linux-kernel - RE: [PATCH] can: m_can: add support for one shot mode

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Date:   Thu, 3 Oct 2019 09:17:32 +0530
From:   "pankj.sharma" <pankj.sharma@...sung.com>
To:     <linux-can@...r.kernel.org>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Cc:     <wg@...ndegger.com>, <mkl@...gutronix.de>, <davem@...emloft.net>,
        <eugen.hristev@...rochip.com>, <ludovic.desroches@...rochip.com>,
        <pankaj.dubey@...sung.com>, <rcsekar@...sung.com>,
        "'Sriram Dash'" <sriram.dash@...sung.com>
Subject: RE: [PATCH] can: m_can: add support for one shot mode

Gentle Ping

> -----Original Message-----
> From: Pankaj Sharma <pankj.sharma@...sung.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@...sung.com>
> Signed-off-by: Sriram Dash <sriram.dash@...sung.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