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SubjectRe: [PATCH 04/12] i2c: qup: schedule EOT and FLUSH tags at the end of transfer
On Sat, Feb 03, 2018 at 01:28:09PM +0530, Abhishek Sahu wrote:
> A single BAM transfer can have multiple read and write messages.
> The EOT and FLUSH tags should be scheduled at the end of BAM HW
> descriptors. Since the READ and WRITE can be present in any order
> so for some of the cases, these tags are not being written
> correctly.
>
> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
> ---
> drivers/i2c/busses/i2c-qup.c | 54 ++++++++++++++++++++------------------------
> 1 file changed, 24 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> index bb83a2967..6357aff 100644
> --- a/drivers/i2c/busses/i2c-qup.c
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -560,7 +560,7 @@ static int qup_i2c_set_tags_smb(u16 addr, u8 *tags, struct qup_i2c_dev *qup,
> }
>
> static int qup_i2c_set_tags(u8 *tags, struct qup_i2c_dev *qup,
> - struct i2c_msg *msg, int is_dma)
> + struct i2c_msg *msg)
> {
> u16 addr = i2c_8bit_addr_from_msg(msg);
> int len = 0;
> @@ -601,11 +601,6 @@ static int qup_i2c_set_tags(u8 *tags, struct qup_i2c_dev *qup,
> else
> tags[len++] = data_len;
>
> - if ((msg->flags & I2C_M_RD) && last && is_dma) {
> - tags[len++] = QUP_BAM_INPUT_EOT;
> - tags[len++] = QUP_BAM_FLUSH_STOP;
> - }
> -

So lets say you have multiple read and 1 write message. These changes will send
a EOT/FLUSH for all reads. I think the intent here was that the last read
message (not the last message) would have the EOT+FLUSH. Can there be an issue
with sending EOT/FLUSH for all reads? And how does this mesh up with the BAM
signaling?


Regards,

Andy

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