From patchwork Tue Mar 19 09:53:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jiri Slaby \(SUSE\)" X-Patchwork-Id: 781309 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 8557480C0C; Tue, 19 Mar 2024 09:54:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710842047; cv=none; b=erouGJl/73rsKfxIpGrzmXVaTC9UOcll4lK0nyYR6Clgb01hbqbJp0jWmCVxtzeIIysDnly9PAA+94mY3SN8MfSm3zKHeWliL+oWE2JtDGpqFLEF67HsYXs1i6T2ua6YDz6yhN8qFgBWP7Om6cAOsxJ4+mTr1j3V0UYY0MlKOFE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710842047; c=relaxed/simple; bh=/FjnStB/yZtMO26TOxQ+YsIrQb3A2biwdW2z1LAyxHw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MOv/rUa0OiUblKgJVLvfzfHS0lhGlwMxaWZ867UE8Nx1lKUyZ95ig+ClffSy2fOc9mM+//Ilqq2F7Nih9aBgp8zxt+Izo6BGFzNuaNg+6OmvUsMKvA02mnzlEP7sTmwLXvXo98TrwdbnBryDV40AlDKwlQ6LF/ETrSw9dur6TbM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uGcwQxif; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uGcwQxif" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35E15C433C7; Tue, 19 Mar 2024 09:54:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710842047; bh=/FjnStB/yZtMO26TOxQ+YsIrQb3A2biwdW2z1LAyxHw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uGcwQxif/Uo4JmAEV3r1g+301UQrm/6b1v5bCFfOPrrHiWif6tJLub83A0a9Wln2l dVGZ2PuzwFC+tNfo3TQEDLJmW2L6fy3X92MeiWSbqXJ42eNev4VW4uIm8j+dab9sod RgCbnoBTmrT/cglZKV3HbFNYaN6nUMtdxrXINQlgXYa1uX+cIWdg+rxuCvxf9MGAo4 dbIf0XPxiI/MoIk9dEMhBx6jU+BDEtb1WS6eVDMLitX4t+11+mPC4/fT3/TRNfLZqa SugaYa2Lv/ul16syZdCW1Hu0b7HpFMGP0bNllTLAnApQ+n4WmLCaWS7vIXmIkOJfaG nE8/3/k9jPFEg== From: "Jiri Slaby (SUSE)" To: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Jiri Slaby (SUSE)" , Richard Genoud , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea , linux-arm-kernel@lists.infradead.org Subject: [RFT 15/15] tty: atmel_serial: use single DMA mapping for RX Date: Tue, 19 Mar 2024 10:53:15 +0100 Message-ID: <20240319095315.27624-17-jirislaby@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240319095315.27624-1-jirislaby@kernel.org> References: <20240319095315.27624-1-jirislaby@kernel.org> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 dma_map_single() provides much easier interface for simple mappings as used for RX in atmel_serial. So switch to that, removing all the s-g unnecessary handling. Signed-off-by: Jiri Slaby (SUSE) Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: linux-arm-kernel@lists.infradead.org --- drivers/tty/serial/atmel_serial.c | 56 ++++++++++++------------------- 1 file changed, 22 insertions(+), 34 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 5cde5077c429..0a90964d6d10 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -135,7 +135,7 @@ struct atmel_uart_port { dma_cookie_t cookie_tx; dma_cookie_t cookie_rx; dma_addr_t tx_phys; - struct scatterlist sg_rx; + dma_addr_t rx_phys; struct tasklet_struct tasklet_rx; struct tasklet_struct tasklet_tx; atomic_t tasklet_shutdown; @@ -1088,8 +1088,8 @@ static void atmel_release_rx_dma(struct uart_port *port) if (chan) { dmaengine_terminate_all(chan); dma_release_channel(chan); - dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1, - DMA_FROM_DEVICE); + dma_unmap_single(port->dev, atmel_port->rx_phys, + ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); } atmel_port->desc_rx = NULL; @@ -1122,10 +1122,8 @@ static void atmel_rx_from_dma(struct uart_port *port) } /* CPU claims ownership of RX DMA buffer */ - dma_sync_sg_for_cpu(port->dev, - &atmel_port->sg_rx, - 1, - DMA_FROM_DEVICE); + dma_sync_single_for_cpu(port->dev, atmel_port->rx_phys, + ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); /* * ring->head points to the end of data already written by the DMA. @@ -1134,8 +1132,8 @@ static void atmel_rx_from_dma(struct uart_port *port) * The current transfer size should not be larger than the dma buffer * length. */ - ring->head = sg_dma_len(&atmel_port->sg_rx) - state.residue; - BUG_ON(ring->head > sg_dma_len(&atmel_port->sg_rx)); + ring->head = ATMEL_SERIAL_RX_SIZE - state.residue; + BUG_ON(ring->head > ATMEL_SERIAL_RX_SIZE); /* * At this point ring->head may point to the first byte right after the * last byte of the dma buffer: @@ -1149,7 +1147,7 @@ static void atmel_rx_from_dma(struct uart_port *port) * tail to the end of the buffer then reset tail. */ if (ring->head < ring->tail) { - count = sg_dma_len(&atmel_port->sg_rx) - ring->tail; + count = ATMEL_SERIAL_RX_SIZE - ring->tail; tty_insert_flip_string(tport, ring->buf + ring->tail, count); ring->tail = 0; @@ -1162,17 +1160,15 @@ static void atmel_rx_from_dma(struct uart_port *port) tty_insert_flip_string(tport, ring->buf + ring->tail, count); /* Wrap ring->head if needed */ - if (ring->head >= sg_dma_len(&atmel_port->sg_rx)) + if (ring->head >= ATMEL_SERIAL_RX_SIZE) ring->head = 0; ring->tail = ring->head; port->icount.rx += count; } /* USART retreives ownership of RX DMA buffer */ - dma_sync_sg_for_device(port->dev, - &atmel_port->sg_rx, - 1, - DMA_FROM_DEVICE); + dma_sync_single_for_device(port->dev, atmel_port->rx_phys, + ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); tty_flip_buffer_push(tport); @@ -1188,7 +1184,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port) struct dma_slave_config config; struct circ_buf *ring; struct dma_chan *chan; - int ret, nent; + int ret; ring = &atmel_port->rx_ring; @@ -1205,26 +1201,18 @@ static int atmel_prepare_rx_dma(struct uart_port *port) dma_chan_name(atmel_port->chan_rx)); spin_lock_init(&atmel_port->lock_rx); - sg_init_table(&atmel_port->sg_rx, 1); /* UART circular rx buffer is an aligned page. */ BUG_ON(!PAGE_ALIGNED(ring->buf)); - sg_set_page(&atmel_port->sg_rx, - virt_to_page(ring->buf), - ATMEL_SERIAL_RX_SIZE, - offset_in_page(ring->buf)); - nent = dma_map_sg(port->dev, - &atmel_port->sg_rx, - 1, - DMA_FROM_DEVICE); - - if (!nent) { + atmel_port->rx_phys = dma_map_single(port->dev, ring->buf, + ATMEL_SERIAL_RX_SIZE, + DMA_FROM_DEVICE); + + if (dma_mapping_error(port->dev, atmel_port->rx_phys)) { dev_dbg(port->dev, "need to release resource of dma\n"); goto chan_err; } else { - dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__, - sg_dma_len(&atmel_port->sg_rx), - ring->buf, - &sg_dma_address(&atmel_port->sg_rx)); + dev_dbg(port->dev, "%s: mapped %zu@%p to %pad\n", __func__, + ATMEL_SERIAL_RX_SIZE, ring->buf, &atmel_port->rx_phys); } /* Configure the slave DMA */ @@ -1245,9 +1233,9 @@ static int atmel_prepare_rx_dma(struct uart_port *port) * each one is half ring buffer size */ desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx, - sg_dma_address(&atmel_port->sg_rx), - sg_dma_len(&atmel_port->sg_rx), - sg_dma_len(&atmel_port->sg_rx)/2, + atmel_port->rx_phys, + ATMEL_SERIAL_RX_SIZE, + ATMEL_SERIAL_RX_SIZE / 2, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); if (!desc) {