[PATCH v3 0/4] R-Car CANFD Improvements

[PATCH v3 0/4] R-Car CANFD Improvements

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

The calculation formula for nominal bit rate of classical CAN is same as
that of nominal bit rate of CANFD on the RZ/G3E SoC and R-Car Gen4
compared to other SoCs. Update the nominal bit rate constants.

Apart from this, for replacing function-like macros, introduced
rcar_canfd_compute_{nominal,data}_bit_rate_cfg().

v2->v3:
 * Replaced "shared_bittiming"->"shared_can_regs" as it is same for RZ/G3E
   and R-Car Gen4.
 * Updated commit header and description for patch#1.
 * Added Rb tag from Geert for patch #2,#3 and #4.
 * Dropped _MASK suffix from RCANFD_CFG_* macros.
 * Dropped _MASK suffix from RCANFD_NCFG_NBRP_MASK macro.
 * Dropped _MASK suffix from the macro RCANFD_DCFG_DBRP_MASK.
 * Followed the order as used in struct can_bittiming{_const} for easy
   maintenance.
v1->v2:
 * Dropped patch#2 as it is accepted.
 * Moved patch#4 to patch#2.
 * Updated commit header and description for patch#2.
 * Kept RCANFD_CFG* macro definitions to give a meaning to the magic
   number using GENMASK macro and used FIELD_PREP to extract value.
 * Split patch#3 for computing nominal  and data 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.
 * Replaced RCANFD_DCFG_DBRP->RCANFD_DCFG_DBRP_MASK and used FIELD_PREP to
   extract value.

Biju Das (4):
  can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4
  can: rcar_canfd: Update RCANFD_CFG_* macros
  can: rcar_canfd: Simplify nominal bit rate config
  can: rcar_canfd: Simplify data bit rate config

 drivers/net/can/rcar/rcar_canfd.c | 84 +++++++++++++++++--------------
 1 file changed, 47 insertions(+), 37 deletions(-)

-- 
2.43.0

[PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

The calculation formula for nominal bit rate of classical CAN is same as
that of nominal bit rate of CANFD on the RZ/G3E and R-Car Gen4 SoCs
compared to other SoCs. Update nominal bit rate constants.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Replaced "shared_bittiming"->"shared_can_regs" as it is same for RZ/G3E
   and R-Car Gen4.
 * Dropped the tags as it is new change.
 * Updated commit header and description.
v1->v2:
 * No change.
---
 drivers/net/can/rcar/rcar_canfd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index b3c8c592fb0e..4185fc5b4a70 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -1912,7 +1912,10 @@ static int rcar_canfd_channel_probe(struct rcar_canfd_global *gpriv, u32 ch,
 		priv->can.fd.do_get_auto_tdcv = rcar_canfd_get_auto_tdcv;
 	} else {
 		/* Controller starts in Classical CAN only mode */
-		priv->can.bittiming_const = &rcar_canfd_bittiming_const;
+		if (gpriv->info->shared_can_regs)
+			priv->can.bittiming_const = gpriv->info->nom_bittiming;
+		else
+			priv->can.bittiming_const = &rcar_canfd_bittiming_const;
 		priv->can.ctrlmode_supported = CAN_CTRLMODE_BERR_REPORTING;
 	}
 
-- 
2.43.0

Re: [PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4

[Geert Uytterhoeven]

On Mon, 8 Sept 2025 at 14:09, Biju <biju.das.au@gmail.com> wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
>
> The calculation formula for nominal bit rate of classical CAN is same as

the same

> that of nominal bit rate of CANFD on the RZ/G3E and R-Car Gen4 SoCs
> compared to other SoCs. Update nominal bit rate constants.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * Replaced "shared_bittiming"->"shared_can_regs" as it is same for RZ/G3E
>    and R-Car Gen4.
>  * Dropped the tags as it is new change.
>  * Updated commit header and description.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

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

RE: [PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4

[Biju Das]

Hi Geert,

Thanks for the feedback.

> -----Original Message-----
> From: Geert Uytterhoeven <geert@linux-m68k.org>
> Sent: 10 September 2025 10:05
> Subject: Re: [PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4
> 
> On Mon, 8 Sept 2025 at 14:09, Biju <biju.das.au@gmail.com> wrote:
> > From: Biju Das <biju.das.jz@bp.renesas.com>
> >
> > The calculation formula for nominal bit rate of classical CAN is same
> > as
> 
> the same

OK, will send new version fixing this.

Cheers,
Biju

Re: [PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4

[Geert Uytterhoeven]

Hi Biju,

On Wed, 10 Sept 2025 at 12:50, Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > From: Geert Uytterhoeven <geert@linux-m68k.org>
Mon, 8 Sept 2025 at 14:09, Biju <biju.das.au@gmail.com> wrote:
> > > From: Biju Das <biju.das.jz@bp.renesas.com>
> > >
> > > The calculation formula for nominal bit rate of classical CAN is same
> > > as
> >
> > the same
>
> OK, will send new version fixing this.

I don't think you have to resend the series just for this. Marc?

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

Re: [PATCH v3 1/4] can: rcar_canfd: Update bit rate constants for RZ/G3E and R-Car Gen4

[Marc Kleine-Budde]

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On 10.09.2025 13:44:35, Geert Uytterhoeven wrote:
> Hi Biju,
> 
> On Wed, 10 Sept 2025 at 12:50, Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > > From: Geert Uytterhoeven <geert@linux-m68k.org>
> Mon, 8 Sept 2025 at 14:09, Biju <biju.das.au@gmail.com> wrote:
> > > > From: Biju Das <biju.das.jz@bp.renesas.com>
> > > >
> > > > The calculation formula for nominal bit rate of classical CAN is same
> > > > as
> > >
> > > the same
> >
> > OK, will send new version fixing this.
> 
> I don't think you have to resend the series just for this. Marc?

No need to resend, I'll fix it up.

Thanks,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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[PATCH v3 2/4] can: rcar_canfd: Update RCANFD_CFG_* macros

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

Update RCANFD_CFG_* macros to give a meaning to the magic number using
GENMASK macro and extract the values using FIELD_PREP macro.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added Rb tag from Geert.
 * Dropped _MASK suffix from RCANFD_CFG_* macros.
v1->v2:
 * Moved from patch#4 to patch#2.
 * Updated commit header and description.
 * Kept RCANFD_CFG* macro definitions to give a meaning to the magic
   number using GENMASK macro and used FIELD_PREP to extract value.
---
 drivers/net/can/rcar/rcar_canfd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 4185fc5b4a70..8d0d0825cb54 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -103,10 +103,10 @@
 /* Channel register bits */
 
 /* RSCFDnCmCFG - Classical CAN only */
-#define RCANFD_CFG_SJW(x)		(((x) & 0x3) << 24)
-#define RCANFD_CFG_TSEG2(x)		(((x) & 0x7) << 20)
-#define RCANFD_CFG_TSEG1(x)		(((x) & 0xf) << 16)
-#define RCANFD_CFG_BRP(x)		(((x) & 0x3ff) << 0)
+#define RCANFD_CFG_SJW		GENMASK(25, 24)
+#define RCANFD_CFG_TSEG2	GENMASK(22, 20)
+#define RCANFD_CFG_TSEG1	GENMASK(19, 16)
+#define RCANFD_CFG_BRP		GENMASK(9, 0)
 
 /* RSCFDnCFDCmNCFG - CAN FD only */
 #define RCANFD_NCFG_NTSEG2(gpriv, x) \
@@ -1411,8 +1411,8 @@ static void rcar_canfd_set_bittiming(struct net_device *ndev)
 		cfg = (RCANFD_NCFG_NTSEG1(gpriv, tseg1) | RCANFD_NCFG_NBRP(brp) |
 		       RCANFD_NCFG_NSJW(gpriv, sjw) | RCANFD_NCFG_NTSEG2(gpriv, tseg2));
 	} else {
-		cfg = (RCANFD_CFG_TSEG1(tseg1) | RCANFD_CFG_BRP(brp) |
-		       RCANFD_CFG_SJW(sjw) | RCANFD_CFG_TSEG2(tseg2));
+		cfg = FIELD_PREP(RCANFD_CFG_TSEG1, tseg1) | FIELD_PREP(RCANFD_CFG_BRP, brp) |
+		      FIELD_PREP(RCANFD_CFG_SJW, sjw) | FIELD_PREP(RCANFD_CFG_TSEG2, tseg2);
 	}
 
 	rcar_canfd_write(priv->base, RCANFD_CCFG(ch), cfg);
-- 
2.43.0

[PATCH v3 3/4] can: rcar_canfd: Simplify nominal bit rate config

[Biju]

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.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added Rb tag from Geert.
 * Dropped _MASK suffix from RCANFD_NCFG_NBRP_MASK macro.
 * Followed the order as used in struct can_bittiming{_const} for easy
   maintenance.
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 | 43 +++++++++++++++++--------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 8d0d0825cb54..99719c84f452 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		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	GENMASK(9, 0)
 
 /* RSCFDnCFDCmCTR / RSCFDnCmCTR */
 #define RCANFD_CCTR_CTME		BIT(24)
@@ -1388,6 +1379,28 @@ 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 tseg2, u16 sjw, u16 brp)
+{
+	struct rcar_canfd_global *gpriv = priv->gpriv;
+	const struct rcar_canfd_hw_info *info = gpriv->info;
+	u32 ntseg1, ntseg2, nsjw, nbrp;
+
+	if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) || gpriv->info->shared_can_regs) {
+		ntseg1 = (tseg1 & (info->nom_bittiming->tseg1_max - 1)) << info->sh->ntseg1;
+		ntseg2 = (tseg2 & (info->nom_bittiming->tseg2_max - 1)) << info->sh->ntseg2;
+		nsjw = (sjw & (info->nom_bittiming->sjw_max - 1)) << info->sh->nsjw;
+		nbrp = FIELD_PREP(RCANFD_NCFG_NBRP, brp);
+	} else {
+		ntseg1 = FIELD_PREP(RCANFD_CFG_TSEG1, tseg1);
+		ntseg2 = FIELD_PREP(RCANFD_CFG_TSEG2, tseg2);
+		nsjw = FIELD_PREP(RCANFD_CFG_SJW, sjw);
+		nbrp = FIELD_PREP(RCANFD_CFG_BRP, brp);
+	}
+
+	return (ntseg1 | ntseg2 | nsjw | nbrp);
+}
+
 static void rcar_canfd_set_bittiming(struct net_device *ndev)
 {
 	u32 mask = RCANFD_FDCFG_TDCO | RCANFD_FDCFG_TDCE | RCANFD_FDCFG_TDCOC;
@@ -1406,15 +1419,7 @@ 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, tseg1) | FIELD_PREP(RCANFD_CFG_BRP, brp) |
-		      FIELD_PREP(RCANFD_CFG_SJW, sjw) | FIELD_PREP(RCANFD_CFG_TSEG2, tseg2);
-	}
-
+	cfg = rcar_canfd_compute_nominal_bit_rate_cfg(priv, tseg1, tseg2, sjw, brp);
 	rcar_canfd_write(priv->base, RCANFD_CCFG(ch), cfg);
 
 	if (!(priv->can.ctrlmode & CAN_CTRLMODE_FD))
-- 
2.43.0

[PATCH v3 4/4] can: rcar_canfd: Simplify data bit rate config

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

Introduce rcar_canfd_compute_data_bit_rate_cfg() for simplifying data bit
rate configuration by replacing function-like macros.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added Rb tag from Geert.
 * Dropped _MASK suffix from the macro RCANFD_DCFG_DBRP_MASK.
 * Followed the order as used in struct can_bittiming{_const} for easy
   maintenance.
v1->v2:
 * Split from patch#3 for computing data bit rate config separate.
   separate.
 * Replaced RCANFD_DCFG_DBRP->RCANFD_DCFG_DBRP_MASK and used FIELD_PREP to
   extract value.
---
 drivers/net/can/rcar/rcar_canfd.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 99719c84f452..401505264676 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -169,15 +169,7 @@
 #define RCANFD_CERFL_ERR(x)		((x) & (0x7fff)) /* above bits 14:0 */
 
 /* RSCFDnCFDCmDCFG */
-#define RCANFD_DCFG_DSJW(gpriv, x)	(((x) & ((gpriv)->info->data_bittiming->sjw_max - 1)) << 24)
-
-#define RCANFD_DCFG_DTSEG2(gpriv, x) \
-	(((x) & ((gpriv)->info->data_bittiming->tseg2_max - 1)) << (gpriv)->info->sh->dtseg2)
-
-#define RCANFD_DCFG_DTSEG1(gpriv, x) \
-	(((x) & ((gpriv)->info->data_bittiming->tseg1_max - 1)) << (gpriv)->info->sh->dtseg1)
-
-#define RCANFD_DCFG_DBRP(x)		(((x) & 0xff) << 0)
+#define RCANFD_DCFG_DBRP		GENMASK(7, 0)
 
 /* RSCFDnCFDCmFDCFG */
 #define RCANFD_GEN4_FDCFG_CLOE		BIT(30)
@@ -1401,6 +1393,19 @@ static inline u32 rcar_canfd_compute_nominal_bit_rate_cfg(struct rcar_canfd_chan
 	return (ntseg1 | ntseg2 | nsjw | nbrp);
 }
 
+static inline u32 rcar_canfd_compute_data_bit_rate_cfg(const struct rcar_canfd_hw_info *info,
+						       u16 tseg1, u16 tseg2, u16 sjw, u16 brp)
+{
+	u32 dtseg1, dtseg2, dsjw, dbrp;
+
+	dtseg1 = (tseg1 & (info->data_bittiming->tseg1_max - 1)) << info->sh->dtseg1;
+	dtseg2 = (tseg2 & (info->data_bittiming->tseg2_max - 1)) << info->sh->dtseg2;
+	dsjw = (sjw & (info->data_bittiming->sjw_max - 1)) << 24;
+	dbrp = FIELD_PREP(RCANFD_DCFG_DBRP, brp);
+
+	return (dtseg1 | dtseg2 | dsjw | dbrp);
+}
+
 static void rcar_canfd_set_bittiming(struct net_device *ndev)
 {
 	u32 mask = RCANFD_FDCFG_TDCO | RCANFD_FDCFG_TDCE | RCANFD_FDCFG_TDCOC;
@@ -1430,10 +1435,7 @@ static void rcar_canfd_set_bittiming(struct net_device *ndev)
 	sjw = dbt->sjw - 1;
 	tseg1 = dbt->prop_seg + dbt->phase_seg1 - 1;
 	tseg2 = dbt->phase_seg2 - 1;
-
-	cfg = (RCANFD_DCFG_DTSEG1(gpriv, tseg1) | RCANFD_DCFG_DBRP(brp) |
-	       RCANFD_DCFG_DSJW(gpriv, sjw) | RCANFD_DCFG_DTSEG2(gpriv, tseg2));
-
+	cfg = rcar_canfd_compute_data_bit_rate_cfg(gpriv->info, tseg1, tseg2, sjw, brp);
 	writel(cfg, &gpriv->fcbase[ch].dcfg);
 
 	/* Transceiver Delay Compensation */
-- 
2.43.0

Re: [PATCH v3 0/4] R-Car CANFD Improvements

[Marc Kleine-Budde]

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On 08.09.2025 13:09:29, Biju wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
> 
> The calculation formula for nominal bit rate of classical CAN is same as
> that of nominal bit rate of CANFD on the RZ/G3E SoC and R-Car Gen4
> compared to other SoCs. Update the nominal bit rate constants.
> 
> Apart from this, for replacing function-like macros, introduced
> rcar_canfd_compute_{nominal,data}_bit_rate_cfg().

Applied with the added "the" in 1/4.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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