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This patch adds the command buffer (CB) module, which allows the user to create and destroy CBs and to map them to the user's process address-space. A command buffer is a memory blocks that reside in DMA-able address-space and is physically contiguous so it can be accessed by the device without MMU translation. The command buffer memory is allocated using the coherent DMA API. When creating a new CB, the IOCTL returns a handle of it, and the user-space process needs to use that handle to mmap the buffer to get a VA in the user's address-space. Before destroying (freeing) a CB, the user must unmap the CB's VA using the CB handle. Each CB has a reference counter, which tracks its usage in command submissions and also its mmaps (only a single mmap is allowed). The driver maintains a pool of pre-allocated CBs in order to reduce latency during command submissions. In case the pool is empty, the driver will go to the slow-path of allocating a new CB, i.e. calling dma_alloc_coherent. Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
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*
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* Copyright 2016-2018 HabanaLabs, Ltd.
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* All Rights Reserved.
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*
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*/
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#ifndef HABANALABS_H_
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#define HABANALABS_H_
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#include <linux/types.h>
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#include <linux/ioctl.h>
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/*
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* Defines that are asic-specific but constitutes as ABI between kernel driver
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* and userspace
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*/
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#define GOYA_KMD_SRAM_RESERVED_SIZE_FROM_START 0x8000 /* 32KB */
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/* Opcode to create a new command buffer */
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#define HL_CB_OP_CREATE 0
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/* Opcode to destroy previously created command buffer */
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#define HL_CB_OP_DESTROY 1
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struct hl_cb_in {
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/* Handle of CB or 0 if we want to create one */
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__u64 cb_handle;
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/* HL_CB_OP_* */
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__u32 op;
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/* Size of CB. Minimum requested size must be PAGE_SIZE */
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__u32 cb_size;
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/* Context ID - Currently not in use */
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__u32 ctx_id;
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__u32 pad;
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};
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struct hl_cb_out {
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/* Handle of CB */
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__u64 cb_handle;
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};
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union hl_cb_args {
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struct hl_cb_in in;
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struct hl_cb_out out;
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};
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/*
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* Command Buffer
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* - Request a Command Buffer
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* - Destroy a Command Buffer
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*
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* The command buffers are memory blocks that reside in DMA-able address
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* space and are physically contiguous so they can be accessed by the device
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* directly. They are allocated using the coherent DMA API.
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*
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* When creating a new CB, the IOCTL returns a handle of it, and the user-space
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* process needs to use that handle to mmap the buffer so it can access them.
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*
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*/
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#define HL_IOCTL_CB \
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_IOWR('H', 0x02, union hl_cb_args)
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#define HL_COMMAND_START 0x02
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#define HL_COMMAND_END 0x03
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#endif /* HABANALABS_H_ */
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