>> The device tree describes _all_ hardware in the system,
>> not just the things that are somewhat harder to probe
>> for.
>
> Actually, for embedded systems, the device tree is really only
> required to describe the things that it's useful for the Linux kernel
> to know.
Sure, for example it cou
Segher Boessenkool writes:
> The device tree describes _all_ hardware in the system,
> not just the things that are somewhat harder to probe
> for.
Actually, for embedded systems, the device tree is really only
required to describe the things that it's useful for the Linux kernel
to know.
The po
> It's not that bad in most respects, though unlike some, I don't
> think we need to stick dogmatically to the exact way that Open
> Firmware(tm) did everything.
s/did/does/
And for the record: neither do I.
Segher
___
Linuxppc-dev mailing list
L
> I thought the idea of the dts/of was for the hardware specific boot
> loader to tell the kernel about hardware that the kernel couldn't
> otherwise know about, because its not detectable by a bus probe
> method,
> etc. Its not there to tell you how to use the device or arbitrate
> which
> oth
Phil Terry wrote:
> Say I'm writing a sound card, video card, widget card, etc., driver.
>
> My driver gets loaded by virtue of detecting the card/device (via of,
> pci, usb, platform, whatever bus mechanisms).
>
> My driver would benefit from using a generic DMA device so it uses the
> internal
o:[EMAIL PROTECTED]
> > Sent: Thursday, July 12, 2007 1:54 AM
> > To: Wood Scott-B07421
> > Cc: Zhang Wei-r63237; linuxppc-dev@ozlabs.org; [EMAIL PROTECTED]
> > Subject: Re: [PATCH 1/4] Add DMA sector to
> > Documentation/powerpc/booting-without-of.txt file.
> >
&g
> -Original Message-
> From: Segher Boessenkool [mailto:[EMAIL PROTECTED]
> Sent: Thursday, July 12, 2007 1:54 AM
> To: Wood Scott-B07421
> Cc: Zhang Wei-r63237; linuxppc-dev@ozlabs.org; [EMAIL PROTECTED]
> Subject: Re: [PATCH 1/4] Add DMA sector to
> Document
Hi,
> -Original Message-
> From: Segher Boessenkool [mailto:[EMAIL PROTECTED]
> >> Call it "extended-chain-mode", perhaps?
> >
> > Is it maybe too long?
>
> Not really no. It's only 19 characters, and it isn't used
> all over the place, so that should be fine.
Ok,
>
> >>> +- res
>>> What if the mem-to-mem channels were explicitly labelled
>>> fsl,mpc8548-dma-mem-to-mem?
>> Why would you? Why would you put _any_ compatible property in
>> the individual channels, even; they aren't separate devices
>> after all.
>
> They should be. :-)
But they're not, no amount of wishi
Segher Boessenkool wrote:
>> What if the mem-to-mem channels were explicitly labelled
>> fsl,mpc8548-dma-mem-to-mem?
>
>
> Why would you? Why would you put _any_ compatible property in
> the individual channels, even; they aren't separate devices
> after all.
They should be. :-)
-Scott
_
>>> that if we really wanted to we could describe as a
>>> second reg resource in each channel, combined with a channel-ID
>>> property.
>> You cannot describe one register in two different nodes.
>
> Why not? It's read-only.
Because a register belongs to one, and only one, device
node. There
Segher Boessenkool wrote:
>> that if we really wanted to we could describe as a
>> second reg resource in each channel, combined with a channel-ID
>> property.
>
>
> You cannot describe one register in two different nodes.
Why not? It's read-only.
>> I'm not inclined to bother, though -- not
>> The generic DMA driver can look at the device tree, too. It's more
>> convenient to only have to look at the dma-controller node, true.
>> But with the proposed tree you have to look at all the channel nodes
>> already.
>
> But if the only way to tell is a phandle from the sound device, it has
Segher Boessenkool wrote:
> The generic DMA driver can look at the device tree, too. It's more
> convenient to only have to look at the dma-controller node, true.
> But with the proposed tree you have to look at all the channel nodes
> already.
But if the only way to tell is a phandle from the so
>>> Some hardware has DMA channels hardwired to certain peripherals,
>>> such as
>>> an audio codec. This keeps them from being used as general
>>> purpose DMA
>>> channels.
>> I think you need this knowledge in the kernel drivers anyway,
>> or at the very least, the device node for for exam
>>> I'd rather just treat the different DMA channels as independent
>>> devices,
>>> rather than children of a dma "bus", and change the compatible
>>> name if
>>> they're not general purpose. There's only one register that's
>>> shared
>>> among the channels, and it's a superfluous status s
Segher Boessenkool wrote:
>> Some hardware has DMA channels hardwired to certain peripherals, such as
>> an audio codec. This keeps them from being used as general purpose DMA
>> channels.
>
>
> I think you need this knowledge in the kernel drivers anyway,
> or at the very least, the device no
Zhang Wei-r63237 wrote:
>>Or don't call it anything. The ability to do extended chain mode is
>>implicit in being compatible with fsl,mpc8548-dma.
>
>
> The basic mode could be used for mpc83xx silicons.
Yes, and the 83xx device trees will list the compatible as
fsl,mpc8349-dma, not fsl,mpc854
>>> +- extended : Set the DMA channel to work at extended
>> chain mode.
>>> + If not set, the DMA channel will work at basic
>>> + chain mode.
>>
>> Call it "extended-chain-mode", perhaps?
>
> Is it maybe too long?
Not really no. It's only 19 characters, and i
>>> +- compatible : Should be "fsl,mpc8xxx-dma"
>>
>> Should _include_, not should _be_. And none of this xxx
>> business, of course.
>
> Especially since the 85xx/86xx version is not 100% compatible with the
> 83xx version. How about fsl,mpc8349-dma and fsl,mpc8548-dma for
> the two
> vari
Hi,
> -Original Message-
> From: Segher Boessenkool [mailto:[EMAIL PROTECTED]
>
> > + k) DMA
> > +
> > + This sector define DMA for dma-engine driver of Freescale
>
> It's called a "device node" or "node", not a "sector".
Ok, "node".
>
> > +- compatible : Should be "fsl,mpc8
Hi,
> -Original Message-
> From: Wood Scott-B07421
>
> On Tue, Jul 10, 2007 at 04:01:19PM +0200, Segher Boessenkool wrote:
> > > +- compatible : Should be "fsl,mpc8xxx-dma"
> >
> > Should _include_, not should _be_. And none of this xxx
> > business, of course.
>
> Especially sin
On Tue, Jul 10, 2007 at 04:01:19PM +0200, Segher Boessenkool wrote:
> > +- compatible : Should be "fsl,mpc8xxx-dma"
>
> Should _include_, not should _be_. And none of this xxx
> business, of course.
Especially since the 85xx/86xx version is not 100% compatible with the
83xx version. How abo
> + k) DMA
> +
> + This sector define DMA for dma-engine driver of Freescale
It's called a "device node" or "node", not a "sector".
> +- compatible : Should be "fsl,mpc8xxx-dma"
Should _include_, not should _be_. And none of this xxx
business, of course.
> +- extended : Set the DMA
This patch adds DMA sector to Documentation/powerpc/booting-without-of.txt file.
Signed-off-by: Zhang Wei <[EMAIL PROTECTED]>
Signed-off-by: Ebony Zhu <[EMAIL PROTECTED]>
---
Documentation/powerpc/booting-without-of.txt | 60 ++
1 files changed, 60 insertions(+), 0 delet
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