This mailbox driver provides a communication channel with the Apple IOP controllers found on Apple SoCs. These IOP controllers are used to implement various functions such as the System Manegement Controller (SMC) and NVMe storage. It allows sending and receiving a 96-bit message over a single channel.
The header file with the struct used for mailbox messages is taken straight from Linux.
Signed-off-by: Mark Kettenis kettenis@openbsd.org Signed-off-by: Sven Peter sven@svenpeter.dev --- arch/arm/Kconfig | 1 + drivers/mailbox/Kconfig | 11 +++++ drivers/mailbox/Makefile | 1 + drivers/mailbox/apple-mbox.c | 92 +++++++++++++++++++++++++++++++++++ include/linux/apple-mailbox.h | 19 ++++++++ 5 files changed, 124 insertions(+) create mode 100644 drivers/mailbox/apple-mbox.c create mode 100644 include/linux/apple-mailbox.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 44954977b6..79eec3aa06 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -934,6 +934,7 @@ config ARCH_APPLE select DM select DM_GPIO select DM_KEYBOARD + select DM_MAILBOX select DM_SERIAL select DM_USB select DM_VIDEO diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index dd4b0ac0c3..73db2af0b8 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -10,6 +10,17 @@ config DM_MAILBOX the basis of a variety of inter-process/inter-CPU communication protocols.
+config APPLE_MBOX + bool "Enable Apple IOP controller support" + depends on DM_MAILBOX && ARCH_APPLE + default y + help + Enable support for the mailboxes that provide a comminucation + channel with Apple IOP controllers integrated on Apple SoCs. + These IOP controllers are used to implement various functions + such as the System Management Controller (SMC) and NVMe and this + driver is required to get that functionality up and running. + config SANDBOX_MBOX bool "Enable the sandbox mailbox test driver" depends on DM_MAILBOX && SANDBOX diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index d2ace8cd21..59e8d0de93 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -4,6 +4,7 @@ #
obj-$(CONFIG_$(SPL_)DM_MAILBOX) += mailbox-uclass.o +obj-$(CONFIG_APPLE_MBOX) += apple-mbox.o obj-$(CONFIG_SANDBOX_MBOX) += sandbox-mbox.o obj-$(CONFIG_SANDBOX_MBOX) += sandbox-mbox-test.o obj-$(CONFIG_STM32_IPCC) += stm32-ipcc.o diff --git a/drivers/mailbox/apple-mbox.c b/drivers/mailbox/apple-mbox.c new file mode 100644 index 0000000000..30c8e2f03f --- /dev/null +++ b/drivers/mailbox/apple-mbox.c @@ -0,0 +1,92 @@ +// 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, +}; diff --git a/include/linux/apple-mailbox.h b/include/linux/apple-mailbox.h new file mode 100644 index 0000000000..720fbb7029 --- /dev/null +++ b/include/linux/apple-mailbox.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-only OR MIT */ +/* + * Apple mailbox message format + * + * Copyright (C) 2021 The Asahi Linux Contributors + */ + +#ifndef _LINUX_APPLE_MAILBOX_H_ +#define _LINUX_APPLE_MAILBOX_H_ + +#include <linux/types.h> + +/* encodes a single 96bit message sent over the single channel */ +struct apple_mbox_msg { + u64 msg0; + u32 msg1; +}; + +#endif