/mailbox/bcm2835-mailbox.c b/drivers/mailbox/bcm2835-mailbox.c new file mode 100644 index 0000000..01ddb53 --- /dev/null +++ b/drivers/mailbox/bcm2835-mailbox.c @@ -0,0 +1,259 @@ +/* + * Copyright (C) 2010 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> +#include <soc/bcm2835/peripheral-workaround.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 MBOX_CHAN_COUNT 16 + +/* Status register: FIFO state. */ +#define ARM_MS_FULL 0x80000000 +#define ARM_MS_EMPTY 0x40000000 + +/* Configuration register: Enable interrupts. */ +#define ARM_MC_IHAVEDATAIRQEN 0x00000001 + +#define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) +#define MBOX_CHAN(msg) ((msg) & 0xf) +#define MBOX_DATA28(msg) ((msg) & ~0xf) + +struct bcm2835_mbox; + +struct bcm2835_channel { + struct bcm2835_mbox *mbox; + struct mbox_chan *link; + u32 chan_num; + bool started; +}; + +struct bcm2835_mbox { + struct platform_device *pdev; + struct device *dev; + void __iomem *regs; + spinlock_t lock; + struct bcm2835_channel channel[MBOX_CHAN_COUNT]; + struct mbox_controller controller; +}; + +#define to_channel(link) ((struct bcm2835_channel *)link->con_priv) + +static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id) +{ + struct bcm2835_mbox *mbox = (struct bcm2835_mbox *) dev_id; + struct device *dev = mbox->dev; + + bcm2835_peripheral_read_workaround(); + + while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) { + u32 msg = readl(mbox->regs + MAIL0_RD); + unsigned int chan = MBOX_CHAN(msg); + u32 data = MBOX_DATA28(msg); + + if (!mbox->channel[chan].started) { + dev_err(dev, "Reply on stopped channel %d\n", chan); + continue; + } + dev_dbg(dev, "Reply 0x%08X\n", msg); + mbox_chan_received_data(mbox->channel[chan].link, &data); + } + return IRQ_HANDLED; +} + +static int bcm2835_send_data(struct mbox_chan *link, void *data) +{ + struct bcm2835_channel *chan = to_channel(link); + struct bcm2835_mbox *mbox = chan->mbox; + int ret = 0; + u32 msg = MBOX_MSG(chan->chan_num, *(u32 *)data); + + if (!chan->started) + return -ENODEV; + spin_lock(&mbox->lock); + bcm2835_peripheral_read_workaround(); + if (readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL) { + ret = -EBUSY; + goto end; + } + writel(msg, mbox->regs + MAIL1_WRT); + dev_dbg(mbox->dev, "Request 0x%08X\n", msg); +end: + spin_unlock(&mbox->lock); + return ret; +} + +static int bcm2835_startup(struct mbox_chan *link) +{ + struct bcm2835_channel *chan = to_channel(link); + + chan->started = true; + return 0; +} + +static void bcm2835_shutdown(struct mbox_chan *link) +{ + struct bcm2835_channel *chan = to_channel(link); + + chan->started = false; +} + +static bool bcm2835_last_tx_done(struct mbox_chan *link) +{ + struct bcm2835_channel *chan = to_channel(link); + struct bcm2835_mbox *mbox = chan->mbox; + bool ret; + + if (!chan->started) + return false; + spin_lock(&mbox->lock); + bcm2835_peripheral_read_workaround(); + ret = !(readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL); + spin_unlock(&mbox->lock); + return ret; +} + +static 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 int bcm2835_mbox_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bcm2835_mbox *mbox; + int i; + int ret = 0; + struct resource *iomem; + + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); + if (mbox == NULL) + return -ENOMEM; + platform_set_drvdata(pdev, mbox); + mbox->pdev = pdev; + mbox->dev = dev; + 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.dev = dev; + mbox->controller.num_chans = MBOX_CHAN_COUNT; + mbox->controller.chans = devm_kzalloc(dev, + sizeof(*mbox->controller.chans) * MBOX_CHAN_COUNT, + GFP_KERNEL); + if (!mbox->controller.chans) + return -ENOMEM; + + for (i = 0; i != MBOX_CHAN_COUNT; ++i) { + mbox->channel[i].mbox = mbox; + mbox->channel[i].link = &mbox->controller.chans[i]; + mbox->channel[i].chan_num = i; + mbox->controller.chans[i].con_priv = + (void *)&mbox->channel[i]; + } + + ret = mbox_controller_register(&mbox->controller); + if (ret) + return ret; + + /* Enable the interrupt on data reception */ + writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF); + 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); + + writel(0, mbox->regs + MAIL0_CNF); + 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", + .owner = THIS_MODULE, + .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@xxxxx>"); +MODULE_DESCRIPTION("BCM2835 mailbox IPC driver"); +MODULE_LICENSE("GPL v2"); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
