[PATCH 3/6] arm: apple: rtkit: Add a generic RTKit helper driver

[Mark Kettenis]

From: Hector Martin <marcan at marcan.st>

This driver handles the MTP ASC coprocessor, which does not need any
special handling on the RTKit side and communicates out-of-band.

Signed-off-by: Hector Martin <marcan at marcan.st>
Signed-off-by: Mark Kettenis <kettenis at openbsd.org>
---
 arch/arm/include/asm/arch-apple/rtkit.h |  2 +
 arch/arm/mach-apple/Makefile            |  1 +
 arch/arm/mach-apple/rtkit_helper.c      | 97 +++++++++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 arch/arm/mach-apple/rtkit_helper.c

diff --git a/arch/arm/include/asm/arch-apple/rtkit.h b/arch/arm/include/asm/arch-apple/rtkit.h
index b795215feb7..1b6c6ccd821 100644
--- a/arch/arm/include/asm/arch-apple/rtkit.h
+++ b/arch/arm/include/asm/arch-apple/rtkit.h
@@ -29,3 +29,5 @@ int apple_rtkit_boot(struct apple_rtkit *rtk);
 int apple_rtkit_set_ap_power(struct apple_rtkit *rtk, int pwrstate);
 int apple_rtkit_poll(struct apple_rtkit *rtk, ulong timeout);
 int apple_rtkit_shutdown(struct apple_rtkit *rtk, int pwrstate);
+
+int apple_rtkit_helper_poll(struct udevice *dev, ulong timeout);
diff --git a/arch/arm/mach-apple/Makefile b/arch/arm/mach-apple/Makefile
index 50b465b9473..d79a3a69592 100644
--- a/arch/arm/mach-apple/Makefile
+++ b/arch/arm/mach-apple/Makefile
@@ -3,4 +3,5 @@
 obj-y += board.o
 obj-y += lowlevel_init.o
 obj-y += rtkit.o
+obj-$(CONFIG_APPLE_MTP_KEYB) += rtkit_helper.o
 obj-$(CONFIG_NVME_APPLE) += sart.o
diff --git a/arch/arm/mach-apple/rtkit_helper.c b/arch/arm/mach-apple/rtkit_helper.c
new file mode 100644
index 00000000000..3b755008195
--- /dev/null
+++ b/arch/arm/mach-apple/rtkit_helper.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0+ OR MIT
+/*
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <dm.h>
+#include <mailbox.h>
+#include <mapmem.h>
+#include <reset.h>
+
+#include <asm/io.h>
+#include <asm/arch/rtkit.h>
+#include <linux/iopoll.h>
+
+/* ASC registers */
+#define REG_CPU_CTRL		0x0044
+#define  REG_CPU_CTRL_RUN	BIT(4)
+
+struct rtkit_helper_priv {
+	void *asc;		/* ASC registers */
+	struct mbox_chan chan;
+	struct apple_rtkit *rtk;
+};
+
+static int rtkit_helper_probe(struct udevice *dev)
+{
+	struct rtkit_helper_priv *priv = dev_get_priv(dev);
+	u32 ctrl;
+	int ret;
+
+	priv->asc = dev_read_addr_ptr(dev);
+	if (!priv->asc)
+		return -EINVAL;
+
+	ret = mbox_get_by_index(dev, 0, &priv->chan);
+	if (ret < 0)
+		return ret;
+
+	ctrl = readl(priv->asc + REG_CPU_CTRL);
+	writel(ctrl | REG_CPU_CTRL_RUN, priv->asc + REG_CPU_CTRL);
+
+	priv->rtk = apple_rtkit_init(&priv->chan, priv, NULL, NULL);
+	if (!priv->rtk)
+		return -ENOMEM;
+
+	ret = apple_rtkit_boot(priv->rtk);
+	if (ret < 0) {
+		printf("%s: Helper apple_rtkit_boot returned: %d\n", __func__, ret);
+		return ret;
+	}
+
+	ret = apple_rtkit_set_ap_power(priv->rtk, APPLE_RTKIT_PWR_STATE_ON);
+	if (ret < 0) {
+		printf("%s: Helper apple_rtkit_set_ap_power returned: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rtkit_helper_remove(struct udevice *dev)
+{
+	struct rtkit_helper_priv *priv = dev_get_priv(dev);
+	u32 ctrl;
+
+	apple_rtkit_shutdown(priv->rtk, APPLE_RTKIT_PWR_STATE_QUIESCED);
+
+	ctrl = readl(priv->asc + REG_CPU_CTRL);
+	writel(ctrl & ~REG_CPU_CTRL_RUN, priv->asc + REG_CPU_CTRL);
+
+	apple_rtkit_free(priv->rtk);
+	priv->rtk = NULL;
+
+	return 0;
+}
+
+int apple_rtkit_helper_poll(struct udevice *dev, ulong timeout)
+{
+	struct rtkit_helper_priv *priv = dev_get_priv(dev);
+
+	return apple_rtkit_poll(priv->rtk, timeout);
+}
+
+static const struct udevice_id rtkit_helper_ids[] = {
+	{ .compatible = "apple,rtk-helper-asc4" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(rtkit_helper) = {
+	.name = "rtkit_helper",
+	.id = UCLASS_MISC,
+	.of_match = rtkit_helper_ids,
+	.priv_auto = sizeof(struct rtkit_helper_priv),
+	.probe = rtkit_helper_probe,
+	.remove = rtkit_helper_remove,
+	.flags = DM_FLAG_OS_PREPARE,
+};
-- 
2.49.0