Re: [PATCH 4/9] dma-buf: heaps: Initialise MediaTek secure heap

[Vijayanand Jitta]

On 9/11/2023 8:00 AM, Yong Wu wrote:
> Initialise a mtk_svp heap. Currently just add a null heap, Prepare for
> the later patches.
> 
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
>  drivers/dma-buf/heaps/Kconfig           |  8 ++
>  drivers/dma-buf/heaps/Makefile          |  1 +
>  drivers/dma-buf/heaps/mtk_secure_heap.c | 99 +++++++++++++++++++++++++
>  3 files changed, 108 insertions(+)
>  create mode 100644 drivers/dma-buf/heaps/mtk_secure_heap.c
> 
> diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
> index a5eef06c4226..729c0cf3eb7c 100644
> --- a/drivers/dma-buf/heaps/Kconfig
> +++ b/drivers/dma-buf/heaps/Kconfig
> @@ -12,3 +12,11 @@ config DMABUF_HEAPS_CMA
>  	  Choose this option to enable dma-buf CMA heap. This heap is backed
>  	  by the Contiguous Memory Allocator (CMA). If your system has these
>  	  regions, you should say Y here.
> +
> +config DMABUF_HEAPS_MTK_SECURE
> +	bool "DMA-BUF MediaTek Secure Heap"
> +	depends on DMABUF_HEAPS && TEE
> +	help
> +	  Choose this option to enable dma-buf MediaTek secure heap for Secure
> +	  Video Path. This heap is backed by TEE client interfaces. If in
> +	  doubt, say N.
> diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
> index 974467791032..df559dbe33fe 100644
> --- a/drivers/dma-buf/heaps/Makefile
> +++ b/drivers/dma-buf/heaps/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)	+= system_heap.o
>  obj-$(CONFIG_DMABUF_HEAPS_CMA)		+= cma_heap.o
> +obj-$(CONFIG_DMABUF_HEAPS_MTK_SECURE)	+= mtk_secure_heap.o
> diff --git a/drivers/dma-buf/heaps/mtk_secure_heap.c b/drivers/dma-buf/heaps/mtk_secure_heap.c
> new file mode 100644
> index 000000000000..bbf1c8dce23e
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/mtk_secure_heap.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DMABUF mtk_secure_heap exporter
> + *
> + * Copyright (C) 2023 MediaTek Inc.
> + */
> +
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +/*
> + * MediaTek secure (chunk) memory type
> + *
> + * @KREE_MEM_SEC_CM_TZ: static chunk memory carved out for trustzone.
> + */
> +enum kree_mem_type {
> +	KREE_MEM_SEC_CM_TZ = 1,
> +};
> +
> +struct mtk_secure_heap_buffer {
> +	struct dma_heap		*heap;
> +	size_t			size;
> +};
> +
> +struct mtk_secure_heap {
> +	const char		*name;
> +	const enum kree_mem_type mem_type;
> +};
> +
> +static struct dma_buf *
> +mtk_sec_heap_allocate(struct dma_heap *heap, size_t size,
> +		      unsigned long fd_flags, unsigned long heap_flags)
> +{
> +	struct mtk_secure_heap_buffer *sec_buf;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +	struct dma_buf *dmabuf;
> +	int ret;
> +
> +	sec_buf = kzalloc(sizeof(*sec_buf), GFP_KERNEL);

As we know, kzalloc can only allocate 4MB at max. So, secure heap has this limitation.
can we have a way to allocate more memory in secure heap ? maybe similar to how system heap does?

Thanks,
Vijay

> +	if (!sec_buf)
> +		return ERR_PTR(-ENOMEM);
> +
> +	sec_buf->size = size;
> +	sec_buf->heap = heap;
> +
> +	exp_info.exp_name = dma_heap_get_name(heap);
> +	exp_info.size = sec_buf->size;
> +	exp_info.flags = fd_flags;
> +	exp_info.priv = sec_buf;
> +
> +	dmabuf = dma_buf_export(&exp_info);
> +	if (IS_ERR(dmabuf)) {
> +		ret = PTR_ERR(dmabuf);
> +		goto err_free_buf;
> +	}
> +
> +	return dmabuf;
> +
> +err_free_buf:
> +	kfree(sec_buf);
> +	return ERR_PTR(ret);
> +}
> +
> +static const struct dma_heap_ops mtk_sec_heap_ops = {
> +	.allocate	= mtk_sec_heap_allocate,
> +};
> +
> +static struct mtk_secure_heap mtk_sec_heap[] = {
> +	{
> +		.name		= "mtk_svp",
> +		.mem_type	= KREE_MEM_SEC_CM_TZ,
> +	},
> +};
> +
> +static int mtk_sec_heap_init(void)
> +{
> +	struct mtk_secure_heap *sec_heap = mtk_sec_heap;
> +	struct dma_heap_export_info exp_info;
> +	struct dma_heap *heap;
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(mtk_sec_heap); i++, sec_heap++) {
> +		exp_info.name = sec_heap->name;
> +		exp_info.ops = &mtk_sec_heap_ops;
> +		exp_info.priv = (void *)sec_heap;
> +
> +		heap = dma_heap_add(&exp_info);
> +		if (IS_ERR(heap))
> +			return PTR_ERR(heap);
> +	}
> +	return 0;
> +}
> +
> +module_init(mtk_sec_heap_init);
> +MODULE_DESCRIPTION("MediaTek Secure Heap Driver");
> +MODULE_LICENSE("GPL");