Messages in this thread | | | Date | Thu, 1 Mar 2018 18:26:49 +0530 | From | Vinod Koul <> | Subject | Re: [PATCH v5 2/3] dmaengine: mediatek: Add MediaTek High-Speed DMA controller for MT7622 and MT7623 SoC |
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On Thu, Mar 01, 2018 at 06:27:01PM +0800, Sean Wang wrote: > On Thu, 2018-03-01 at 13:53 +0530, Vinod Koul wrote: > > On Sun, Feb 18, 2018 at 03:08:30AM +0800, sean.wang@mediatek.com wrote: > > > > > @@ -0,0 +1,1054 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > // Copyright ... > > > > The copyright line needs to follow SPDX tag line > > > > okay, I will make it reorder and be something like that > > // SPDX-License-Identifier: GPL-2.0 > /* > * Copyright (c) 2017-2018 MediaTek Inc. > * Author: Sean Wang <sean.wang@mediatek.com> > * > * Driver for MediaTek High-Speed DMA Controller > * > */
It needs to be:
// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2017-2018 MediaTek Inc.
/* * whatever else you want */
The first two lines are in C99 style comment and need to have SPDX tag and Copyright info
> the point is I learned from other subsystem makes the driver name be > same with the module name with KBUILD_MODNAME. > > If you really don't like it, I can just change it into > > #define MTK_DMA_DEV "mtk-hsdma"
It is used only once, why not use KBUILD_MODNAME directly?
> > > > + > > > +#define MTK_HSDMA_USEC_POLL 20 > > > +#define MTK_HSDMA_TIMEOUT_POLL 200000 > > > +#define MTK_HSDMA_DMA_BUSWIDTHS BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) > > > > Undefined buswidth??
??
> > > +/** > > > + * struct mtk_hsdma_pdesc - This is the struct holding info describing physical > > > + * descriptor (PD) and its placement must be kept at > > > + * 4-bytes alignment in little endian order. > > > + * @desc[1-4]: The control pad used to indicate hardware how to > > > > pls align to 80char or lesser > > > > weird, it seems the line is already with 80 char and pass the > checkpatch.pl. or do I misunderstand something ?
Okay please check. With text it helps to wrap before that
> > > + /* > > > + * Updating into hardware the pointer of TX ring lets HSDMA to take > > > + * action for those pending PDs. > > > + */ > > > + mtk_dma_write(hsdma, MTK_HSDMA_TX_CPU, ring->cur_tptr); > > > + > > > + spin_unlock_irqrestore(&hsdma->lock, flags); > > > + > > > + return !hvd->len ? 0 : -ENOSPC; > > > > you already wrote and started txn, so why this? > > > > it's possible just partial virtual descriptor fits into hardware and > then return -ENOSPC. And it will start it to complete the remaining part > as soon as possible when some rooms is being freed.
Either ways you have issued the descriptor, so you succeed right?
> > shouldn't we check if next is in range, we can crash if we get bad value > > from hardware.. > > okay, there are checks for next with ddone bit check and null check in > the corresponding descriptor as the following.
what if you get bad next value
> > > > + rxd = &pc->ring.rxd[next];
resulting in bad ref here
-- ~Vinod
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