lkml.org 
[lkml]   [2018]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH i2c-next] i2c: aspeed: Handle master/slave combined irq events properly
Date
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
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);
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,
--
2.18.0
\
 
 \ /
  Last update: 2018-07-23 19:48    [W:0.060 / U:1.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site