Re: [PATCH v7 2/2] drm/lima: driver for ARM Mali4xx GPUs

[Qiang Yu <yuq825@gmail.com>]

On Thu, Mar 7, 2019 at 8:15 AM Dave Airlie <airlied@gmail.com> wrote:
>
> > +#endif
> > diff --git a/include/uapi/drm/lima_drm.h b/include/uapi/drm/lima_drm.h
> > new file mode 100644
> > index 000000000000..05f8c910d7fb
> > --- /dev/null
> > +++ b/include/uapi/drm/lima_drm.h
> > @@ -0,0 +1,164 @@
> > +/* SPDX-License-Identifier: (GPL-2.0 WITH Linux-syscall-note) OR MIT */
> > +/* Copyright 2017-2018 Qiang Yu <yuq825@gmail.com> */
> > +
> > +#ifndef __LIMA_DRM_H__
> > +#define __LIMA_DRM_H__
> > +
> > +#include "drm.h"
> > +
> > +#if defined(__cplusplus)
> > +extern "C" {
> > +#endif
> > +
> > +enum drm_lima_param_gpu_id {
> > +       DRM_LIMA_PARAM_GPU_ID_UNKNOWN,
> > +       DRM_LIMA_PARAM_GPU_ID_MALI400,
> > +       DRM_LIMA_PARAM_GPU_ID_MALI450,
> > +};
> > +
> > +enum drm_lima_param {
> > +       DRM_LIMA_PARAM_GPU_ID,
> > +       DRM_LIMA_PARAM_NUM_PP,
> > +       DRM_LIMA_PARAM_GP_VERSION,
> > +       DRM_LIMA_PARAM_PP_VERSION,
> > +};
> > +
> > +/**
> > + * get various information of the GPU
> > + */
> > +struct drm_lima_get_param {
> > +       __u32 param; /* in, value in enum drm_lima_param */
> > +       __u32 pad;   /* pad, must be zero */
> > +       __u64 value; /* out, parameter value */
> > +};
> > +
> > +/**
> > + * create a buffer for used by GPU
> > + */
> > +struct drm_lima_gem_create {
> > +       __u32 size;    /* in, buffer size */
> > +       __u32 flags;   /* in, currently no flags, must be zero */
> > +       __u32 handle;  /* out, GEM buffer handle */
> > +       __u32 pad;     /* pad, must be zero */
> > +};
> > +
> > +/**
> > + * get information of a buffer
> > + */
> > +struct drm_lima_gem_info {
> > +       __u32 handle;  /* in, GEM buffer handle */
> > +       __u32 va;      /* out, virtual address mapped into GPU MMU */
> > +       __u64 offset;  /* out, used to mmap this buffer to CPU */
> > +};
> > +
> > +#define LIMA_SUBMIT_BO_READ   0x01
> > +#define LIMA_SUBMIT_BO_WRITE  0x02
> > +
> > +/* buffer information used by one task */
> > +struct drm_lima_gem_submit_bo {
> > +       __u32 handle;  /* in, GEM buffer handle */
> > +       __u32 flags;   /* in, buffer read/write by GPU */
> > +};
> > +
> > +#define LIMA_GP_FRAME_REG_NUM 6
> > +
> > +/* frame used to setup GP for each task */
> > +struct drm_lima_gp_frame {
> > +       __u32 frame[LIMA_GP_FRAME_REG_NUM];
> > +};
> > +
> > +#define LIMA_PP_FRAME_REG_NUM 23
> > +#define LIMA_PP_WB_REG_NUM 12
> > +
> > +/* frame used to setup mali400 GPU PP for each task */
> > +struct drm_lima_m400_pp_frame {
> > +       __u32 frame[LIMA_PP_FRAME_REG_NUM];
> > +       __u32 num_pp;
> > +       __u32 wb[3 * LIMA_PP_WB_REG_NUM];
> > +       __u32 plbu_array_address[4];
> > +       __u32 fragment_stack_address[4];
> > +};
> > +
> > +/* frame used to setup mali450 GPU PP for each task */
> > +struct drm_lima_m450_pp_frame {
> > +       __u32 frame[LIMA_PP_FRAME_REG_NUM];
> > +       __u32 num_pp;
> > +       __u32 wb[3 * LIMA_PP_WB_REG_NUM];
> > +       __u32 use_dlbu;
> > +       __u32 _pad;
> > +       union {
> > +               __u32 plbu_array_address[8];
> > +               __u32 dlbu_regs[4];
> > +       };
> > +       __u32 fragment_stack_address[8];
> > +};
> > +
> > +#define LIMA_PIPE_GP  0x00
> > +#define LIMA_PIPE_PP  0x01
> > +
> > +#define LIMA_SUBMIT_FLAG_EXPLICIT_FENCE (1 << 0)
> > +
> > +/**
> > + * submit a task to GPU
> > + */
> > +struct drm_lima_gem_submit {
> > +       __u32 ctx;         /* in, context handle task is submitted to */
> > +       __u32 pipe;        /* in, which pipe to use, GP/PP */
> > +       __u32 nr_bos;      /* in, array length of bos field */
> > +       __u32 frame_size;  /* in, size of frame field */
> > +       __u64 bos;         /* in, array of drm_lima_gem_submit_bo */
> > +       __u64 frame;       /* in, GP/PP frame */
> > +       __u32 flags;       /* in, submit flags */
> > +       __u32 out_sync;    /* in, drm_syncobj handle used to wait task finish after submission */
> > +       __u32 in_sync[2];  /* in, drm_syncobj handle used to wait before start this task */
> > +};
>
> This seems a bit limited, is there a reason it's two, at least in
> Vulkan drivers we'd want more than two I suspect (Vulkan may not work
> on this hw anyways), but it might be required in the future to make
> this extensible.
Mali4xx GPU does not support Vulkan, the reason I pick two is, one for
sync_file fd imported drm_syncobj, one for GP out_sync be able to pass
to PP in_sync directly when explicit fence without
drm_syncobj -> sync_file -> merge sync_file -> drm_syncobj
pass.

>
> At least a comment stating why 2 was picked is sufficient for current use cases.
>
OK, will add it.

Regards,
Qiang
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