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authorSudeep Holla <sudeep.holla@arm.com>2019-07-08 09:41:08 +0100
committerSudeep Holla <sudeep.holla@arm.com>2019-08-12 12:23:02 +0100
commitc8ae9c2da1cc5d18b6d51d10160508a3dc3436bf (patch)
tree7989bce13cd03daf76cf99ea5bc5ccf8a0d66e3d /drivers/reset/reset-scmi.c
parent95a15d80aa0de938299acfcbc6aa6f2b16f5d7e5 (diff)
downloadlinux-c8ae9c2da1cc5d18b6d51d10160508a3dc3436bf.tar.bz2
reset: Add support for resets provided by SCMI
On some ARM based systems, a separate Cortex-M based System Control Processor(SCP) provides the overall power, clock, reset and system control. System Control and Management Interface(SCMI) Message Protocol is defined for the communication between the Application Cores(AP) and the SCP. Adds support for the resets provided using SCMI protocol for performing reset management of various devices present on the SoC. Various reset functionalities are achieved by the means of different ARM SCMI device operations provided by the ARM SCMI framework. Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/reset/reset-scmi.c')
-rw-r--r--drivers/reset/reset-scmi.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
new file mode 100644
index 000000000000..c6d3c8427f14
--- /dev/null
+++ b/drivers/reset/reset-scmi.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM System Control and Management Interface (ARM SCMI) reset driver
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/reset-controller.h>
+#include <linux/scmi_protocol.h>
+
+/**
+ * struct scmi_reset_data - reset controller information structure
+ * @rcdev: reset controller entity
+ * @handle: ARM SCMI handle used for communication with system controller
+ */
+struct scmi_reset_data {
+ struct reset_controller_dev rcdev;
+ const struct scmi_handle *handle;
+};
+
+#define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev)
+#define to_scmi_handle(p) (to_scmi_reset_data(p)->handle)
+
+/**
+ * scmi_reset_assert() - assert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be asserted
+ *
+ * This function implements the reset driver op to assert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->assert(handle, id);
+}
+
+/**
+ * scmi_reset_deassert() - deassert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be deasserted
+ *
+ * This function implements the reset driver op to deassert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->deassert(handle, id);
+}
+
+/**
+ * scmi_reset_reset() - reset the device
+ * @rcdev: reset controller entity
+ * @id: ID of the reset signal to be reset(assert + deassert)
+ *
+ * This function implements the reset driver op to trigger a device's
+ * reset signal using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->reset(handle, id);
+}
+
+static const struct reset_control_ops scmi_reset_ops = {
+ .assert = scmi_reset_assert,
+ .deassert = scmi_reset_deassert,
+ .reset = scmi_reset_reset,
+};
+
+static int scmi_reset_probe(struct scmi_device *sdev)
+{
+ struct scmi_reset_data *data;
+ struct device *dev = &sdev->dev;
+ struct device_node *np = dev->of_node;
+ const struct scmi_handle *handle = sdev->handle;
+
+ if (!handle || !handle->reset_ops)
+ return -ENODEV;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->rcdev.ops = &scmi_reset_ops;
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.of_node = np;
+ data->rcdev.nr_resets = handle->reset_ops->num_domains_get(handle);
+
+ return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+ { SCMI_PROTOCOL_RESET },
+ { },
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static struct scmi_driver scmi_reset_driver = {
+ .name = "scmi-reset",
+ .probe = scmi_reset_probe,
+ .id_table = scmi_id_table,
+};
+module_scmi_driver(scmi_reset_driver);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCMI reset controller driver");
+MODULE_LICENSE("GPL v2");