From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Bruens Subject: Re: [PATCH 07/10] dmaengine: sun6i: Retrieve channel count/max request from devicetree Date: Mon, 4 Sep 2017 02:12:07 +0200 Message-ID: <2286861.ip18xhFNEq@pebbles.site> References: <20170903224100.17893-1-stefan.bruens@rwth-aachen.de> <20170903224100.17893-8-stefan.bruens@rwth-aachen.de> Reply-To: stefan.bruens-vA1bhqPz9FBZXbeN9DUtxg@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: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: =?ISO-8859-1?Q?Andr=E9?= Przywara Cc: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, 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 On Montag, 4. September 2017 01:44:54 CEST Andr=C3=A9 Przywara wrote: > Hi, >=20 > On 03/09/17 23:40, Stefan Br=C3=BCns wrote: > > To avoid introduction of a new compatible for each small SoC/DMA > > controller > > 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 > > --- > >=20 > > 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 channel= s > > */ > > +#define DMA_MAX_CHANNELS (DMA_IRQ_CHAN_NR * 0x10 / 4) > > + > >=20 > > /* > > =20 > > * sun8i specific registers > > */ > >=20 > > @@ -65,7 +68,8 @@ > >=20 > > #define DMA_CHAN_LLI_ADDR 0x08 > > =20 > > #define DMA_CHAN_CUR_CFG 0x0c > >=20 > > -#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) > >=20 > > #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) > >=20 > > @@ -1173,6 +1177,35 @@ static int sun6i_dma_probe(struct platform_devic= e > > *pdev)>=20 > > 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); >=20 > 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; Well spotted, that assignment is actually missing. With this line added, your comment for patch 8/10 should also be addressed= =20 (regarding the default value). =20 > Otherwise this is looking good, thanks for picking up the DT property > approach! >=20 > Cheers, > Andre. >=20 Kind regards, Stefan --=20 Stefan Br=C3=BCns / Bergstra=C3=9Fe 21 / 52062 Aachen home: +49 241 53809034 mobile: +49 151 50412019 --=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.