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Message-ID: <6721ef3b-2c74-9f4a-1b67-5335e7878a0c@linux.intel.com>
Date: Mon, 23 Jul 2018 11:13:30 -0700
From: Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>
To: James Feist <james.feist@...ux.intel.com>,
Brendan Higgins <brendanhiggins@...gle.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Joel Stanley <joel@....id.au>,
Andrew Jeffery <andrew@...id.au>, linux-i2c@...r.kernel.org,
openbmc@...ts.ozlabs.org, linux-arm-kernel@...ts.infradead.org,
linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Cc: Vernon Mauery <vernon.mauery@...ux.intel.com>,
Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Subject: Re: [PATCH i2c-next] i2c: aspeed: Handle master/slave combined irq
events properly
Thanks James for the review. Please see my inline answers.
On 7/23/2018 11:10 AM, James Feist wrote:
> On 07/23/2018 10:48 AM, 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 in multi-master environment
>
> much more
>
Thanks! Will fix it.
>> 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 <jae.hyun.yoo@...ux.intel.com>
>> ---
>> drivers/i2c/busses/i2c-aspeed.c | 137 ++++++++++++++++++--------------
>> 1 file changed, 76 insertions(+), 61 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-aspeed.c
>> b/drivers/i2c/busses/i2c-aspeed.c
>> index efb89422d496..24d43f143a55 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_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 | \
>> @@ -150,6 +155,7 @@ struct aspeed_i2c_bus {
>> int cmd_err;
>> /* Protected only by i2c_lock_bus */
>> int master_xfer_result;
>> + u32 irq_status;
>> #if IS_ENABLED(CONFIG_I2C_SLAVE)
>> struct i2c_client *slave;
>> enum aspeed_i2c_slave_state slave_state;
>> @@ -229,36 +235,30 @@ 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)
>> {
>> - 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 false;
>> 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) {
>> + if (bus->irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
>> status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH;
>> bus->slave_state = ASPEED_I2C_SLAVE_START;
>> }
>> /* 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 false;
>> dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
>> - irq_status, command);
>> + bus->irq_status, command);
>> /* Slave was sent something. */
>> - if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
>> + if (bus->irq_status & ASPEED_I2CD_INTR_RX_DONE) {
>> value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
>> /* Handle address frame. */
>> if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
>> @@ -273,28 +273,29 @@ static bool aspeed_i2c_slave_irq(struct
>> aspeed_i2c_bus *bus)
>> }
>> /* Slave was asked to stop. */
>> - if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
>> + if (bus->irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
>> status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
>> bus->slave_state = ASPEED_I2C_SLAVE_STOP;
>> }
>> - if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
>> + if (bus->irq_status & ASPEED_I2CD_INTR_TX_NAK) {
>> status_ack |= ASPEED_I2CD_INTR_TX_NAK;
>> bus->slave_state = ASPEED_I2C_SLAVE_STOP;
>> }
>> + if (bus->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)
>> + if (bus->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))
>> + if (!(bus->irq_status & ASPEED_I2CD_INTR_TX_ACK))
>> dev_err(bus->dev,
>> "Expected ACK after processed read.\n");
>> i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
>> @@ -317,14 +318,8 @@ 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;
>> + bus->irq_status ^= status_ack;
>> + return !bus->irq_status;
>> }
>> #endif /* CONFIG_I2C_SLAVE */
>> @@ -382,19 +377,19 @@ static int aspeed_i2c_is_irq_error(u32 irq_status)
>> static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
>> {
>> - 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) {
>> + if (bus->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;
>> }
>> /*
>> @@ -402,20 +397,23 @@ static bool aspeed_i2c_master_irq(struct
>> aspeed_i2c_bus *bus)
>> * should clear the command queue effectively taking us back to the
>> * INACTIVE state.
>> */
>> - ret = aspeed_i2c_is_irq_error(irq_status);
>> - if (ret < 0) {
>> + ret = aspeed_i2c_is_irq_error(bus->irq_status);
>> + if (ret) {
>> dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
>> - irq_status);
>> + bus->irq_status);
>> bus->cmd_err = ret;
>> bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
>> + status_ack |= (bus->irq_status & ASPEED_I2CD_INTR_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",
>> + bus->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;
>> }
>> @@ -427,8 +425,14 @@ static bool aspeed_i2c_master_irq(struct
>> aspeed_i2c_bus *bus)
>> * then update the state and handle the new state below.
>> */
>> if (bus->master_state == ASPEED_I2C_MASTER_START) {
>> - if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
>> - pr_devel("no slave present at %02x\n", msg->addr);
>> + if (unlikely(!(bus->irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
>> + if (unlikely(!(bus->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", msg->addr);
> Missing line feed character
Thanks for your pointing it out. Will add '\n' at the end of the
message.
>> status_ack |= ASPEED_I2CD_INTR_TX_NAK;
>> bus->cmd_err = -ENXIO;
>> aspeed_i2c_do_stop(bus);
>> @@ -447,11 +451,12 @@ static bool aspeed_i2c_master_irq(struct
>> aspeed_i2c_bus *bus)
>> switch (bus->master_state) {
>> case ASPEED_I2C_MASTER_TX:
>> - if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
>> + if (unlikely(bus->irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
>> dev_dbg(bus->dev, "slave NACKed TX\n");
>> status_ack |= ASPEED_I2CD_INTR_TX_NAK;
>> goto error_and_stop;
>> - } else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
>> + } else if (unlikely(!(bus->irq_status &
>> + ASPEED_I2CD_INTR_TX_ACK))) {
>> dev_err(bus->dev, "slave failed to ACK TX\n");
>> goto error_and_stop;
>> }
>> @@ -470,11 +475,11 @@ static bool aspeed_i2c_master_irq(struct
>> aspeed_i2c_bus *bus)
>> goto out_no_complete;
>> case ASPEED_I2C_MASTER_RX_FIRST:
>> /* RX may not have completed yet (only address cycle) */
>> - if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
>> + if (!(bus->irq_status & ASPEED_I2CD_INTR_RX_DONE))
>> goto out_no_complete;
>> /* fallthrough intended */
>> case ASPEED_I2C_MASTER_RX:
>> - if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
>> + if (unlikely(!(bus->irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
>> dev_err(bus->dev, "master failed to RX\n");
>> goto error_and_stop;
>> }
>> @@ -505,8 +510,11 @@ 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");
>> + if (unlikely(!(bus->irq_status &
>> + ASPEED_I2CD_INTR_NORMAL_STOP))) {
>> + dev_err(bus->dev,
>> + "master failed to STOP irq_status:0x%x\n",
>> + bus->irq_status);
>> bus->cmd_err = -EIO;
>> /* Do not STOP as we have already tried. */
>> } else {
>> @@ -518,7 +526,7 @@ static bool aspeed_i2c_master_irq(struct
>> aspeed_i2c_bus *bus)
>> case ASPEED_I2C_MASTER_INACTIVE:
>> dev_err(bus->dev,
>> "master received interrupt 0x%08x, but is inactive\n",
>> - irq_status);
>> + bus->irq_status);
>> bus->cmd_err = -EIO;
>> /* Do not STOP as we should be inactive. */
>> goto out_complete;
>> @@ -540,33 +548,40 @@ 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;
>> + bus->irq_status ^= status_ack;
>> + return !bus->irq_status;
>> }
>> static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
>> {
>> struct aspeed_i2c_bus *bus = dev_id;
>> - bool ret;
>> + u32 irq_received;
>> spin_lock(&bus->lock);
>> + irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
>> + bus->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;
>> + if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
>> + if (!aspeed_i2c_master_irq(bus))
>> + aspeed_i2c_slave_irq(bus);
>> + } else {
>> + if (!aspeed_i2c_slave_irq(bus))
>> + aspeed_i2c_master_irq(bus);
>> }
>> +#else
>> + aspeed_i2c_master_irq(bus);
>> #endif /* CONFIG_I2C_SLAVE */
>> - ret = aspeed_i2c_master_irq(bus);
>> + if (bus->irq_status)
>> + dev_err(bus->dev,
>> + "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
>> + irq_received, irq_received ^ bus->irq_status);
>> -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 bus->irq_status ? IRQ_NONE : IRQ_HANDLED;
>> }
>> static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
>>
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