new file mode 100644
@@ -0,0 +1,33 @@
+ARM MHU Mailbox Driver
+======================
+
+The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has
+3 independent channels/links to communicate with remote processor(s).
+ MHU links are hardwired on a platform. A link raises interrupt for any
+received data. However, there is no specified way of knowing if the sent
+data has been read by the remote. This driver assumes the sender polls
+STAT register and the remote clears it after having read the data.
+
+Mailbox Device Node:
+====================
+
+Required properties:
+--------------------
+- compatible: Shall be "arm,mbox-mhu"
+- reg: Contains the mailbox register address range (base
+ address and length)
+- #mbox-cells Shall be 1
+- interrupts: Contains the interrupt information corresponding to
+ each of the 3 links of MHU.
+
+Example:
+--------
+
+ mhu: mailbox@2b1f0000 {
+ #mbox-cells = <1>;
+ compatible = "arm,mbox-mhu";
+ reg = <0 0x2b1f0000 0x1000>;
+ interrupts = <0 36 4>,
+ <0 35 4>,
+ <0 37 4>;
+ };
@@ -6,6 +6,13 @@ menuconfig MAILBOX
signals. Say Y if your platform supports hardware mailboxes.
if MAILBOX
+
+config ARM_MHU
+ tristate "ARM MHU Mailbox"
+ depends on ARM
+ help
+ Say Y here if you want to build the ARM MHU controller driver
+
config PL320_MBOX
bool "ARM PL320 Mailbox"
depends on ARM_AMBA
@@ -2,6 +2,8 @@
obj-$(CONFIG_MAILBOX) += mailbox.o
+obj-$(CONFIG_ARM_MHU) += arm_mhu.o
+
obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o
obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o
new file mode 100644
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
+ * Copyright (C) 2015 Linaro Ltd.
+ * Author: Jassi Brar <jaswinder.singh@linaro.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/mailbox_controller.h>
+#include <linux/platform_device.h>
+
+#define INTR_STAT_OFS 0x0
+#define INTR_SET_OFS 0x8
+#define INTR_CLR_OFS 0x10
+
+struct mhu_link {
+ unsigned irq;
+ void __iomem *tx_reg;
+ void __iomem *rx_reg;
+};
+
+struct arm_mhu {
+ void __iomem *base;
+ struct clk *clk;
+ struct mhu_link mlink[3];
+ struct mbox_chan chan[3];
+ struct mbox_controller mbox;
+};
+
+static irqreturn_t mhu_rx_interrupt(int irq, void *p)
+{
+ struct mbox_chan *chan = p;
+ struct mhu_link *mlink = chan->con_priv;
+ u32 val;
+
+ pr_debug("%s:%d\n", __func__, __LINE__);
+ val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
+ if (!val)
+ return IRQ_NONE;
+
+ mbox_chan_received_data(chan, (void *)val);
+
+ writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
+
+ return IRQ_HANDLED;
+}
+
+static bool mhu_last_tx_done(struct mbox_chan *chan)
+{
+ struct mhu_link *mlink = chan->con_priv;
+ u32 val;
+
+ pr_debug("%s:%d\n", __func__, __LINE__);
+ val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
+
+ return (val == 0);
+}
+
+static int mhu_send_data(struct mbox_chan *chan, void *data)
+{
+ struct mhu_link *mlink = chan->con_priv;
+
+ pr_debug("%s:%d\n", __func__, __LINE__);
+ if (!mhu_last_tx_done(chan)) {
+ dev_err(chan->mbox->dev, "Last TX(%d) pending!\n", mlink->irq);
+ return -EBUSY;
+ }
+
+ writel_relaxed((u32)data, mlink->tx_reg + INTR_SET_OFS);
+
+ return 0;
+}
+
+static int mhu_startup(struct mbox_chan *chan)
+{
+ struct mhu_link *mlink = chan->con_priv;
+ u32 val;
+ int ret;
+
+ pr_debug("%s:%d\n", __func__, __LINE__);
+ val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
+ writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
+
+ ret = request_irq(mlink->irq, mhu_rx_interrupt, 0, "mhu_link", chan);
+ if (ret) {
+ dev_err(chan->mbox->dev,
+ "Unable to aquire IRQ %d\n", mlink->irq);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void mhu_shutdown(struct mbox_chan *chan)
+{
+ struct mhu_link *mlink = chan->con_priv;
+
+ pr_debug("%s:%d\n", __func__, __LINE__);
+ free_irq(mlink->irq, chan);
+}
+
+static struct mbox_chan_ops mhu_ops = {
+ .send_data = mhu_send_data,
+ .startup = mhu_startup,
+ .shutdown = mhu_shutdown,
+ .last_tx_done = mhu_last_tx_done,
+};
+
+static int arm_mhu_probe(struct platform_device *pdev)
+{
+ int i, err;
+ struct arm_mhu *mhu;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+ int mhu_reg[3] = {0x0, 0x20, 0x200};
+
+ /* Allocate memory for device */
+ mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
+ if (!mhu)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "No IOMEM found\n");
+ return -ENXIO;
+ }
+ mhu->base = devm_ioremap(dev, res->start, resource_size(res));
+ if (!mhu->base) {
+ dev_err(dev, "ioremap failed\n");
+ return -ENXIO;
+ }
+
+ for (i = 0; i < 3; i++) {
+ mhu->chan[i].con_priv = &mhu->mlink[i];
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+ mhu->mlink[i].irq = res->start;
+ mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
+ mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + 0x100;
+ }
+
+ mhu->mbox.dev = dev;
+ mhu->mbox.chans = &mhu->chan[0];
+ mhu->mbox.num_chans = 3;
+ mhu->mbox.ops = &mhu_ops;
+ mhu->mbox.txdone_irq = false;
+ mhu->mbox.txdone_poll = true;
+ mhu->mbox.txpoll_period = 10;
+
+ platform_set_drvdata(pdev, mhu);
+
+ err = mbox_controller_register(&mhu->mbox);
+ if (err) {
+ dev_err(dev, "Failed to register mailboxes %d\n", err);
+ return err;
+ }
+
+ mhu->clk = devm_clk_get(dev, "clk");
+ if (IS_ERR(mhu->clk))
+ dev_info(dev, "unable to init clock\n");
+ else
+ clk_prepare_enable(mhu->clk);
+
+ dev_info(dev, "ARM MHU Mailbox registered\n");
+ return 0;
+}
+
+static int arm_mhu_remove(struct platform_device *pdev)
+{
+ struct arm_mhu *mhu = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(mhu->clk);
+ mbox_controller_unregister(&mhu->mbox);
+
+ return 0;
+}
+
+static const struct of_device_id arm_mhu_dt_ids[] = {
+ { .compatible = "arm,mbox-mhu" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, arm_mhu_dt_ids);
+
+static struct platform_driver arm_mhu_driver = {
+ .driver = {
+ .name = "arm_mhu",
+ .of_match_table = arm_mhu_dt_ids,
+ },
+ .probe = arm_mhu_probe,
+ .remove = arm_mhu_remove,
+};
+module_platform_driver(arm_mhu_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ARM MHU Driver");
+MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");