1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/reset/reset-ti-sci.c b/drivers/reset/reset-ti-sci.c
new file mode 100644
index 0000000000..c8a76dfb04
--- /dev/null
+++ b/drivers/reset/reset-ti-sci.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Texas Instruments System Control Interface (TI SCI) reset driver
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andreas Dannenberg <dannenberg@ti.com>
+ *
+ * Loosely based on Linux kernel reset-ti-sci.c...
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <reset-uclass.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+/**
+ * struct ti_sci_reset_data - reset controller information structure
+ * @sci: TI SCI handle used for communication with system controller
+ */
+struct ti_sci_reset_data {
+	const struct ti_sci_handle *sci;
+};
+
+static int ti_sci_reset_probe(struct udevice *dev)
+{
+	struct ti_sci_reset_data *data = dev_get_priv(dev);
+
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	if (!data)
+		return -ENOMEM;
+
+	/* Store handle for communication with the system controller */
+	data->sci = ti_sci_get_handle(dev);
+	if (IS_ERR(data->sci))
+		return PTR_ERR(data->sci);
+
+	return 0;
+}
+
+static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
+				 struct ofnode_phandle_args *args)
+{
+	debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
+
+	if (args->args_count != 2) {
+		debug("Invalid args_count: %d\n", args->args_count);
+		return -EINVAL;
+	}
+
+	/*
+	 * On TI SCI-based devices, the reset provider id field is used as a
+	 * device ID, and the data field is used as the associated reset mask.
+	 */
+	rst->id = args->args[0];
+	rst->data = args->args[1];
+
+	return 0;
+}
+
+static int ti_sci_reset_request(struct reset_ctl *rst)
+{
+	debug("%s(rst=%p)\n", __func__, rst);
+	return 0;
+}
+
+static int ti_sci_reset_free(struct reset_ctl *rst)
+{
+	debug("%s(rst=%p)\n", __func__, rst);
+	return 0;
+}
+
+/**
+ * ti_sci_reset_set() - program a device's reset
+ * @rst: Handle to a single reset signal
+ * @assert: boolean flag to indicate assert or deassert
+ *
+ * This is a common internal function used to assert or deassert a device's
+ * reset using the TI SCI protocol. The device's reset is asserted if the
+ * @assert argument is true, or deasserted if @assert argument is false.
+ * The mechanism itself is a read-modify-write procedure, the current device
+ * reset register is read using a TI SCI device operation, the new value is
+ * set or un-set using the reset's mask, and the new reset value written by
+ * using another TI SCI device operation.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int ti_sci_reset_set(struct reset_ctl *rst, bool assert)
+{
+	struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
+	const struct ti_sci_handle *sci = data->sci;
+	const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
+	u32 reset_state;
+	int ret;
+
+	ret = dops->get_device_resets(sci, rst->id, &reset_state);
+	if (ret) {
+		dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	if (assert)
+		reset_state |= rst->data;
+	else
+		reset_state &= ~rst->data;
+
+	ret = dops->set_device_resets(sci, rst->id, reset_state);
+	if (ret) {
+		dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * ti_sci_reset_assert() - assert device reset
+ * @rst: Handle to a single reset signal
+ *
+ * This function implements the reset driver op to assert a device's reset
+ * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
+ * with the corresponding parameters as passed in, but with the @assert
+ * argument set to true for asserting the reset.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int ti_sci_reset_assert(struct reset_ctl *rst)
+{
+	debug("%s(rst=%p)\n", __func__, rst);
+	return ti_sci_reset_set(rst, true);
+}
+
+/**
+ * ti_sci_reset_deassert() - deassert device reset
+ * @rst: Handle to a single reset signal
+ *
+ * This function implements the reset driver op to deassert a device's reset
+ * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
+ * with the corresponding parameters as passed in, but with the @assert
+ * argument set to false for deasserting the reset.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int ti_sci_reset_deassert(struct reset_ctl *rst)
+{
+	debug("%s(rst=%p)\n", __func__, rst);
+	return ti_sci_reset_set(rst, false);
+}
+
+/**
+ * ti_sci_reset_status() - check device reset status
+ * @rst: Handle to a single reset signal
+ *
+ * This function implements the reset driver op to return the status of a
+ * device's reset using the TI SCI protocol. The reset register value is read
+ * by invoking the TI SCI device operation .get_device_resets(), and the
+ * status of the specific reset is extracted and returned using this reset's
+ * reset mask.
+ *
+ * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
+ */
+static int ti_sci_reset_status(struct reset_ctl *rst)
+{
+	struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
+	const struct ti_sci_handle *sci = data->sci;
+	const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
+	u32 reset_state;
+	int ret;
+
+	debug("%s(rst=%p)\n", __func__, rst);
+
+	ret = dops->get_device_resets(sci, rst->id, &reset_state);
+	if (ret) {
+		dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return reset_state & rst->data;
+}
+
+static const struct udevice_id ti_sci_reset_of_match[] = {
+	{ .compatible = "ti,sci-reset", },
+	{ /* sentinel */ },
+};
+
+static struct reset_ops ti_sci_reset_ops = {
+	.of_xlate = ti_sci_reset_of_xlate,
+	.request = ti_sci_reset_request,
+	.free = ti_sci_reset_free,
+	.rst_assert = ti_sci_reset_assert,
+	.rst_deassert = ti_sci_reset_deassert,
+	.rst_status = ti_sci_reset_status,
+};
+
+U_BOOT_DRIVER(ti_sci_reset) = {
+	.name = "ti-sci-reset",
+	.id = UCLASS_RESET,
+	.of_match = ti_sci_reset_of_match,
+	.probe = ti_sci_reset_probe,
+	.priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
+	.ops = &ti_sci_reset_ops,
+};