Hi, Vinod On Thu, 2018-03-01 at 18:26 +0530, Vinod Koul wrote: > 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@xxxxxxxxxxxx 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@xxxxxxxxxxxx> > > * > > * 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 Sure, I can do it using C99 style comments at the first two lines. In addition, I'm really curious where we can find a reference to the rule and if it 's a strict rule for all the drivers. Because I'm considering whether I should turn other driver into using the same rule. > > 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? > Yup, it can 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?? > > ?? Sorry for I didn't answer the question in the short time. After spending some time on a confirmation with design, it is DMA_SLAVE_BUSWIDTH_4_BYTES and not be configurable. > > > > > +/** > > > > + * 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 > After check again, these lines are all already aligned to 80 chars > > > > + /* > > > > + * 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? > I think I should get your points. I guessed what you meant is that it should be returning 0 instead of -ENOSPC for all successful descriptor issuing either in part or in full I will refine this flow based on the thought. > > > 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 > next is not hardware value. it's maintained by software which is always between 0 to MTK_DMA_SIZE - 1, and definitely doesn't get a bad value. > > > > > > + rxd = &pc->ring.rxd[next]; > > resulting in bad ref here rxd is also definitely a good ref > -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
