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-rw-r--r--drivers/i2c/busses/i2c-cadence.c175
1 files changed, 102 insertions, 73 deletions
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 626f74ecd4be..871cb58aaa06 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -128,6 +128,7 @@
* @suspended: Flag holding the device's PM status
* @send_count: Number of bytes still expected to send
* @recv_count: Number of bytes still expected to receive
+ * @curr_recv_count: Number of bytes to be received in current transfer
* @irq: IRQ number
* @input_clk: Input clock to I2C controller
* @i2c_clk: Maximum I2C clock speed
@@ -146,6 +147,7 @@ struct cdns_i2c {
u8 suspended;
unsigned int send_count;
unsigned int recv_count;
+ unsigned int curr_recv_count;
int irq;
unsigned long input_clk;
unsigned int i2c_clk;
@@ -182,14 +184,15 @@ static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id)
*/
static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
{
- unsigned int isr_status, avail_bytes;
- unsigned int bytes_to_recv, bytes_to_send;
+ unsigned int isr_status, avail_bytes, updatetx;
+ unsigned int bytes_to_send;
struct cdns_i2c *id = ptr;
/* Signal completion only after everything is updated */
int done_flag = 0;
irqreturn_t status = IRQ_NONE;
isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
+ cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
/* Handling nack and arbitration lost interrupt */
if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) {
@@ -197,89 +200,112 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
status = IRQ_HANDLED;
}
- /* Handling Data interrupt */
- if ((isr_status & CDNS_I2C_IXR_DATA) &&
- (id->recv_count >= CDNS_I2C_DATA_INTR_DEPTH)) {
- /* Always read data interrupt threshold bytes */
- bytes_to_recv = CDNS_I2C_DATA_INTR_DEPTH;
- id->recv_count -= CDNS_I2C_DATA_INTR_DEPTH;
- avail_bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
-
- /*
- * if the tranfer size register value is zero, then
- * check for the remaining bytes and update the
- * transfer size register.
- */
- if (!avail_bytes) {
- if (id->recv_count > CDNS_I2C_TRANSFER_SIZE)
- cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
- CDNS_I2C_XFER_SIZE_OFFSET);
- else
- cdns_i2c_writereg(id->recv_count,
- CDNS_I2C_XFER_SIZE_OFFSET);
- }
+ /*
+ * Check if transfer size register needs to be updated again for a
+ * large data receive operation.
+ */
+ updatetx = 0;
+ if (id->recv_count > id->curr_recv_count)
+ updatetx = 1;
+
+ /* When receiving, handle data interrupt and completion interrupt */
+ if (id->p_recv_buf &&
+ ((isr_status & CDNS_I2C_IXR_COMP) ||
+ (isr_status & CDNS_I2C_IXR_DATA))) {
+ /* Read data if receive data valid is set */
+ while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
+ CDNS_I2C_SR_RXDV) {
+ /*
+ * Clear hold bit that was set for FIFO control if
+ * RX data left is less than FIFO depth, unless
+ * repeated start is selected.
+ */
+ if ((id->recv_count < CDNS_I2C_FIFO_DEPTH) &&
+ !id->bus_hold_flag)
+ cdns_i2c_clear_bus_hold(id);
- /* Process the data received */
- while (bytes_to_recv--)
*(id->p_recv_buf)++ =
cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
+ id->recv_count--;
+ id->curr_recv_count--;
- if (!id->bus_hold_flag &&
- (id->recv_count <= CDNS_I2C_FIFO_DEPTH))
- cdns_i2c_clear_bus_hold(id);
+ if (updatetx &&
+ (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1))
+ break;
+ }
- status = IRQ_HANDLED;
- }
+ /*
+ * The controller sends NACK to the slave when transfer size
+ * register reaches zero without considering the HOLD bit.
+ * This workaround is implemented for large data transfers to
+ * maintain transfer size non-zero while performing a large
+ * receive operation.
+ */
+ if (updatetx &&
+ (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1)) {
+ /* wait while fifo is full */
+ while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) !=
+ (id->curr_recv_count - CDNS_I2C_FIFO_DEPTH))
+ ;
- /* Handling Transfer Complete interrupt */
- if (isr_status & CDNS_I2C_IXR_COMP) {
- if (!id->p_recv_buf) {
/*
- * If the device is sending data If there is further
- * data to be sent. Calculate the available space
- * in FIFO and fill the FIFO with that many bytes.
+ * Check number of bytes to be received against maximum
+ * transfer size and update register accordingly.
*/
- if (id->send_count) {
- avail_bytes = CDNS_I2C_FIFO_DEPTH -
- cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
- if (id->send_count > avail_bytes)
- bytes_to_send = avail_bytes;
- else
- bytes_to_send = id->send_count;
-
- while (bytes_to_send--) {
- cdns_i2c_writereg(
- (*(id->p_send_buf)++),
- CDNS_I2C_DATA_OFFSET);
- id->send_count--;
- }
+ if (((int)(id->recv_count) - CDNS_I2C_FIFO_DEPTH) >
+ CDNS_I2C_TRANSFER_SIZE) {
+ cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
+ CDNS_I2C_XFER_SIZE_OFFSET);
+ id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
+ CDNS_I2C_FIFO_DEPTH;
} else {
- /*
- * Signal the completion of transaction and
- * clear the hold bus bit if there are no
- * further messages to be processed.
- */
- done_flag = 1;
+ cdns_i2c_writereg(id->recv_count -
+ CDNS_I2C_FIFO_DEPTH,
+ CDNS_I2C_XFER_SIZE_OFFSET);
+ id->curr_recv_count = id->recv_count;
}
- if (!id->send_count && !id->bus_hold_flag)
- cdns_i2c_clear_bus_hold(id);
- } else {
+ }
+
+ /* Clear hold (if not repeated start) and signal completion */
+ if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) {
if (!id->bus_hold_flag)
cdns_i2c_clear_bus_hold(id);
+ done_flag = 1;
+ }
+
+ status = IRQ_HANDLED;
+ }
+
+ /* When sending, handle transfer complete interrupt */
+ if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) {
+ /*
+ * If there is more data to be sent, calculate the
+ * space available in FIFO and fill with that many bytes.
+ */
+ if (id->send_count) {
+ avail_bytes = CDNS_I2C_FIFO_DEPTH -
+ cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
+ if (id->send_count > avail_bytes)
+ bytes_to_send = avail_bytes;
+ else
+ bytes_to_send = id->send_count;
+
+ while (bytes_to_send--) {
+ cdns_i2c_writereg(
+ (*(id->p_send_buf)++),
+ CDNS_I2C_DATA_OFFSET);
+ id->send_count--;
+ }
+ } else {
/*
- * If the device is receiving data, then signal
- * the completion of transaction and read the data
- * present in the FIFO. Signal the completion of
- * transaction.
+ * Signal the completion of transaction and
+ * clear the hold bus bit if there are no
+ * further messages to be processed.
*/
- while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
- CDNS_I2C_SR_RXDV) {
- *(id->p_recv_buf)++ =
- cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
- id->recv_count--;
- }
done_flag = 1;
}
+ if (!id->send_count && !id->bus_hold_flag)
+ cdns_i2c_clear_bus_hold(id);
status = IRQ_HANDLED;
}
@@ -289,8 +315,6 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
if (id->err_status)
status = IRQ_HANDLED;
- cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
-
if (done_flag)
complete(&id->xfer_done);
@@ -316,6 +340,8 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
if (id->p_msg->flags & I2C_M_RECV_LEN)
id->recv_count = I2C_SMBUS_BLOCK_MAX + 1;
+ id->curr_recv_count = id->recv_count;
+
/*
* Check for the message size against FIFO depth and set the
* 'hold bus' bit if it is greater than FIFO depth.
@@ -335,11 +361,14 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
* receive if it is less than transfer size and transfer size if
* it is more. Enable the interrupts.
*/
- if (id->recv_count > CDNS_I2C_TRANSFER_SIZE)
+ if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) {
cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
CDNS_I2C_XFER_SIZE_OFFSET);
- else
+ id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
+ } else {
cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET);
+ }
+
/* Clear the bus hold flag if bytes to receive is less than FIFO size */
if (!id->bus_hold_flag &&
((id->p_msg->flags & I2C_M_RECV_LEN) != I2C_M_RECV_LEN) &&
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-10 06:08:07 +0000