diff options
Diffstat (limited to 'drivers/soc/apple/mailbox.c')
| -rw-r--r-- | drivers/soc/apple/mailbox.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/drivers/soc/apple/mailbox.c b/drivers/soc/apple/mailbox.c new file mode 100644 index 0000000000..49a0955e82 --- /dev/null +++ b/drivers/soc/apple/mailbox.c @@ -0,0 +1,437 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple mailbox driver + * + * Copyright 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/bitfield.h> +#include <linux/bits.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/spinlock.h> +#include <linux/types.h> +#include "mailbox.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) + +#define APPLE_MBOX_TX_TIMEOUT 500 + +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; +}; + +int apple_mbox_send(struct apple_mbox *mbox, const struct apple_mbox_msg msg, + bool atomic) +{ + unsigned long flags; + int ret; + u32 mbox_ctrl; + long t; + + spin_lock_irqsave(&mbox->tx_lock, flags); + mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->a2i_control); + + while (mbox_ctrl & mbox->hw->control_full) { + if (atomic) { + ret = readl_poll_timeout_atomic( + mbox->regs + mbox->hw->a2i_control, mbox_ctrl, + !(mbox_ctrl & mbox->hw->control_full), 100, + APPLE_MBOX_TX_TIMEOUT * 1000); + + if (ret) { + spin_unlock_irqrestore(&mbox->tx_lock, flags); + return ret; + } + + break; + } + /* + * 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 (mbox->hw->has_irq_controls) { + writel_relaxed(mbox->hw->irq_bit_send_empty, + mbox->regs + mbox->hw->irq_ack); + } + enable_irq(mbox->irq_send_empty); + reinit_completion(&mbox->tx_empty); + spin_unlock_irqrestore(&mbox->tx_lock, flags); + + t = wait_for_completion_interruptible_timeout( + &mbox->tx_empty, + msecs_to_jiffies(APPLE_MBOX_TX_TIMEOUT)); + if (t < 0) + return t; + else if (t == 0) + return -ETIMEDOUT; + + spin_lock_irqsave(&mbox->tx_lock, flags); + mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->a2i_control); + } + + writeq_relaxed(msg.msg0, mbox->regs + mbox->hw->a2i_send0); + writeq_relaxed(FIELD_PREP(APPLE_MBOX_MSG1_MSG, msg.msg1), + mbox->regs + mbox->hw->a2i_send1); + + spin_unlock_irqrestore(&mbox->tx_lock, flags); + + return 0; +} +EXPORT_SYMBOL(apple_mbox_send); + +static irqreturn_t apple_mbox_send_empty_irq(int irq, void *data) +{ + struct apple_mbox *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_send will acknowledge it before enabling + * it at the main controller again. + */ + spin_lock(&mbox->tx_lock); + disable_irq_nosync(mbox->irq_send_empty); + complete(&mbox->tx_empty); + spin_unlock(&mbox->tx_lock); + + return IRQ_HANDLED; +} + +static int apple_mbox_poll_locked(struct apple_mbox *mbox) +{ + struct apple_mbox_msg msg; + int ret = 0; + + u32 mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->i2a_control); + + while (!(mbox_ctrl & mbox->hw->control_empty)) { + msg.msg0 = readq_relaxed(mbox->regs + mbox->hw->i2a_recv0); + msg.msg1 = FIELD_GET( + APPLE_MBOX_MSG1_MSG, + readq_relaxed(mbox->regs + mbox->hw->i2a_recv1)); + + mbox->rx(mbox, msg, mbox->cookie); + ret++; + mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->i2a_control); + } + + /* + * 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 (mbox->hw->has_irq_controls) { + writel_relaxed(mbox->hw->irq_bit_recv_not_empty, + mbox->regs + mbox->hw->irq_ack); + } + + return ret; +} + +static irqreturn_t apple_mbox_recv_irq(int irq, void *data) +{ + struct apple_mbox *mbox = data; + + spin_lock(&mbox->rx_lock); + apple_mbox_poll_locked(mbox); + spin_unlock(&mbox->rx_lock); + + return IRQ_HANDLED; +} + +int apple_mbox_poll(struct apple_mbox *mbox) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&mbox->rx_lock, flags); + ret = apple_mbox_poll_locked(mbox); + spin_unlock_irqrestore(&mbox->rx_lock, flags); + + return ret; +} +EXPORT_SYMBOL(apple_mbox_poll); + +int apple_mbox_start(struct apple_mbox *mbox) +{ + int ret; + + if (mbox->active) + return 0; + + ret = pm_runtime_resume_and_get(mbox->dev); + if (ret) + return ret; + + /* + * 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 (mbox->hw->has_irq_controls) { + writel_relaxed(mbox->hw->irq_bit_recv_not_empty | + mbox->hw->irq_bit_send_empty, + mbox->regs + mbox->hw->irq_enable); + } + + enable_irq(mbox->irq_recv_not_empty); + mbox->active = true; + return 0; +} +EXPORT_SYMBOL(apple_mbox_start); + +void apple_mbox_stop(struct apple_mbox *mbox) +{ + if (!mbox->active) + return; + + mbox->active = false; + disable_irq(mbox->irq_recv_not_empty); + pm_runtime_mark_last_busy(mbox->dev); + pm_runtime_put_autosuspend(mbox->dev); +} +EXPORT_SYMBOL(apple_mbox_stop); + +struct apple_mbox *apple_mbox_get(struct device *dev, int index) +{ + struct of_phandle_args args; + struct platform_device *pdev; + struct apple_mbox *mbox; + int ret; + + ret = of_parse_phandle_with_args(dev->of_node, "mboxes", "#mbox-cells", + index, &args); + if (ret || !args.np) + return ERR_PTR(ret); + + pdev = of_find_device_by_node(args.np); + of_node_put(args.np); + + if (!pdev) + return ERR_PTR(-EPROBE_DEFER); + + mbox = platform_get_drvdata(pdev); + if (!mbox) + return ERR_PTR(-EPROBE_DEFER); + + if (!device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER)) + return ERR_PTR(-ENODEV); + + return mbox; +} +EXPORT_SYMBOL(apple_mbox_get); + +struct apple_mbox *apple_mbox_get_byname(struct device *dev, const char *name) +{ + int index; + + index = of_property_match_string(dev->of_node, "mbox-names", name); + if (index < 0) + return ERR_PTR(index); + + return apple_mbox_get(dev, index); +} +EXPORT_SYMBOL(apple_mbox_get_byname); + +static int apple_mbox_probe(struct platform_device *pdev) +{ + int ret; + char *irqname; + struct apple_mbox *mbox; + struct device *dev = &pdev->dev; + + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); + if (!mbox) + return -ENOMEM; + + mbox->dev = &pdev->dev; + mbox->hw = of_device_get_match_data(dev); + if (!mbox->hw) + return -EINVAL; + + mbox->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(mbox->regs)) + return PTR_ERR(mbox->regs); + + 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; + + spin_lock_init(&mbox->rx_lock); + spin_lock_init(&mbox->tx_lock); + init_completion(&mbox->tx_empty); + + irqname = devm_kasprintf(dev, GFP_KERNEL, "%s-recv", dev_name(dev)); + if (!irqname) + return -ENOMEM; + + ret = devm_request_irq(dev, mbox->irq_recv_not_empty, + apple_mbox_recv_irq, + IRQF_NO_AUTOEN | IRQF_NO_SUSPEND, 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 | IRQF_NO_SUSPEND, irqname, mbox); + if (ret) + return ret; + + ret = devm_pm_runtime_enable(dev); + if (ret) + return ret; + + platform_set_drvdata(pdev, mbox); + return 0; +} + +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,asc-mailbox-v4", .data = &apple_mbox_asc_hw }, + { .compatible = "apple,m3-mailbox-v2", .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"); |