Messages in this thread | | | Subject | Re: [PATCH] serial: sh-sci: don't filter on DMA device, use only channel ID | From | Vinod Koul <> | Date | Tue, 30 Aug 2011 16:53:46 +0530 |
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On Tue, 2011-08-30 at 13:20 +0200, Guennadi Liakhovetski wrote: > On Tue, 30 Aug 2011, Vinod Koul wrote: > > > On Tue, 2011-08-30 at 09:54 +0200, Guennadi Liakhovetski wrote: > > > On Mon, 29 Aug 2011, Vinod Koul wrote: > > > > > >> You should not assign chan->private. > > > > > >> Please move this to dma_slave_control API > > > > > > > > > > > > I haven't seen any reply to this comment and this patch seems to still be > > > > > > outstanding, is there an updated version of this patch that I've missed? > > > > I don't recall seeing any updated version fixing this > > > > > > As a matter of fact, when you say "use dma_slave_control API," you > > > actually mean the dma_slave_config, right? Then, how is one supposed to > > > use it in this case? Shall we be issuing a DMA_SLAVE_CONFIG call inside of > > > the filter and check the return code? The problem is, that not all DMA > > > controllers on sh-mobile SoCs can service the same slave devices. So, if > > > we don't check in the filter we might well get an unsuitable DMA channel. > > Here you are assigning to chan->private your specific values, which > > should be moved to the dma_slave_config. > > But here you are removing the checks, and accepting the first channel > > you got, so how do you find channel is suitable or not. > > That's done in the driver's .device_alloc_chan_resources() method. It > checkx the .private pointer, tries to find a suitable channel, if it fails > - it returns -EINVAL. See > drivers/dma/shdma.c::sh_dmae_alloc_chan_resources(): > > if (param) { > const struct sh_dmae_slave_config *cfg; > > cfg = sh_dmae_find_slave(sh_chan, param); > if (!cfg) { > ret = -EINVAL; > goto efindslave; > } Now am doubly confused. Are you saying that you are using alloc_chan_resources for doing filtering??
-- ~Vinod
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