mailbox: Enable BCM2835 mailbox support
This mailbox driver provides a single mailbox channel to write 32-bit
values to the VPU and get a 32-bit response. The Raspberry Pi
firmware uses this mailbox channel to implement firmware calls, while
Roku 2 (despite being derived from the same firmware tree) doesn't.
The driver was originally submitted by Lubomir, based on the
out-of-tree 2708 mailbox driver. Eric Anholt fixed it up for
upstreaming, with the major functional change being that it now has no
notion of multiple channels (since that is a firmware-dependent
concept) and instead the raspberrypi-firmware driver will do that
bit-twiddling in its own messages.
[Jassi: made the 'mbox_chan_ops' struct as const and removed a redundant
variable]
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Craig McGeachie <slapdau@yahoo.com.au>
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
diff --git a/drivers/mailbox/bcm2835-mailbox.c b/drivers/mailbox/bcm2835-mailbox.c
new file mode 100644
index 0000000..4b13268
--- /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)
+
+/* 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 + MAIL0_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",
+ .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@v3.sk>");
+MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
+MODULE_LICENSE("GPL v2");