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From: "Troy Mitchell" <troy.mitchell@linux.spacemit.com>
To: "Conor Dooley" <conor@kernel.org>,
	"Troy Mitchell" <troy.mitchell@linux.spacemit.com>
Cc: "Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Paul Walmsley" <pjw@kernel.org>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Alexandre Ghiti" <alex@ghiti.fr>, "Yixun Lan" <dlan@kernel.org>,
	"Vinod Koul" <vkoul@kernel.org>, "Frank Li" <Frank.Li@kernel.org>,
	"Guodong Xu" <guodong@riscstar.com>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>, <devicetree@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <spacemit@lists.linux.dev>,
	<linux-kernel@vger.kernel.org>, <dmaengine@vger.kernel.org>,
	<linux-clk@vger.kernel.org>
Subject: Re: [PATCH v2 2/7] dt-bindings: dmaengine: Add SpacemiT K3 DMA compatible string
Date: Fri, 27 Mar 2026 15:04:46 +0800	[thread overview]
Message-ID: <DHDDGG4TDFOS.2DPHBA6U2JMVE@linux.spacemit.com> (raw)
In-Reply-To: <20260326-explode-surplus-24c0e0813099@spud>

Hi Conor,

On Fri Mar 27, 2026 at 2:34 AM CST, Conor Dooley wrote:
> On Thu, Mar 26, 2026 at 04:17:17PM +0800, Troy Mitchell wrote:
>> From: Guodong Xu <guodong@riscstar.com>
>> 
>> Add k3 compatible string.
>
> That's obvious. What you need to explain is why it is not compatible with
> the existing k1.
>
Thanks for the review.

The SpacemiT K3 PDMA requires a new compatible string because it is not fully
backward compatible with the K1 implementation due to two main hardware differences:
- Variable extended DRCMR base: The DRCMR (DMA Request/Command Register) base
  address for extended DMA request numbers (>= 64) is different in the K3 hardware
  implementation.
- Memory addressing capabilities: Unlike the K1 SoC, where some DMA masters had
  memory addressing limitations (restricted to the 0-4GB space) and required a
  dedicated dma-bus, the K3 DMA masters have full memory addressing capabilities.

I will update the commit message in the v3 series.

                                              -Troy

WARNING: multiple messages have this Message-ID (diff)
From: "Troy Mitchell" <troy.mitchell@linux.spacemit.com>
To: "Conor Dooley" <conor@kernel.org>,
	"Troy Mitchell" <troy.mitchell@linux.spacemit.com>
Cc: "Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Paul Walmsley" <pjw@kernel.org>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Alexandre Ghiti" <alex@ghiti.fr>, "Yixun Lan" <dlan@kernel.org>,
	"Vinod Koul" <vkoul@kernel.org>, "Frank Li" <Frank.Li@kernel.org>,
	"Guodong Xu" <guodong@riscstar.com>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>, <devicetree@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <spacemit@lists.linux.dev>,
	<linux-kernel@vger.kernel.org>, <dmaengine@vger.kernel.org>,
	<linux-clk@vger.kernel.org>
Subject: Re: [PATCH v2 2/7] dt-bindings: dmaengine: Add SpacemiT K3 DMA compatible string
Date: Fri, 27 Mar 2026 15:04:46 +0800	[thread overview]
Message-ID: <DHDDGG4TDFOS.2DPHBA6U2JMVE@linux.spacemit.com> (raw)
In-Reply-To: <20260326-explode-surplus-24c0e0813099@spud>

Hi Conor,

On Fri Mar 27, 2026 at 2:34 AM CST, Conor Dooley wrote:
> On Thu, Mar 26, 2026 at 04:17:17PM +0800, Troy Mitchell wrote:
>> From: Guodong Xu <guodong@riscstar.com>
>> 
>> Add k3 compatible string.
>
> That's obvious. What you need to explain is why it is not compatible with
> the existing k1.
>
Thanks for the review.

The SpacemiT K3 PDMA requires a new compatible string because it is not fully
backward compatible with the K1 implementation due to two main hardware differences:
- Variable extended DRCMR base: The DRCMR (DMA Request/Command Register) base
  address for extended DMA request numbers (>= 64) is different in the K3 hardware
  implementation.
- Memory addressing capabilities: Unlike the K1 SoC, where some DMA masters had
  memory addressing limitations (restricted to the 0-4GB space) and required a
  dedicated dma-bus, the K3 DMA masters have full memory addressing capabilities.

I will update the commit message in the v3 series.

                                              -Troy

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  reply	other threads:[~2026-03-27  7:06 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-26  8:17 [PATCH v2 0/7] dmaengine: Add Peripheral DMA support for SpacemiT K3 SoC Troy Mitchell
2026-03-26  8:17 ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 1/7] dt-bindings: dmaengine: Add SpacemiT K1 DMA request definitions Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-27  7:27   ` Krzysztof Kozlowski
2026-03-27  7:27     ` Krzysztof Kozlowski
2026-03-28  9:46     ` Troy Mitchell
2026-03-28  9:46       ` Troy Mitchell
2026-03-27  7:28   ` Krzysztof Kozlowski
2026-03-27  7:28     ` Krzysztof Kozlowski
2026-03-28  9:48     ` Troy Mitchell
2026-03-28  9:48       ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 2/7] dt-bindings: dmaengine: Add SpacemiT K3 DMA compatible string Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-26 18:34   ` Conor Dooley
2026-03-26 18:34     ` Conor Dooley
2026-03-27  7:04     ` Troy Mitchell [this message]
2026-03-27  7:04       ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 3/7] dt-bindings: dmaengine: Add SpacemiT K3 DMA request definitions Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-27  7:30   ` Krzysztof Kozlowski
2026-03-27  7:30     ` Krzysztof Kozlowski
2026-03-28  9:58     ` Troy Mitchell
2026-03-28  9:58       ` Troy Mitchell
2026-03-28 11:35       ` Krzysztof Kozlowski
2026-03-28 11:35         ` Krzysztof Kozlowski
2026-03-26  8:17 ` [PATCH v2 4/7] dmaengine: mmp_pdma: support variable extended DRCMR base Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 5/7] dmaengine: mmp_pdma: add Spacemit K3 support Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 6/7] clk: spacemit: k3: mark top_dclk as CLK_IS_CRITICAL Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell
2026-03-26  8:17 ` [PATCH v2 7/7] riscv: dts: spacemit: Add PDMA controller node for K3 SoC Troy Mitchell
2026-03-26  8:17   ` Troy Mitchell

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