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[PATCH v2 3/4] can: rcar_canfd: Simplify nominal bit rate config

Biju posted 4 patches 1 month, 1 week ago
There is a newer version of this series
[PATCH v2 3/4] can: rcar_canfd: Simplify nominal bit rate config
Posted by Biju 1 month, 1 week ago 
From: Biju Das <biju.das.jz@bp.renesas.com>

Introduce rcar_canfd_compute_nominal_bit_rate_cfg() for simplifying
nominal bit rate configuration by replacing function-like macros.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v1->v2:
 * Split from patch#3 for computing nominal bit rate config separate.
 * Updated rcar_canfd_compute_nominal_bit_rate_cfg() to handle
   nominal bit rate configuration for both classical CAN and CANFD.
 * Replaced RCANFD_NCFG_NBRP->RCANFD_NCFG_NBRP_MASK and used FIELD_PREP to
   extract value.
---
 drivers/net/can/rcar/rcar_canfd.c | 45 ++++++++++++++++---------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 8bae25758924..944b960c0b5e 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -109,16 +109,7 @@
 #define RCANFD_CFG_BRP_MASK		GENMASK(9, 0)
 
 /* RSCFDnCFDCmNCFG - CAN FD only */
-#define RCANFD_NCFG_NTSEG2(gpriv, x) \
-	(((x) & ((gpriv)->info->nom_bittiming->tseg2_max - 1)) << (gpriv)->info->sh->ntseg2)
-
-#define RCANFD_NCFG_NTSEG1(gpriv, x) \
-	(((x) & ((gpriv)->info->nom_bittiming->tseg1_max - 1)) << (gpriv)->info->sh->ntseg1)
-
-#define RCANFD_NCFG_NSJW(gpriv, x) \
-	(((x) & ((gpriv)->info->nom_bittiming->sjw_max - 1)) << (gpriv)->info->sh->nsjw)
-
-#define RCANFD_NCFG_NBRP(x)		(((x) & 0x3ff) << 0)
+#define RCANFD_NCFG_NBRP_MASK		GENMASK(9, 0)
 
 /* RSCFDnCFDCmCTR / RSCFDnCmCTR */
 #define RCANFD_CCTR_CTME		BIT(24)
@@ -1393,6 +1384,28 @@ static irqreturn_t rcar_canfd_channel_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static inline u32 rcar_canfd_compute_nominal_bit_rate_cfg(struct rcar_canfd_channel *priv,
+							  u16 tseg1, u16 brp, u16 sjw, u16 tseg2)
+{
+	struct rcar_canfd_global *gpriv = priv->gpriv;
+	const struct rcar_canfd_hw_info *info = gpriv->info;
+	u32 ntseg2, ntseg1, nsjw, nbrp;
+
+	if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) || gpriv->info->shared_can_regs) {
+		ntseg2 = (tseg2 & (info->nom_bittiming->tseg2_max - 1)) << info->sh->ntseg2;
+		ntseg1 = (tseg1 & (info->nom_bittiming->tseg1_max - 1)) << info->sh->ntseg1;
+		nsjw = (sjw & (info->nom_bittiming->sjw_max - 1)) << info->sh->nsjw;
+		nbrp = FIELD_PREP(RCANFD_NCFG_NBRP_MASK, brp);
+	} else {
+		ntseg2 = FIELD_PREP(RCANFD_CFG_TSEG2_MASK, tseg2);
+		ntseg1 = FIELD_PREP(RCANFD_CFG_TSEG1_MASK, tseg1);
+		nsjw = FIELD_PREP(RCANFD_CFG_SJW_MASK, sjw);
+		nbrp = FIELD_PREP(RCANFD_CFG_BRP_MASK, brp);
+	}
+
+	return (ntseg1 | nbrp | nsjw | ntseg2);
+}
+
 static void rcar_canfd_set_bittiming(struct net_device *ndev)
 {
 	u32 mask = RCANFD_FDCFG_TDCO | RCANFD_FDCFG_TDCE | RCANFD_FDCFG_TDCOC;
@@ -1411,17 +1424,7 @@ static void rcar_canfd_set_bittiming(struct net_device *ndev)
 	sjw = bt->sjw - 1;
 	tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
 	tseg2 = bt->phase_seg2 - 1;
-
-	if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) || gpriv->info->shared_can_regs) {
-		cfg = (RCANFD_NCFG_NTSEG1(gpriv, tseg1) | RCANFD_NCFG_NBRP(brp) |
-		       RCANFD_NCFG_NSJW(gpriv, sjw) | RCANFD_NCFG_NTSEG2(gpriv, tseg2));
-	} else {
-		cfg = FIELD_PREP(RCANFD_CFG_TSEG1_MASK, tseg1) |
-		      FIELD_PREP(RCANFD_CFG_BRP_MASK, brp) |
-		      FIELD_PREP(RCANFD_CFG_SJW_MASK, sjw) |
-		      FIELD_PREP(RCANFD_CFG_TSEG2_MASK, tseg2);
-	}
-
+	cfg = rcar_canfd_compute_nominal_bit_rate_cfg(priv, tseg1, brp, sjw, tseg2);
 	rcar_canfd_write(priv->base, RCANFD_CCFG(ch), cfg);
 
 	if (!(priv->can.ctrlmode & CAN_CTRLMODE_FD))
-- 
2.43.0
Re: [PATCH v2 3/4] can: rcar_canfd: Simplify nominal bit rate config
Posted by Geert Uytterhoeven 1 month ago 
Hi Biju,

On Thu, 21 Aug 2025 at 16:14, Biju <biju.das.au@gmail.com> wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
>
> Introduce rcar_canfd_compute_nominal_bit_rate_cfg() for simplifying
> nominal bit rate configuration by replacing function-like macros.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v1->v2:
>  * Split from patch#3 for computing nominal bit rate config separate.
>  * Updated rcar_canfd_compute_nominal_bit_rate_cfg() to handle
>    nominal bit rate configuration for both classical CAN and CANFD.
>  * Replaced RCANFD_NCFG_NBRP->RCANFD_NCFG_NBRP_MASK and used FIELD_PREP to
>    extract value.

Thanks for your patch!

Your patch is correct, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Still a few suggestions for improvement below...

> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
> @@ -109,16 +109,7 @@
>  #define RCANFD_CFG_BRP_MASK            GENMASK(9, 0)
>
>  /* RSCFDnCFDCmNCFG - CAN FD only */
> -#define RCANFD_NCFG_NTSEG2(gpriv, x) \
> -       (((x) & ((gpriv)->info->nom_bittiming->tseg2_max - 1)) << (gpriv)->info->sh->ntseg2)
> -
> -#define RCANFD_NCFG_NTSEG1(gpriv, x) \
> -       (((x) & ((gpriv)->info->nom_bittiming->tseg1_max - 1)) << (gpriv)->info->sh->ntseg1)
> -
> -#define RCANFD_NCFG_NSJW(gpriv, x) \
> -       (((x) & ((gpriv)->info->nom_bittiming->sjw_max - 1)) << (gpriv)->info->sh->nsjw)
> -
> -#define RCANFD_NCFG_NBRP(x)            (((x) & 0x3ff) << 0)
> +#define RCANFD_NCFG_NBRP_MASK          GENMASK(9, 0)

I would drop the "_MASK" suffix.

> @@ -1393,6 +1384,28 @@ static irqreturn_t rcar_canfd_channel_interrupt(int irq, void *dev_id)
>         return IRQ_HANDLED;
>  }
>
> +static inline u32 rcar_canfd_compute_nominal_bit_rate_cfg(struct rcar_canfd_channel *priv,
> +                                                         u16 tseg1, u16 brp, u16 sjw, u16 tseg2)

Perhaps follow the order as used in struct can_bittiming{_const}?
I.e. tseg1, tseg2, sjw, brp.

> +{
> +       struct rcar_canfd_global *gpriv = priv->gpriv;
> +       const struct rcar_canfd_hw_info *info = gpriv->info;
> +       u32 ntseg2, ntseg1, nsjw, nbrp;
> +
> +       if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) || gpriv->info->shared_can_regs) {
> +               ntseg2 = (tseg2 & (info->nom_bittiming->tseg2_max - 1)) << info->sh->ntseg2;
> +               ntseg1 = (tseg1 & (info->nom_bittiming->tseg1_max - 1)) << info->sh->ntseg1;
> +               nsjw = (sjw & (info->nom_bittiming->sjw_max - 1)) << info->sh->nsjw;
> +               nbrp = FIELD_PREP(RCANFD_NCFG_NBRP_MASK, brp);

Perhaps use the order of the function parameters?

> +       } else {
> +               ntseg2 = FIELD_PREP(RCANFD_CFG_TSEG2_MASK, tseg2);
> +               ntseg1 = FIELD_PREP(RCANFD_CFG_TSEG1_MASK, tseg1);
> +               nsjw = FIELD_PREP(RCANFD_CFG_SJW_MASK, sjw);
> +               nbrp = FIELD_PREP(RCANFD_CFG_BRP_MASK, brp);

Likewise.

> +       }
> +
> +       return (ntseg1 | nbrp | nsjw | ntseg2);

Likewise.

> +}
> +
>  static void rcar_canfd_set_bittiming(struct net_device *ndev)
>  {
>         u32 mask = RCANFD_FDCFG_TDCO | RCANFD_FDCFG_TDCE | RCANFD_FDCFG_TDCOC;

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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