Messages in this thread | | | Date | Thu, 16 Mar 2023 10:27:41 +0100 | From | Simon Horman <> | Subject | Re: [PATCH v3 06/16] can: m_can: Write transmit header and data in one transaction |
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On Wed, Mar 15, 2023 at 12:05:36PM +0100, Markus Schneider-Pargmann wrote: > Combine header and data before writing to the transmit fifo to reduce > the overhead for peripheral chips. > > Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Thanks for addressing my comments on v2.
> --- > drivers/net/can/m_can/m_can.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index a5003435802b..35a2332464e5 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -1681,6 +1681,8 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) > m_can_write(cdev, M_CAN_TXBAR, 0x1); > /* End of xmit function for version 3.0.x */ > } else { > + char buf[TXB_ELEMENT_SIZE]; > + u8 len_padded = DIV_ROUND_UP(cf->len, 4); > /* Transmit routine for version >= v3.1.x */ > > txfqs = m_can_read(cdev, M_CAN_TXFQS); > @@ -1720,12 +1722,11 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) > fifo_header.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) | > FIELD_PREP(TX_BUF_DLC_MASK, can_fd_len2dlc(cf->len)) | > fdflags | TX_BUF_EFC; > - err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, &fifo_header, 2); > - if (err) > - goto out_fail; > + memcpy(buf, &fifo_header, 8); > + memcpy_and_pad(&buf[8], len_padded, &cf->data, cf->len, 0);
I'm probably missing something obvious here but I'm seeing:
* len_padded is the number of 4-byte words * but the 2nd argument to memcpy_and_pad should be a length in bytes * so perhaps it should be: len_padded * 4
> > - err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA, > - cf->data, DIV_ROUND_UP(cf->len, 4)); > + err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, > + buf, 2 + len_padded);
This part looks good to me :)
> if (err) > goto out_fail; > > -- > 2.39.2 >
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