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From: Vinod Koul <vkoul@kernel.org>
To: Sugar Zhang <sugar.zhang@rock-chips.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
	linux-rockchip@lists.infradead.org,
	Dan Williams <dan.j.williams@intel.com>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/13] dmaengine: pl330: Add quirk 'arm,pl330-periph-burst'
Date: Wed, 24 Jun 2020 13:49:29 +0530	[thread overview]
Message-ID: <20200624081929.GU2324254@vkoul-mobl> (raw)
In-Reply-To: <1591665267-37713-3-git-send-email-sugar.zhang@rock-chips.com>

On 09-06-20, 09:14, Sugar Zhang wrote:
> This patch adds the qurik to use busrt transfers only

s/busrt/burst

> for pl330 controller, even for request with a length of 1.
> 
> Although, the correct way should be: if the peripheral request
> length is 1, the peripheral should use SINGLE request, and then
> notify the dmac using SINGLE mode by src/dst_maxburst with 1.
> 
> For example, on the Rockchip SoCs, all the peripherals can use
> SINGLE or BURST request by setting GRF registers. it is possible
> that if these peripheral drivers are used only for Rockchip SoCs.
> Unfortunately, it's not, such as dw uart, which is used so widely,
> and we can't set src/dst_maxburst according to the SoCs' specific
> to compatible with all the other SoCs.
> 
> So, for convenience, all the peripherals are set as BURST request
> by default on the Rockchip SoCs. even for request with a length of 1.
> the current pl330 driver will perform SINGLE transfer if the client's
> maxburst is 1, which still should be working according to chapter 2.6.6
> of datasheet which describe how DMAC performs SINGLE transfers for
> a BURST request. unfortunately, it's broken on the Rockchip SoCs,

s/unfortunately/Unfortunately

> which support only matching transfers, such as BURST transfer for
> BURST request, SINGLE transfer for SINGLE request.
> 
> Finaly, we add the quirk to specify pl330 to use burst transfers only.

s/Finaly/Finally

Below looks fine, pls reorder the series and have binding patch come
first and then the use of binding. Below looks fine though

-- 
~Vinod

  reply	other threads:[~2020-06-24  8:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-09  1:14 [PATCH v2 0/13] Patches to improve transfer efficiency for Rockchip SoCs Sugar Zhang
2020-06-09  1:14 ` [PATCH v2 01/13] dmaengine: pl330: Remove the burst limit for quirk 'NO-FLUSHP' Sugar Zhang
2020-06-24  7:54   ` Vinod Koul
2020-06-29  1:38     ` sugar zhang
2020-06-09  1:14 ` [PATCH v2 02/13] dmaengine: pl330: Add quirk 'arm,pl330-periph-burst' Sugar Zhang
2020-06-24  8:19   ` Vinod Koul [this message]
2020-06-09  1:14 ` [PATCH v2 03/13] dt-bindings: dma: pl330: Document the " Sugar Zhang
2020-06-17 20:58   ` Rob Herring
2020-06-09  1:14 ` [PATCH v2 04/13] ARM: dts: rk3036: Add 'arm,pl330-periph-burst' for dmac Sugar Zhang
2020-06-12  1:06 ` [PATCH v2 0/13] Patches to improve transfer efficiency for Rockchip SoCs Peter Geis
2020-06-12  1:15   ` Peter Geis
2020-06-12  8:58     ` sugar zhang

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