> -----Original Message-----
> From: linux-i2c-owner@xxxxxxxxxxxxxxx <linux-i2c-owner@xxxxxxxxxxxxxxx> On
> Behalf Of Marek Vasut
> Sent: Saturday, June 13, 2020 8:38 PM
> To: linux-i2c@xxxxxxxxxxxxxxx
> Cc: Marek Vasut <marex@xxxxxxx>; Michal Simek <michals@xxxxxxxxxx>;
> Shubhrajyoti Datta <shubhraj@xxxxxxxxxx>; Wolfram Sang <wsa@xxxxxxxxxx>
> Subject: [PATCH 3/5] i2c: xiic: Defer xiic_wakeup() and __xiic_start_xfer() in
> xiic_process()
>
> The __xiic_start_xfer() manipulates the interrupt flags, xiic_wakeup() may
> result in return from xiic_xfer() early. Defer both to the end of the
> xiic_process() interrupt thread, so that they are executed after all the other
> interrupt bits handling completed and once it completely safe to perform
> changes to the interrupt bits in the hardware.
>
> Signed-off-by: Marek Vasut <marex@xxxxxxx>
> Cc: Michal Simek <michal.simek@xxxxxxxxxx>
> Cc: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> Cc: Wolfram Sang <wsa@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-xiic.c | 37 ++++++++++++++++++++++++-----------
> 1 file changed, 26 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c index
> 6db71c0fb6583..87eca9d46afd9 100644
> --- a/drivers/i2c/busses/i2c-xiic.c
> +++ b/drivers/i2c/busses/i2c-xiic.c
> @@ -373,6 +373,9 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> struct xiic_i2c *i2c = dev_id;
> u32 pend, isr, ier;
> u32 clr = 0;
> + int xfer_more = 0;
> + int wakeup_req = 0;
> + int wakeup_code = 0;
>
> /* Get the interrupt Status from the IPIF. There is no clearing of
> * interrupts in the IPIF. Interrupts must be cleared at the source.
> @@ -409,10 +412,14 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> */
> xiic_reinit(i2c);
>
> - if (i2c->rx_msg)
> - xiic_wakeup(i2c, STATE_ERROR);
> - if (i2c->tx_msg)
> - xiic_wakeup(i2c, STATE_ERROR);
> + if (i2c->rx_msg) {
> + wakeup_req = 1;
> + wakeup_code = STATE_ERROR;
> + }
> + if (i2c->tx_msg) {
> + wakeup_req = 1;
> + wakeup_code = STATE_ERROR;
> + }
> }
> if (pend & XIIC_INTR_RX_FULL_MASK) {
> /* Receive register/FIFO is full */
> @@ -446,8 +453,7 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> i2c->tx_msg++;
> dev_dbg(i2c->adap.dev.parent,
> "%s will start next...\n", __func__);
> -
> - __xiic_start_xfer(i2c);
> + xfer_more = 1;
> }
> }
> }
> @@ -461,11 +467,13 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> if (!i2c->tx_msg)
> goto out;
>
> - if ((i2c->nmsgs == 1) && !i2c->rx_msg &&
> - xiic_tx_space(i2c) == 0)
> - xiic_wakeup(i2c, STATE_DONE);
> + wakeup_req = 1;
> +
> + if (i2c->nmsgs == 1 && !i2c->rx_msg &&
> + xiic_tx_space(i2c) == 0)
> + wakeup_code = STATE_DONE;
> else
> - xiic_wakeup(i2c, STATE_ERROR);
> + wakeup_code = STATE_ERROR;
> }
> if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK))
> {
> /* Transmit register/FIFO is empty or ½ empty */ @@ -489,7
> +497,7 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> if (i2c->nmsgs > 1) {
> i2c->nmsgs--;
> i2c->tx_msg++;
> - __xiic_start_xfer(i2c);
> + xfer_more = 1;
> } else {
> xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
>
> @@ -507,6 +515,13 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
> dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr);
>
> xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr);
> + if (xfer_more)
> + __xiic_start_xfer(i2c);
> + if (wakeup_req)
> + xiic_wakeup(i2c, wakeup_code);
> +
> + WARN_ON(xfer_more && wakeup_req);
> +
> mutex_unlock(&i2c->lock);
> return IRQ_HANDLED;
> }
This is tested and working fine.
Raviteja N
