From: Sylvain Munaut <tnt@246tNt•com>
To: Arnd Bergmann <arnd@arndb•de>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [PATCH 4/9] powerpc: BestComm core support for Freescale MPC5200
Date: Sun, 13 May 2007 09:17:10 +0200 [thread overview]
Message-ID: <4646BB76.1080602@246tNt.com> (raw)
In-Reply-To: <200705130224.46114.arnd@arndb.de>
>> However, you could totally implement a "DMA devices" that would just
>> use a simple "copy from there to there" task using this BestComm driver.
>> So other part of the kernel (like network) could use that interface to
>> use the dma engine ...
>>
>
> Can it also do the advanced operations like XOR on DMA that the
> Intel ioat has? That would be even more interesting, I guess.
>
Actually yes it can.
It just need someone motivated enough to write it ;)
>>>> +static int __init
>>>> +mpc52xx_bcom_init(void)
>>>> +{
>>>> + struct device_node *ofn_bcom, *ofn_sram;
>>>> + struct resource res_bcom;
>>>> +
>>>> + int rv;
>>>> +
>>>> + /* Find the bestcomm node. If none, fails 'silently' since
>>>> + * we may just be on another platform */
>>>> + ofn_bcom = of_find_compatible_node(
>>>> + NULL, "dma-controller", "mpc5200-bestcomm");
>>>> + if (!ofn_bcom)
>>>> + return -ENODEV;
>>>>
>>> I know, my usual rant is getting old, but why is this one not an
>>> of_platform_driver? It's not shared with arch/ppc or with arch/mips,
>>> and it's not needed before module_init() time.
>>>
>> It needs to be initialized before _any_ other driver that uses bestcomm.
>> When compiled as module that could be an of_platform_driver but when
>> built-in there is apparently no way to ensure it's going to be probed
>> first. (At least no clean way ... )
>>
>
> Initialization order is always a little tricky, but if you use a
> subsys_initcall, it should at least come before any regular driver
> like network or disk, and arch/ drivers come before any code in drivers/,
> so I don't see much of a problem here.
>
Mmm ... Silly of me but I didn't think of that.
I'll give it a shot.
(Actually before the transition to arch/powerpc, this was a
platform_driver ...
but there I could control the probe order with ppc_sys ).
>>> Why don't you use EXPORT_SYMBOL_GPL?
>>>
>> Why would I ? Is it mandatory now ?
>> I don't really have an objection to non-gpl modules to use the exported
>> functions ...
>>
>
> It's your choice, but there is a strong recommendation to use _GPL for
> all new interfaces nowadays. If you don't, people might suspect that
> you have a hidden agenda and actually plan to do non-gpl modules
> yourself.
>
Well if it's recommended ... And since Dale is in favor of it, so be it,
I don't have any hidden agenda ;)
Sylvain
next prev parent reply other threads:[~2007-05-13 7:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-12 20:31 [PATCH 0/9] BestComm : better late than never heh ;) Sylvain Munaut
2007-05-12 20:31 ` [PATCH 1/9] powerpc: exports rheap symbol to modules Sylvain Munaut
2007-05-12 20:31 ` [PATCH 2/9] powerpc: Changes the config mechanism for rheap Sylvain Munaut
2007-05-12 20:31 ` [PATCH 3/9] powerpc/ppc32: Update mpc52xx_psc structure with B revision changes Sylvain Munaut
2007-05-12 20:31 ` [PATCH 4/9] powerpc: BestComm core support for Freescale MPC5200 Sylvain Munaut
2007-05-12 20:31 ` [PATCH 5/9] powerpc: BestcComm ATA task support Sylvain Munaut
2007-05-12 20:31 ` [PATCH 6/9] powerpc: BestcComm FEC " Sylvain Munaut
2007-05-12 20:31 ` [PATCH 7/9] powerpc: BestcComm GenBD " Sylvain Munaut
2007-05-12 20:31 ` [PATCH 8/9] drivers/net: Add support for Freescale MPC5200 SoC internal FEC Sylvain Munaut
2007-05-12 20:31 ` [PATCH 9/9] sound: Add support for Freescale MPC5200 AC97 interface Sylvain Munaut
2007-05-12 23:30 ` [PATCH 5/9] powerpc: BestcComm ATA task support Arnd Bergmann
2007-05-12 23:27 ` [PATCH 4/9] powerpc: BestComm core support for Freescale MPC5200 Arnd Bergmann
2007-05-12 23:49 ` Sylvain Munaut
2007-05-13 0:24 ` Arnd Bergmann
2007-05-13 7:17 ` Sylvain Munaut [this message]
2007-05-13 23:29 ` Matt Sealey
2007-05-14 5:15 ` Sylvain Munaut
2007-05-13 3:36 ` Dale Farnsworth
2007-05-15 21:37 ` Kumar Gala
2007-05-15 22:27 ` Sylvain Munaut
2007-05-13 23:46 ` [PATCH 3/9] powerpc/ppc32: Update mpc52xx_psc structure with B revision changes Matt Sealey
2007-05-14 5:27 ` Sylvain Munaut
2007-05-15 10:59 ` Raquel Velasco and Bill Buck
2007-05-15 21:20 ` [PATCH 2/9] powerpc: Changes the config mechanism for rheap Kumar Gala
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