6.18: Add PAS over OP-TEE support for open-firmware platforms

MAINTAINERS

@@ -21347,6 +21347,15 @@ F:	Documentation/devicetree/bindings/media/*qcom*
 F:	drivers/media/platform/qcom
 F:	include/dt-bindings/media/*qcom*
 
+QUALCOMM PAS TZ SERVICE
+M:	Sumit Garg <sumit.garg@oss.qualcomm.com>
+L:	linux-arm-msm@vger.kernel.org
+S:	Maintained
+F:	drivers/firmware/qcom/qcom_pas.c
+F:	drivers/firmware/qcom/qcom_pas.h
+F:	drivers/firmware/qcom/qcom_pas_tee.c
+F:	include/linux/firmware/qcom/qcom_pas.h
+
 QUALCOMM SMB CHARGER DRIVER
 M:	Casey Connolly <casey.connolly@linaro.org>
 L:	linux-arm-msm@vger.kernel.org

drivers/firmware/qcom/Kconfig

@@ -6,9 +6,29 @@
 
 menu "Qualcomm firmware drivers"
 
+config QCOM_PAS
+	tristate "Qualcomm generic PAS interface driver"
+	help
+	  Enable the generic Peripheral Authentication Service (PAS) provided
+	  by the firmware. It acts as the common layer with different TZ
+	  backends plugged in whether it's an SCM implementation or a proper
+	  TEE bus based PAS service implementation.
+
+config QCOM_PAS_TEE
+	tristate "Qualcomm PAS TEE interface driver"
+	select QCOM_PAS
+	depends on TEE
+	depends on !CPU_BIG_ENDIAN
+	default m if ARCH_QCOM
+	help
+	  Enable the generic Peripheral Authentication Service (PAS) provided
+	  by the firmware TEE implementation as the backend.
+
 config QCOM_SCM
+	tristate "Qualcomm PAS SCM interface driver"
+	select QCOM_PAS
 	select QCOM_TZMEM
-	tristate
+	default y if ARCH_QCOM
 
 config QCOM_TZMEM
 	tristate

drivers/firmware/qcom/Makefile

@@ -8,5 +8,7 @@ qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
 obj-$(CONFIG_QCOM_TZMEM)	+= qcom_tzmem.o
 obj-$(CONFIG_QCOM_QSEECOM)	+= qcom_qseecom.o
 obj-$(CONFIG_QCOM_QSEECOM_UEFISECAPP) += qcom_qseecom_uefisecapp.o
+obj-$(CONFIG_QCOM_PAS)		+= qcom_pas.o
+obj-$(CONFIG_QCOM_PAS_TEE)	+= qcom_pas_tee.o
 obj-$(CONFIG_QCOM_MEMORY_DUMP_V2) += memory_dump_v2.o
 obj-$(CONFIG_QCOM_MEMORY_DUMP_DEV) += memory_dump_dev.o

drivers/firmware/qcom/qcom_pas.c

@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2010,2015,2019 The Linux Foundation. All rights reserved.
+ * Copyright (C) 2015 Linaro Ltd.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/device/devres.h>
+#include <linux/firmware/qcom/qcom_pas.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include "qcom_pas.h"
+
+static struct qcom_pas_ops *ops_ptr;
+
+/**
+ * devm_qcom_pas_context_alloc() - Allocate peripheral authentication service
+ *				   context for a given peripheral
+ *
+ * PAS context is device-resource managed, so the caller does not need
+ * to worry about freeing the context memory.
+ *
+ * @dev:	  PAS firmware device
+ * @pas_id:	  peripheral authentication service id
+ * @mem_phys:	  Subsystem reserve memory start address
+ * @mem_size:	  Subsystem reserve memory size
+ *
+ * Return: The new PAS context, or ERR_PTR() on failure.
+ */
+struct qcom_pas_context *devm_qcom_pas_context_alloc(struct device *dev,
+						     u32 pas_id,
+						     phys_addr_t mem_phys,
+						     size_t mem_size)
+{
+	struct qcom_pas_context *ctx;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->dev = dev;
+	ctx->pas_id = pas_id;
+	ctx->mem_phys = mem_phys;
+	ctx->mem_size = mem_size;
+
+	return ctx;
+}
+EXPORT_SYMBOL_GPL(devm_qcom_pas_context_alloc);
+
+/**
+ * qcom_pas_init_image() - Initialize peripheral authentication service state
+ *			   machine for a given peripheral, using the metadata
+ * @pas_id:	peripheral authentication service id
+ * @metadata:	pointer to memory containing ELF header, program header table
+ *		and optional blob of data used for authenticating the metadata
+ *		and the rest of the firmware
+ * @size:	size of the metadata
+ * @ctx:	optional pas context
+ *
+ * Return: 0 on success.
+ *
+ * Upon successful return, the PAS metadata context (@ctx) will be used to
+ * track the metadata allocation, this needs to be released by invoking
+ * qcom_pas_metadata_release() by the caller.
+ */
+int qcom_pas_init_image(u32 pas_id, const void *metadata, size_t size,
+			struct qcom_pas_context *ctx)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+
+	return ops_ptr->init_image(ops_ptr->dev, pas_id, metadata, size, ctx);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_init_image);
+
+/**
+ * qcom_pas_metadata_release() - release metadata context
+ * @ctx:	pas context
+ */
+void qcom_pas_metadata_release(struct qcom_pas_context *ctx)
+{
+	if (!ops_ptr || !ctx || !ctx->ptr)
+		return;
+
+	ops_ptr->metadata_release(ops_ptr->dev, ctx);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_metadata_release);
+
+/**
+ * qcom_pas_mem_setup() - Prepare the memory related to a given peripheral
+ *			  for firmware loading
+ * @pas_id:	peripheral authentication service id
+ * @addr:	start address of memory area to prepare
+ * @size:	size of the memory area to prepare
+ *
+ * Return: 0 on success.
+ */
+int qcom_pas_mem_setup(u32 pas_id, phys_addr_t addr, phys_addr_t size)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+
+	return ops_ptr->mem_setup(ops_ptr->dev, pas_id, addr, size);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_mem_setup);
+
+/**
+ * qcom_pas_get_rsc_table() - Retrieve the resource table in passed output buffer
+ *			      for a given peripheral.
+ *
+ * Qualcomm remote processor may rely on both static and dynamic resources for
+ * its functionality. Static resources typically refer to memory-mapped
+ * addresses required by the subsystem and are often embedded within the
+ * firmware binary and dynamic resources, such as shared memory in DDR etc.,
+ * are determined at runtime during the boot process.
+ *
+ * On Qualcomm Technologies devices, it's possible that static resources are
+ * not embedded in the firmware binary and instead are provided by TrustZone.
+ * However, dynamic resources are always expected to come from TrustZone. This
+ * indicates that for Qualcomm devices, all resources (static and dynamic) will
+ * be provided by TrustZone PAS service.
+ *
+ * If the remote processor firmware binary does contain static resources, they
+ * should be passed in input_rt. These will be forwarded to TrustZone for
+ * authentication. TrustZone will then append the dynamic resources and return
+ * the complete resource table in output_rt_tzm.
+ *
+ * If the remote processor firmware binary does not include a resource table,
+ * the caller of this function should set input_rt as NULL and input_rt_size
+ * as zero respectively.
+ *
+ * More about documentation on resource table data structures can be found in
+ * include/linux/remoteproc.h
+ *
+ * @ctx:	    PAS context
+ * @input_rt:       resource table buffer which is present in firmware binary
+ * @input_rt_size:  size of the resource table present in firmware binary
+ * @output_rt_size: TrustZone expects caller should pass worst case size for
+ *		    the output_rt_tzm.
+ *
+ * Return:
+ *  On success, returns a pointer to the allocated buffer containing the final
+ *  resource table and output_rt_size will have actual resource table size from
+ *  TrustZone. The caller is responsible for freeing the buffer. On failure,
+ *  returns ERR_PTR(-errno).
+ */
+struct resource_table *qcom_pas_get_rsc_table(struct qcom_pas_context *ctx,
+					      void *input_rt,
+					      size_t input_rt_size,
+					      size_t *output_rt_size)
+{
+	if (!ops_ptr)
+		return ERR_PTR(-ENODEV);
+	if (!ctx)
+		return ERR_PTR(-EINVAL);
+
+	return ops_ptr->get_rsc_table(ops_ptr->dev, ctx, input_rt,
+				      input_rt_size, output_rt_size);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_get_rsc_table);
+
+/**
+ * qcom_pas_auth_and_reset() - Authenticate the given peripheral firmware
+ *			       and reset the remote processor
+ * @pas_id:	peripheral authentication service id
+ *
+ * Return: 0 on success.
+ */
+int qcom_pas_auth_and_reset(u32 pas_id)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+
+	return ops_ptr->auth_and_reset(ops_ptr->dev, pas_id);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_auth_and_reset);
+
+/**
+ * qcom_pas_prepare_and_auth_reset() - Prepare, authenticate, and reset the
+ *				       remote processor
+ *
+ * @ctx:	Context saved during call to devm_qcom_pas_context_alloc()
+ *
+ * This function performs the necessary steps to prepare a PAS subsystem,
+ * authenticate it using the provided metadata, and initiate a reset sequence.
+ *
+ * It should be used when Linux is in control setting up the IOMMU hardware
+ * for remote subsystem during secure firmware loading processes. The
+ * preparation step sets up a shmbridge over the firmware memory before
+ * TrustZone accesses the firmware memory region for authentication. The
+ * authentication step verifies the integrity and authenticity of the firmware
+ * or configuration using secure metadata. Finally, the reset step ensures the
+ * subsystem starts in a clean and sane state.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int qcom_pas_prepare_and_auth_reset(struct qcom_pas_context *ctx)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+	if (!ctx)
+		return -EINVAL;
+
+	return ops_ptr->prepare_and_auth_reset(ops_ptr->dev, ctx);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_prepare_and_auth_reset);
+
+/**
+ * qcom_pas_set_remote_state() - Set the remote processor state
+ * @state:	peripheral state
+ * @pas_id:	peripheral authentication service id
+ *
+ * Return: 0 on success.
+ */
+int qcom_pas_set_remote_state(u32 state, u32 pas_id)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+
+	return ops_ptr->set_remote_state(ops_ptr->dev, state, pas_id);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_set_remote_state);
+
+/**
+ * qcom_pas_shutdown() - Shut down the remote processor
+ * @pas_id:	peripheral authentication service id
+ *
+ * Return: 0 on success.
+ */
+int qcom_pas_shutdown(u32 pas_id)
+{
+	if (!ops_ptr)
+		return -ENODEV;
+
+	return ops_ptr->shutdown(ops_ptr->dev, pas_id);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_shutdown);
+
+/**
+ * qcom_pas_supported() - Check if the peripheral authentication service is
+ *			  supported for the given peripheral
+ * @pas_id:	peripheral authentication service id
+ *
+ * Return: true if PAS is supported for this peripheral, otherwise false.
+ */
+bool qcom_pas_supported(u32 pas_id)
+{
+	if (!ops_ptr)
+		return false;
+
+	return ops_ptr->supported(ops_ptr->dev, pas_id);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_supported);
+
+const char *qcom_pas_get_backend(void)
+{
+	struct qcom_pas_ops *ops = ops_ptr;
+
+	return ops ? ops->drv_name : NULL;
+}
+EXPORT_SYMBOL_GPL(qcom_pas_get_backend);
+
+/**
+ * qcom_pas_is_available() - Check if the peripheral authentication service is
+ *			     available. Note that it is mandatory for any PAS
+ *			     client to invoke this API. If it returns true then
+ *			     only any other PAS API can be invoked.
+ *
+ * Return: true if PAS is available, otherwise false.
+ */
+bool qcom_pas_is_available(void)
+{
+	/*
+	 * The barrier for ops_ptr is intended to synchronize the data stores
+	 * for the ops data structure when client drivers are in parallel
+	 * checking for PAS service availability.
+	 *
+	 * Once the PAS backend becomes available, it is allowed for multiple
+	 * threads to enter TZ for parallel bringup of co-processors during
+	 * boot.
+	 */
+	return !!smp_load_acquire(&ops_ptr);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_is_available);
+
+void qcom_pas_ops_register(struct qcom_pas_ops *ops)
+{
+	if (!qcom_pas_is_available())
+		/* Paired with smp_load_acquire() in qcom_pas_is_available() */
+		smp_store_release(&ops_ptr, ops);
+	else
+		pr_err("qcom_pas: ops already registered by %s\n",
+		       ops_ptr->drv_name);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_ops_register);
+
+void qcom_pas_ops_unregister(void)
+{
+	/* Paired with smp_load_acquire() in qcom_pas_is_available() */
+	smp_store_release(&ops_ptr, NULL);
+}
+EXPORT_SYMBOL_GPL(qcom_pas_ops_unregister);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Qualcomm generic TZ PAS driver");