linux-kernel - Re: [PATCH] can: rcar_canfd: Fix CAN-FD mode as default

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Message-ID: <20251126-nocturnal-busy-honeybee-ca8a15-mkl@pengutronix.de>
Date: Wed, 26 Nov 2025 11:27:44 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Biju <biju.das.au@...il.com>
Cc: Vincent Mailhol <mailhol@...nel.org>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, Magnus Damm <magnus.damm@...il.com>, 
	Biju Das <biju.das.jz@...renesas.com>, Tranh Ha <tranh.ha.xb@...esas.com>, 
	Duy Nguyen <duy.nguyen.rh@...esas.com>, linux-can@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>, 
	stable@...r.kernel.org
Subject: Re: [PATCH] can: rcar_canfd: Fix CAN-FD mode as default

Hello Biju,

is this patch ready to go to linux-can?

regards,
Marc

On 18.11.2025 12:39:25, Biju wrote:
> From: Biju Das <biju.das.jz@...renesas.com>
>
> The commit 5cff263606a1 ("can: rcar_canfd: Fix controller mode setting")
> has aligned with the flow mentioned in the hardware manual for all SoCs
> except R-Car Gen3 and RZ/G2L SoCs. On R-Car Gen4 and RZ/G3E SoCs, due to
> the wrong logic in the commit[1] sets the default mode to FD-Only mode
> instead of CAN-FD mode.
>
> This patch sets the CAN-FD mode as the default for all SoCs by dropping
> the rcar_canfd_set_mode() as some SoC requires mode setting in global
> reset mode, and the rest of the SoCs in channel reset mode and update the
> rcar_canfd_reset_controller() to take care of these constraints. Moreover,
> the RZ/G3E and R-Car Gen4 SoCs support 3 modes compared to 2 modes on the
> R-Car Gen3. Use inverted logic in rcar_canfd_reset_controller() to
> simplify the code later to support FD-only mode.
>
> [1]
> commit 45721c406dcf ("can: rcar_canfd: Add support for r8a779a0 SoC")
>
> Fixes: 5cff263606a1 ("can: rcar_canfd: Fix controller mode setting")
> Cc: stable@...r.kernel.org
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> ---
>  drivers/net/can/rcar/rcar_canfd.c | 53 ++++++++++++++++++-------------
>  1 file changed, 31 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
> index 49ab65274b51..05dbdf46dd6f 100644
> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
> @@ -709,6 +709,11 @@ static void rcar_canfd_set_bit_reg(void __iomem *addr, u32 val)
>  	rcar_canfd_update(val, val, addr);
>  }
>
> +static void rcar_canfd_clear_bit_reg(void __iomem *addr, u32 val)
> +{
> +	rcar_canfd_update(val, 0, addr);
> +}
> +
>  static void rcar_canfd_update_bit_reg(void __iomem *addr, u32 mask, u32 val)
>  {
>  	rcar_canfd_update(mask, val, addr);
> @@ -755,25 +760,6 @@ static void rcar_canfd_set_rnc(struct rcar_canfd_global *gpriv, unsigned int ch,
>  	rcar_canfd_set_bit(gpriv->base, RCANFD_GAFLCFG(w), rnc);
>  }
>
> -static void rcar_canfd_set_mode(struct rcar_canfd_global *gpriv)
> -{
> -	if (gpriv->info->ch_interface_mode) {
> -		u32 ch, val = gpriv->fdmode ? RCANFD_GEN4_FDCFG_FDOE
> -					    : RCANFD_GEN4_FDCFG_CLOE;
> -
> -		for_each_set_bit(ch, &gpriv->channels_mask,
> -				 gpriv->info->max_channels)
> -			rcar_canfd_set_bit_reg(&gpriv->fcbase[ch].cfdcfg, val);
> -	} else {
> -		if (gpriv->fdmode)
> -			rcar_canfd_set_bit(gpriv->base, RCANFD_GRMCFG,
> -					   RCANFD_GRMCFG_RCMC);
> -		else
> -			rcar_canfd_clear_bit(gpriv->base, RCANFD_GRMCFG,
> -					     RCANFD_GRMCFG_RCMC);
> -	}
> -}
> -
>  static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
>  {
>  	struct device *dev = &gpriv->pdev->dev;
> @@ -806,6 +792,16 @@ static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
>  	/* Reset Global error flags */
>  	rcar_canfd_write(gpriv->base, RCANFD_GERFL, 0x0);
>
> +	/* Set the controller into appropriate mode */
> +	if (!gpriv->info->ch_interface_mode) {
> +		if (gpriv->fdmode)
> +			rcar_canfd_set_bit(gpriv->base, RCANFD_GRMCFG,
> +					   RCANFD_GRMCFG_RCMC);
> +		else
> +			rcar_canfd_clear_bit(gpriv->base, RCANFD_GRMCFG,
> +					     RCANFD_GRMCFG_RCMC);
> +	}
> +
>  	/* Transition all Channels to reset mode */
>  	for_each_set_bit(ch, &gpriv->channels_mask, gpriv->info->max_channels) {
>  		rcar_canfd_clear_bit(gpriv->base,
> @@ -823,10 +819,23 @@ static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
>  			dev_dbg(dev, "channel %u reset failed\n", ch);
>  			return err;
>  		}
> -	}
>
> -	/* Set the controller into appropriate mode */
> -	rcar_canfd_set_mode(gpriv);
> +		/* Set the controller into appropriate mode */
> +		if (gpriv->info->ch_interface_mode) {
> +			/* Do not set CLOE and FDOE simultaneously */
> +			if (!gpriv->fdmode) {
> +				rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
> +							 RCANFD_GEN4_FDCFG_FDOE);
> +				rcar_canfd_set_bit_reg(&gpriv->fcbase[ch].cfdcfg,
> +						       RCANFD_GEN4_FDCFG_CLOE);
> +			} else {
> +				rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
> +							 RCANFD_GEN4_FDCFG_FDOE);
> +				rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
> +							 RCANFD_GEN4_FDCFG_CLOE);
> +			}
> +		}
> +	}
>
>  	return 0;
>  }
> --
> 2.43.0
>
>
>

--
Pengutronix e.K.                 | Marc Kleine-Budde          |
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