Re: [PATCH 06/14] dmaengine: dma-jz4780: Add support for the JZ4725B SoC

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





Le mer. 11 juil. 2018 à 14:18, Vinod <vkoul@xxxxxxxxxx> a écrit :
On 10-07-18, 17:45, Paul Cercueil wrote:


 Le lun. 9 juil. 2018 à 19:14, Vinod <vkoul@xxxxxxxxxx> a écrit :
 > On 03-07-18, 14:32, Paul Cercueil wrote:
 > >  The JZ4725B has one DMA core starring six DMA channels.
 > >  As for the JZ4770, each DMA channel's clock can be enabled with
> > a register write, the difference here being that once started, it
 > >  is not possible to turn it off.
 >
 > ok so disable for this, right..
 >
 > >  @@ -204,6 +205,8 @@ static inline void
 > > jz4780_dma_chan_enable(struct jz4780_dma_dev *jzdma,
 > >   {
 > >   	if (jzdma->version == ID_JZ4770)
 > >   		jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKES, BIT(chn));
 > >  +	else if (jzdma->version == ID_JZ4725B)
 > >  +		jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKE, BIT(chn));
 >
 > but you are writing to a different register here..

Yes. SoCs >= JZ4770 have the DCKE read-only register, and DCKES/DCKEC to
 set/clear bits in DCKE.
On JZ4725B, DCKE is read/write, but the zeros written are ignored (at least
 that's what the
 documentation says).

and that was not documented in the log... so i though it maybe a typo.

Right, I will add a comment in-code to explain that it's normal.

--
~Vinod

Thanks,
-Paul

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux