From: Amit Tomer <amittomer25@gmail.com>
To: "André Przywara" <andre.przywara@arm.com>
Cc: "Vinod Koul" <vkoul@kernel.org>,
"Andreas Färber" <afaerber@suse.de>,
"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
dan.j.williams@intel.com, cristian.ciocaltea@gmail.com,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-actions@lists.infradead.org
Subject: Re: [PATCH v4 02/10] dmaengine: Actions: Add support for S700 DMA engine
Date: Mon, 29 Jun 2020 13:58:31 +0530 [thread overview]
Message-ID: <CABHD4K-uFzzHLcH8SXGYkn_ZburG-g0f-ECrefU2V61Fp+z3fQ@mail.gmail.com> (raw)
In-Reply-To: <75d154d0-2962-99e6-a7c7-bf0928ec8b2a@arm.com>
Hi,
On Wed, Jun 24, 2020 at 3:06 PM André Przywara <andre.przywara@arm.com> wrote:
>
> On 24/06/2020 07:15, Vinod Koul wrote:
>
> Hi,
>
> > On 09-06-20, 15:47, Amit Singh Tomar wrote:
> >
> >> @@ -372,6 +383,7 @@ static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan,
> >> struct dma_slave_config *sconfig,
> >> bool is_cyclic)
> >> {
> >> + struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
> >> u32 mode, ctrlb;
> >>
> >> mode = OWL_DMA_MODE_PW(0);
> >> @@ -427,14 +439,26 @@ static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan,
> >> lli->hw[OWL_DMADESC_DADDR] = dst;
> >> lli->hw[OWL_DMADESC_SRC_STRIDE] = 0;
> >> lli->hw[OWL_DMADESC_DST_STRIDE] = 0;
> >> - /*
> >> - * Word starts from offset 0xC is shared between frame length
> >> - * (max frame length is 1MB) and frame count, where first 20
> >> - * bits are for frame length and rest of 12 bits are for frame
> >> - * count.
> >> - */
> >> - lli->hw[OWL_DMADESC_FLEN] = len | FCNT_VAL << 20;
> >> - lli->hw[OWL_DMADESC_CTRLB] = ctrlb;
> >> +
> >> + if (od->devid == S700_DMA) {
> >> + /* Max frame length is 1MB */
> >> + lli->hw[OWL_DMADESC_FLEN] = len;
> >> + /*
> >> + * On S700, word starts from offset 0x1C is shared between
> >> + * frame count and ctrlb, where first 12 bits are for frame
> >> + * count and rest of 20 bits are for ctrlb.
> >> + */
> >> + lli->hw[OWL_DMADESC_CTRLB] = FCNT_VAL | ctrlb;
> >> + } else {
> >> + /*
> >> + * On S900, word starts from offset 0xC is shared between
> >> + * frame length (max frame length is 1MB) and frame count,
> >> + * where first 20 bits are for frame length and rest of
> >> + * 12 bits are for frame count.
> >> + */
> >> + lli->hw[OWL_DMADESC_FLEN] = len | FCNT_VAL << 20;
> >> + lli->hw[OWL_DMADESC_CTRLB] = ctrlb;
> >
> > Unfortunately this wont scale, we will keep adding new conditions for
> > newer SoC's! So rather than this why not encode max frame length in
> > driver_data rather than S900_DMA/S700_DMA.. In future one can add values
> > for newer SoC and not code above logic again.
>
> What newer SoCs? I don't think we should try to guess the future here.
> We can always introduce further abstractions later, once we actually
> *know* what we are looking at.
>
Apart from it , we have *one* more SoC from Actions .i.e. S500 where
the DMA controller is
identical to S900, and requires *no* additional code to work properly.
So, I think we are safe to have the changes proposed in this patch.
Thanks
-Amit
next prev parent reply other threads:[~2020-06-29 20:57 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-09 10:17 [PATCH v4 00/10] Add MMC and DMA support for Actions S700 Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 01/10] dmaengine: Actions: get rid of bit fields from dma descriptor Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 02/10] dmaengine: Actions: Add support for S700 DMA engine Amit Singh Tomar
2020-06-24 6:15 ` Vinod Koul
2020-06-24 9:35 ` André Przywara
2020-06-29 8:28 ` Amit Tomer [this message]
2020-06-29 9:54 ` Vinod Koul
2020-06-29 11:19 ` André Przywara
2020-06-29 13:21 ` Vinod Koul
2020-06-29 8:19 ` Amit Tomer
2020-06-29 9:52 ` Vinod Koul
2020-06-30 9:47 ` Amit Tomer
2020-06-30 14:24 ` Vinod Koul
2020-06-30 18:14 ` Amit Tomer
2020-06-09 10:17 ` [PATCH v4 03/10] clk: actions: Add MMC clock-register reset bits Amit Singh Tomar
2020-06-09 11:29 ` kernel test robot
2020-06-09 10:17 ` [PATCH v4 04/10] arm64: dts: actions: limit address range for pinctrl node Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 05/10] dt-bindings: dmaengine: convert Actions Semi Owl SoCs bindings to yaml Amit Singh Tomar
2020-06-17 21:16 ` Rob Herring
2020-06-09 10:17 ` [PATCH v4 06/10] arm64: dts: actions: Add DMA Controller for S700 Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 07/10] dt-bindings: reset: s700: Add binding constants for mmc Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 08/10] dt-bindings: mmc: owl: add compatible string actions,s700-mmc Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 09/10] arm64: dts: actions: Add MMC controller support for S700 Amit Singh Tomar
2020-06-09 10:17 ` [PATCH v4 10/10] arm64: dts: actions: Add uSD support for Cubieboard7 Amit Singh Tomar
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