From patchwork Fri Aug 18 16:01:27 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Radu Rendec X-Patchwork-Id: 803328 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="BqpypyII"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3xYnrt2Zmlz9t2K for ; Sat, 19 Aug 2017 02:01:50 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751328AbdHRQBt (ORCPT ); Fri, 18 Aug 2017 12:01:49 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36682 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993AbdHRQBt (ORCPT ); Fri, 18 Aug 2017 12:01:49 -0400 Received: by mail-wm0-f66.google.com with SMTP id d40so4692456wma.3 for ; Fri, 18 Aug 2017 09:01:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tyhAgzm1ITk85wxqa9rUmJIV1U0FuPzACr1Rl+ZfFAY=; b=BqpypyIIpbB2Ftv0dHn7RlRUtFpL2V4G1I8sei5IbbP6tETA5ZwchLzo9/I3Vi9gut ObUyi9XgOLb7WzaJGjL+GZd9xOUDfHBd9Jerg/dCuJT/beWNcUhekr7APOEbpY4pXgxR tapVObdfYCmg+4A4ajyyt/4J86G47zvR4v3GI4R0FUo4oemQIxUGv766EamTe8Agu71a IK4FJhLdZD4aHSoRX/Ycc8ccuAZ2KjrgbZ/71wecu9UbEMfnLWCg3th/eevzjrUe0boU 9ezQBffTYtD2V02i09Rb5OKuOdTBHN3uMAkfU8pC0hhRrXQZo0IaXJ++6KtreGF1gPhz wEpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tyhAgzm1ITk85wxqa9rUmJIV1U0FuPzACr1Rl+ZfFAY=; b=U4UPwTDGhlrqIS16dB3mnOhuEYkhdUwiD7UQi5kf+Hokr0o1neg2xf/Oe95pgKb7p6 t1kRiTJvje1o4vgbBJUDkw9gj92rKFl6uLFGEFiFuiPlyUD9ziZKtpT91C0oC7ttWRwu xu6AVdDmGLgecWeBJqtzVJIe2ww8t9wlVA8AfhzELcDtxPnsFfVgdUe9aY6FbX+Q47A7 XRBI9wfm1+SlF8XVD0xMaz5e/cSBNlnj077rDEiF9y5BYfnaNDP2gjc94iZV7GW8ltw1 aV+BQUhEvuqrAogB81q3a7mnObIppwUmMQTxvC+hIVlQKXtsro5HKBA9nFMPCHlu6g7T /QUQ== X-Gm-Message-State: AHYfb5i5qYVupcHgWfd2O4uIUQYtyS7/l+Olqm5H47rGd2O2K38kqqra mxji2xY0yHGoord/ X-Received: by 10.80.142.68 with SMTP id 4mr5465926edx.186.1503072107441; Fri, 18 Aug 2017 09:01:47 -0700 (PDT) Received: from rrendec.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id j16sm3866597eda.46.2017.08.18.09.01.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Aug 2017 09:01:46 -0700 (PDT) From: Radu Rendec To: linux-i2c@vger.kernel.org Cc: Radu Rendec Subject: [PATCH 1/2] i2c: ismt: 16-byte align the DMA buffer address Date: Fri, 18 Aug 2017 17:01:27 +0100 Message-Id: <20170818160128.21228-2-radu.rendec@gmail.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20170818160128.21228-1-radu.rendec@gmail.com> References: <20170818160128.21228-1-radu.rendec@gmail.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Use only a portion of the data buffer for DMA transfers, which is always 16-byte aligned. This makes the DMA buffer address 16-byte aligned and compensates for spurious hardware parity errors that may appear when the DMA buffer address is not 16-byte aligned. The data buffer is enlarged in order to accommodate any possible 16-byte alignment offset and changes the DMA code to only use a portion of the data buffer, which is 16-byte aligned. The symptom of the hardware issue is the same as the one addressed in v3.12-rc2-5-gbf41691 and manifests by transfers failing with EIO, with bit 9 being set in the ERRSTS register. Signed-off-by: Radu Rendec Acked-by: Neil Horman --- drivers/i2c/busses/i2c-ismt.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-) diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c index e98e44e..ccce0ca 100644 --- a/drivers/i2c/busses/i2c-ismt.c +++ b/drivers/i2c/busses/i2c-ismt.c @@ -172,7 +172,7 @@ struct ismt_priv { dma_addr_t io_rng_dma; /* descriptor HW base addr */ u8 head; /* ring buffer head pointer */ struct completion cmp; /* interrupt completion */ - u8 dma_buffer[I2C_SMBUS_BLOCK_MAX + 1]; /* temp R/W data buffer */ + u8 buffer[I2C_SMBUS_BLOCK_MAX + 16]; /* temp R/W data buffer */ }; /** @@ -320,7 +320,7 @@ static int ismt_process_desc(const struct ismt_desc *desc, struct ismt_priv *priv, int size, char read_write) { - u8 *dma_buffer = priv->dma_buffer; + u8 *dma_buffer = (u8*)ALIGN((unsigned long)&priv->buffer[0], 16); dev_dbg(&priv->pci_dev->dev, "Processing completed descriptor\n"); __ismt_desc_dump(&priv->pci_dev->dev, desc); @@ -388,11 +388,12 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, struct ismt_desc *desc; struct ismt_priv *priv = i2c_get_adapdata(adap); struct device *dev = &priv->pci_dev->dev; + u8 *dma_buffer = (u8*)ALIGN((unsigned long)&priv->buffer[0], 16); desc = &priv->hw[priv->head]; /* Initialize the DMA buffer */ - memset(priv->dma_buffer, 0, sizeof(priv->dma_buffer)); + memset(priv->buffer, 0, sizeof(priv->buffer)); /* Initialize the descriptor */ memset(desc, 0, sizeof(struct ismt_desc)); @@ -441,8 +442,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, desc->wr_len_cmd = 2; dma_size = 2; dma_direction = DMA_TO_DEVICE; - priv->dma_buffer[0] = command; - priv->dma_buffer[1] = data->byte; + dma_buffer[0] = command; + dma_buffer[1] = data->byte; } else { /* Read Byte */ dev_dbg(dev, "I2C_SMBUS_BYTE_DATA: READ\n"); @@ -461,9 +462,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, desc->wr_len_cmd = 3; dma_size = 3; dma_direction = DMA_TO_DEVICE; - priv->dma_buffer[0] = command; - priv->dma_buffer[1] = data->word & 0xff; - priv->dma_buffer[2] = data->word >> 8; + dma_buffer[0] = command; + dma_buffer[1] = data->word & 0xff; + dma_buffer[2] = data->word >> 8; } else { /* Read Word */ dev_dbg(dev, "I2C_SMBUS_WORD_DATA: READ\n"); @@ -481,9 +482,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, desc->rd_len = 2; dma_size = 3; dma_direction = DMA_BIDIRECTIONAL; - priv->dma_buffer[0] = command; - priv->dma_buffer[1] = data->word & 0xff; - priv->dma_buffer[2] = data->word >> 8; + dma_buffer[0] = command; + dma_buffer[1] = data->word & 0xff; + dma_buffer[2] = data->word >> 8; break; case I2C_SMBUS_BLOCK_DATA: @@ -494,8 +495,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, dma_direction = DMA_TO_DEVICE; desc->wr_len_cmd = dma_size; desc->control |= ISMT_DESC_BLK; - priv->dma_buffer[0] = command; - memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1); + dma_buffer[0] = command; + memcpy(&dma_buffer[1], &data->block[1], dma_size - 1); } else { /* Block Read */ dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA: READ\n"); @@ -522,8 +523,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, dma_direction = DMA_TO_DEVICE; desc->wr_len_cmd = dma_size; desc->control |= ISMT_DESC_I2C; - priv->dma_buffer[0] = command; - memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1); + dma_buffer[0] = command; + memcpy(&dma_buffer[1], &data->block[1], dma_size - 1); } else { /* i2c Block Read */ dev_dbg(dev, "I2C_SMBUS_I2C_BLOCK_DATA: READ\n"); @@ -552,18 +553,18 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, if (dma_size != 0) { dev_dbg(dev, " dev=%p\n", dev); dev_dbg(dev, " data=%p\n", data); - dev_dbg(dev, " dma_buffer=%p\n", priv->dma_buffer); + dev_dbg(dev, " dma_buffer=%p\n", dma_buffer); dev_dbg(dev, " dma_size=%d\n", dma_size); dev_dbg(dev, " dma_direction=%d\n", dma_direction); dma_addr = dma_map_single(dev, - priv->dma_buffer, + dma_buffer, dma_size, dma_direction); if (dma_mapping_error(dev, dma_addr)) { dev_err(dev, "Error in mapping dma buffer %p\n", - priv->dma_buffer); + dma_buffer); return -EIO; }