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

[Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>]

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,
>>