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SubjectRE: [PATCH] can: m_can: add support for one shot mode
Date
Gentle Ping

> -----Original Message-----
> From: Pankaj Sharma <pankj.sharma@samsung.com>
> Subject: [PATCH] can: m_can: add support for one shot mode
>
> According to the CAN Specification (see ISO 11898-1:2015, 8.3.4 Recovery
> Management), the M_CAN provides means for automatic retransmission of
> frames that have lost arbitration or that have been disturbed by errors during
> transmission. By default automatic retransmission is enabled.
>
> The Bosch MCAN controller has support for disabling automatic retransmission.
>
> To support time-triggered communication as described in ISO 11898-1:2015,
> chapter 9.2, the automatic retransmission may be disabled via CCCR.DAR.
>
> CAN_CTRLMODE_ONE_SHOT is used for disabling automatic retransmission.
>
> Signed-off-by: Pankaj Sharma <pankj.sharma@samsung.com>
> Signed-off-by: Sriram Dash <sriram.dash@samsung.com>
> ---
> drivers/net/can/m_can/m_can.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index deb274a19ba0..e7165404ba8a 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -150,6 +150,7 @@ enum m_can_mram_cfg {
> #define CCCR_CME_CANFD_BRS 0x2
> #define CCCR_TXP BIT(14)
> #define CCCR_TEST BIT(7)
> +#define CCCR_DAR BIT(6)
> #define CCCR_MON BIT(5)
> #define CCCR_CSR BIT(4)
> #define CCCR_CSA BIT(3)
> @@ -1123,7 +1124,7 @@ static void m_can_chip_config(struct net_device
> *dev)
> if (priv->version == 30) {
> /* Version 3.0.x */
>
> - cccr &= ~(CCCR_TEST | CCCR_MON |
> + cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_DAR |
> (CCCR_CMR_MASK << CCCR_CMR_SHIFT) |
> (CCCR_CME_MASK << CCCR_CME_SHIFT));
>
> @@ -1133,7 +1134,7 @@ static void m_can_chip_config(struct net_device
> *dev)
> } else {
> /* Version 3.1.x or 3.2.x */
> cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE
> |
> - CCCR_NISO);
> + CCCR_NISO | CCCR_DAR);
>
> /* Only 3.2.x has NISO Bit implemented */
> if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO) @@ -
> 1153,6 +1154,10 @@ static void m_can_chip_config(struct net_device *dev)
> if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> cccr |= CCCR_MON;
>
> + /* Disable Auto Retransmission (all versions) */
> + if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
> + cccr |= CCCR_DAR;
> +
> /* Write config */
> m_can_write(priv, M_CAN_CCCR, cccr);
> m_can_write(priv, M_CAN_TEST, test);
> @@ -1291,7 +1296,8 @@ static int m_can_dev_setup(struct platform_device
> *pdev, struct net_device *dev,
> priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
> CAN_CTRLMODE_LISTENONLY |
> CAN_CTRLMODE_BERR_REPORTING |
> - CAN_CTRLMODE_FD;
> + CAN_CTRLMODE_FD |
> + CAN_CTRLMODE_ONE_SHOT;
>
> /* Set properties depending on M_CAN version */
> switch (priv->version) {
> --
> 2.17.1


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