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Message-ID: <eeca2c7a694cbed0d7598177ebdd3bb4bf341622.camel@collabora.com>
Date: Tue, 28 Sep 2021 14:59:05 -0400
From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
To: Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
Andrzej Pietrasiewicz <andrzej.p@...labora.com>
Cc: linux-media@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
linux-staging@...ts.linux.dev,
Benjamin Gaignard <benjamin.gaignard@...labora.com>,
Boris Brezillon <boris.brezillon@...labora.com>,
Fabio Estevam <festevam@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Hans Verkuil <hverkuil-cisco@...all.nl>,
Heiko Stuebner <heiko@...ech.de>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
NXP Linux Team <linux-imx@....com>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Philipp Zabel <p.zabel@...gutronix.de>,
Sascha Hauer <s.hauer@...gutronix.de>,
Shawn Guo <shawnguo@...nel.org>, kernel@...labora.com,
bob.beckett@...labora.com
Subject: Re: [PATCH v6 09/10] media: hantro: Support VP9 on the G2 core
Le mardi 28 septembre 2021 à 13:55 -0300, Ezequiel Garcia a écrit :
> On Tue, Sep 28, 2021 at 05:39:02PM +0200, Andrzej Pietrasiewicz wrote:
> > Hi Nicolas,
> >
> > W dniu 27.09.2021 o 21:17, Nicolas Dufresne pisze:
> > > Le lundi 27 septembre 2021 à 17:19 +0200, Andrzej Pietrasiewicz a écrit :
> > > > VeriSilicon Hantro G2 core supports VP9 codec.
> > > >
> > > > Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@...labora.com>
> > > > Reviewed-by: Benjamin Gaignard <benjamin.gaignard@...labora.com>
> > > > ---
> > > > drivers/staging/media/hantro/Kconfig | 1 +
> > > > drivers/staging/media/hantro/Makefile | 6 +-
> > > > drivers/staging/media/hantro/hantro.h | 26 +
> > > > drivers/staging/media/hantro/hantro_drv.c | 18 +-
> > > > drivers/staging/media/hantro/hantro_g2_regs.h | 97 ++
> > > > .../staging/media/hantro/hantro_g2_vp9_dec.c | 978 ++++++++++++++++++
> > > > drivers/staging/media/hantro/hantro_hw.h | 67 ++
> > > > drivers/staging/media/hantro/hantro_v4l2.c | 6 +
> > > > drivers/staging/media/hantro/hantro_vp9.c | 240 +++++
> > > > drivers/staging/media/hantro/hantro_vp9.h | 103 ++
> > > > drivers/staging/media/hantro/imx8m_vpu_hw.c | 22 +-
> > > > 11 files changed, 1560 insertions(+), 4 deletions(-)
> > > > create mode 100644 drivers/staging/media/hantro/hantro_g2_vp9_dec.c
> > > > create mode 100644 drivers/staging/media/hantro/hantro_vp9.c
> > > > create mode 100644 drivers/staging/media/hantro/hantro_vp9.h
> > > >
> > > > diff --git a/drivers/staging/media/hantro/Kconfig b/drivers/staging/media/hantro/Kconfig
> > > > index 20b1f6d7b69c..00a57d88c92e 100644
> > > > --- a/drivers/staging/media/hantro/Kconfig
> > > > +++ b/drivers/staging/media/hantro/Kconfig
> > > > @@ -9,6 +9,7 @@ config VIDEO_HANTRO
> > > > select VIDEOBUF2_VMALLOC
> > > > select V4L2_MEM2MEM_DEV
> > > > select V4L2_H264
> > > > + select V4L2_VP9
> > > > help
> > > > Support for the Hantro IP based Video Processing Units present on
> > > > Rockchip and NXP i.MX8M SoCs, which accelerate video and image
> > > > diff --git a/drivers/staging/media/hantro/Makefile b/drivers/staging/media/hantro/Makefile
> > > > index fe6d84871d07..28af0a1ee4bf 100644
> > > > --- a/drivers/staging/media/hantro/Makefile
> > > > +++ b/drivers/staging/media/hantro/Makefile
> > > > @@ -10,9 +10,10 @@ hantro-vpu-y += \
> > > > hantro_g1.o \
> > > > hantro_g1_h264_dec.o \
> > > > hantro_g1_mpeg2_dec.o \
> > > > - hantro_g2_hevc_dec.o \
> > > > hantro_g1_vp8_dec.o \
> > > > hantro_g2.o \
> > > > + hantro_g2_hevc_dec.o \
> > > > + hantro_g2_vp9_dec.o \
> > > > rockchip_vpu2_hw_jpeg_enc.o \
> > > > rockchip_vpu2_hw_h264_dec.o \
> > > > rockchip_vpu2_hw_mpeg2_dec.o \
> > > > @@ -21,7 +22,8 @@ hantro-vpu-y += \
> > > > hantro_h264.o \
> > > > hantro_hevc.o \
> > > > hantro_mpeg2.o \
> > > > - hantro_vp8.o
> > > > + hantro_vp8.o \
> > > > + hantro_vp9.o
> > > > hantro-vpu-$(CONFIG_VIDEO_HANTRO_IMX8M) += \
> > > > imx8m_vpu_hw.o
> > > > diff --git a/drivers/staging/media/hantro/hantro.h b/drivers/staging/media/hantro/hantro.h
> > > > index d91eb2b1c509..1e8c1a6e3eb0 100644
> > > > --- a/drivers/staging/media/hantro/hantro.h
> > > > +++ b/drivers/staging/media/hantro/hantro.h
> > > > @@ -36,6 +36,7 @@ struct hantro_postproc_ops;
> > > > #define HANTRO_VP8_DECODER BIT(17)
> > > > #define HANTRO_H264_DECODER BIT(18)
> > > > #define HANTRO_HEVC_DECODER BIT(19)
> > > > +#define HANTRO_VP9_DECODER BIT(20)
> > > > #define HANTRO_DECODERS 0xffff0000
> > > > /**
> > > > @@ -110,6 +111,7 @@ enum hantro_codec_mode {
> > > > HANTRO_MODE_MPEG2_DEC,
> > > > HANTRO_MODE_VP8_DEC,
> > > > HANTRO_MODE_HEVC_DEC,
> > > > + HANTRO_MODE_VP9_DEC,
> > > > };
> > > > /*
> > > > @@ -223,6 +225,7 @@ struct hantro_dev {
> > > > * @mpeg2_dec: MPEG-2-decoding context.
> > > > * @vp8_dec: VP8-decoding context.
> > > > * @hevc_dec: HEVC-decoding context.
> > > > + * @vp9_dec: VP9-decoding context.
> > > > */
> > > > struct hantro_ctx {
> > > > struct hantro_dev *dev;
> > > > @@ -250,6 +253,7 @@ struct hantro_ctx {
> > > > struct hantro_mpeg2_dec_hw_ctx mpeg2_dec;
> > > > struct hantro_vp8_dec_hw_ctx vp8_dec;
> > > > struct hantro_hevc_dec_hw_ctx hevc_dec;
> > > > + struct hantro_vp9_dec_hw_ctx vp9_dec;
> > > > };
> > > > };
> > > > @@ -299,6 +303,22 @@ struct hantro_postproc_regs {
> > > > struct hantro_reg display_width;
> > > > };
> > > > +struct hantro_vp9_decoded_buffer_info {
> > > > + /* Info needed when the decoded frame serves as a reference frame. */
> > > > + unsigned short width;
> > > > + unsigned short height;
> > > > + u32 bit_depth : 4;
> > > > +};
> > > > +
> > > > +struct hantro_decoded_buffer {
> > > > + /* Must be the first field in this struct. */
> > > > + struct v4l2_m2m_buffer base;
> > > > +
> > > > + union {
> > > > + struct hantro_vp9_decoded_buffer_info vp9;
> > > > + };
> > > > +};
> > > > +
> > > > /* Logging helpers */
> > > > /**
> > > > @@ -436,6 +456,12 @@ hantro_get_dec_buf_addr(struct hantro_ctx *ctx, struct vb2_buffer *vb)
> > > > return vb2_dma_contig_plane_dma_addr(vb, 0);
> > > > }
> > > > +static inline struct hantro_decoded_buffer *
> > > > +vb2_to_hantro_decoded_buf(struct vb2_buffer *buf)
> > > > +{
> > > > + return container_of(buf, struct hantro_decoded_buffer, base.vb.vb2_buf);
> > > > +}
> > > > +
> > > > void hantro_postproc_disable(struct hantro_ctx *ctx);
> > > > void hantro_postproc_enable(struct hantro_ctx *ctx);
> > > > void hantro_postproc_free(struct hantro_ctx *ctx);
> > > > diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
> > > > index 8a2edd67f2c6..800c8879aee0 100644
> > > > --- a/drivers/staging/media/hantro/hantro_drv.c
> > > > +++ b/drivers/staging/media/hantro/hantro_drv.c
> > > > @@ -232,7 +232,7 @@ queue_init(void *priv, struct vb2_queue *src_vq, struct vb2_queue *dst_vq)
> > > > dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> > > > dst_vq->drv_priv = ctx;
> > > > dst_vq->ops = &hantro_queue_ops;
> > > > - dst_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
> > > > + dst_vq->buf_struct_size = sizeof(struct hantro_decoded_buffer);
> > > > dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> > > > dst_vq->lock = &ctx->dev->vpu_mutex;
> > > > dst_vq->dev = ctx->dev->v4l2_dev.dev;
> > > > @@ -266,6 +266,12 @@ static int hantro_try_ctrl(struct v4l2_ctrl *ctrl)
> > > > if (sps->flags & V4L2_HEVC_SPS_FLAG_SCALING_LIST_ENABLED)
> > > > /* No scaling support */
> > > > return -EINVAL;
> > > > + } else if (ctrl->id == V4L2_CID_STATELESS_VP9_FRAME) {
> > > > + const struct v4l2_ctrl_vp9_frame *dec_params = ctrl->p_new.p_vp9_frame;
> > > > +
> > > > + /* We only support profile 0 */
> > > > + if (dec_params->profile != 0)
> > > > + return -EINVAL;
> > > > }
> > > > return 0;
> > > > }
> > > > @@ -459,6 +465,16 @@ static const struct hantro_ctrl controls[] = {
> > > > .step = 1,
> > > > .ops = &hantro_hevc_ctrl_ops,
> > > > },
> > > > + }, {
> > > > + .codec = HANTRO_VP9_DECODER,
> > > > + .cfg = {
> > > > + .id = V4L2_CID_STATELESS_VP9_FRAME,
> > > > + },
> > > > + }, {
> > > > + .codec = HANTRO_VP9_DECODER,
> > > > + .cfg = {
> > > > + .id = V4L2_CID_STATELESS_VP9_COMPRESSED_HDR,
> > > > + },
> > > > },
> > > > };
> > > > diff --git a/drivers/staging/media/hantro/hantro_g2_regs.h b/drivers/staging/media/hantro/hantro_g2_regs.h
> > > > index 0ac0ba375e80..21ca21648614 100644
> > > > --- a/drivers/staging/media/hantro/hantro_g2_regs.h
> > > > +++ b/drivers/staging/media/hantro/hantro_g2_regs.h
> > > > @@ -28,6 +28,7 @@
> > > > #define G2_REG_INTERRUPT_DEC_E BIT(0)
> > > > #define HEVC_DEC_MODE 0xc
> > > > +#define VP9_DEC_MODE 0xd
> > > > #define BUS_WIDTH_32 0
> > > > #define BUS_WIDTH_64 1
> > > > @@ -49,6 +50,7 @@
> > > > #define g2_pic_height_in_cbs G2_DEC_REG(4, 6, 0x1fff)
> > > > #define g2_num_ref_frames G2_DEC_REG(4, 0, 0x1f)
> > > > +#define g2_start_bit G2_DEC_REG(5, 25, 0x7f)
> > > > #define g2_scaling_list_e G2_DEC_REG(5, 24, 0x1)
> > > > #define g2_cb_qp_offset G2_DEC_REG(5, 19, 0x1f)
> > > > #define g2_cr_qp_offset G2_DEC_REG(5, 14, 0x1f)
> > > > @@ -84,6 +86,7 @@
> > > > #define g2_bit_depth_y_minus8 G2_DEC_REG(8, 6, 0x3)
> > > > #define g2_bit_depth_c_minus8 G2_DEC_REG(8, 4, 0x3)
> > > > #define g2_output_8_bits G2_DEC_REG(8, 3, 0x1)
> > > > +#define g2_output_format G2_DEC_REG(8, 0, 0x7)
> > > > #define g2_refidx1_active G2_DEC_REG(9, 19, 0x1f)
> > > > #define g2_refidx0_active G2_DEC_REG(9, 14, 0x1f)
> > > > @@ -96,6 +99,14 @@
> > > > #define g2_tile_e G2_DEC_REG(10, 1, 0x1)
> > > > #define g2_entropy_sync_e G2_DEC_REG(10, 0, 0x1)
> > > > +#define vp9_transform_mode G2_DEC_REG(11, 27, 0x7)
> > > > +#define vp9_filt_sharpness G2_DEC_REG(11, 21, 0x7)
> > > > +#define vp9_mcomp_filt_type G2_DEC_REG(11, 8, 0x7)
> > > > +#define vp9_high_prec_mv_e G2_DEC_REG(11, 7, 0x1)
> > > > +#define vp9_comp_pred_mode G2_DEC_REG(11, 4, 0x3)
> > > > +#define vp9_gref_sign_bias G2_DEC_REG(11, 2, 0x1)
> > > > +#define vp9_aref_sign_bias G2_DEC_REG(11, 0, 0x1)
> > > > +
> > > > #define g2_refer_lterm_e G2_DEC_REG(12, 16, 0xffff)
> > > > #define g2_min_cb_size G2_DEC_REG(12, 13, 0x7)
> > > > #define g2_max_cb_size G2_DEC_REG(12, 10, 0x7)
> > > > @@ -154,6 +165,50 @@
> > > > #define g2_partial_ctb_y G2_DEC_REG(20, 30, 0x1)
> > > > #define g2_pic_width_4x4 G2_DEC_REG(20, 16, 0xfff)
> > > > #define g2_pic_height_4x4 G2_DEC_REG(20, 0, 0xfff)
> > > > +
> > > > +#define vp9_qp_delta_y_dc G2_DEC_REG(13, 23, 0x3f)
> > > > +#define vp9_qp_delta_ch_dc G2_DEC_REG(13, 17, 0x3f)
> > > > +#define vp9_qp_delta_ch_ac G2_DEC_REG(13, 11, 0x3f)
> > > > +#define vp9_last_sign_bias G2_DEC_REG(13, 10, 0x1)
> > > > +#define vp9_lossless_e G2_DEC_REG(13, 9, 0x1)
> > > > +#define vp9_comp_pred_var_ref1 G2_DEC_REG(13, 7, 0x3)
> > > > +#define vp9_comp_pred_var_ref0 G2_DEC_REG(13, 5, 0x3)
> > > > +#define vp9_comp_pred_fixed_ref G2_DEC_REG(13, 3, 0x3)
> > > > +#define vp9_segment_temp_upd_e G2_DEC_REG(13, 2, 0x1)
> > > > +#define vp9_segment_upd_e G2_DEC_REG(13, 1, 0x1)
> > > > +#define vp9_segment_e G2_DEC_REG(13, 0, 0x1)
> > > > +
> > > > +#define vp9_filt_level G2_DEC_REG(14, 18, 0x3f)
> > > > +#define vp9_refpic_seg0 G2_DEC_REG(14, 15, 0x7)
> > > > +#define vp9_skip_seg0 G2_DEC_REG(14, 14, 0x1)
> > > > +#define vp9_filt_level_seg0 G2_DEC_REG(14, 8, 0x3f)
> > > > +#define vp9_quant_seg0 G2_DEC_REG(14, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg1 G2_DEC_REG(15, 15, 0x7)
> > > > +#define vp9_skip_seg1 G2_DEC_REG(15, 14, 0x1)
> > > > +#define vp9_filt_level_seg1 G2_DEC_REG(15, 8, 0x3f)
> > > > +#define vp9_quant_seg1 G2_DEC_REG(15, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg2 G2_DEC_REG(16, 15, 0x7)
> > > > +#define vp9_skip_seg2 G2_DEC_REG(16, 14, 0x1)
> > > > +#define vp9_filt_level_seg2 G2_DEC_REG(16, 8, 0x3f)
> > > > +#define vp9_quant_seg2 G2_DEC_REG(16, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg3 G2_DEC_REG(17, 15, 0x7)
> > > > +#define vp9_skip_seg3 G2_DEC_REG(17, 14, 0x1)
> > > > +#define vp9_filt_level_seg3 G2_DEC_REG(17, 8, 0x3f)
> > > > +#define vp9_quant_seg3 G2_DEC_REG(17, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg4 G2_DEC_REG(18, 15, 0x7)
> > > > +#define vp9_skip_seg4 G2_DEC_REG(18, 14, 0x1)
> > > > +#define vp9_filt_level_seg4 G2_DEC_REG(18, 8, 0x3f)
> > > > +#define vp9_quant_seg4 G2_DEC_REG(18, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg5 G2_DEC_REG(19, 15, 0x7)
> > > > +#define vp9_skip_seg5 G2_DEC_REG(19, 14, 0x1)
> > > > +#define vp9_filt_level_seg5 G2_DEC_REG(19, 8, 0x3f)
> > > > +#define vp9_quant_seg5 G2_DEC_REG(19, 0, 0xff)
> > > > +
> > > > #define hevc_cur_poc_00 G2_DEC_REG(46, 24, 0xff)
> > > > #define hevc_cur_poc_01 G2_DEC_REG(46, 16, 0xff)
> > > > #define hevc_cur_poc_02 G2_DEC_REG(46, 8, 0xff)
> > > > @@ -174,6 +229,44 @@
> > > > #define hevc_cur_poc_14 G2_DEC_REG(49, 8, 0xff)
> > > > #define hevc_cur_poc_15 G2_DEC_REG(49, 0, 0xff)
> > > > +#define vp9_refpic_seg6 G2_DEC_REG(31, 15, 0x7)
> > > > +#define vp9_skip_seg6 G2_DEC_REG(31, 14, 0x1)
> > > > +#define vp9_filt_level_seg6 G2_DEC_REG(31, 8, 0x3f)
> > > > +#define vp9_quant_seg6 G2_DEC_REG(31, 0, 0xff)
> > > > +
> > > > +#define vp9_refpic_seg7 G2_DEC_REG(32, 15, 0x7)
> > > > +#define vp9_skip_seg7 G2_DEC_REG(32, 14, 0x1)
> > > > +#define vp9_filt_level_seg7 G2_DEC_REG(32, 8, 0x3f)
> > > > +#define vp9_quant_seg7 G2_DEC_REG(32, 0, 0xff)
> > > > +
> > > > +#define vp9_lref_width G2_DEC_REG(33, 16, 0xffff)
> > > > +#define vp9_lref_height G2_DEC_REG(33, 0, 0xffff)
> > > > +
> > > > +#define vp9_gref_width G2_DEC_REG(34, 16, 0xffff)
> > > > +#define vp9_gref_height G2_DEC_REG(34, 0, 0xffff)
> > > > +
> > > > +#define vp9_aref_width G2_DEC_REG(35, 16, 0xffff)
> > > > +#define vp9_aref_height G2_DEC_REG(35, 0, 0xffff)
> > > > +
> > > > +#define vp9_lref_hor_scale G2_DEC_REG(36, 16, 0xffff)
> > > > +#define vp9_lref_ver_scale G2_DEC_REG(36, 0, 0xffff)
> > > > +
> > > > +#define vp9_gref_hor_scale G2_DEC_REG(37, 16, 0xffff)
> > > > +#define vp9_gref_ver_scale G2_DEC_REG(37, 0, 0xffff)
> > > > +
> > > > +#define vp9_aref_hor_scale G2_DEC_REG(38, 16, 0xffff)
> > > > +#define vp9_aref_ver_scale G2_DEC_REG(38, 0, 0xffff)
> > > > +
> > > > +#define vp9_filt_ref_adj_0 G2_DEC_REG(46, 24, 0x7f)
> > > > +#define vp9_filt_ref_adj_1 G2_DEC_REG(46, 16, 0x7f)
> > > > +#define vp9_filt_ref_adj_2 G2_DEC_REG(46, 8, 0x7f)
> > > > +#define vp9_filt_ref_adj_3 G2_DEC_REG(46, 0, 0x7f)
> > > > +
> > > > +#define vp9_filt_mb_adj_0 G2_DEC_REG(47, 24, 0x7f)
> > > > +#define vp9_filt_mb_adj_1 G2_DEC_REG(47, 16, 0x7f)
> > > > +#define vp9_filt_mb_adj_2 G2_DEC_REG(47, 8, 0x7f)
> > > > +#define vp9_filt_mb_adj_3 G2_DEC_REG(47, 0, 0x7f)
> > > > +
> > > > #define g2_apf_threshold G2_DEC_REG(55, 0, 0xffff)
> > > > #define g2_clk_gate_e G2_DEC_REG(58, 16, 0x1)
> > > > @@ -186,6 +279,8 @@
> > > > #define G2_ADDR_DST (G2_SWREG(65))
> > > > #define G2_REG_ADDR_REF(i) (G2_SWREG(67) + ((i) * 0x8))
> > > > +#define VP9_ADDR_SEGMENT_WRITE (G2_SWREG(79))
> > > > +#define VP9_ADDR_SEGMENT_READ (G2_SWREG(81))
> > > > #define G2_ADDR_DST_CHR (G2_SWREG(99))
> > > > #define G2_REG_CHR_REF(i) (G2_SWREG(101) + ((i) * 0x8))
> > > > #define G2_ADDR_DST_MV (G2_SWREG(133))
> > > > @@ -193,6 +288,8 @@
> > > > #define G2_ADDR_TILE_SIZE (G2_SWREG(167))
> > >
> > > I think this name can be improved. We don't say "G2 address tile size", but "G2
> > > tile size address". Also, there is multiple tile sizes, so I'd prefer if we say
> > > "G2 tile sizes address". May I suggest this naming then ?
> > >
> > > #define G2_TILE_SIZES_ADDR_LSB ...
> > >
> > > As a reference, VSI names this sw_tile_base_lsb . That denotes that the name
> > > also fails to capture that this is only the lower 32bit of the tile_sizes
> > > address and that if someone have a G2 core on a larger amount of RAM it will
> > > need to figure where is the second half (spoiler, it looks like it's
> > > G1_SWREG(166) ). Anyway, that's why I'm proposing dropping LSB in there. Not
> > > sure between LSB_ADDR or ADDR_LSB.
> >
> > The LSB/MSB point is indeed valid. I think I will change hantro_write_addr() to
> > something on the lines of:
> >
> > static inline void hantro_write_addr(struct hantro_dev *vpu,
> > unsigned long offset,
> > dma_addr_t addr)
> > {
> > vdpu_write(vpu, addr & 0xffffffff, offset);
> > #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> > vdpu_write(vpu, (addr >> 32) & 0xffffffff, offset + 4);
> > #endif
> > }
> >
> > Then the #defines will not need the _LSB/_MSB suffixes at all
> > (and will remain as they are) and the modified function will
> > still do the right thing.
> >
>
> I'd rather not go in this direction. First of all, ifdefs are something
> to avoid, and only use if really needed. I know there are other drivers
> doing this, but that doesn't mean it's nice.
>
> And then I'm not sure if this is even correct. The MSB bits are needed
> if the device is sitting on a bus that can do 64-bits DMA.
> That _may_ be something you can figure out per architecture,
> but doesn't have to be like that.
>
> For instance, the Hantro device could be sitting on PCI (Adding
> Robert in Cc who can comment on this).
>
> For now, I don't think we care given we are setting
> the DMA mask to 32-bits (see hantro_probe). So we won't get
> 64-bit addresses. I'd really like to see 64-bit support
> via the LSB/MSB registers, but I think it's not something
> we should cover on this VP9 patchset.
Perhaps you wanted to suggest to just clear the MSB to 0 for now ? Or perhaps
you forgot to make a suggestion and have something else in mind ?
The register names are written as foot guns, they don't match either HW designer
doc, or vendor code, and they are missing previous information, like being an
address, or having a companion MSB addr. We don't have to fix everything, but I
think when we notice such thing, it should at least go into TODOs of the
respective staging driver if not already there.
>
> One more thing: is it correct to assume that the MSB register
> is always right after the LSB register? Is that the case
> for all buffers and Hantro-like variants?
Well, no, since it's always before (e.g. REG 166 is sw_tile_base_msb and REG
167 is sw_tile_base_lsb). I didn't comment as this was commented as "something
on the lines of:" and I'm pretty sure Andrzej Pietrasiewicz would have noticed.
Though, from the best of my reading of the ref code and register map document I
have, it's consistent for all addresses.
>
> Thanks,
> Ezequiel
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