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SubjectRe: [PATCH i2c-next] i2c: aspeed: Handle master/slave combined irq events properly
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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@linux.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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