[PATCH v4 7/7] dma_buf: heaps: restricted_heap_mtk: Add a new CMA heap

[Yong Wu]

Create a new MediaTek CMA heap from the CMA reserved buffer.

In this heap, When the first allocating buffer, use cma_alloc to prepare
whole the CMA range, then send its range to TEE to protect and manage.
For the later allocating, we just adds the cma_used_size.

When SVP done, cma_release will release the buffer, then kernel may
reuse it.

For the "CMA" restricted heap, "struct cma *cma" is a common property,
not just for MediaTek, so put it into "struct restricted_heap" instead of
our private data.

Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
 drivers/dma-buf/heaps/Kconfig               |   2 +-
 drivers/dma-buf/heaps/restricted_heap.h     |   4 +
 drivers/dma-buf/heaps/restricted_heap_mtk.c | 120 +++++++++++++++++++-
 3 files changed, 123 insertions(+), 3 deletions(-)

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 84f748fb2856..58903bc62ac8 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -24,7 +24,7 @@ config DMABUF_HEAPS_RESTRICTED
 
 config DMABUF_HEAPS_RESTRICTED_MTK
 	bool "MediaTek DMA-BUF Restricted Heap"
-	depends on DMABUF_HEAPS_RESTRICTED && TEE=y
+	depends on DMABUF_HEAPS_RESTRICTED && DMA_CMA && TEE=y
 	help
 	  Enable restricted dma-buf heaps for MediaTek platform. This heap is backed by
 	  TEE client interfaces. If in doubt, say N.
diff --git a/drivers/dma-buf/heaps/restricted_heap.h b/drivers/dma-buf/heaps/restricted_heap.h
index 6c93f6d257dc..8d17c39b65de 100644
--- a/drivers/dma-buf/heaps/restricted_heap.h
+++ b/drivers/dma-buf/heaps/restricted_heap.h
@@ -21,6 +21,10 @@ struct restricted_heap {
 
 	const struct restricted_heap_ops *ops;
 
+	struct cma		*cma;
+	unsigned long		cma_paddr;
+	unsigned long		cma_size;
+
 	void			*priv_data;
 };
 
diff --git a/drivers/dma-buf/heaps/restricted_heap_mtk.c b/drivers/dma-buf/heaps/restricted_heap_mtk.c
index 902add95bb7e..0180d04076e2 100644
--- a/drivers/dma-buf/heaps/restricted_heap_mtk.c
+++ b/drivers/dma-buf/heaps/restricted_heap_mtk.c
@@ -4,9 +4,11 @@
  *
  * Copyright (C) 2024 MediaTek Inc.
  */
+#include <linux/cma.h>
 #include <linux/dma-buf.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/slab.h>
 #include <linux/tee_drv.h>
 #include <linux/uuid.h>
@@ -23,6 +25,13 @@ enum mtk_secure_mem_type {
 	 * management is inside the TEE.
 	 */
 	MTK_SECURE_MEMORY_TYPE_CM_TZ	= 1,
+	/*
+	 * MediaTek dynamic chunk memory carved out from CMA.
+	 * In normal case, the CMA could be used in kernel; When SVP start, we will
+	 * allocate whole this CMA and pass whole the CMA PA and size into TEE to
+	 * protect it, then the detail memory management also is inside the TEE.
+	 */
+	MTK_SECURE_MEMORY_TYPE_CM_CMA	= 2,
 };
 
 enum mtk_secure_buffer_tee_cmd {
@@ -32,6 +41,8 @@ enum mtk_secure_buffer_tee_cmd {
 	 * [in]  value[0].a: The buffer size.
 	 *       value[0].b: alignment.
 	 * [in]  value[1].a: enum mtk_secure_mem_type.
+	 * [in]  value[2].a: pa base in cma case.
+	 *       value[2].b: The buffer size in cma case.
 	 * [out] value[3].a: The secure handle.
 	 */
 	MTK_TZCMD_SECMEM_ZALLOC	= 0x10000, /* MTK TEE Command ID Base */
@@ -52,6 +63,9 @@ struct mtk_restricted_heap_data {
 
 	const enum mtk_secure_mem_type mem_type;
 
+	struct page		*cma_page;
+	unsigned long		cma_used_size;
+	struct mutex		lock; /* lock for cma_used_size */
 };
 
 static int mtk_tee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
@@ -125,6 +139,10 @@ static int mtk_tee_restrict_memory(struct restricted_heap *heap, struct restrict
 	params[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
 	params[1].u.value.a = data->mem_type;
 	params[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
+	if (heap->cma && data->mem_type == MTK_SECURE_MEMORY_TYPE_CM_CMA) {
+		params[2].u.value.a = heap->cma_paddr;
+		params[2].u.value.b = heap->cma_size;
+	}
 	params[3].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
 	ret = mtk_tee_service_call(data->tee_ctx, data->tee_session,
 				   MTK_TZCMD_SECMEM_ZALLOC, params);
@@ -163,6 +181,48 @@ mtk_restricted_memory_free(struct restricted_heap *heap, struct restricted_buffe
 {
 }
 
+static int mtk_restricted_memory_cma_allocate(struct restricted_heap *heap,
+					      struct restricted_buffer *buf)
+{
+	struct mtk_restricted_heap_data *data = heap->priv_data;
+	int ret = 0;
+	/*
+	 * Allocate CMA only when allocating buffer for the first time, and just
+	 * increase cma_used_size at the other time, Actually the memory
+	 * allocating is within the TEE.
+	 */
+	mutex_lock(&data->lock);
+	if (!data->cma_used_size) {
+		data->cma_page = cma_alloc(heap->cma, heap->cma_size >> PAGE_SHIFT,
+					   get_order(PAGE_SIZE), false);
+		if (!data->cma_page) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
+	} else if (data->cma_used_size + buf->size > heap->cma_size) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	data->cma_used_size += buf->size;
+
+out_unlock:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static void mtk_restricted_memory_cma_free(struct restricted_heap *heap,
+					   struct restricted_buffer *buf)
+{
+	struct mtk_restricted_heap_data *data = heap->priv_data;
+
+	mutex_lock(&data->lock);
+	data->cma_used_size -= buf->size;
+	if (!data->cma_used_size)
+		cma_release(heap->cma, data->cma_page,
+			    heap->cma_size >> PAGE_SHIFT);
+	mutex_unlock(&data->lock);
+}
+
 static int mtk_restricted_heap_init(struct restricted_heap *heap)
 {
 	struct mtk_restricted_heap_data *data = heap->priv_data;
@@ -184,21 +244,77 @@ static struct mtk_restricted_heap_data mtk_restricted_heap_data = {
 	.mem_type		= MTK_SECURE_MEMORY_TYPE_CM_TZ,
 };
 
+static const struct restricted_heap_ops mtk_restricted_heap_ops_cma = {
+	.heap_init		= mtk_restricted_heap_init,
+	.memory_alloc		= mtk_restricted_memory_cma_allocate,
+	.memory_free		= mtk_restricted_memory_cma_free,
+	.memory_restrict	= mtk_tee_restrict_memory,
+	.memory_unrestrict	= mtk_tee_unrestrict_memory,
+};
+
+static struct mtk_restricted_heap_data mtk_restricted_heap_data_cma = {
+	.mem_type		= MTK_SECURE_MEMORY_TYPE_CM_CMA,
+};
+
 static struct restricted_heap mtk_restricted_heaps[] = {
 	{
 		.name		= "restricted_mtk_cm",
 		.ops		= &mtk_restricted_heap_ops,
 		.priv_data	= &mtk_restricted_heap_data,
 	},
+	{
+		.name		= "restricted_mtk_cma",
+		.ops		= &mtk_restricted_heap_ops_cma,
+		.priv_data	= &mtk_restricted_heap_data_cma,
+	},
 };
 
+static int __init mtk_restricted_cma_init(struct reserved_mem *rmem)
+{
+	struct restricted_heap *rstrd_heap = mtk_restricted_heaps, *rstrd_heap_cma = NULL;
+	struct mtk_restricted_heap_data *data;
+	struct cma *cma;
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(mtk_restricted_heaps); i++, rstrd_heap++) {
+		data = rstrd_heap->priv_data;
+		if (data->mem_type == MTK_SECURE_MEMORY_TYPE_CM_CMA) {
+			rstrd_heap_cma = rstrd_heap;
+			break;
+		}
+	}
+	if (!rstrd_heap_cma)
+		return -EINVAL;
+
+	ret = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name,
+				    &cma);
+	if (ret) {
+		pr_err("%s: %s set up CMA fail\n", __func__, rmem->name);
+		return ret;
+	}
+
+	rstrd_heap_cma->cma = cma;
+	rstrd_heap_cma->cma_paddr = rmem->base;
+	rstrd_heap_cma->cma_size = rmem->size;
+	return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(restricted_cma, "mediatek,dynamic-restricted-region",
+		       mtk_restricted_cma_init);
+
 static int mtk_restricted_heap_initialize(void)
 {
 	struct restricted_heap *rstrd_heap = mtk_restricted_heaps;
+	struct mtk_restricted_heap_data *data;
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(mtk_restricted_heaps); i++, rstrd_heap++)
-		restricted_heap_add(rstrd_heap);
+	for (i = 0; i < ARRAY_SIZE(mtk_restricted_heaps); i++, rstrd_heap++) {
+		data = rstrd_heap->priv_data;
+		if (data->mem_type == MTK_SECURE_MEMORY_TYPE_CM_CMA && !rstrd_heap->cma)
+			continue;
+		if (!restricted_heap_add(rstrd_heap))
+			mutex_init(&data->lock);
+	}
 	return 0;
 }
 module_init(mtk_restricted_heap_initialize);
-- 
2.25.1