From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B5AC28DB6 for ; Mon, 16 Oct 2023 14:49:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ccXXQeWc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC7DBC433C9; Mon, 16 Oct 2023 14:49:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697467797; bh=+X1e9UZ7H+S/xOBiYYVv3JlcEE7Om0gUuhz8yFbdfP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ccXXQeWcUepvk+bfgWHwwbt4/7FWPQ7LvEWcTTkuS+xYKrFknecTxVA0MCcCjP/Yt LlTV5e09hGvgBGiwpj7dg1zNyvWDScST7sp68dTdKegzEGNC0o0bT6LLQiIhwg/4gb g5N3VHzx65UQot1BhIcFTnLuWhVRhTrItre38bW8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Amelie Delaunay , Vinod Koul Subject: [PATCH 6.5 097/191] dmaengine: stm32-mdma: use Link Address Register to compute residue Date: Mon, 16 Oct 2023 10:41:22 +0200 Message-ID: <20231016084017.655795009@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016084015.400031271@linuxfoundation.org> References: <20231016084015.400031271@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Amelie Delaunay commit a4b306eb83579c07b63dc65cd5bae53b7b4019d0 upstream. Current implementation relies on curr_hwdesc index. But to keep this index up to date, Block Transfer interrupt (BTIE) has to be enabled. If it is not, curr_hwdesc is not updated, and then residue is not reliable. Rely on Link Address Register instead. And disable BTIE interrupt in stm32_mdma_setup_xfer() because it is no more needed in case of _prep_slave_sg() to maintain curr_hwdesc up to date. It avoids extra interrupts and also ensures a reliable residue. These improvements are required for STM32 DCMI camera capture use case, which need STM32 DMA and MDMA chaining for good performance. Fixes: 696874322771 ("dmaengine: stm32-mdma: add support to be triggered by STM32 DMA") Signed-off-by: Amelie Delaunay Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231004163531.2864160-2-amelie.delaunay@foss.st.com Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/stm32-mdma.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -778,8 +778,6 @@ static int stm32_mdma_setup_xfer(struct /* Enable interrupts */ ccr &= ~STM32_MDMA_CCR_IRQ_MASK; ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE; - if (sg_len > 1) - ccr |= STM32_MDMA_CCR_BTIE; desc->ccr = ccr; return 0; @@ -1325,12 +1323,21 @@ static size_t stm32_mdma_desc_residue(st { struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan); struct stm32_mdma_hwdesc *hwdesc; - u32 cbndtr, residue, modulo, burst_size; + u32 cisr, clar, cbndtr, residue, modulo, burst_size; int i; + cisr = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id)); + residue = 0; - for (i = curr_hwdesc + 1; i < desc->count; i++) { + /* Get the next hw descriptor to process from current transfer */ + clar = stm32_mdma_read(dmadev, STM32_MDMA_CLAR(chan->id)); + for (i = desc->count - 1; i >= 0; i--) { hwdesc = desc->node[i].hwdesc; + + if (hwdesc->clar == clar) + break;/* Current transfer found, stop cumulating */ + + /* Cumulate residue of unprocessed hw descriptors */ residue += STM32_MDMA_CBNDTR_BNDT(hwdesc->cbndtr); } cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));