[PATCH 2/3] mailbox: rockchip: Add Rockchip mailbox driver

[Caesar Wang <wxt@rock-chips.com>]

This driver is found on RK3368 SoCs.

The Mailbox module is a simple APB peripheral that allows both
the Cortex-A53 MCU system to communicate by writing operation to
generate interrupt.
The registers are accessible by both CPU via APB interface.

The Mailbox has the following main features:

@ Support dual-core system: Cortex-A53 and MCU.
@ Support APB interface.
@ Support four mailbox elements, each element includes one data word, one
  command word register and one flag bit that can represent one interrupt.
@ Four interrupts to Cortex-A53.
@ Four interrupts to MCU.
@ Provide 32 lock registers for software to use to indicate whether mailbox
  is occupied.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
---

 drivers/mailbox/Kconfig            |   9 ++
 drivers/mailbox/Makefile           |   2 +
 drivers/mailbox/rockchip-mailbox.c | 317 +++++++++++++++++++++++++++++++++++++
 3 files changed, 328 insertions(+)
 create mode 100644 drivers/mailbox/rockchip-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index bbec500..a548d700 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -43,6 +43,15 @@ config OMAP_MBOX_KFIFO_SIZE
 	  This can also be changed at runtime (via the mbox_kfifo_size
 	  module parameter).
 
+config ROCKCHIP_MBOX
+	bool "Rockchip Soc Intergrated Mailbox Support"
+	depends on ARCH_ROCKCHIP
+	help
+	  This driver provides support for inter-processor communication
+	  between CPU cores and MCU processor on Some Rockchip SOCs.
+	  Please check it that the Soc you use have Mailbox hardware.
+	  Say Y here if you want to use the Rockchip Mailbox support.
+
 config PCC
 	bool "Platform Communication Channel Driver"
 	depends on ACPI
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 8e6d822..730cb5d 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -8,6 +8,8 @@ obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
 
 obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 
+obj-$(CONFIG_ROCKCHIP_MBOX)	+= rockchip-mailbox.o
+
 obj-$(CONFIG_PCC)		+= pcc.o
 
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
diff --git a/drivers/mailbox/rockchip-mailbox.c b/drivers/mailbox/rockchip-mailbox.c
new file mode 100644
index 0000000..715ab96
--- /dev/null
+++ b/drivers/mailbox/rockchip-mailbox.c
@@ -0,0 +1,317 @@
+/*
+ * Copyright (c) 2015, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * Authors:	Addy Ke <addy.ke@rock-chips.com>
+ *		Caesar Wang <wxt@rock-chips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define MAILBOX_A2B_INTEN		0x00
+#define MAILBOX_A2B_STATUS		0x04
+#define MAILBOX_A2B_CMD(x)		(0x08 + (x) * 8)
+#define MAILBOX_A2B_DAT(x)		(0x0c + (x) * 8)
+
+#define MAILBOX_B2A_INTEN		0x28
+#define MAILBOX_B2A_STATUS		0x2C
+#define MAILBOX_B2A_CMD(x)		(0x30 + (x) * 8)
+#define MAILBOX_B2A_DAT(x)		(0x34 + (x) * 8)
+
+#define MAILBOX_ATOMIC_LOCK(x)		(0x100 + (x) * 8)
+
+/* A2B: 0 - 2k */
+#define A2B_BUF(size, idx)		((idx) * (size))
+
+/* B2A: 2k - 4k */
+#define B2A_BUF(size, idx)		(((idx) + 4) * (size))
+
+struct rockchip_mbox_msg {
+	u32 cmd;
+	int tx_size;
+	void *tx_buf;
+	int rx_size;
+	void *rx_buf;
+	void *cl_data;
+};
+
+struct rockchip_mbox_data {
+	int num_chans;
+};
+
+struct rockchip_mbox_chan {
+	int idx;
+	int irq;
+	struct rockchip_mbox_msg *msg;
+	struct rockchip_mbox *mb;
+};
+
+struct rockchip_mbox {
+	struct mbox_controller mbox;
+	struct clk *pclk;
+	void __iomem *mbox_base;
+
+	/* The base address of share memory to transfer data */
+	void __iomem *buf_base;
+
+	/* The maximum size of buf for each channel */
+	u32 buf_size;
+
+	struct rockchip_mbox_chan *chans;
+};
+
+static inline int chan_to_idx(struct rockchip_mbox *mb,
+			      struct mbox_chan *chan)
+{
+	return (chan - mb->mbox.chans);
+}
+
+static int rockchip_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
+	struct rockchip_mbox_msg *msg = data;
+	int idx = chan_to_idx(mb, chan);
+
+	if (!msg)
+		return -EINVAL;
+
+	if ((msg->tx_size > mb->buf_size) ||
+	    (msg->rx_size > mb->buf_size)) {
+		dev_err(mb->mbox.dev, "Transmit size over buf size(%d)\n",
+			mb->buf_size);
+		return -EINVAL;
+	}
+
+	dev_dbg(mb->mbox.dev, "Chan[%d]: A2B message, cmd 0x%08x\n",
+		idx, msg->cmd);
+
+	mb->chans[idx].msg = msg;
+
+	if (msg->tx_buf)
+		memcpy(mb->buf_base + A2B_BUF(mb->buf_size, idx),
+		       msg->tx_buf, msg->tx_size);
+
+	writel_relaxed(msg->cmd, mb->mbox_base + MAILBOX_A2B_CMD(idx));
+	writel_relaxed(msg->rx_size, mb->mbox_base + MAILBOX_A2B_DAT(idx));
+
+	return 0;
+}
+
+static int rockchip_mbox_startup(struct mbox_chan *chan)
+{
+	return 0;
+}
+
+static void rockchip_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
+	int idx = chan_to_idx(mb, chan);
+
+	mb->chans[idx].msg = NULL;
+}
+
+static const struct mbox_chan_ops rockchip_mbox_chan_ops = {
+	.send_data	= rockchip_mbox_send_data,
+	.startup	= rockchip_mbox_startup,
+	.shutdown	= rockchip_mbox_shutdown,
+};
+
+static irqreturn_t rockchip_mbox_irq(int irq, void *dev_id)
+{
+	int idx;
+	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
+	u32 status = readl_relaxed(mb->mbox_base + MAILBOX_B2A_STATUS);
+
+	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
+		if ((status & (1 << idx)) && (irq == mb->chans[idx].irq)) {
+			/* Clear mbox interrupt */
+			writel_relaxed(1 << idx,
+				       mb->mbox_base + MAILBOX_B2A_STATUS);
+			return IRQ_WAKE_THREAD;
+		}
+	}
+
+	return IRQ_NONE;
+}
+
+static irqreturn_t rockchip_mbox_isr(int irq, void *dev_id)
+{
+	int idx;
+	struct rockchip_mbox_msg *msg = NULL;
+	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
+
+	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
+		if (irq != mb->chans[idx].irq)
+			continue;
+
+		msg = mb->chans[idx].msg;
+		if (!msg) {
+			dev_err(mb->mbox.dev,
+				"Chan[%d]: B2A message is NULL\n", idx);
+			break; /* spurious */
+		}
+
+		if (msg->rx_buf)
+			memcpy(msg->rx_buf,
+			       mb->buf_base + B2A_BUF(mb->buf_size, idx),
+			       msg->rx_size);
+
+		mbox_chan_received_data(&mb->mbox.chans[idx], msg);
+		mb->chans[idx].msg = NULL;
+
+		dev_dbg(mb->mbox.dev, "Chan[%d]: B2A message, cmd 0x%08x\n",
+			idx, msg->cmd);
+
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static const struct rockchip_mbox_data rk3368_drv_data = {
+	.num_chans = 4,
+};
+
+static const struct of_device_id rockchip_mbox_of_match[] = {
+	{ .compatible = "rockchip,rk3368-mailbox", .data = &rk3368_drv_data},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rockchp_mbox_of_match);
+
+static int rockchip_mbox_probe(struct platform_device *pdev)
+{
+	struct rockchip_mbox *mb;
+	const struct of_device_id *match;
+	const struct rockchip_mbox_data *drv_data;
+	struct resource *res;
+	int ret, irq, i;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	match = of_match_node(rockchip_mbox_of_match, pdev->dev.of_node);
+	drv_data = (const struct rockchip_mbox_data *)match->data;
+
+	mb = devm_kzalloc(&pdev->dev, sizeof(*mb), GFP_KERNEL);
+	if (!mb)
+		return -ENOMEM;
+
+	mb->chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
+				 sizeof(*mb->chans), GFP_KERNEL);
+	if (!mb->chans)
+		return -ENOMEM;
+
+	mb->mbox.chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
+				      sizeof(*mb->mbox.chans), GFP_KERNEL);
+	if (!mb->mbox.chans)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, mb);
+
+	mb->mbox.dev = &pdev->dev;
+	mb->mbox.num_chans = drv_data->num_chans;
+	mb->mbox.ops = &rockchip_mbox_chan_ops;
+	mb->mbox.txdone_irq = true;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	mb->mbox_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mb->mbox_base))
+		return PTR_ERR(mb->mbox_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res)
+		return -ENODEV;
+
+	/* Each channel has two buffers for A2B and B2A */
+	mb->buf_size = resource_size(res) / (drv_data->num_chans * 2);
+	mb->buf_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mb->buf_base))
+		return PTR_ERR(mb->buf_base);
+
+	mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
+	if (IS_ERR(mb->pclk)) {
+		ret = PTR_ERR(mb->pclk);
+		dev_err(&pdev->dev, "failed to get pclk_mailbox clock: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(mb->pclk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable pclk: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < mb->mbox.num_chans; i++) {
+		irq = platform_get_irq(pdev, i);
+		if (irq < 0)
+			return irq;
+
+		ret = devm_request_threaded_irq(&pdev->dev, irq,
+						rockchip_mbox_irq,
+						rockchip_mbox_isr, IRQF_ONESHOT,
+						dev_name(&pdev->dev), mb);
+		if (ret < 0)
+			return ret;
+
+		mb->chans[i].idx = i;
+		mb->chans[i].mb = mb;
+		mb->chans[i].msg = NULL;
+		mb->chans[i].irq = irq;
+	}
+
+	/* Enable all B2A interrupts */
+	writel_relaxed((1 << mb->mbox.num_chans) - 1,
+		       mb->mbox_base + MAILBOX_B2A_INTEN);
+
+	ret = mbox_controller_register(&mb->mbox);
+	if (ret < 0)
+		dev_err(&pdev->dev, "Failed to register mailbox: %d\n", ret);
+
+	return ret;
+}
+
+static int rockchip_mbox_remove(struct platform_device *pdev)
+{
+	struct rockchip_mbox *mb = platform_get_drvdata(pdev);
+
+	if (!mb)
+		return -EINVAL;
+
+	mbox_controller_unregister(&mb->mbox);
+
+	return 0;
+}
+
+static struct platform_driver rockchip_mbox_driver = {
+	.probe	= rockchip_mbox_probe,
+	.remove	= rockchip_mbox_remove,
+	.driver = {
+		.name = "rockchip-mailbox",
+		.of_match_table = of_match_ptr(rockchip_mbox_of_match),
+	},
+};
+
+static int __init rockchip_mbox_init(void)
+{
+	return platform_driver_register(&rockchip_mbox_driver);
+}
+subsys_initcall(rockchip_mbox_init);
-- 
1.9.1