Add corstone700 mhu v2 mailbox driver

Copy arm_mhu_v2.c driver as published on git.linaro.org:
https://git.linaro.org/landing-teams/working/arm/kernel-release.git/plain/drivers/mailbox/arm_mhu_v2.c?h=CORSTONE-700-2020.02.10

Change-Id: Ie994cb0146ba211c4a610cdd18894e024bf98ff1

1 files changed, 262 insertions, 0 deletions

diff --git a/mailbox/arm_mhu_v2.c b/mailbox/arm_mhu_v2.c
new file mode 100644
index 0000000..56fb31e
--- /dev/null
+++ b/mailbox/arm_mhu_v2.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Message Handling Unit version 2 controller driver
+ * Copyright (C) 2019 ARM Ltd.
+ *
+ * Based on drivers/mailbox/arm_mhu.c
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/amba/bus.h>
+#include <linux/mailbox_controller.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+
+#define MHU_V2_REG_STAT_OFS		0x0
+#define MHU_V2_REG_CLR_OFS		0x8
+#define MHU_V2_REG_SET_OFS		0xC
+#define MHU_V2_REG_MSG_NO_CAP_OFS	0xF80
+#define MHU_V2_REG_ACC_REQ_OFS		0xF88
+#define MHU_V2_REG_ACC_RDY_OFS		0xF8C
+#define MHU_V2_INT_EN_OFS		0xF98
+#define MHU_V2_AIDR_OFS			0xFCC
+
+#define MHU_V2_CHCOMB			BIT(2)
+#define MHU_V2_AIDR_MINOR(_reg)		((_reg) & 0xF)
+
+#define MHU_V2_EACH_CHANNEL_SIZE	0x20
+
+#define mbox_to_arm_mhuv2(c) container_of(c, struct arm_mhuv2, mbox)
+
+struct mhuv2_link {
+	unsigned int irq;
+	void __iomem *tx_reg;
+	void __iomem *rx_reg;
+};
+
+struct arm_mhuv2 {
+	void __iomem *base;
+	struct mhuv2_link *mlink;
+	struct mbox_chan *chan;
+	struct mbox_controller mbox;
+};
+
+static irqreturn_t mhuv2_rx_interrupt(int irq, void *p)
+{
+	struct mbox_chan *chan = p;
+	struct mhuv2_link *mlink = chan->con_priv;
+	u32 val;
+
+	val = readl_relaxed(mlink->rx_reg + MHU_V2_REG_STAT_OFS);
+	if (!val)
+		return IRQ_NONE;
+
+	mbox_chan_received_data(chan, (void *)&val);
+
+	writel_relaxed(val, mlink->rx_reg + MHU_V2_REG_CLR_OFS);
+
+	return IRQ_HANDLED;
+}
+
+static bool mhuv2_last_tx_done(struct mbox_chan *chan)
+{
+	struct mhuv2_link *mlink = chan->con_priv;
+	u32 val = readl_relaxed(mlink->tx_reg + MHU_V2_REG_STAT_OFS);
+
+	return (val == 0);
+}
+
+static int mhuv2_send_data(struct mbox_chan *chan, void *data)
+{
+	struct mhuv2_link *mlink = chan->con_priv;
+	u32 *arg = data;
+
+	writel_relaxed(*arg, mlink->tx_reg + MHU_V2_REG_SET_OFS);
+
+	return 0;
+}
+
+static int mhuv2_startup(struct mbox_chan *chan)
+{
+	struct mhuv2_link *mlink = chan->con_priv;
+	u32 val;
+	int ret;
+	struct arm_mhuv2 *mhuv2 = mbox_to_arm_mhuv2(chan->mbox);
+
+	writel_relaxed(0x1, mhuv2->base + MHU_V2_REG_ACC_REQ_OFS);
+
+	val = readl_relaxed(mlink->tx_reg + MHU_V2_REG_STAT_OFS);
+	writel_relaxed(val, mlink->tx_reg + MHU_V2_REG_CLR_OFS);
+
+	ret = request_irq(mlink->irq, mhuv2_rx_interrupt,
+			  IRQF_SHARED, "mhuv2_link", chan);
+	if (ret) {
+		dev_err(chan->mbox->dev,
+			"unable to acquire IRQ %d\n", mlink->irq);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void mhuv2_shutdown(struct mbox_chan *chan)
+{
+	struct mhuv2_link *mlink = chan->con_priv;
+	struct arm_mhuv2 *mhuv2 = mbox_to_arm_mhuv2(chan->mbox);
+
+	writel_relaxed(0x0, mhuv2->base + MHU_V2_REG_ACC_REQ_OFS);
+
+	free_irq(mlink->irq, chan);
+}
+
+static const struct mbox_chan_ops mhuv2_ops = {
+	.send_data = mhuv2_send_data,
+	.startup = mhuv2_startup,
+	.shutdown = mhuv2_shutdown,
+	.last_tx_done = mhuv2_last_tx_done,
+};
+
+void mhuv2_check_enable_cmbint(struct mhuv2_link *link)
+{
+	const u32 aidr = readl_relaxed(link->rx_reg + MHU_V2_AIDR_OFS);
+
+	if (MHU_V2_AIDR_MINOR(aidr) == 1) {
+		// Enable combined receiver interrupt for MHUv2.1
+		writel_relaxed(MHU_V2_CHCOMB, link->rx_reg + MHU_V2_INT_EN_OFS);
+	}
+}
+
+static int mhuv2_probe(struct amba_device *adev, const struct amba_id *id)
+{
+	int i, err;
+	struct arm_mhuv2 *mhuv2;
+	struct device *dev = &adev->dev;
+	void __iomem *rx_base, *tx_base;
+	const struct device_node *np = dev->of_node;
+	unsigned int pchans;
+	struct mhuv2_link *mlink;
+	struct mbox_chan *chan;
+
+
+	/* Allocate memory for device */
+	mhuv2 = devm_kzalloc(dev, sizeof(*mhuv2), GFP_KERNEL);
+	if (!mhuv2)
+		return -ENOMEM;
+
+	tx_base = of_iomap((struct device_node *)np, 0);
+	if (!tx_base) {
+		dev_err(dev, "failed to map tx registers\n");
+		iounmap(rx_base);
+		return -ENOMEM;
+	}
+
+	rx_base = of_iomap((struct device_node *)np, 1);
+	if (!rx_base) {
+		dev_err(dev, "failed to map rx registers\n");
+		return -ENOMEM;
+	}
+
+	pchans = readl_relaxed(tx_base + MHU_V2_REG_MSG_NO_CAP_OFS);
+	if (pchans == 0 || pchans % 2) {
+		dev_err(dev, "invalid number of channels %d\n", pchans);
+		iounmap(rx_base);
+		iounmap(tx_base);
+		return -EINVAL;
+	}
+
+	mhuv2->mlink = devm_kcalloc(dev, pchans, sizeof(*mlink), GFP_KERNEL);
+	if (!mhuv2->mlink) {
+		iounmap(rx_base);
+		iounmap(tx_base);
+		return -ENOMEM;
+	}
+
+	mhuv2->chan = devm_kcalloc(dev, pchans, sizeof(*chan), GFP_KERNEL);
+	if (!mhuv2->chan) {
+		iounmap(rx_base);
+		iounmap(tx_base);
+		kfree(mhuv2->mlink);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < pchans; i++) {
+		mlink = mhuv2->mlink + i;
+		chan = mhuv2->chan + i;
+		chan->con_priv = mlink;
+		mlink->rx_reg = rx_base + (i * MHU_V2_EACH_CHANNEL_SIZE);
+		mlink->tx_reg = tx_base + (i * MHU_V2_EACH_CHANNEL_SIZE);
+	}
+
+	mhuv2->mlink->irq = adev->irq[0];
+	mhuv2_check_enable_cmbint(mhuv2->mlink);
+
+	mhuv2->base = tx_base;
+	mhuv2->mbox.dev = dev;
+	mhuv2->mbox.chans = mhuv2->chan;
+	mhuv2->mbox.num_chans = pchans;
+	mhuv2->mbox.ops = &mhuv2_ops;
+	mhuv2->mbox.txdone_irq = false;
+	mhuv2->mbox.txdone_poll = true;
+	mhuv2->mbox.txpoll_period = 1;
+
+	amba_set_drvdata(adev, mhuv2);
+
+	err = mbox_controller_register(&mhuv2->mbox);
+	if (err) {
+		dev_err(dev, "failed to register mailboxes %d\n", err);
+		iounmap(rx_base);
+		iounmap(tx_base);
+		kfree(mhuv2->mlink);
+		kfree(mhuv2->chan);
+		return err;
+	}
+
+	dev_info(dev, "ARM MHUv2 Mailbox driver registered\n");
+	return 0;
+}
+
+static int mhuv2_remove(struct amba_device *adev)
+{
+	struct arm_mhuv2 *mhuv2 = amba_get_drvdata(adev);
+
+	mbox_controller_unregister(&mhuv2->mbox);
+
+	return 0;
+}
+
+static struct amba_id mhuv2_ids[] = {
+	{
+		.id     = 0x4b0d1,
+		.mask   = 0xfffff,
+	},
+	{
+		.id     = 0xbb0d1,
+		.mask   = 0xfffff,
+	},
+	{
+		.id     = 0xbb076,
+		.mask   = 0xfffff,
+	},
+	{ 0, 0 },
+};
+MODULE_DEVICE_TABLE(amba, mhuv2_ids);
+
+static struct amba_driver arm_mhuv2_driver = {
+	.drv = {
+		.name	= "mhuv2",
+	},
+	.id_table	= mhuv2_ids,
+	.probe		= mhuv2_probe,
+	.remove		= mhuv2_remove,
+};
+module_amba_driver(arm_mhuv2_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ARM MHUv2 Driver");
+MODULE_AUTHOR("Samarth Parikh <samarthp@ymail.com>");