--- /dev/null
+// 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");
projects / thirdparty / kernel / linux.git / commitdiff
