Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 10 Jan 2022 09:57:51 +0100 | Subject | Re: [PATCH 3/3] dmaengine: sf-pdma: Get number of channel by device tree |
| |
Hi Zong,
On Wed, Jan 5, 2022 at 6:44 AM Zong Li <zong.li@sifive.com> wrote: > It currently assumes that there are four channels by default, it might > cause the error if there is actually less than four channels. Change > that by getting number of channel from device tree. > > Signed-off-by: Zong Li <zong.li@sifive.com>
Thanks for your patch!
> --- a/drivers/dma/sf-pdma/sf-pdma.c > +++ b/drivers/dma/sf-pdma/sf-pdma.c > @@ -484,21 +484,24 @@ static int sf_pdma_probe(struct platform_device *pdev) > struct sf_pdma *pdma; > struct sf_pdma_chan *chan; > struct resource *res; > - int len, chans; > - int ret; > + int len, ret; > const enum dma_slave_buswidth widths = > DMA_SLAVE_BUSWIDTH_1_BYTE | DMA_SLAVE_BUSWIDTH_2_BYTES | > DMA_SLAVE_BUSWIDTH_4_BYTES | DMA_SLAVE_BUSWIDTH_8_BYTES | > DMA_SLAVE_BUSWIDTH_16_BYTES | DMA_SLAVE_BUSWIDTH_32_BYTES | > DMA_SLAVE_BUSWIDTH_64_BYTES; > > - chans = PDMA_NR_CH; > - len = sizeof(*pdma) + sizeof(*chan) * chans; > + len = sizeof(*pdma) + sizeof(*chan) * PDMA_MAX_NR_CH; > pdma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL); > if (!pdma) > return -ENOMEM; > > - pdma->n_chans = chans; > + ret = of_property_read_u32(pdev->dev.of_node, "dma-channels", > + &pdma->n_chans); > + if (ret) { > + dev_err(&pdev->dev, "failed to read dma-channels\n"); > + return ret;
Note that this is not backwards-compatible with existing DTBs, which lack the "dma-channels" property. Perhaps you want to fallback to a default of 4 instead?
> + } > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > pdma->membase = devm_ioremap_resource(&pdev->dev, res);
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
| |