From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:59391 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751975AbdAROiE (ORCPT ); Wed, 18 Jan 2017 09:38:04 -0500 Subject: Re: [PATCH] [media] s5p-mfc: Align stream buffer and CPB buffer to 512 To: Smitha T Murthy , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kyungmin.park@samsung.com, kamil@wypas.org, jtp.park@samsung.com, mchehab@kernel.org, pankaj.dubey@samsung.com, krzk@kernel.org, m.szyprowski@samsung.com From: Andrzej Hajda Message-id: Date: Wed, 18 Jan 2017 15:37:09 +0100 MIME-version: 1.0 In-reply-to: <1484732223-24670-1-git-send-email-smitha.t@samsung.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit References: <1484732223-24670-1-git-send-email-smitha.t@samsung.com> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Smitha, On 18.01.2017 10:37, Smitha T Murthy wrote: > >From MFCv6 onwards encoder stream buffer and decoder CPB buffer Unexpected char at the beginning. > need to be aligned with 512. Patch below adds checks only if buffer size is multiple of 512, am I right? If yes, please precise the subject, for example "...CPB buffer size need to be...". > > Signed-off-by: Smitha T Murthy > --- > drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c | 9 +++++++++ > drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.h | 3 +++ > 2 files changed, 12 insertions(+), 0 deletions(-) > > diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c b/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c > index d6f207e..57da798 100644 > --- a/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c > +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.c > @@ -408,8 +408,15 @@ static int s5p_mfc_set_dec_stream_buffer_v6(struct s5p_mfc_ctx *ctx, > struct s5p_mfc_dev *dev = ctx->dev; > const struct s5p_mfc_regs *mfc_regs = dev->mfc_regs; > struct s5p_mfc_buf_size *buf_size = dev->variant->buf_size; > + size_t cpb_buf_size; > > mfc_debug_enter(); > + cpb_buf_size = ALIGN(buf_size->cpb, CPB_ALIGN); Since buf_size->cpb is constant of know size there is no need to align it here. > + if (strm_size >= set_strm_size_max(cpb_buf_size)) { > + mfc_debug(2, "Decrease strm_size : %u -> %zu, gap : %d\n", > + strm_size, set_strm_size_max(cpb_buf_size), CPB_ALIGN); > + strm_size = set_strm_size_max(cpb_buf_size); > + } As I understand strm_size here is a size of buffer to be decoded, why it cannot be equal to buf_size->cpb? Commit message says nothing about it. > mfc_debug(2, "inst_no: %d, buf_addr: 0x%08x,\n" > "buf_size: 0x%08x (%d)\n", > ctx->inst_no, buf_addr, strm_size, strm_size); > @@ -519,6 +526,8 @@ static int s5p_mfc_set_enc_stream_buffer_v6(struct s5p_mfc_ctx *ctx, > struct s5p_mfc_dev *dev = ctx->dev; > const struct s5p_mfc_regs *mfc_regs = dev->mfc_regs; > > + size = ALIGN(size, 512); > + Shouldn't be CPB_ALIGN instead of 512? And more importantly size is a length of buffer for encoded stream, by up-aligning you tell MFC that it can write beyond the buffer, it could potentially overwrite random memory? Am I right? > writel(addr, mfc_regs->e_stream_buffer_addr); /* 16B align */ > writel(size, mfc_regs->e_stream_buffer_size); > > diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.h b/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.h > index 8055848..16a7b1d 100644 > --- a/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.h > +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_opr_v6.h > @@ -40,6 +40,9 @@ > #define FRAME_DELTA_H264_H263 1 > #define TIGHT_CBR_MAX 10 > > +#define CPB_ALIGN 512 > +#define set_strm_size_max(cpb_max) ((cpb_max) - CPB_ALIGN) Name of the macro is misleading. Regards Andrzej > + > struct s5p_mfc_hw_ops *s5p_mfc_init_hw_ops_v6(void); > const struct s5p_mfc_regs *s5p_mfc_init_regs_v6_plus(struct s5p_mfc_dev *dev); > #endif /* S5P_MFC_OPR_V6_H_ */