ARM SCMI updates/fixes for v5.4

Handful of fixes/updates including:
 1. SCMI v2.0(recently released) support for:
 	- Performance protocol fast channels
 	- Reset Management Protocol
 2. SCMI infrastructure/core support for recieve(Rx) channels,
    asynchronous commands and delayed response
 3. Usage of asynchronous commands for clock rate setting and sensor
    reading based on the attributes read from the firmware
 4. Miscellaneous cleanups(typos, naming alignment with specification,
    and SPDX License identifier)
 5. Couple of fixes: removal of extra check for invalid length and
    additional check to ensure platform/firmware has released shared
    memory before using it in OSPM
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Merge tag 'scmi-updates-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/drivers

ARM SCMI updates/fixes for v5.4

Handful of fixes/updates including:
1. SCMI v2.0(recently released) support for:
	- Performance protocol fast channels
	- Reset Management Protocol
2. SCMI infrastructure/core support for recieve(Rx) channels,
   asynchronous commands and delayed response
3. Usage of asynchronous commands for clock rate setting and sensor
   reading based on the attributes read from the firmware
4. Miscellaneous cleanups(typos, naming alignment with specification,
   and SPDX License identifier)
5. Couple of fixes: removal of extra check for invalid length and
   additional check to ensure platform/firmware has released shared
   memory before using it in OSPM

* tag 'scmi-updates-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux: (22 commits)
  reset: Add support for resets provided by SCMI
  firmware: arm_scmi: Add RESET protocol in SCMI v2.0
  dt-bindings: arm: Extend SCMI to support new reset protocol
  firmware: arm_scmi: Make use SCMI v2.0 fastchannel for performance protocol
  firmware: arm_scmi: Add discovery of SCMI v2.0 performance fastchannels
  firmware: arm_scmi: Use {get,put}_unaligned_le{32,64} accessors
  firmware: arm_scmi: Use asynchronous CLOCK_RATE_SET when possible
  firmware: arm_scmi: Drop config flag in clk_ops->rate_set
  firmware: arm_scmi: Add asynchronous sensor read if it supports
  firmware: arm_scmi: Drop async flag in sensor_ops->reading_get
  firmware: arm_scmi: Add support for asynchronous commands and delayed response
  firmware: arm_scmi: Add mechanism to unpack message headers
  firmware: arm_scmi: Separate out tx buffer handling and prepare to add rx
  firmware: arm_scmi: Add receive channel support for notifications
  firmware: arm_scmi: Segregate tx channel handling and prepare to add rx
  firmware: arm_scmi: Reorder some functions to avoid forward declarations
  firmware: arm_scmi: Check if platform has released shmem before using
  firmware: arm_scmi: Use the term 'message' instead of 'command'
  firmware: arm_scmi: Fix few trivial typos in comments
  firmware: arm_scmi: Remove extra check for invalid length message responses
  ...

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>

drivers/reset/Kconfig

@@ -116,6 +116,17 @@ config RESET_QCOM_PDC
 	  to control reset signals provided by PDC for Modem, Compute,
 	  Display, GPU, Debug, AOP, Sensors, Audio, SP and APPS.
 
+config RESET_SCMI
+	tristate "Reset driver controlled via ARM SCMI interface"
+	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
+	default ARM_SCMI_PROTOCOL
+	help
+	  This driver provides support for reset signal/domains that are
+	  controlled by firmware that implements the SCMI interface.
+
+	  This driver uses SCMI Message Protocol to interact with the
+	  firmware controlling all the reset signals.
+
 config RESET_SIMPLE
 	bool "Simple Reset Controller Driver" if COMPILE_TEST
 	default ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED || ARCH_BITMAIN || ARC

drivers/reset/Makefile

@@ -18,6 +18,7 @@ obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
 obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
 obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
 obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o
+obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
 obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
 obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o

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 <[email protected]>");
+MODULE_DESCRIPTION("ARM SCMI reset controller driver");
+MODULE_LICENSE("GPL v2");