From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Andr=c3=a9_Przywara?= Subject: Re: [PATCH 07/10] dmaengine: sun6i: Retrieve channel count/max request from devicetree Date: Mon, 4 Sep 2017 00:44:54 +0100 Message-ID: References: <20170903224100.17893-1-stefan.bruens@rwth-aachen.de> <20170903224100.17893-8-stefan.bruens@rwth-aachen.de> Reply-To: andre.przywara-5wv7dgnIgG8@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20170903224100.17893-8-stefan.bruens-vA1bhqPz9FBZXbeN9DUtxg@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: =?UTF-8?Q?Stefan_Br=c3=bcns?= , linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vinod Koul , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Maxime Ripard , Chen-Yu Tsai , Rob Herring , Code Kipper List-Id: devicetree@vger.kernel.org Hi, On 03/09/17 23:40, Stefan Br=C3=BCns wrote: > To avoid introduction of a new compatible for each small SoC/DMA controll= er > variation, move the definition of the channel count to the devicetree. >=20 > The number of vchans is no longer explicit, but limited by the highest > port/DMA request number. The result is a slight overallocation for SoCs > with a sparse port mapping. >=20 > Signed-off-by: Stefan Br=C3=BCns > --- > drivers/dma/sun6i-dma.c | 35 ++++++++++++++++++++++++++++++++++- > 1 file changed, 34 insertions(+), 1 deletion(-) >=20 > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > index c69dadb853d2..bd4c2e4a759b 100644 > --- a/drivers/dma/sun6i-dma.c > +++ b/drivers/dma/sun6i-dma.c > @@ -42,6 +42,9 @@ > =20 > #define DMA_STAT 0x30 > =20 > +/* Offset between DMA_IRQ_EN and DMA_IRQ_STAT limits number of channels = */ > +#define DMA_MAX_CHANNELS (DMA_IRQ_CHAN_NR * 0x10 / 4) > + > /* > * sun8i specific registers > */ > @@ -65,7 +68,8 @@ > #define DMA_CHAN_LLI_ADDR 0x08 > =20 > #define DMA_CHAN_CUR_CFG 0x0c > -#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & 0x1f) > +#define DMA_CHAN_MAX_DRQ 0x1f > +#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & DMA_CHAN_MAX_DRQ) > #define DMA_CHAN_CFG_SRC_IO_MODE BIT(5) > #define DMA_CHAN_CFG_SRC_LINEAR_MODE (0 << 5) > #define DMA_CHAN_CFG_SRC_BURST_A31(x) (((x) & 0x3) << 7) > @@ -1173,6 +1177,35 @@ static int sun6i_dma_probe(struct platform_device = *pdev) > sdc->num_vchans =3D sdc->cfg->nr_max_vchans; > sdc->max_request =3D sdc->cfg->nr_max_requests; > =20 > + ret =3D of_property_read_u32(np, "dma-channels", &sdc->num_pchans); > + if (ret && !sdc->num_pchans) { > + dev_err(&pdev->dev, "Can't get dma-channels.\n"); > + return ret; > + } > + > + if (sdc->num_pchans > DMA_MAX_CHANNELS) { > + dev_err(&pdev->dev, "Number of dma-channels out of range.\n"); > + return -EINVAL; > + } > + > + ret =3D of_property_read_u32(np, "dma-requests", &sdc->max_request); > + if (ret && !sdc->max_request) { > + dev_info(&pdev->dev, "Missing dma-requests, using %u.\n", > + DMA_CHAN_MAX_DRQ); Mmmh, is this mapping of "!sdc->max_request" -> DMA_CHAN_MAX_DRQ implemented somewhere else? Or is it just missing here: sdc->max_request =3D DMA_CHAN_MAX_DRQ; Otherwise this is looking good, thanks for picking up the DT property approach! Cheers, Andre. > + } > + > + if (sdc->max_request > DMA_CHAN_MAX_DRQ) { > + dev_err(&pdev->dev, "Value of dma-requests out of range.\n"); > + return -EINVAL; > + } > + > + /* > + * If the number of vchans is not specified, derive it from the > + * highest port number, at most one channel per port and direction. > + */ > + if (!sdc->num_vchans) > + sdc->num_vchans =3D 2 * (sdc->max_request + 1); > + > sdc->pchans =3D devm_kcalloc(&pdev->dev, sdc->num_pchans, > sizeof(struct sun6i_pchan), GFP_KERNEL); > if (!sdc->pchans) >=20 --=20 You received this message because you are subscribed to the Google Groups "= linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to linux-sunxi+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit https://groups.google.com/d/optout.