| Message ID | 5a7786cff08d55d0e084cd28bc2800565fa2dce7.1641289490.git.zong.li@sifive.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Determine number of DMA channels by 'dma-channels' property | expand |
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
On Mon, Jan 10, 2022 at 4:58 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > 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? > Thanks for your advice. I would set n_chans to 4 in failure condition for backwards-compatible. > > + } > > > > 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
diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c index f12606aeff87..c941150fc830 100644 --- 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; + } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); pdma->membase = devm_ioremap_resource(&pdev->dev, res); @@ -556,7 +559,7 @@ static int sf_pdma_remove(struct platform_device *pdev) struct sf_pdma_chan *ch; int i; - for (i = 0; i < PDMA_NR_CH; i++) { + for (i = 0; i < pdma->n_chans; i++) { ch = &pdma->chans[i]; devm_free_irq(&pdev->dev, ch->txirq, ch); diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h index 0c20167b097d..8127d792f639 100644 --- a/drivers/dma/sf-pdma/sf-pdma.h +++ b/drivers/dma/sf-pdma/sf-pdma.h @@ -22,11 +22,7 @@ #include "../dmaengine.h" #include "../virt-dma.h" -#define PDMA_NR_CH 4 - -#if (PDMA_NR_CH != 4) -#error "Please define PDMA_NR_CH to 4" -#endif +#define PDMA_MAX_NR_CH 4 #define PDMA_BASE_ADDR 0x3000000 #define PDMA_CHAN_OFFSET 0x1000 @@ -118,7 +114,7 @@ struct sf_pdma { void __iomem *membase; void __iomem *mappedbase; u32 n_chans; - struct sf_pdma_chan chans[PDMA_NR_CH]; + struct sf_pdma_chan chans[PDMA_MAX_NR_CH]; }; #endif /* _SF_PDMA_H */
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> --- drivers/dma/sf-pdma/sf-pdma.c | 15 +++++++++------ drivers/dma/sf-pdma/sf-pdma.h | 8 ++------ 2 files changed, 11 insertions(+), 12 deletions(-)