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SubjectRE: [PATCH 2/2] can: flexcan: add support for ISO CAN-FD
Date

> -----Original Message-----
> From: Michael Walle <michael@walle.cc>
> Sent: 2020年6月30日 2:18
> To: linux-can@vger.kernel.org; netdev@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Cc: Wolfgang Grandegger <wg@grandegger.com>; Marc Kleine-Budde
> <mkl@pengutronix.de>; David S . Miller <davem@davemloft.net>; Jakub
> Kicinski <kuba@kernel.org>; Joakim Zhang <qiangqing.zhang@nxp.com>;
> dl-linux-imx <linux-imx@nxp.com>; Michael Walle <michael@walle.cc>
> Subject: [PATCH 2/2] can: flexcan: add support for ISO CAN-FD
>
> Up until now, the controller used non-ISO CAN-FD mode, although it supports it.
> Add support for ISO mode, too. By default the hardware is in non-ISO mode and
> an enable bit has to be explicitly set.
>
> Signed-off-by: Michael Walle <michael@walle.cc>
> ---
> drivers/net/can/flexcan.c | 19 ++++++++++++++++---
> 1 file changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index
> 183e094f8d66..a92d3cdf4195 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -94,6 +94,7 @@
> #define FLEXCAN_CTRL2_MRP BIT(18)
> #define FLEXCAN_CTRL2_RRS BIT(17)
> #define FLEXCAN_CTRL2_EACEN BIT(16)
> +#define FLEXCAN_CTRL2_ISOCANFDEN BIT(12)
>
> /* FLEXCAN memory error control register (MECR) bits */
> #define FLEXCAN_MECR_ECRWRDIS BIT(31)
> @@ -1344,14 +1345,25 @@ static int flexcan_chip_start(struct net_device
> *dev)
> else
> reg_mcr |= FLEXCAN_MCR_SRX_DIS;
>
> - /* MCR - CAN-FD */
> - if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
> + /* MCR, CTRL2
> + *
> + * CAN-FD mode
> + * ISO CAN-FD mode
> + */
> + reg_ctrl2 = priv->read(&regs->ctrl2);
> + if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
> reg_mcr |= FLEXCAN_MCR_FDEN;
> - else
> + reg_ctrl2 |= FLEXCAN_CTRL2_ISOCANFDEN;
> + } else {
> reg_mcr &= ~FLEXCAN_MCR_FDEN;
> + }
> +
> + if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
> + reg_ctrl2 &= ~FLEXCAN_CTRL2_ISOCANFDEN;


Hi Michael,

ip link set can0 up type can bitrate 1000000 dbitrate 5000000 fd on
Above cmd can configure ISO CAN-FD.

However, if users want to configure NON-ISO CAN-FD, should use below cmd, what I did before.
ip link set can0 up type can bitrate 1000000 dbitrate 5000000 fd on fd-non-iso on

Marc may not satisfy with it, to be honest, this looks not good, had better configure like below to enable NON-ISO CAN-FD.
ip link set can0 up type can bitrate 1000000 dbitrate 5000000 fd-non-iso on

I haven't got any good ideas yet.

Best Regards,
Joakim Zhang
> netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);
> priv->write(reg_mcr, &regs->mcr);
> + priv->write(reg_ctrl2, &regs->ctrl2);
>
> /* CTRL
> *
> @@ -1952,6 +1964,7 @@ static int flexcan_probe(struct platform_device
> *pdev)
>
> if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SUPPORT_FD) {
> priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
> + priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD_NON_ISO;
> priv->can.bittiming_const = &flexcan_fd_bittiming_const;
> priv->can.data_bittiming_const =
> &flexcan_fd_data_bittiming_const;
> --
> 2.20.1

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