Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752744Ab2FMI2M (ORCPT ); Wed, 13 Jun 2012 04:28:12 -0400 Received: from [65.55.88.11] ([65.55.88.11]:57978 "EHLO tx2outboundpool.messaging.microsoft.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751182Ab2FMI2C (ORCPT ); Wed, 13 Jun 2012 04:28:02 -0400 X-Forefront-Antispam-Report: CIP:137.71.25.57;KIP:(null);UIP:(null);IPV:NLI;H:nwd2mta2.analog.com;RD:nwd2mail11.analog.com;EFVD:NLI X-SpamScore: 1 X-BigFish: VS1(zzzz1202hzz8275bhz2ei87h2a8h668h839hd24he5bhe96h) X-FB-DOMAIN-IP-MATCH: fail From: Sonic Zhang To: Wolfram Sang , Ben Dooks CC: , LKML , , Sonic Zhang Subject: [PATCH 2/8 v2] i2c: i2c-bfin-twi: Improve the patch for bug "Illegal i2c bus lock upon certain transfer scenarios". Date: Wed, 13 Jun 2012 16:22:41 +0800 Message-ID: <1339575767-22985-2-git-send-email-sonic.adi@gmail.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1339575767-22985-1-git-send-email-sonic.adi@gmail.com> References: <1339575767-22985-1-git-send-email-sonic.adi@gmail.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3369 Lines: 99 From: Sonic Zhang For transfer counts > 255 bytes i2c-bfin-twi sets the data transfer counter DCNT to 0xFF indicating unlimited transfers. It then uses a flag iface->manual_stop to manually issue the STOP condition, once the required amount of bytes are received. We found that on I2C receive operation issuing the STOP condition together with a FULL RCV FIFO (2bytes) will cause SDA and SCL be constantly driven low. This patch stops receiving operation immediately in last rx interrupt. This patch also wakes up waiting process when transfer completes. Signed-off-by: Sonic Zhang --- drivers/i2c/busses/i2c-bfin-twi.c | 43 ++++++++++++++++++++---------------- 1 files changed, 24 insertions(+), 19 deletions(-) diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 33031f0..dbe8fa0 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -130,21 +130,25 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, } iface->transPtr++; iface->readNum--; - } else if (iface->manual_stop) { - /* Temporary workaround to avoid possible bus stall - - * Flush FIFO before issuing the STOP condition - */ - read_RCV_DATA16(iface); - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) | STOP); - } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && - iface->cur_msg + 1 < iface->msg_num) { - if (iface->pmsg[iface->cur_msg + 1].flags & I2C_M_RD) - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) | RSTART | MDIR); - else + } + + if (iface->readNum == 0) { + if (iface->manual_stop) { + /* Temporary workaround to avoid possible bus stall - + * Flush FIFO before issuing the STOP condition + */ + read_RCV_DATA16(iface); write_MASTER_CTL(iface, - (read_MASTER_CTL(iface) | RSTART) & ~MDIR); + read_MASTER_CTL(iface) | STOP); + } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && + iface->cur_msg + 1 < iface->msg_num) { + if (iface->pmsg[iface->cur_msg + 1].flags & I2C_M_RD) + write_MASTER_CTL(iface, + read_MASTER_CTL(iface) | RSTART | MDIR); + else + write_MASTER_CTL(iface, + (read_MASTER_CTL(iface) | RSTART) & ~MDIR); + } } } if (twi_int_status & MERR) { @@ -245,12 +249,13 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, } } - if (iface->pmsg[iface->cur_msg].len <= 255) - write_MASTER_CTL(iface, + if (iface->pmsg[iface->cur_msg].len <= 255) { + write_MASTER_CTL(iface, (read_MASTER_CTL(iface) & (~(0xff << 6))) | - (iface->pmsg[iface->cur_msg].len << 6)); - else { + (iface->pmsg[iface->cur_msg].len << 6)); + iface->manual_stop = 0; + } else { write_MASTER_CTL(iface, (read_MASTER_CTL(iface) | (0xff << 6))); @@ -264,8 +269,8 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, write_INT_MASK(iface, 0); write_MASTER_CTL(iface, 0); } + complete(&iface->complete); } - complete(&iface->complete); } /* Interrupt handler */ -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/