From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E37FC4321D for ; Thu, 23 Aug 2018 21:39:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD7712086B for ; Thu, 23 Aug 2018 21:39:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD7712086B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728224AbeHXBKm (ORCPT ); Thu, 23 Aug 2018 21:10:42 -0400 Received: from mga05.intel.com ([192.55.52.43]:37753 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727485AbeHXBKm (ORCPT ); Thu, 23 Aug 2018 21:10:42 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Aug 2018 14:39:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,279,1531810800"; d="scan'208";a="68637991" Received: from yoojae-mobl1.amr.corp.intel.com (HELO [10.7.153.143]) ([10.7.153.143]) by orsmga006.jf.intel.com with ESMTP; 23 Aug 2018 14:38:59 -0700 Subject: Re: [PATCH i2c-next v5] i2c: aspeed: Handle master/slave combined irq events properly To: Brendan Higgins Cc: linux-aspeed@lists.ozlabs.org, james.feist@linux.intel.com, Andrew Jeffery , OpenBMC Maillist , Linux Kernel Mailing List , jarkko.nikula@linux.intel.com, vernon.mauery@linux.intel.com, Linux ARM , linux-i2c@vger.kernel.org References: <20180823205647.12417-1-jae.hyun.yoo@linux.intel.com> From: Jae Hyun Yoo Message-ID: Date: Thu, 23 Aug 2018 14:39:01 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/23/2018 2:18 PM, Brendan Higgins wrote: > On Thu, Aug 23, 2018 at 1:56 PM Jae Hyun Yoo > wrote: >> >> In most of cases, interrupt bits are set one by one but there are >> also a lot of other cases that Aspeed I2C IP sends multiple >> interrupt bits with combining master and slave events using a >> single interrupt call. It happens much more in multi-master >> environment than single-master. For an example, when master is >> waiting for a NORMAL_STOP interrupt in its MASTER_STOP state, >> SLAVE_MATCH and RX_DONE interrupts could come along with the >> NORMAL_STOP in case of an another master immediately sends data >> just after acquiring the bus. In this case, the NORMAL_STOP >> interrupt should be handled by master_irq and the SLAVE_MATCH and >> RX_DONE interrupts should be handled by slave_irq. This commit >> modifies irq hadling logic to handle the master/slave combined >> events properly. >> >> Signed-off-by: Jae Hyun Yoo >> Reviewed-by: Brendan Higgins >> --- >> Changes since v4: >> - Fixed an error printing message that handlers didn't handle all interrupts. >> >> Changes since v3: >> - Fixed typos in a comment. >> >> Changes since v2: >> - Changed the name of ASPEED_I2CD_INTR_ERRORS to ASPEED_I2CD_INTR_MASTER_ERRORS >> - Removed a member irq_status from the struct aspeed_i2c_bus and changed >> master_irq and slave_irq handlers to make them return status_ack. >> - Added a comment to explain why it needs to try both irq handlers. >> >> Changes since v1: >> - Fixed a grammar issue in commit message. >> - Added a missing line feed character into a message printing. >> >> drivers/i2c/busses/i2c-aspeed.c | 115 +++++++++++++++++++------------- >> 1 file changed, 70 insertions(+), 45 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c >> index a4f956c6d567..8341e384f4f1 100644 >> --- a/drivers/i2c/busses/i2c-aspeed.c >> +++ b/drivers/i2c/busses/i2c-aspeed.c >> @@ -82,6 +82,11 @@ >> #define ASPEED_I2CD_INTR_RX_DONE BIT(2) >> #define ASPEED_I2CD_INTR_TX_NAK BIT(1) >> #define ASPEED_I2CD_INTR_TX_ACK BIT(0) >> +#define ASPEED_I2CD_INTR_MASTER_ERRORS \ >> + (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \ >> + ASPEED_I2CD_INTR_SCL_TIMEOUT | \ >> + ASPEED_I2CD_INTR_ABNORMAL | \ >> + ASPEED_I2CD_INTR_ARBIT_LOSS) >> #define ASPEED_I2CD_INTR_ALL \ >> (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \ >> ASPEED_I2CD_INTR_BUS_RECOVER_DONE | \ >> @@ -227,20 +232,16 @@ static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus) >> } >> >> #if IS_ENABLED(CONFIG_I2C_SLAVE) >> -static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus) >> +static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status) >> { >> - u32 command, irq_status, status_ack = 0; >> + u32 command, status_ack = 0; >> struct i2c_client *slave = bus->slave; >> - bool irq_handled = true; >> u8 value; >> >> - if (!slave) { >> - irq_handled = false; >> - goto out; >> - } >> + if (!slave) >> + return 0; >> >> command = readl(bus->base + ASPEED_I2C_CMD_REG); >> - irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG); >> >> /* Slave was requested, restart state machine. */ >> if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) { >> @@ -249,10 +250,8 @@ static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus) >> } >> >> /* Slave is not currently active, irq was for someone else. */ >> - if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) { >> - irq_handled = false; >> - goto out; >> - } >> + if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) >> + return status_ack; >> >> dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n", >> irq_status, command); >> @@ -281,19 +280,19 @@ static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus) >> status_ack |= ASPEED_I2CD_INTR_TX_NAK; >> bus->slave_state = ASPEED_I2C_SLAVE_STOP; >> } >> + if (irq_status & ASPEED_I2CD_INTR_TX_ACK) >> + status_ack |= ASPEED_I2CD_INTR_TX_ACK; >> >> switch (bus->slave_state) { >> case ASPEED_I2C_SLAVE_READ_REQUESTED: >> if (irq_status & ASPEED_I2CD_INTR_TX_ACK) >> dev_err(bus->dev, "Unexpected ACK on read request.\n"); >> bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED; >> - >> i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value); >> writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG); >> writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG); >> break; >> case ASPEED_I2C_SLAVE_READ_PROCESSED: >> - status_ack |= ASPEED_I2CD_INTR_TX_ACK; >> if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK)) >> dev_err(bus->dev, >> "Expected ACK after processed read.\n"); >> @@ -317,14 +316,7 @@ static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus) >> break; >> } >> >> - if (status_ack != irq_status) >> - dev_err(bus->dev, >> - "irq handled != irq. expected %x, but was %x\n", >> - irq_status, status_ack); >> - writel(status_ack, bus->base + ASPEED_I2C_INTR_STS_REG); >> - >> -out: >> - return irq_handled; >> + return status_ack; >> } >> #endif /* CONFIG_I2C_SLAVE */ >> >> @@ -380,21 +372,21 @@ static int aspeed_i2c_is_irq_error(u32 irq_status) >> return 0; >> } >> >> -static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus) >> +static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status) >> { >> - u32 irq_status, status_ack = 0, command = 0; >> + u32 status_ack = 0, command = 0; >> struct i2c_msg *msg; >> u8 recv_byte; >> int ret; >> >> - irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG); >> - /* Ack all interrupt bits. */ >> - writel(irq_status, bus->base + ASPEED_I2C_INTR_STS_REG); >> - >> if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) { >> bus->master_state = ASPEED_I2C_MASTER_INACTIVE; >> status_ack |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE; >> goto out_complete; >> + } else { >> + /* Master is not currently active, irq was for someone else. */ >> + if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE) >> + goto out_no_complete; >> } >> >> /* >> @@ -403,19 +395,22 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus) >> * INACTIVE state. >> */ >> ret = aspeed_i2c_is_irq_error(irq_status); >> - if (ret < 0) { >> + if (ret) { >> dev_dbg(bus->dev, "received error interrupt: 0x%08x\n", >> irq_status); >> bus->cmd_err = ret; >> bus->master_state = ASPEED_I2C_MASTER_INACTIVE; >> + status_ack |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS); >> goto out_complete; >> } >> >> /* We are in an invalid state; reset bus to a known state. */ >> if (!bus->msgs) { >> - dev_err(bus->dev, "bus in unknown state\n"); >> + dev_err(bus->dev, "bus in unknown state. irq_status: 0x%x\n", >> + irq_status); >> bus->cmd_err = -EIO; >> - if (bus->master_state != ASPEED_I2C_MASTER_STOP) >> + if (bus->master_state != ASPEED_I2C_MASTER_STOP && >> + bus->master_state != ASPEED_I2C_MASTER_INACTIVE) >> aspeed_i2c_do_stop(bus); >> goto out_no_complete; >> } >> @@ -428,6 +423,11 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus) >> */ >> if (bus->master_state == ASPEED_I2C_MASTER_START) { >> if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) { >> + if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_NAK))) { >> + bus->cmd_err = -ENXIO; >> + bus->master_state = ASPEED_I2C_MASTER_INACTIVE; >> + goto out_complete; >> + } >> pr_devel("no slave present at %02x\n", msg->addr); >> status_ack |= ASPEED_I2CD_INTR_TX_NAK; >> bus->cmd_err = -ENXIO; >> @@ -506,7 +506,9 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus) >> goto out_no_complete; >> case ASPEED_I2C_MASTER_STOP: >> if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) { >> - dev_err(bus->dev, "master failed to STOP\n"); >> + dev_err(bus->dev, >> + "master failed to STOP. irq_status:0x%x\n", >> + irq_status); >> bus->cmd_err = -EIO; >> /* Do not STOP as we have already tried. */ >> } else { >> @@ -540,33 +542,56 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus) >> bus->master_xfer_result = bus->msgs_index + 1; >> complete(&bus->cmd_complete); >> out_no_complete: >> - if (irq_status != status_ack) >> - dev_err(bus->dev, >> - "irq handled != irq. expected 0x%08x, but was 0x%08x\n", >> - irq_status, status_ack); >> - return !!irq_status; >> + return status_ack; >> } >> >> static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id) >> { >> struct aspeed_i2c_bus *bus = dev_id; >> - bool ret; >> + u32 irq_received, irq_status, irq_acked; > > Thinking more about how irq_status is used below, I think you can pick > a better name, maybe `irq_bits_remaining` or `irq_status_remaining`? > > Come to think of it, `irq_acked` is a bit misleading too, maybe > `irq_handled`? This might seem pedantic, but you ack the bits at the > end of the function, so it does not actually contain acked bits. > > It also might make more sense to just have the `irq_handled` and > `irq_received` fields, and then make the `irq_handled` cumulative. > That way, anywhere you use the `irq_status` it is immediately obvious > that you are comparing the received bits with the bits that have been > handled up to this point. I am not 100% sure, what do you think? > I agree with you about naming of the variables. Will also check if it can use a cumulative variable for the handled bits as you suggested. Thanks! >> >> spin_lock(&bus->lock); >> + irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG); >> + irq_status = irq_received; >> >> #if IS_ENABLED(CONFIG_I2C_SLAVE) >> - if (aspeed_i2c_slave_irq(bus)) { >> - dev_dbg(bus->dev, "irq handled by slave.\n"); >> - ret = true; >> - goto out; >> + /* >> + * In most cases, interrupt bits will be set one by one, although >> + * multiple interrupt bits could be set at the same time. It's also >> + * possible that master interrupt bits could be set along with slave >> + * interrupt bits. Each case needs to be handled using corresponding >> + * handlers depending on the current state. >> + */ >> + if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) { >> + irq_acked = aspeed_i2c_master_irq(bus, irq_status); >> + irq_status &= ~irq_acked; >> + if (irq_status) >> + irq_acked = aspeed_i2c_slave_irq(bus, irq_status); >> + } else { >> + irq_acked = aspeed_i2c_slave_irq(bus, irq_status); >> + irq_status &= ~irq_acked; >> + if (irq_status) >> + irq_acked = aspeed_i2c_master_irq(bus, irq_status); >> } >> +#else >> + irq_acked = aspeed_i2c_master_irq(bus, irq_status); >> #endif /* CONFIG_I2C_SLAVE */ >> >> - ret = aspeed_i2c_master_irq(bus); >> + irq_status &= ~irq_acked; >> + if (irq_status) { >> + /* >> + * 'irq_received ^ irq_status' indicates accumulated bits acked >> + * by both master and slave irq handlers. >> + */ >> + dev_err(bus->dev, >> + "irq acked != irq. expected 0x%08x, but was 0x%08x\n", >> + irq_received, irq_received ^ irq_status); > > My point was that you are still using the `irq_received ^ irq_status`, right? > > If you want a cumulative irq_acked, you can either or the first > instance of irq_acked with the following, or take a not of irq_status. > Xoring with a mask is not immediately clear. > Okay. I'll check your suggestions and will replace the 'irq_received ^ irq_status' use. >> + } >> >> -out: >> + /* Ack all interrupt bits. */ >> + writel(irq_received, bus->base + ASPEED_I2C_INTR_STS_REG); >> spin_unlock(&bus->lock); >> - return ret ? IRQ_HANDLED : IRQ_NONE; >> + return irq_status ? IRQ_NONE : IRQ_HANDLED; >> } >> >> static int aspeed_i2c_master_xfer(struct i2c_adapter *adap, >> -- >> 2.18.0 >> > > Cheers > Thanks for your review. I'll submit v6 without adding your tag. Please review and comment the patch then. Thanks!