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>
---
drivers/net/can/m_can/m_can.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index a5003435802b..5251073987ee 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -317,6 +317,12 @@ struct id_and_dlc {
u32 dlc;
};
+struct m_can_fifo_element {
+ u32 id;
+ u32 dlc;
+ u8 data[CANFD_MAX_DLEN];
+};
+
static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
{
return cdev->ops->read_reg(cdev, reg);
@@ -1622,6 +1628,8 @@ static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx)
static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
{
struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
+ u8 len_padded = DIV_ROUND_UP(cf->len, 4);
+ struct m_can_fifo_element fifo_element;
struct net_device *dev = cdev->net;
struct sk_buff *skb = cdev->tx_skb;
struct id_and_dlc fifo_header;
@@ -1635,27 +1643,27 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
/* Generate ID field for TX buffer Element */
/* Common to all supported M_CAN versions */
if (cf->can_id & CAN_EFF_FLAG) {
- fifo_header.id = cf->can_id & CAN_EFF_MASK;
- fifo_header.id |= TX_BUF_XTD;
+ fifo_element.id = cf->can_id & CAN_EFF_MASK;
+ fifo_element.id |= TX_BUF_XTD;
} else {
- fifo_header.id = ((cf->can_id & CAN_SFF_MASK) << 18);
+ fifo_element.id = ((cf->can_id & CAN_SFF_MASK) << 18);
}
if (cf->can_id & CAN_RTR_FLAG)
- fifo_header.id |= TX_BUF_RTR;
+ fifo_element.id |= TX_BUF_RTR;
if (cdev->version == 30) {
netif_stop_queue(dev);
- fifo_header.dlc = can_fd_len2dlc(cf->len) << 16;
+ fifo_element.dlc = can_fd_len2dlc(cf->len) << 16;
/* Write the frame ID, DLC, and payload to the FIFO element. */
- err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_header, 2);
+ err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_element, 2);
if (err)
goto out_fail;
err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_DATA,
- cf->data, DIV_ROUND_UP(cf->len, 4));
+ cf->data, len_padded);
if (err)
goto out_fail;
@@ -1717,15 +1725,15 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
fdflags |= TX_BUF_BRS;
}
- fifo_header.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |
+ fifo_element.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;
- err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA,
- cf->data, DIV_ROUND_UP(cf->len, 4));
+ memcpy_and_pad(fifo_element.data, CANFD_MAX_DLEN, &cf->data,
+ cf->len, 0);
+
+ err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID,
+ &fifo_element, 2 + len_padded);
if (err)
goto out_fail;
--
2.40.1Hi Markus,
kernel test robot noticed the following build warnings:
[auto build test WARNING on ac9a78681b921877518763ba0e89202254349d1b]
url: https://github.com/intel-lab-lkp/linux/commits/Markus-Schneider-Pargmann/can-m_can-Write-transmit-header-and-data-in-one-transaction/20230621-173848
base: ac9a78681b921877518763ba0e89202254349d1b
patch link: https://lore.kernel.org/r/20230621092350.3130866-2-msp%40baylibre.com
patch subject: [PATCH v4 01/12] can: m_can: Write transmit header and data in one transaction
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20230622/202306220154.20bzOw90-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230622/202306220154.20bzOw90-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306220154.20bzOw90-lkp@intel.com/
All warnings (new ones prefixed by >>):
drivers/net/can/m_can/m_can.c: In function 'm_can_tx_handler':
>> drivers/net/can/m_can/m_can.c:1635:27: warning: unused variable 'fifo_header' [-Wunused-variable]
1635 | struct id_and_dlc fifo_header;
| ^~~~~~~~~~~
vim +/fifo_header +1635 drivers/net/can/m_can/m_can.c
10c1c3975a6663 Mario Huettel 2017-04-08 1627
441ac340169b79 Dan Murphy 2019-05-09 1628 static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1629 {
441ac340169b79 Dan Murphy 2019-05-09 1630 struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1631 u8 len_padded = DIV_ROUND_UP(cf->len, 4);
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1632 struct m_can_fifo_element fifo_element;
441ac340169b79 Dan Murphy 2019-05-09 1633 struct net_device *dev = cdev->net;
441ac340169b79 Dan Murphy 2019-05-09 1634 struct sk_buff *skb = cdev->tx_skb;
812270e5445bd1 Matt Kline 2021-08-16 @1635 struct id_and_dlc fifo_header;
812270e5445bd1 Matt Kline 2021-08-16 1636 u32 cccr, fdflags;
c1eaf8b9bd3145 Markus Schneider-Pargmann 2022-12-06 1637 u32 txfqs;
812270e5445bd1 Matt Kline 2021-08-16 1638 int err;
10c1c3975a6663 Mario Huettel 2017-04-08 1639 int putidx;
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1640
e04b2cfe61072c Marc Kleine-Budde 2021-05-05 1641 cdev->tx_skb = NULL;
e04b2cfe61072c Marc Kleine-Budde 2021-05-05 1642
10c1c3975a6663 Mario Huettel 2017-04-08 1643 /* Generate ID field for TX buffer Element */
10c1c3975a6663 Mario Huettel 2017-04-08 1644 /* Common to all supported M_CAN versions */
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1645 if (cf->can_id & CAN_EFF_FLAG) {
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1646 fifo_element.id = cf->can_id & CAN_EFF_MASK;
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1647 fifo_element.id |= TX_BUF_XTD;
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1648 } else {
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1649 fifo_element.id = ((cf->can_id & CAN_SFF_MASK) << 18);
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1650 }
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1651
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1652 if (cf->can_id & CAN_RTR_FLAG)
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1653 fifo_element.id |= TX_BUF_RTR;
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1654
441ac340169b79 Dan Murphy 2019-05-09 1655 if (cdev->version == 30) {
10c1c3975a6663 Mario Huettel 2017-04-08 1656 netif_stop_queue(dev);
10c1c3975a6663 Mario Huettel 2017-04-08 1657
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1658 fifo_element.dlc = can_fd_len2dlc(cf->len) << 16;
80646733f11c2e Dong Aisheng 2014-11-18 1659
812270e5445bd1 Matt Kline 2021-08-16 1660 /* Write the frame ID, DLC, and payload to the FIFO element. */
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1661 err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_element, 2);
e39381770ec9ca Matt Kline 2021-08-16 1662 if (err)
e39381770ec9ca Matt Kline 2021-08-16 1663 goto out_fail;
e39381770ec9ca Matt Kline 2021-08-16 1664
812270e5445bd1 Matt Kline 2021-08-16 1665 err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_DATA,
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1666 cf->data, len_padded);
e39381770ec9ca Matt Kline 2021-08-16 1667 if (err)
e39381770ec9ca Matt Kline 2021-08-16 1668 goto out_fail;
80646733f11c2e Dong Aisheng 2014-11-18 1669
441ac340169b79 Dan Murphy 2019-05-09 1670 if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
441ac340169b79 Dan Murphy 2019-05-09 1671 cccr = m_can_read(cdev, M_CAN_CCCR);
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1672 cccr &= ~CCCR_CMR_MASK;
80646733f11c2e Dong Aisheng 2014-11-18 1673 if (can_is_canfd_skb(skb)) {
80646733f11c2e Dong Aisheng 2014-11-18 1674 if (cf->flags & CANFD_BRS)
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1675 cccr |= FIELD_PREP(CCCR_CMR_MASK,
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1676 CCCR_CMR_CANFD_BRS);
80646733f11c2e Dong Aisheng 2014-11-18 1677 else
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1678 cccr |= FIELD_PREP(CCCR_CMR_MASK,
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1679 CCCR_CMR_CANFD);
80646733f11c2e Dong Aisheng 2014-11-18 1680 } else {
20779943a080c5 Torin Cooper-Bennun 2021-05-04 1681 cccr |= FIELD_PREP(CCCR_CMR_MASK, CCCR_CMR_CAN);
80646733f11c2e Dong Aisheng 2014-11-18 1682 }
441ac340169b79 Dan Murphy 2019-05-09 1683 m_can_write(cdev, M_CAN_CCCR, cccr);
80646733f11c2e Dong Aisheng 2014-11-18 1684 }
441ac340169b79 Dan Murphy 2019-05-09 1685 m_can_write(cdev, M_CAN_TXBTIE, 0x1);
2e8e79c416aae1 Marc Kleine-Budde 2022-03-17 1686
2e8e79c416aae1 Marc Kleine-Budde 2022-03-17 1687 can_put_echo_skb(skb, dev, 0, 0);
2e8e79c416aae1 Marc Kleine-Budde 2022-03-17 1688
441ac340169b79 Dan Murphy 2019-05-09 1689 m_can_write(cdev, M_CAN_TXBAR, 0x1);
10c1c3975a6663 Mario Huettel 2017-04-08 1690 /* End of xmit function for version 3.0.x */
10c1c3975a6663 Mario Huettel 2017-04-08 1691 } else {
10c1c3975a6663 Mario Huettel 2017-04-08 1692 /* Transmit routine for version >= v3.1.x */
10c1c3975a6663 Mario Huettel 2017-04-08 1693
c1eaf8b9bd3145 Markus Schneider-Pargmann 2022-12-06 1694 txfqs = m_can_read(cdev, M_CAN_TXFQS);
c1eaf8b9bd3145 Markus Schneider-Pargmann 2022-12-06 1695
10c1c3975a6663 Mario Huettel 2017-04-08 1696 /* Check if FIFO full */
c1eaf8b9bd3145 Markus Schneider-Pargmann 2022-12-06 1697 if (_m_can_tx_fifo_full(txfqs)) {
10c1c3975a6663 Mario Huettel 2017-04-08 1698 /* This shouldn't happen */
10c1c3975a6663 Mario Huettel 2017-04-08 1699 netif_stop_queue(dev);
10c1c3975a6663 Mario Huettel 2017-04-08 1700 netdev_warn(dev,
10c1c3975a6663 Mario Huettel 2017-04-08 1701 "TX queue active although FIFO is full.");
441ac340169b79 Dan Murphy 2019-05-09 1702
441ac340169b79 Dan Murphy 2019-05-09 1703 if (cdev->is_peripheral) {
f524f829b75a7d Dan Murphy 2019-05-09 1704 kfree_skb(skb);
f524f829b75a7d Dan Murphy 2019-05-09 1705 dev->stats.tx_dropped++;
f524f829b75a7d Dan Murphy 2019-05-09 1706 return NETDEV_TX_OK;
f524f829b75a7d Dan Murphy 2019-05-09 1707 } else {
10c1c3975a6663 Mario Huettel 2017-04-08 1708 return NETDEV_TX_BUSY;
10c1c3975a6663 Mario Huettel 2017-04-08 1709 }
f524f829b75a7d Dan Murphy 2019-05-09 1710 }
10c1c3975a6663 Mario Huettel 2017-04-08 1711
10c1c3975a6663 Mario Huettel 2017-04-08 1712 /* get put index for frame */
c1eaf8b9bd3145 Markus Schneider-Pargmann 2022-12-06 1713 putidx = FIELD_GET(TXFQS_TFQPI_MASK, txfqs);
812270e5445bd1 Matt Kline 2021-08-16 1714
812270e5445bd1 Matt Kline 2021-08-16 1715 /* Construct DLC Field, with CAN-FD configuration.
812270e5445bd1 Matt Kline 2021-08-16 1716 * Use the put index of the fifo as the message marker,
812270e5445bd1 Matt Kline 2021-08-16 1717 * used in the TX interrupt for sending the correct echo frame.
812270e5445bd1 Matt Kline 2021-08-16 1718 */
10c1c3975a6663 Mario Huettel 2017-04-08 1719
10c1c3975a6663 Mario Huettel 2017-04-08 1720 /* get CAN FD configuration of frame */
10c1c3975a6663 Mario Huettel 2017-04-08 1721 fdflags = 0;
10c1c3975a6663 Mario Huettel 2017-04-08 1722 if (can_is_canfd_skb(skb)) {
10c1c3975a6663 Mario Huettel 2017-04-08 1723 fdflags |= TX_BUF_FDF;
10c1c3975a6663 Mario Huettel 2017-04-08 1724 if (cf->flags & CANFD_BRS)
10c1c3975a6663 Mario Huettel 2017-04-08 1725 fdflags |= TX_BUF_BRS;
10c1c3975a6663 Mario Huettel 2017-04-08 1726 }
10c1c3975a6663 Mario Huettel 2017-04-08 1727
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1728 fifo_element.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |
e39381770ec9ca Matt Kline 2021-08-16 1729 FIELD_PREP(TX_BUF_DLC_MASK, can_fd_len2dlc(cf->len)) |
e39381770ec9ca Matt Kline 2021-08-16 1730 fdflags | TX_BUF_EFC;
10c1c3975a6663 Mario Huettel 2017-04-08 1731
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1732 memcpy_and_pad(fifo_element.data, CANFD_MAX_DLEN, &cf->data,
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1733 cf->len, 0);
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1734
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1735 err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID,
9a10b9d9f7e946 Markus Schneider-Pargmann 2023-06-21 1736 &fifo_element, 2 + len_padded);
e39381770ec9ca Matt Kline 2021-08-16 1737 if (err)
e39381770ec9ca Matt Kline 2021-08-16 1738 goto out_fail;
10c1c3975a6663 Mario Huettel 2017-04-08 1739
10c1c3975a6663 Mario Huettel 2017-04-08 1740 /* Push loopback echo.
10c1c3975a6663 Mario Huettel 2017-04-08 1741 * Will be looped back on TX interrupt based on message marker
10c1c3975a6663 Mario Huettel 2017-04-08 1742 */
1dcb6e57db8334 Vincent Mailhol 2021-01-11 1743 can_put_echo_skb(skb, dev, putidx, 0);
10c1c3975a6663 Mario Huettel 2017-04-08 1744
10c1c3975a6663 Mario Huettel 2017-04-08 1745 /* Enable TX FIFO element to start transfer */
441ac340169b79 Dan Murphy 2019-05-09 1746 m_can_write(cdev, M_CAN_TXBAR, (1 << putidx));
10c1c3975a6663 Mario Huettel 2017-04-08 1747
10c1c3975a6663 Mario Huettel 2017-04-08 1748 /* stop network queue if fifo full */
441ac340169b79 Dan Murphy 2019-05-09 1749 if (m_can_tx_fifo_full(cdev) ||
10c1c3975a6663 Mario Huettel 2017-04-08 1750 m_can_next_echo_skb_occupied(dev, putidx))
10c1c3975a6663 Mario Huettel 2017-04-08 1751 netif_stop_queue(dev);
10c1c3975a6663 Mario Huettel 2017-04-08 1752 }
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1753
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1754 return NETDEV_TX_OK;
e39381770ec9ca Matt Kline 2021-08-16 1755
e39381770ec9ca Matt Kline 2021-08-16 1756 out_fail:
e39381770ec9ca Matt Kline 2021-08-16 1757 netdev_err(dev, "FIFO write returned %d\n", err);
e39381770ec9ca Matt Kline 2021-08-16 1758 m_can_disable_all_interrupts(cdev);
e39381770ec9ca Matt Kline 2021-08-16 1759 return NETDEV_TX_BUSY;
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1760 }
e0d1f4816f2a7e Dong Aisheng 2014-07-16 1761
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Wed, Jun 21, 2023 at 11:23:39AM +0200, 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>
> ---
> drivers/net/can/m_can/m_can.c | 34 +++++++++++++++++++++-------------
> 1 file changed, 21 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index a5003435802b..5251073987ee 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -317,6 +317,12 @@ struct id_and_dlc {
> u32 dlc;
> };
>
> +struct m_can_fifo_element {
> + u32 id;
> + u32 dlc;
> + u8 data[CANFD_MAX_DLEN];
> +};
> +
> static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
> {
> return cdev->ops->read_reg(cdev, reg);
> @@ -1622,6 +1628,8 @@ static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx)
> static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
> {
> struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
> + u8 len_padded = DIV_ROUND_UP(cf->len, 4);
> + struct m_can_fifo_element fifo_element;
> struct net_device *dev = cdev->net;
> struct sk_buff *skb = cdev->tx_skb;
> struct id_and_dlc fifo_header;
Hi Markus,
GCC 12.3.0 complains that fifo_header is not (no longer) used.
drivers/net/can/m_can/m_can.c:1635:20: warning: unused variable 'fifo_header' [-Wunused-variable]
struct id_and_dlc fifo_header;
--
pw-bot: changes-requested
Hi Simon,
On Wed, Jun 21, 2023 at 04:19:06PM +0200, Simon Horman wrote:
> On Wed, Jun 21, 2023 at 11:23:39AM +0200, 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>
> > ---
> > drivers/net/can/m_can/m_can.c | 34 +++++++++++++++++++++-------------
> > 1 file changed, 21 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> > index a5003435802b..5251073987ee 100644
> > --- a/drivers/net/can/m_can/m_can.c
> > +++ b/drivers/net/can/m_can/m_can.c
> > @@ -317,6 +317,12 @@ struct id_and_dlc {
> > u32 dlc;
> > };
> >
> > +struct m_can_fifo_element {
> > + u32 id;
> > + u32 dlc;
> > + u8 data[CANFD_MAX_DLEN];
> > +};
> > +
> > static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
> > {
> > return cdev->ops->read_reg(cdev, reg);
> > @@ -1622,6 +1628,8 @@ static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx)
> > static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
> > {
> > struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
> > + u8 len_padded = DIV_ROUND_UP(cf->len, 4);
> > + struct m_can_fifo_element fifo_element;
> > struct net_device *dev = cdev->net;
> > struct sk_buff *skb = cdev->tx_skb;
> > struct id_and_dlc fifo_header;
>
> Hi Markus,
>
> GCC 12.3.0 complains that fifo_header is not (no longer) used.
>
> drivers/net/can/m_can/m_can.c:1635:20: warning: unused variable 'fifo_header' [-Wunused-variable]
> struct id_and_dlc fifo_header;
Yes, I moved everything to fifo_element on purpose and then forgot to
remove fifo_header. Removing it now.
Thanks,
Markus
>
> --
> pw-bot: changes-requested
>
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