From patchwork Thu Jan 29 17:33:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 5744201 X-Patchwork-Delegate: geert@linux-m68k.org Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 84D019F358 for ; Thu, 29 Jan 2015 17:33:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6FFD22024D for ; Thu, 29 Jan 2015 17:33:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 227F62024C for ; Thu, 29 Jan 2015 17:33:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756282AbbA2RdZ (ORCPT ); Thu, 29 Jan 2015 12:33:25 -0500 Received: from sauhun.de ([89.238.76.85]:39466 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756254AbbA2RdZ (ORCPT ); Thu, 29 Jan 2015 12:33:25 -0500 Received: from p4fe25857.dip0.t-ipconnect.de ([79.226.88.87]:57101 helo=localhost) by pokefinder.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1YGsy2-0000zQ-Gn; Thu, 29 Jan 2015 18:33:22 +0100 From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Wolfram Sang , Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven Subject: [PATCH] i2c: sh_mobile: terminate DMA reads properly Date: Thu, 29 Jan 2015 18:33:16 +0100 Message-Id: <1422552796-11315-1-git-send-email-wsa@the-dreams.de> X-Mailer: git-send-email 2.1.4 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wolfram Sang DMA read requests could miss proper termination, so two more bytes would have been read via PIO overwriting the end of the buffer with wrong data. Make DMA stop handling more readable while we are here. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sh_mobile.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index 440d5dbc8b5f..007818b3e174 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -139,6 +139,7 @@ struct sh_mobile_i2c_data { int pos; int sr; bool send_stop; + bool stop_after_dma; struct resource *res; struct dma_chan *dma_tx; @@ -407,7 +408,7 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) if (pd->pos == pd->msg->len) { /* Send stop if we haven't yet (DMA case) */ - if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY)) + if (pd->send_stop && pd->stop_after_dma) i2c_op(pd, OP_TX_STOP, 0); return 1; } @@ -449,6 +450,13 @@ static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) real_pos = pd->pos - 2; if (pd->pos == pd->msg->len) { + if (pd->stop_after_dma) { + /* Simulate PIO end condition after DMA transfer */ + i2c_op(pd, OP_RX_STOP, 0); + pd->pos++; + break; + } + if (real_pos < 0) { i2c_op(pd, OP_RX_STOP, 0); break; @@ -536,6 +544,7 @@ static void sh_mobile_i2c_dma_callback(void *data) sh_mobile_i2c_dma_unmap(pd); pd->pos = pd->msg->len; + pd->stop_after_dma = true; iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); } @@ -726,6 +735,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, bool do_start = pd->send_stop || !i; msg = &msgs[i]; pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP; + pd->stop_after_dma = false; err = start_ch(pd, msg, do_start); if (err)