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From: Vinod Koul <vkoul@kernel.org>
To: Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	 Alexandre Torgue <alexandre.torgue@foss.st.com>,
	 Amelie Delaunay <amelie.delaunay@foss.st.com>
Cc: dmaengine@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	 linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND] dmaengine: stm32-dma: configure next sg only if there are more than 2 sgs
Date: Thu, 26 Jun 2025 15:48:09 -0700	[thread overview]
Message-ID: <175097808959.79884.12989914478900786264.b4-ty@kernel.org> (raw)
In-Reply-To: <20250624-stm32_dma_dbm_fix-v1-1-337c40d6c93e@foss.st.com>


On Tue, 24 Jun 2025 09:31:37 +0200, Amelie Delaunay wrote:
> DMA operates in Double Buffer Mode (DBM) when the transfer is cyclic and
> there are at least two periods.
> When DBM is enabled, the DMA toggles between two memory targets (SxM0AR and
> SxM1AR), indicated by the SxSCR.CT bit (Current Target).
> There is no need to update the next memory address if two periods are
> configured, as SxM0AR and SxM1AR are already properly set up before the
> transfer begins in the stm32_dma_start_transfer() function.
> This avoids unnecessary updates to SxM0AR/SxM1AR, thereby preventing
> potential Transfer Errors. Specifically, when the channel is enabled,
> SxM0AR and SxM1AR can only be written if SxSCR.CT=1 and SxSCR.CT=0,
> respectively. Otherwise, a Transfer Error interrupt is triggered, and the
> stream is automatically disabled.
> 
> [...]

Applied, thanks!

[1/1] dmaengine: stm32-dma: configure next sg only if there are more than 2 sgs
      commit: e19bdbaa31082b43dab1d936e20efcebc30aa73d

Best regards,
-- 
~Vinod



      reply	other threads:[~2025-06-26 22:48 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-24  7:31 Amelie Delaunay
2025-06-26 22:48 ` Vinod Koul [this message]

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