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i2c: aspeed: Handle master/slave combined irq events properly

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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 <jae.hyun.yoo@linux.intel.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jae Hyun Yoo 2018-08-23 15:57:31 -07:00 committed by Wolfram Sang
parent fc66b39fe3
commit 3e9efc3299
1 changed files with 76 additions and 55 deletions
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131
drivers/i2c/busses/i2c-aspeed.c
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@ -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 | \
@ -227,32 +232,26 @@ reset_out:
}
#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, irq_handled = 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) {
status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH;
irq_handled |= 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 irq_handled;
dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
irq_status, command);
@ -269,31 +268,31 @@ static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus)
bus->slave_state =
ASPEED_I2C_SLAVE_WRITE_REQUESTED;
}
status_ack |= ASPEED_I2CD_INTR_RX_DONE;
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
}
/* Slave was asked to stop. */
if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
status_ack |= ASPEED_I2CD_INTR_TX_NAK;
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
if (irq_status & ASPEED_I2CD_INTR_TX_ACK)
irq_handled |= 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");
@ -317,13 +316,6 @@ 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;
}
#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 irq_handled = 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;
irq_handled |= 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;
irq_handled |= (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;
}
@ -428,13 +423,18 @@ 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;
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->cmd_err = -ENXIO;
aspeed_i2c_do_stop(bus);
goto out_no_complete;
}
status_ack |= ASPEED_I2CD_INTR_TX_ACK;
irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
if (msg->len == 0) { /* SMBUS_QUICK */
aspeed_i2c_do_stop(bus);
goto out_no_complete;
@ -449,13 +449,13 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
case ASPEED_I2C_MASTER_TX:
if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
dev_dbg(bus->dev, "slave NACKed TX\n");
status_ack |= ASPEED_I2CD_INTR_TX_NAK;
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
goto error_and_stop;
} else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
dev_err(bus->dev, "slave failed to ACK TX\n");
goto error_and_stop;
}
status_ack |= ASPEED_I2CD_INTR_TX_ACK;
irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
/* fallthrough intended */
case ASPEED_I2C_MASTER_TX_FIRST:
if (bus->buf_index < msg->len) {
@ -478,7 +478,7 @@ static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
dev_err(bus->dev, "master failed to RX\n");
goto error_and_stop;
}
status_ack |= ASPEED_I2CD_INTR_RX_DONE;
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
msg->buf[bus->buf_index++] = recv_byte;
@ -506,11 +506,13 @@ 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 {
status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
}
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
@ -540,33 +542,52 @@ out_complete:
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 irq_handled;
}
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_remaining, irq_handled;
spin_lock(&bus->lock);
irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
irq_remaining = 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_handled = aspeed_i2c_master_irq(bus, irq_remaining);
irq_remaining &= ~irq_handled;
if (irq_remaining)
irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);
} else {
irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);
irq_remaining &= ~irq_handled;
if (irq_remaining)
irq_handled |= aspeed_i2c_master_irq(bus,
irq_remaining);
}
#else
irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
#endif /* CONFIG_I2C_SLAVE */
ret = aspeed_i2c_master_irq(bus);
irq_remaining &= ~irq_handled;
if (irq_remaining)
dev_err(bus->dev,
"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
irq_received, irq_handled);
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_remaining ? IRQ_NONE : IRQ_HANDLED;
}
static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,