1 files changed, 467 insertions, 0 deletions
diff --git a/drivers/firmware/qcom/qcom_tzmem.c b/drivers/firmware/qcom/qcom_tzmem.c
new file mode 100644
index 000000000000..5d526753183d
--- /dev/null
+++ b/drivers/firmware/qcom/qcom_tzmem.c
@@ -0,0 +1,467 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Memory allocator for buffers shared with the TrustZone.
+ *
+ * Copyright (C) 2023-2024 Linaro Ltd.
+ */
+
+#include <linux/bug.h>
+#include <linux/cleanup.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/firmware/qcom/qcom_tzmem.h>
+#include <linux/genalloc.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/radix-tree.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include "qcom_tzmem.h"
+
+struct qcom_tzmem_area {
+	struct list_head list;
+	void *vaddr;
+	dma_addr_t paddr;
+	size_t size;
+	void *priv;
+};
+
+struct qcom_tzmem_pool {
+	struct gen_pool *genpool;
+	struct list_head areas;
+	enum qcom_tzmem_policy policy;
+	size_t increment;
+	size_t max_size;
+	spinlock_t lock;
+};
+
+struct qcom_tzmem_chunk {
+	phys_addr_t paddr;
+	size_t size;
+	struct qcom_tzmem_pool *owner;
+};
+
+static struct device *qcom_tzmem_dev;
+static RADIX_TREE(qcom_tzmem_chunks, GFP_ATOMIC);
+static DEFINE_SPINLOCK(qcom_tzmem_chunks_lock);
+
+#if IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_GENERIC)
+
+static int qcom_tzmem_init(void)
+{
+	return 0;
+}
+
+static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
+{
+	return 0;
+}
+
+static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
+{
+
+}
+
+#elif IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE)
+
+#include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/of.h>
+
+#define QCOM_SHM_BRIDGE_NUM_VM_SHIFT 9
+
+static bool qcom_tzmem_using_shm_bridge;
+
+/* List of machines that are known to not support SHM bridge correctly. */
+static const char *const qcom_tzmem_blacklist[] = {
+	"qcom,sc8180x",
+	NULL
+};
+
+static int qcom_tzmem_init(void)
+{
+	const char *const *platform;
+	int ret;
+
+	for (platform = qcom_tzmem_blacklist; *platform; platform++) {
+		if (of_machine_is_compatible(*platform))
+			goto notsupp;
+	}
+
+	ret = qcom_scm_shm_bridge_enable();
+	if (ret == -EOPNOTSUPP)
+		goto notsupp;
+
+	if (!ret)
+		qcom_tzmem_using_shm_bridge = true;
+
+	return ret;
+
+notsupp:
+	dev_info(qcom_tzmem_dev, "SHM Bridge not supported\n");
+	return 0;
+}
+
+static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
+{
+	u64 pfn_and_ns_perm, ipfn_and_s_perm, size_and_flags;
+	int ret;
+
+	if (!qcom_tzmem_using_shm_bridge)
+		return 0;
+
+	pfn_and_ns_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
+	ipfn_and_s_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
+	size_and_flags = area->size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);
+
+	u64 *handle __free(kfree) = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (!handle)
+		return -ENOMEM;
+
+	ret = qcom_scm_shm_bridge_create(qcom_tzmem_dev, pfn_and_ns_perm,
+					 ipfn_and_s_perm, size_and_flags,
+					 QCOM_SCM_VMID_HLOS, handle);
+	if (ret)
+		return ret;
+
+	area->priv = no_free_ptr(handle);
+
+	return 0;
+}
+
+static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
+{
+	u64 *handle = area->priv;
+
+	if (!qcom_tzmem_using_shm_bridge)
+		return;
+
+	qcom_scm_shm_bridge_delete(qcom_tzmem_dev, *handle);
+	kfree(handle);
+}
+
+#endif /* CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE */
+
+static int qcom_tzmem_pool_add_memory(struct qcom_tzmem_pool *pool,
+				      size_t size, gfp_t gfp)
+{
+	int ret;
+
+	struct qcom_tzmem_area *area __free(kfree) = kzalloc(sizeof(*area),
+							     gfp);
+	if (!area)
+		return -ENOMEM;
+
+	area->size = PAGE_ALIGN(size);
+
+	area->vaddr = dma_alloc_coherent(qcom_tzmem_dev, area->size,
+					 &area->paddr, gfp);
+	if (!area->vaddr)
+		return -ENOMEM;
+
+	ret = qcom_tzmem_init_area(area);
+	if (ret) {
+		dma_free_coherent(qcom_tzmem_dev, area->size,
+				  area->vaddr, area->paddr);
+		return ret;
+	}
+
+	ret = gen_pool_add_virt(pool->genpool, (unsigned long)area->vaddr,
+				(phys_addr_t)area->paddr, size, -1);
+	if (ret) {
+		dma_free_coherent(qcom_tzmem_dev, area->size,
+				  area->vaddr, area->paddr);
+		return ret;
+	}
+
+	scoped_guard(spinlock_irqsave, &pool->lock)
+		list_add_tail(&area->list, &pool->areas);
+
+	area = NULL;
+	return 0;
+}
+
+/**
+ * qcom_tzmem_pool_new() - Create a new TZ memory pool.
+ * @config: Pool configuration.
+ *
+ * Create a new pool of memory suitable for sharing with the TrustZone.
+ *
+ * Must not be used in atomic context.
+ *
+ * Return: New memory pool address or ERR_PTR() on error.
+ */
+struct qcom_tzmem_pool *
+qcom_tzmem_pool_new(const struct qcom_tzmem_pool_config *config)
+{
+	int ret = -ENOMEM;
+
+	might_sleep();
+
+	switch (config->policy) {
+	case QCOM_TZMEM_POLICY_STATIC:
+		if (!config->initial_size)
+			return ERR_PTR(-EINVAL);
+		break;
+	case QCOM_TZMEM_POLICY_MULTIPLIER:
+		if (!config->increment)
+			return ERR_PTR(-EINVAL);
+		break;
+	case QCOM_TZMEM_POLICY_ON_DEMAND:
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	struct qcom_tzmem_pool *pool __free(kfree) = kzalloc(sizeof(*pool),
+							     GFP_KERNEL);
+	if (!pool)
+		return ERR_PTR(-ENOMEM);
+
+	pool->genpool = gen_pool_create(PAGE_SHIFT, -1);
+	if (!pool->genpool)
+		return ERR_PTR(-ENOMEM);
+
+	gen_pool_set_algo(pool->genpool, gen_pool_best_fit, NULL);
+
+	pool->policy = config->policy;
+	pool->increment = config->increment;
+	pool->max_size = config->max_size;
+	INIT_LIST_HEAD(&pool->areas);
+	spin_lock_init(&pool->lock);
+
+	if (config->initial_size) {
+		ret = qcom_tzmem_pool_add_memory(pool, config->initial_size,
+						 GFP_KERNEL);
+		if (ret) {
+			gen_pool_destroy(pool->genpool);
+			return ERR_PTR(ret);
+		}
+	}
+
+	return no_free_ptr(pool);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_pool_new);
+
+/**
+ * qcom_tzmem_pool_free() - Destroy a TZ memory pool and free all resources.
+ * @pool: Memory pool to free.
+ *
+ * Must not be called if any of the allocated chunks has not been freed.
+ * Must not be used in atomic context.
+ */
+void qcom_tzmem_pool_free(struct qcom_tzmem_pool *pool)
+{
+	struct qcom_tzmem_area *area, *next;
+	struct qcom_tzmem_chunk *chunk;
+	struct radix_tree_iter iter;
+	bool non_empty = false;
+	void __rcu **slot;
+
+	might_sleep();
+
+	if (!pool)
+		return;
+
+	scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock) {
+		radix_tree_for_each_slot(slot, &qcom_tzmem_chunks, &iter, 0) {
+			chunk = radix_tree_deref_slot_protected(slot,
+						&qcom_tzmem_chunks_lock);
+
+			if (chunk->owner == pool)
+				non_empty = true;
+		}
+	}
+
+	WARN(non_empty, "Freeing TZ memory pool with memory still allocated");
+
+	list_for_each_entry_safe(area, next, &pool->areas, list) {
+		list_del(&area->list);
+		qcom_tzmem_cleanup_area(area);
+		dma_free_coherent(qcom_tzmem_dev, area->size,
+				  area->vaddr, area->paddr);
+		kfree(area);
+	}
+
+	gen_pool_destroy(pool->genpool);
+	kfree(pool);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_pool_free);
+
+static void devm_qcom_tzmem_pool_free(void *data)
+{
+	struct qcom_tzmem_pool *pool = data;
+
+	qcom_tzmem_pool_free(pool);
+}
+
+/**
+ * devm_qcom_tzmem_pool_new() - Managed variant of qcom_tzmem_pool_new().
+ * @dev: Device managing this resource.
+ * @config: Pool configuration.
+ *
+ * Must not be used in atomic context.
+ *
+ * Return: Address of the managed pool or ERR_PTR() on failure.
+ */
+struct qcom_tzmem_pool *
+devm_qcom_tzmem_pool_new(struct device *dev,
+			 const struct qcom_tzmem_pool_config *config)
+{
+	struct qcom_tzmem_pool *pool;
+	int ret;
+
+	pool = qcom_tzmem_pool_new(config);
+	if (IS_ERR(pool))
+		return pool;
+
+	ret = devm_add_action_or_reset(dev, devm_qcom_tzmem_pool_free, pool);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return pool;
+}
+EXPORT_SYMBOL_GPL(devm_qcom_tzmem_pool_new);
+
+static bool qcom_tzmem_try_grow_pool(struct qcom_tzmem_pool *pool,
+				     size_t requested, gfp_t gfp)
+{
+	size_t current_size = gen_pool_size(pool->genpool);
+
+	if (pool->max_size && (current_size + requested) > pool->max_size)
+		return false;
+
+	switch (pool->policy) {
+	case QCOM_TZMEM_POLICY_STATIC:
+		return false;
+	case QCOM_TZMEM_POLICY_MULTIPLIER:
+		requested = current_size * pool->increment;
+		break;
+	case QCOM_TZMEM_POLICY_ON_DEMAND:
+		break;
+	}
+
+	return !qcom_tzmem_pool_add_memory(pool, requested, gfp);
+}
+
+/**
+ * qcom_tzmem_alloc() - Allocate a memory chunk suitable for sharing with TZ.
+ * @pool: TZ memory pool from which to allocate memory.
+ * @size: Number of bytes to allocate.
+ * @gfp: GFP flags.
+ *
+ * Can be used in any context.
+ *
+ * Return:
+ * Address of the allocated buffer or NULL if no more memory can be allocated.
+ * The buffer must be released using qcom_tzmem_free().
+ */
+void *qcom_tzmem_alloc(struct qcom_tzmem_pool *pool, size_t size, gfp_t gfp)
+{
+	unsigned long vaddr;
+	int ret;
+
+	if (!size)
+		return NULL;
+
+	size = PAGE_ALIGN(size);
+
+	struct qcom_tzmem_chunk *chunk __free(kfree) = kzalloc(sizeof(*chunk),
+							       gfp);
+	if (!chunk)
+		return NULL;
+
+again:
+	vaddr = gen_pool_alloc(pool->genpool, size);
+	if (!vaddr) {
+		if (qcom_tzmem_try_grow_pool(pool, size, gfp))
+			goto again;
+
+		return NULL;
+	}
+
+	chunk->paddr = gen_pool_virt_to_phys(pool->genpool, vaddr);
+	chunk->size = size;
+	chunk->owner = pool;
+
+	scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock) {
+		ret = radix_tree_insert(&qcom_tzmem_chunks, vaddr, chunk);
+		if (ret) {
+			gen_pool_free(pool->genpool, vaddr, size);
+			return NULL;
+		}
+
+		chunk = NULL;
+	}
+
+	return (void *)vaddr;
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_alloc);
+
+/**
+ * qcom_tzmem_free() - Release a buffer allocated from a TZ memory pool.
+ * @vaddr: Virtual address of the buffer.
+ *
+ * Can be used in any context.
+ */
+void qcom_tzmem_free(void *vaddr)
+{
+	struct qcom_tzmem_chunk *chunk;
+
+	scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock)
+		chunk = radix_tree_delete_item(&qcom_tzmem_chunks,
+					       (unsigned long)vaddr, NULL);
+
+	if (!chunk) {
+		WARN(1, "Virtual address %p not owned by TZ memory allocator",
+		     vaddr);
+		return;
+	}
+
+	scoped_guard(spinlock_irqsave, &chunk->owner->lock)
+		gen_pool_free(chunk->owner->genpool, (unsigned long)vaddr,
+			      chunk->size);
+	kfree(chunk);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_free);
+
+/**
+ * qcom_tzmem_to_phys() - Map the virtual address of a TZ buffer to physical.
+ * @vaddr: Virtual address of the buffer allocated from a TZ memory pool.
+ *
+ * Can be used in any context. The address must have been returned by a call
+ * to qcom_tzmem_alloc().
+ *
+ * Returns: Physical address of the buffer.
+ */
+phys_addr_t qcom_tzmem_to_phys(void *vaddr)
+{
+	struct qcom_tzmem_chunk *chunk;
+
+	guard(spinlock_irqsave)(&qcom_tzmem_chunks_lock);
+
+	chunk = radix_tree_lookup(&qcom_tzmem_chunks, (unsigned long)vaddr);
+	if (!chunk)
+		return 0;
+
+	return chunk->paddr;
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_to_phys);
+
+int qcom_tzmem_enable(struct device *dev)
+{
+	if (qcom_tzmem_dev)
+		return -EBUSY;
+
+	qcom_tzmem_dev = dev;
+
+	return qcom_tzmem_init();
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_enable);
+
+MODULE_DESCRIPTION("TrustZone memory allocator for Qualcomm firmware drivers");
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_LICENSE("GPL");