diff options
Diffstat (limited to 'drivers/mailbox')
| -rw-r--r-- | drivers/mailbox/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/mailbox/Makefile | 2 | ||||
| -rw-r--r-- | drivers/mailbox/apple-mailbox.c | 384 |
3 files changed, 398 insertions, 0 deletions
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index c9fc06c7e685..d9cd3606040e 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -8,6 +8,18 @@ menuconfig MAILBOX if MAILBOX +config APPLE_MAILBOX + tristate "Apple Mailbox driver" + depends on ARCH_APPLE || (ARM64 && COMPILE_TEST) + default ARCH_APPLE + help + Apple SoCs have various co-processors required for certain + peripherals to work (NVMe, display controller, etc.). This + driver adds support for the mailbox controller used to + communicate with those. + + Say Y here if you have a Apple SoC. + config ARM_MHU tristate "ARM MHU Mailbox" depends on ARM_AMBA diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index c2089f04887e..338cc05e5431 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -58,3 +58,5 @@ obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox.o obj-$(CONFIG_QCOM_IPCC) += qcom-ipcc.o + +obj-$(CONFIG_APPLE_MAILBOX) += apple-mailbox.o diff --git a/drivers/mailbox/apple-mailbox.c b/drivers/mailbox/apple-mailbox.c new file mode 100644 index 000000000000..72942002a54a --- /dev/null +++ b/drivers/mailbox/apple-mailbox.c @@ -0,0 +1,384 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple mailbox driver + * + * Copyright (C) 2021 The Asahi Linux Contributors + * + * This driver adds support for two mailbox variants (called ASC and M3 by + * Apple) found in Apple SoCs such as the M1. It consists of two FIFOs used to + * exchange 64+32 bit messages between the main CPU and a co-processor. + * Various coprocessors implement different IPC protocols based on these simple + * messages and shared memory buffers. + * + * Both the main CPU and the co-processor see the same set of registers but + * the first FIFO (A2I) is always used to transfer messages from the application + * processor (us) to the I/O processor and the second one (I2A) for the + * other direction. + */ + +#include <linux/apple-mailbox.h> +#include <linux/device.h> +#include <linux/gfp.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/mailbox_controller.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/types.h> + +#define APPLE_ASC_MBOX_CONTROL_FULL BIT(16) +#define APPLE_ASC_MBOX_CONTROL_EMPTY BIT(17) + +#define APPLE_ASC_MBOX_A2I_CONTROL 0x110 +#define APPLE_ASC_MBOX_A2I_SEND0 0x800 +#define APPLE_ASC_MBOX_A2I_SEND1 0x808 +#define APPLE_ASC_MBOX_A2I_RECV0 0x810 +#define APPLE_ASC_MBOX_A2I_RECV1 0x818 + +#define APPLE_ASC_MBOX_I2A_CONTROL 0x114 +#define APPLE_ASC_MBOX_I2A_SEND0 0x820 +#define APPLE_ASC_MBOX_I2A_SEND1 0x828 +#define APPLE_ASC_MBOX_I2A_RECV0 0x830 +#define APPLE_ASC_MBOX_I2A_RECV1 0x838 + +#define APPLE_M3_MBOX_CONTROL_FULL BIT(16) +#define APPLE_M3_MBOX_CONTROL_EMPTY BIT(17) + +#define APPLE_M3_MBOX_A2I_CONTROL 0x50 +#define APPLE_M3_MBOX_A2I_SEND0 0x60 +#define APPLE_M3_MBOX_A2I_SEND1 0x68 +#define APPLE_M3_MBOX_A2I_RECV0 0x70 +#define APPLE_M3_MBOX_A2I_RECV1 0x78 + +#define APPLE_M3_MBOX_I2A_CONTROL 0x80 +#define APPLE_M3_MBOX_I2A_SEND0 0x90 +#define APPLE_M3_MBOX_I2A_SEND1 0x98 +#define APPLE_M3_MBOX_I2A_RECV0 0xa0 +#define APPLE_M3_MBOX_I2A_RECV1 0xa8 + +#define APPLE_M3_MBOX_IRQ_ENABLE 0x48 +#define APPLE_M3_MBOX_IRQ_ACK 0x4c +#define APPLE_M3_MBOX_IRQ_A2I_EMPTY BIT(0) +#define APPLE_M3_MBOX_IRQ_A2I_NOT_EMPTY BIT(1) +#define APPLE_M3_MBOX_IRQ_I2A_EMPTY BIT(2) +#define APPLE_M3_MBOX_IRQ_I2A_NOT_EMPTY BIT(3) + +#define APPLE_MBOX_MSG1_OUTCNT GENMASK(56, 52) +#define APPLE_MBOX_MSG1_INCNT GENMASK(51, 48) +#define APPLE_MBOX_MSG1_OUTPTR GENMASK(47, 44) +#define APPLE_MBOX_MSG1_INPTR GENMASK(43, 40) +#define APPLE_MBOX_MSG1_MSG GENMASK(31, 0) + +struct apple_mbox_hw { + unsigned int control_full; + unsigned int control_empty; + + unsigned int a2i_control; + unsigned int a2i_send0; + unsigned int a2i_send1; + + unsigned int i2a_control; + unsigned int i2a_recv0; + unsigned int i2a_recv1; + + bool has_irq_controls; + unsigned int irq_enable; + unsigned int irq_ack; + unsigned int irq_bit_recv_not_empty; + unsigned int irq_bit_send_empty; +}; + +struct apple_mbox { + void __iomem *regs; + const struct apple_mbox_hw *hw; + + int irq_recv_not_empty; + int irq_send_empty; + + struct mbox_chan chan; + + struct device *dev; + struct mbox_controller controller; +}; + +static const struct of_device_id apple_mbox_of_match[]; + +static bool apple_mbox_hw_can_send(struct apple_mbox *apple_mbox) +{ + u32 mbox_ctrl = + readl_relaxed(apple_mbox->regs + apple_mbox->hw->a2i_control); + + return !(mbox_ctrl & apple_mbox->hw->control_full); +} + +static int apple_mbox_hw_send(struct apple_mbox *apple_mbox, + struct apple_mbox_msg *msg) +{ + if (!apple_mbox_hw_can_send(apple_mbox)) + return -EBUSY; + + dev_dbg(apple_mbox->dev, "> TX %016llx %08x\n", msg->msg0, msg->msg1); + + writeq_relaxed(msg->msg0, apple_mbox->regs + apple_mbox->hw->a2i_send0); + writeq_relaxed(FIELD_PREP(APPLE_MBOX_MSG1_MSG, msg->msg1), + apple_mbox->regs + apple_mbox->hw->a2i_send1); + + return 0; +} + +static bool apple_mbox_hw_can_recv(struct apple_mbox *apple_mbox) +{ + u32 mbox_ctrl = + readl_relaxed(apple_mbox->regs + apple_mbox->hw->i2a_control); + + return !(mbox_ctrl & apple_mbox->hw->control_empty); +} + +static int apple_mbox_hw_recv(struct apple_mbox *apple_mbox, + struct apple_mbox_msg *msg) +{ + if (!apple_mbox_hw_can_recv(apple_mbox)) + return -ENOMSG; + + msg->msg0 = readq_relaxed(apple_mbox->regs + apple_mbox->hw->i2a_recv0); + msg->msg1 = FIELD_GET( + APPLE_MBOX_MSG1_MSG, + readq_relaxed(apple_mbox->regs + apple_mbox->hw->i2a_recv1)); + + dev_dbg(apple_mbox->dev, "< RX %016llx %08x\n", msg->msg0, msg->msg1); + + return 0; +} + +static int apple_mbox_chan_send_data(struct mbox_chan *chan, void *data) +{ + struct apple_mbox *apple_mbox = chan->con_priv; + struct apple_mbox_msg *msg = data; + int ret; + + ret = apple_mbox_hw_send(apple_mbox, msg); + if (ret) + return ret; + + /* + * The interrupt is level triggered and will keep firing as long as the + * FIFO is empty. It will also keep firing if the FIFO was empty + * at any point in the past until it has been acknowledged at the + * mailbox level. By acknowledging it here we can ensure that we will + * only get the interrupt once the FIFO has been cleared again. + * If the FIFO is already empty before the ack it will fire again + * immediately after the ack. + */ + if (apple_mbox->hw->has_irq_controls) { + writel_relaxed(apple_mbox->hw->irq_bit_send_empty, + apple_mbox->regs + apple_mbox->hw->irq_ack); + } + enable_irq(apple_mbox->irq_send_empty); + + return 0; +} + +static irqreturn_t apple_mbox_send_empty_irq(int irq, void *data) +{ + struct apple_mbox *apple_mbox = data; + + /* + * We don't need to acknowledge the interrupt at the mailbox level + * here even if supported by the hardware. It will keep firing but that + * doesn't matter since it's disabled at the main interrupt controller. + * apple_mbox_chan_send_data will acknowledge it before enabling + * it at the main controller again. + */ + disable_irq_nosync(apple_mbox->irq_send_empty); + mbox_chan_txdone(&apple_mbox->chan, 0); + return IRQ_HANDLED; +} + +static irqreturn_t apple_mbox_recv_irq(int irq, void *data) +{ + struct apple_mbox *apple_mbox = data; + struct apple_mbox_msg msg; + + while (apple_mbox_hw_recv(apple_mbox, &msg) == 0) + mbox_chan_received_data(&apple_mbox->chan, (void *)&msg); + + /* + * The interrupt will keep firing even if there are no more messages + * unless we also acknowledge it at the mailbox level here. + * There's no race if a message comes in between the check in the while + * loop above and the ack below: If a new messages arrives inbetween + * those two the interrupt will just fire again immediately after the + * ack since it's level triggered. + */ + if (apple_mbox->hw->has_irq_controls) { + writel_relaxed(apple_mbox->hw->irq_bit_recv_not_empty, + apple_mbox->regs + apple_mbox->hw->irq_ack); + } + + return IRQ_HANDLED; +} + +static int apple_mbox_chan_startup(struct mbox_chan *chan) +{ + struct apple_mbox *apple_mbox = chan->con_priv; + + /* + * Only some variants of this mailbox HW provide interrupt control + * at the mailbox level. We therefore need to handle enabling/disabling + * interrupts at the main interrupt controller anyway for hardware that + * doesn't. Just always keep the interrupts we care about enabled at + * the mailbox level so that both hardware revisions behave almost + * the same. + */ + if (apple_mbox->hw->has_irq_controls) { + writel_relaxed(apple_mbox->hw->irq_bit_recv_not_empty | + apple_mbox->hw->irq_bit_send_empty, + apple_mbox->regs + apple_mbox->hw->irq_enable); + } + + enable_irq(apple_mbox->irq_recv_not_empty); + return 0; +} + +static void apple_mbox_chan_shutdown(struct mbox_chan *chan) +{ + struct apple_mbox *apple_mbox = chan->con_priv; + + disable_irq(apple_mbox->irq_recv_not_empty); +} + +static const struct mbox_chan_ops apple_mbox_ops = { + .send_data = apple_mbox_chan_send_data, + .startup = apple_mbox_chan_startup, + .shutdown = apple_mbox_chan_shutdown, +}; + +static struct mbox_chan *apple_mbox_of_xlate(struct mbox_controller *mbox, + const struct of_phandle_args *args) +{ + if (args->args_count != 0) + return ERR_PTR(-EINVAL); + + return &mbox->chans[0]; +} + +static int apple_mbox_probe(struct platform_device *pdev) +{ + int ret; + const struct of_device_id *match; + char *irqname; + struct apple_mbox *mbox; + struct device *dev = &pdev->dev; + + match = of_match_node(apple_mbox_of_match, pdev->dev.of_node); + if (!match) + return -EINVAL; + if (!match->data) + return -EINVAL; + + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); + if (!mbox) + return -ENOMEM; + platform_set_drvdata(pdev, mbox); + + mbox->dev = dev; + mbox->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(mbox->regs)) + return PTR_ERR(mbox->regs); + + mbox->hw = match->data; + mbox->irq_recv_not_empty = + platform_get_irq_byname(pdev, "recv-not-empty"); + if (mbox->irq_recv_not_empty < 0) + return -ENODEV; + + mbox->irq_send_empty = platform_get_irq_byname(pdev, "send-empty"); + if (mbox->irq_send_empty < 0) + return -ENODEV; + + mbox->controller.dev = mbox->dev; + mbox->controller.num_chans = 1; + mbox->controller.chans = &mbox->chan; + mbox->controller.ops = &apple_mbox_ops; + mbox->controller.txdone_irq = true; + mbox->controller.of_xlate = apple_mbox_of_xlate; + mbox->chan.con_priv = mbox; + + irqname = devm_kasprintf(dev, GFP_KERNEL, "%s-recv", dev_name(dev)); + if (!irqname) + return -ENOMEM; + + ret = devm_request_threaded_irq(dev, mbox->irq_recv_not_empty, NULL, + apple_mbox_recv_irq, + IRQF_NO_AUTOEN | IRQF_ONESHOT, irqname, + mbox); + if (ret) + return ret; + + irqname = devm_kasprintf(dev, GFP_KERNEL, "%s-send", dev_name(dev)); + if (!irqname) + return -ENOMEM; + + ret = devm_request_irq(dev, mbox->irq_send_empty, + apple_mbox_send_empty_irq, IRQF_NO_AUTOEN, + irqname, mbox); + if (ret) + return ret; + + return devm_mbox_controller_register(dev, &mbox->controller); +} + +static const struct apple_mbox_hw apple_mbox_asc_hw = { + .control_full = APPLE_ASC_MBOX_CONTROL_FULL, + .control_empty = APPLE_ASC_MBOX_CONTROL_EMPTY, + + .a2i_control = APPLE_ASC_MBOX_A2I_CONTROL, + .a2i_send0 = APPLE_ASC_MBOX_A2I_SEND0, + .a2i_send1 = APPLE_ASC_MBOX_A2I_SEND1, + + .i2a_control = APPLE_ASC_MBOX_I2A_CONTROL, + .i2a_recv0 = APPLE_ASC_MBOX_I2A_RECV0, + .i2a_recv1 = APPLE_ASC_MBOX_I2A_RECV1, + + .has_irq_controls = false, +}; + +static const struct apple_mbox_hw apple_mbox_m3_hw = { + .control_full = APPLE_M3_MBOX_CONTROL_FULL, + .control_empty = APPLE_M3_MBOX_CONTROL_EMPTY, + + .a2i_control = APPLE_M3_MBOX_A2I_CONTROL, + .a2i_send0 = APPLE_M3_MBOX_A2I_SEND0, + .a2i_send1 = APPLE_M3_MBOX_A2I_SEND1, + + .i2a_control = APPLE_M3_MBOX_I2A_CONTROL, + .i2a_recv0 = APPLE_M3_MBOX_I2A_RECV0, + .i2a_recv1 = APPLE_M3_MBOX_I2A_RECV1, + + .has_irq_controls = true, + .irq_enable = APPLE_M3_MBOX_IRQ_ENABLE, + .irq_ack = APPLE_M3_MBOX_IRQ_ACK, + .irq_bit_recv_not_empty = APPLE_M3_MBOX_IRQ_I2A_NOT_EMPTY, + .irq_bit_send_empty = APPLE_M3_MBOX_IRQ_A2I_EMPTY, +}; + +static const struct of_device_id apple_mbox_of_match[] = { + { .compatible = "apple,t8103-asc-mailbox", .data = &apple_mbox_asc_hw }, + { .compatible = "apple,t8103-m3-mailbox", .data = &apple_mbox_m3_hw }, + {} +}; +MODULE_DEVICE_TABLE(of, apple_mbox_of_match); + +static struct platform_driver apple_mbox_driver = { + .driver = { + .name = "apple-mailbox", + .of_match_table = apple_mbox_of_match, + }, + .probe = apple_mbox_probe, +}; +module_platform_driver(apple_mbox_driver); + +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); +MODULE_DESCRIPTION("Apple Mailbox driver"); |