u-boot/drivers/mailbox/apple-mbox.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
*/
#include <common.h>
#include <dm.h>
#include <mailbox-uclass.h>
#include <asm/io.h>
#include <linux/apple-mailbox.h>
#include <linux/delay.h>
#define REG_A2I_STAT 0x110
#define REG_A2I_STAT_EMPTY BIT(17)
#define REG_A2I_STAT_FULL BIT(16)
#define REG_I2A_STAT 0x114
#define REG_I2A_STAT_EMPTY BIT(17)
#define REG_I2A_STAT_FULL BIT(16)
#define REG_A2I_MSG0 0x800
#define REG_A2I_MSG1 0x808
#define REG_I2A_MSG0 0x830
#define REG_I2A_MSG1 0x838
struct apple_mbox_priv {
void *base;
};
static int apple_mbox_of_xlate(struct mbox_chan *chan,
struct ofnode_phandle_args *args)
{
if (args->args_count != 0)
return -EINVAL;
return 0;
}
static int apple_mbox_send(struct mbox_chan *chan, const void *data)
{
struct apple_mbox_priv *priv = dev_get_priv(chan->dev);
const struct apple_mbox_msg *msg = data;
writeq(msg->msg0, priv->base + REG_A2I_MSG0);
writeq(msg->msg1, priv->base + REG_A2I_MSG1);
while (readl(priv->base + REG_A2I_STAT) & REG_A2I_STAT_FULL)
udelay(1);
return 0;
}
static int apple_mbox_recv(struct mbox_chan *chan, void *data)
{
struct apple_mbox_priv *priv = dev_get_priv(chan->dev);
struct apple_mbox_msg *msg = data;
if (readl(priv->base + REG_I2A_STAT) & REG_I2A_STAT_EMPTY)
return -ENODATA;
msg->msg0 = readq(priv->base + REG_I2A_MSG0);
msg->msg1 = readq(priv->base + REG_I2A_MSG1);
return 0;
}
struct mbox_ops apple_mbox_ops = {
.of_xlate = apple_mbox_of_xlate,
.send = apple_mbox_send,
.recv = apple_mbox_recv,
};
static int apple_mbox_probe(struct udevice *dev)
{
struct apple_mbox_priv *priv = dev_get_priv(dev);
priv->base = dev_read_addr_ptr(dev);
if (!priv->base)
return -EINVAL;
return 0;
}
static const struct udevice_id apple_mbox_of_match[] = {
{ .compatible = "apple,asc-mailbox-v4" },
{ /* sentinel */ }
};
U_BOOT_DRIVER(apple_mbox) = {
.name = "apple-mbox",
.id = UCLASS_MAILBOX,
.of_match = apple_mbox_of_match,
.probe = apple_mbox_probe,
.priv_auto = sizeof(struct apple_mbox_priv),
.ops = &apple_mbox_ops,
};