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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright Aspeed Technology Inc. (C) 2025. All rights reserved
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
/* Each bit in the register represents an IPC ID */
#define IPCR_TX_TRIG 0x00
#define IPCR_ENABLE 0x04
#define IPCR_STATUS 0x08
#define RX_IRQ(n) BIT(n)
#define RX_IRQ_MASK 0xf
#define IPCR_DATA 0x10
struct ast2700_mbox_data {
u8 num_chans;
u8 msg_size;
};
struct ast2700_mbox {
struct mbox_controller mbox;
u8 msg_size;
void __iomem *tx_regs;
void __iomem *rx_regs;
spinlock_t lock;
};
static inline int ch_num(struct mbox_chan *chan)
{
return chan - chan->mbox->chans;
}
static inline bool ast2700_mbox_tx_done(struct ast2700_mbox *mb, int idx)
{
return !(readl(mb->tx_regs + IPCR_STATUS) & BIT(idx));
}
static irqreturn_t ast2700_mbox_irq(int irq, void *p)
{
struct ast2700_mbox *mb = p;
void __iomem *data_reg;
int num_words = mb->msg_size / sizeof(u32);
u32 *word_data;
u32 status;
int n, i;
/* Only examine channels that are currently enabled. */
status = readl(mb->rx_regs + IPCR_ENABLE) &
readl(mb->rx_regs + IPCR_STATUS);
if (!(status & RX_IRQ_MASK))
return IRQ_NONE;
for (n = 0; n < mb->mbox.num_chans; ++n) {
struct mbox_chan *chan = &mb->mbox.chans[n];
if (!(status & RX_IRQ(n)))
continue;
data_reg = mb->rx_regs + IPCR_DATA + mb->msg_size * n;
word_data = chan->con_priv;
/* Read the message data */
for (i = 0; i < num_words; i++)
word_data[i] = readl(data_reg + i * sizeof(u32));
mbox_chan_received_data(chan, chan->con_priv);
/* The IRQ can be cleared only once the FIFO is empty. */
writel(RX_IRQ(n), mb->rx_regs + IPCR_STATUS);
}
return IRQ_HANDLED;
}
static int ast2700_mbox_send_data(struct mbox_chan *chan, void *data)
{
struct ast2700_mbox *mb = dev_get_drvdata(chan->mbox->dev);
int idx = ch_num(chan);
void __iomem *data_reg = mb->tx_regs + IPCR_DATA + mb->msg_size * idx;
u32 *word_data = data;
int num_words = mb->msg_size / sizeof(u32);
int i;
if (!(readl(mb->tx_regs + IPCR_ENABLE) & BIT(idx))) {
dev_warn(mb->mbox.dev, "%s: Ch-%d not enabled yet\n", __func__, idx);
return -ENODEV;
}
if (!(ast2700_mbox_tx_done(mb, idx))) {
dev_warn(mb->mbox.dev, "%s: Ch-%d last data has not finished\n", __func__, idx);
return -EBUSY;
}
/* Write the message data */
for (i = 0 ; i < num_words; i++)
writel(word_data[i], data_reg + i * sizeof(u32));
writel(BIT(idx), mb->tx_regs + IPCR_TX_TRIG);
dev_dbg(mb->mbox.dev, "%s: Ch-%d sent\n", __func__, idx);
return 0;
}
static int ast2700_mbox_startup(struct mbox_chan *chan)
{
struct ast2700_mbox *mb = dev_get_drvdata(chan->mbox->dev);
int idx = ch_num(chan);
void __iomem *reg = mb->rx_regs + IPCR_ENABLE;
unsigned long flags;
spin_lock_irqsave(&mb->lock, flags);
writel(readl(reg) | BIT(idx), reg);
spin_unlock_irqrestore(&mb->lock, flags);
return 0;
}
static void ast2700_mbox_shutdown(struct mbox_chan *chan)
{
struct ast2700_mbox *mb = dev_get_drvdata(chan->mbox->dev);
int idx = ch_num(chan);
void __iomem *reg = mb->rx_regs + IPCR_ENABLE;
unsigned long flags;
spin_lock_irqsave(&mb->lock, flags);
writel(readl(reg) & ~BIT(idx), reg);
spin_unlock_irqrestore(&mb->lock, flags);
}
static bool ast2700_mbox_last_tx_done(struct mbox_chan *chan)
{
struct ast2700_mbox *mb = dev_get_drvdata(chan->mbox->dev);
int idx = ch_num(chan);
return ast2700_mbox_tx_done(mb, idx);
}
static const struct mbox_chan_ops ast2700_mbox_chan_ops = {
.send_data = ast2700_mbox_send_data,
.startup = ast2700_mbox_startup,
.shutdown = ast2700_mbox_shutdown,
.last_tx_done = ast2700_mbox_last_tx_done,
};
static int ast2700_mbox_probe(struct platform_device *pdev)
{
struct ast2700_mbox *mb;
const struct ast2700_mbox_data *dev_data;
struct device *dev = &pdev->dev;
int irq, ret;
if (!pdev->dev.of_node)
return -ENODEV;
dev_data = device_get_match_data(&pdev->dev);
mb = devm_kzalloc(dev, sizeof(*mb), GFP_KERNEL);
if (!mb)
return -ENOMEM;
mb->mbox.chans = devm_kcalloc(&pdev->dev, dev_data->num_chans,
sizeof(*mb->mbox.chans), GFP_KERNEL);
if (!mb->mbox.chans)
return -ENOMEM;
/* con_priv of each channel is used to store the message received */
for (int i = 0; i < dev_data->num_chans; i++) {
mb->mbox.chans[i].con_priv = devm_kcalloc(dev, dev_data->msg_size,
sizeof(u8), GFP_KERNEL);
if (!mb->mbox.chans[i].con_priv)
return -ENOMEM;
}
platform_set_drvdata(pdev, mb);
mb->tx_regs = devm_platform_ioremap_resource_byname(pdev, "tx");
if (IS_ERR(mb->tx_regs))
return PTR_ERR(mb->tx_regs);
mb->rx_regs = devm_platform_ioremap_resource_byname(pdev, "rx");
if (IS_ERR(mb->rx_regs))
return PTR_ERR(mb->rx_regs);
mb->msg_size = dev_data->msg_size;
mb->mbox.dev = dev;
mb->mbox.num_chans = dev_data->num_chans;
mb->mbox.ops = &ast2700_mbox_chan_ops;
mb->mbox.txdone_irq = false;
mb->mbox.txdone_poll = true;
mb->mbox.txpoll_period = 5;
spin_lock_init(&mb->lock);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
ret = devm_request_irq(dev, irq, ast2700_mbox_irq, 0, dev_name(dev), mb);
if (ret)
return ret;
return devm_mbox_controller_register(dev, &mb->mbox);
}
static const struct ast2700_mbox_data ast2700_dev_data = {
.num_chans = 4,
.msg_size = 0x20,
};
static const struct of_device_id ast2700_mbox_of_match[] = {
{ .compatible = "aspeed,ast2700-mailbox", .data = &ast2700_dev_data },
{}
};
MODULE_DEVICE_TABLE(of, ast2700_mbox_of_match);
static struct platform_driver ast2700_mbox_driver = {
.driver = {
.name = "ast2700-mailbox",
.of_match_table = ast2700_mbox_of_match,
},
.probe = ast2700_mbox_probe,
};
module_platform_driver(ast2700_mbox_driver);
MODULE_AUTHOR("Jammy Huang <jammy_huang@aspeedtech.com>");
MODULE_DESCRIPTION("ASPEED AST2700 IPC driver");
MODULE_LICENSE("GPL");
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