@@ -212,6 +212,7 @@ struct reset_control;
* @msg_err: error status of the current transfer
* @status: i2c master status, one of STATUS_*
* @abort_source: copy of the TX_ABRT_SOURCE register
+ * @sw_mask: SW mask of DW_IC_INTR_MASK used in polling mode
* @irq: interrupt number for the i2c master
* @flags: platform specific flags like type of IO accessors or model
* @adapter: i2c subsystem adapter node
@@ -270,6 +271,7 @@ struct dw_i2c_dev {
int msg_err;
unsigned int status;
unsigned int abort_source;
+ unsigned int sw_mask;
int irq;
u32 flags;
struct i2c_adapter adapter;
@@ -358,6 +360,7 @@ static inline void __i2c_dw_write_intr_mask(struct dw_i2c_dev *dev,
unsigned int val = dev->flags & ACCESS_POLLING ? 0 : intr_mask;
regmap_write(dev->map, DW_IC_INTR_MASK, val);
+ dev->sw_mask = intr_mask;
}
static inline void __i2c_dw_read_intr_mask(struct dw_i2c_dev *dev,
@@ -365,6 +368,8 @@ static inline void __i2c_dw_read_intr_mask(struct dw_i2c_dev *dev,
{
if (!(dev->flags & ACCESS_POLLING))
regmap_read(dev->map, DW_IC_INTR_MASK, intr_mask);
+ else
+ *intr_mask = dev->sw_mask;
}
void __i2c_dw_disable(struct dw_i2c_dev *dev);
@@ -354,67 +354,6 @@ static int amd_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs,
return 0;
}
-static int i2c_dw_poll_tx_empty(struct dw_i2c_dev *dev)
-{
- u32 val;
-
- return regmap_read_poll_timeout(dev->map, DW_IC_RAW_INTR_STAT, val,
- val & DW_IC_INTR_TX_EMPTY,
- 100, 1000);
-}
-
-static int i2c_dw_poll_rx_full(struct dw_i2c_dev *dev)
-{
- u32 val;
-
- return regmap_read_poll_timeout(dev->map, DW_IC_RAW_INTR_STAT, val,
- val & DW_IC_INTR_RX_FULL,
- 100, 1000);
-}
-
-static int txgbe_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs,
- int num_msgs)
-{
- struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
- int msg_idx, buf_len, data_idx, ret;
- unsigned int val, stop = 0;
- u8 *buf;
-
- dev->msgs = msgs;
- dev->msgs_num = num_msgs;
- i2c_dw_xfer_init(dev);
-
- for (msg_idx = 0; msg_idx < num_msgs; msg_idx++) {
- buf = msgs[msg_idx].buf;
- buf_len = msgs[msg_idx].len;
-
- for (data_idx = 0; data_idx < buf_len; data_idx++) {
- if (msg_idx == num_msgs - 1 && data_idx == buf_len - 1)
- stop |= BIT(9);
-
- if (msgs[msg_idx].flags & I2C_M_RD) {
- regmap_write(dev->map, DW_IC_DATA_CMD, 0x100 | stop);
-
- ret = i2c_dw_poll_rx_full(dev);
- if (ret)
- return ret;
-
- regmap_read(dev->map, DW_IC_DATA_CMD, &val);
- buf[data_idx] = val;
- } else {
- ret = i2c_dw_poll_tx_empty(dev);
- if (ret)
- return ret;
-
- regmap_write(dev->map, DW_IC_DATA_CMD,
- buf[data_idx] | stop);
- }
- }
- }
-
- return num_msgs;
-}
-
/*
* Initiate (and continue) low level master read/write transaction.
* This function is only called from i2c_dw_isr, and pumping i2c_msg
@@ -649,7 +588,12 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
*
* The raw version might be useful for debugging purposes.
*/
- regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
+ if (!(dev->flags & ACCESS_POLLING)) {
+ regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
+ } else {
+ regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &stat);
+ stat &= dev->sw_mask;
+ }
/*
* Do not use the IC_CLR_INTR register to clear interrupts, or
@@ -689,37 +633,8 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
return stat;
}
-/*
- * Interrupt service routine. This gets called whenever an I2C master interrupt
- * occurs.
- */
-static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
+static void i2c_dw_process_transfer(struct dw_i2c_dev *dev, unsigned int stat)
{
- struct dw_i2c_dev *dev = dev_id;
- unsigned int stat, enabled;
-
- regmap_read(dev->map, DW_IC_ENABLE, &enabled);
- regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &stat);
- if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
- return IRQ_NONE;
- if (pm_runtime_suspended(dev->dev) || stat == GENMASK(31, 0))
- return IRQ_NONE;
- dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat);
-
- stat = i2c_dw_read_clear_intrbits(dev);
-
- if (!(dev->status & STATUS_ACTIVE)) {
- /*
- * Unexpected interrupt in driver point of view. State
- * variables are either unset or stale so acknowledge and
- * disable interrupts for suppressing further interrupts if
- * interrupt really came from this HW (E.g. firmware has left
- * the HW active).
- */
- __i2c_dw_write_intr_mask(dev, 0);
- return IRQ_HANDLED;
- }
-
if (stat & DW_IC_INTR_TX_ABRT) {
dev->cmd_err |= DW_IC_ERR_TX_ABRT;
dev->status &= ~STATUS_MASK;
@@ -755,10 +670,73 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
__i2c_dw_write_intr_mask(dev, 0);
__i2c_dw_write_intr_mask(dev, stat);
}
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C master interrupt
+ * occurs.
+ */
+static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
+{
+ struct dw_i2c_dev *dev = dev_id;
+ unsigned int stat, enabled;
+
+ regmap_read(dev->map, DW_IC_ENABLE, &enabled);
+ regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &stat);
+ if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
+ return IRQ_NONE;
+ if (pm_runtime_suspended(dev->dev) || stat == GENMASK(31, 0))
+ return IRQ_NONE;
+ dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat);
+
+ stat = i2c_dw_read_clear_intrbits(dev);
+
+ if (!(dev->status & STATUS_ACTIVE)) {
+ /*
+ * Unexpected interrupt in driver point of view. State
+ * variables are either unset or stale so acknowledge and
+ * disable interrupts for suppressing further interrupts if
+ * interrupt really came from this HW (E.g. firmware has left
+ * the HW active).
+ */
+ __i2c_dw_write_intr_mask(dev, 0);
+ return IRQ_HANDLED;
+ }
+
+ i2c_dw_process_transfer(dev, stat);
return IRQ_HANDLED;
}
+static int i2c_dw_wait_transfer(struct dw_i2c_dev *dev)
+{
+ unsigned long timeout = dev->adapter.timeout;
+ unsigned int stat;
+ int ret = 0;
+
+ if (!(dev->flags & ACCESS_POLLING)) {
+ ret = wait_for_completion_timeout(&dev->cmd_complete,
+ timeout) ? 0 : -ETIMEDOUT;
+ } else {
+ timeout += jiffies;
+ do {
+ if (try_wait_for_completion(&dev->cmd_complete))
+ goto out;
+
+ stat = i2c_dw_read_clear_intrbits(dev);
+ if (stat)
+ i2c_dw_process_transfer(dev, stat);
+ else
+ /* Try save some power */
+ usleep_range(3, 25);
+ } while (time_before(jiffies, timeout));
+ ret = ETIMEDOUT;
+ }
+
+out:
+ return ret;
+}
+
/*
* Prepare controller for a transaction and call i2c_dw_xfer_msg.
*/
@@ -781,9 +759,6 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
case MODEL_AMD_NAVI_GPU:
ret = amd_i2c_dw_xfer_quirk(adap, msgs, num);
goto done_nolock;
- case MODEL_WANGXUN_SP:
- ret = txgbe_i2c_dw_xfer_quirk(adap, msgs, num);
- goto done_nolock;
default:
break;
}
@@ -811,12 +786,12 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
i2c_dw_xfer_init(dev);
/* Wait for tx to complete */
- if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
+ ret = i2c_dw_wait_transfer(dev);
+ if (ret) {
dev_err(dev->dev, "controller timed out\n");
/* i2c_dw_init implicitly disables the adapter */
i2c_recover_bus(&dev->adapter);
i2c_dw_init_master(dev);
- ret = -ETIMEDOUT;
goto done;
}
I got an idea the i2c-designware should not need duplicated state machines for the interrupt and polling modes. The IP is practically the same and state transitions happens in response to the events that can be observed from the DW_IC_RAW_INTR_STAT register. Either by interrupts or by polling. Another reasons are the interrupt mode is the most tested, has handling for many exceptions as well as transmit abort handling and those are missing from two polling mode quirks. Patch implements generic polling mode code which shares the same code with interrupt mode code. This is done by moving event handling from the i2c_dw_isr() into a new i2c_dw_process_transfer() that will be called both from the i2c_dw_isr() and polling loop. Polling loop is implemented in a new i2c_dw_wait_transfer() that is shared between both modes. In interrupt mode it waits for the completion object as before. In polling mode both completion object and DW_IC_RAW_INTR_STAT are polled. I decided to convert the txgbe_i2c_dw_xfer_quirk() straight to generic polling mode code in this patch. It doesn't have HW dependent quirks like the amd_i2c_dw_xfer_quirk() does have and without users this patch is needless. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> --- drivers/i2c/busses/i2c-designware-core.h | 5 + drivers/i2c/busses/i2c-designware-master.c | 169 +++++++++------------ 2 files changed, 77 insertions(+), 97 deletions(-)