| Message ID | 1446190649-1318-1-git-send-email-jszhang@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi On 10/30/2015 09:37 AM, Jisheng Zhang wrote: > Currently when i2c_msg index search is completed, TX_EMPTY interrupt > will be masked. But if the size of i2c_msg data is longer than the size > of the tx buffer, we still need TX_EMPTY interrupt, otherwise we will > get "controller timed out" error. > > This patch fixes this issue by only masking TX_EMPTY if i2c_msg index > search is completed and write is not in progress. > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > drivers/i2c/busses/i2c-designware-core.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c > index 7441cdc..a2eb212 100644 > --- a/drivers/i2c/busses/i2c-designware-core.c > +++ b/drivers/i2c/busses/i2c-designware-core.c > @@ -542,10 +542,11 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) > } > > /* > - * If i2c_msg index search is completed, we don't need TX_EMPTY > - * interrupt any more. > + * If i2c_msg index search is completed and writing is not in progress, > + * we don't need TX_EMPTY interrupt any more. > */ > - if (dev->msg_write_idx == dev->msgs_num) > + if (dev->msg_write_idx == dev->msgs_num && > + !(dev->status & STATUS_WRITE_IN_PROGRESS)) > intr_mask &= ~DW_IC_INTR_TX_EMPTY; > This looks a possible scenario here. What I'm wondering how is the transfer ending and what condition in i2c_dw_isr() causes the complete() call? Assuming we break the for loop in i2c_dw_xfer_msg() with buf_len > 0 and dev->msg_write_idx == dev->msgs_num how we get back inside the for loop for writing the remaining bytes and stop command?
Dear Jarkko, On Fri, 30 Oct 2015 14:03:53 +0200 Jarkko Nikula wrote: > Hi > > On 10/30/2015 09:37 AM, Jisheng Zhang wrote: > > Currently when i2c_msg index search is completed, TX_EMPTY interrupt > > will be masked. But if the size of i2c_msg data is longer than the size > > of the tx buffer, we still need TX_EMPTY interrupt, otherwise we will > > get "controller timed out" error. > > > > This patch fixes this issue by only masking TX_EMPTY if i2c_msg index > > search is completed and write is not in progress. > > > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > > --- > > drivers/i2c/busses/i2c-designware-core.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c > > index 7441cdc..a2eb212 100644 > > --- a/drivers/i2c/busses/i2c-designware-core.c > > +++ b/drivers/i2c/busses/i2c-designware-core.c > > @@ -542,10 +542,11 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) > > } > > > > /* > > - * If i2c_msg index search is completed, we don't need TX_EMPTY > > - * interrupt any more. > > + * If i2c_msg index search is completed and writing is not in progress, > > + * we don't need TX_EMPTY interrupt any more. > > */ > > - if (dev->msg_write_idx == dev->msgs_num) > > + if (dev->msg_write_idx == dev->msgs_num && > > + !(dev->status & STATUS_WRITE_IN_PROGRESS)) > > intr_mask &= ~DW_IC_INTR_TX_EMPTY; > > > This looks a possible scenario here. What I'm wondering how is the > transfer ending and what condition in i2c_dw_isr() causes the complete() > call? > > Assuming we break the for loop in i2c_dw_xfer_msg() with buf_len > 0 and > dev->msg_write_idx == dev->msgs_num how we get back inside the for loop > for writing the remaining bytes and stop command? This is a good question. After more consideration, I think the following condition can't exist: (msg_write_idx == dev->msgs_num) && (dev->status & STATUS_WRITE_IN_PROGRESS) so this patch isn't necessary. Thanks for your review, Jisheng
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 7441cdc..a2eb212 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -542,10 +542,11 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) } /* - * If i2c_msg index search is completed, we don't need TX_EMPTY - * interrupt any more. + * If i2c_msg index search is completed and writing is not in progress, + * we don't need TX_EMPTY interrupt any more. */ - if (dev->msg_write_idx == dev->msgs_num) + if (dev->msg_write_idx == dev->msgs_num && + !(dev->status & STATUS_WRITE_IN_PROGRESS)) intr_mask &= ~DW_IC_INTR_TX_EMPTY; if (dev->msg_err)
Currently when i2c_msg index search is completed, TX_EMPTY interrupt will be masked. But if the size of i2c_msg data is longer than the size of the tx buffer, we still need TX_EMPTY interrupt, otherwise we will get "controller timed out" error. This patch fixes this issue by only masking TX_EMPTY if i2c_msg index search is completed and write is not in progress. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> --- drivers/i2c/busses/i2c-designware-core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)