netdev - [PATCH net-next 09/22] can: rcar_canfd: Add rnc_field_width variable to struct rcar_canfd_hw

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Message-ID: <20250522084128.501049-10-mkl@pengutronix.de>
Date: Thu, 22 May 2025 10:36:37 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	kuba@...nel.org,
	linux-can@...r.kernel.org,
	kernel@...gutronix.de,
	Biju Das <biju.das.jz@...renesas.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 09/22] can: rcar_canfd: Add rnc_field_width variable to struct rcar_canfd_hw_info

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

The shift and w value in rcar_canfd_setrnc() are dictated by the
field width:
  - R-Car Gen4 packs 2 values in a 32-bit word, using a field width
    of 16 bits,
  - R-Car Gen3 packs up to 4 values in a 32-bit word, using a field
    width of 8 bits.

Add rnc_field_width variable to struct rcar_canfd_hw_info to handle this
difference. The rnc_stride is 32 / rnc_field_width and the index parameter
w is calculated by ch / rnc_stride. The shift value in rcar_canfd_setrnc()
is computed by using (32 - (ch % rnc_stride + 1) * rnc_field_width).

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>
Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
Link: https://patch.msgid.link/20250417054320.14100-10-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/rcar/rcar_canfd.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index fded4da50103..558291a36043 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -503,6 +503,7 @@
 struct rcar_canfd_global;
 
 struct rcar_canfd_hw_info {
+	u8 rnc_field_width;
 	u8 max_channels;
 	u8 postdiv;
 	/* hardware features */
@@ -579,18 +580,21 @@ static const struct can_bittiming_const rcar_canfd_bittiming_const = {
 };
 
 static const struct rcar_canfd_hw_info rcar_gen3_hw_info = {
+	.rnc_field_width = 8,
 	.max_channels = 2,
 	.postdiv = 2,
 	.shared_global_irqs = 1,
 };
 
 static const struct rcar_canfd_hw_info rcar_gen4_hw_info = {
+	.rnc_field_width = 16,
 	.max_channels = 8,
 	.postdiv = 2,
 	.shared_global_irqs = 1,
 };
 
 static const struct rcar_canfd_hw_info rzg2l_hw_info = {
+	.rnc_field_width = 8,
 	.max_channels = 2,
 	.postdiv = 1,
 	.multi_channel_irqs = 1,
@@ -676,9 +680,10 @@ static void rcar_canfd_tx_failure_cleanup(struct net_device *ndev)
 static void rcar_canfd_setrnc(struct rcar_canfd_global *gpriv, unsigned int ch,
 			      unsigned int num_rules)
 {
-	unsigned int shift = reg_gen4(gpriv, 16, 24) - (ch & 1) * reg_gen4(gpriv, 16, 8);
+	unsigned int rnc_stride = 32 / gpriv->info->rnc_field_width;
+	unsigned int shift = 32 - (ch % rnc_stride + 1) * gpriv->info->rnc_field_width;
+	unsigned int w = ch / rnc_stride;
 	u32 rnc = num_rules << shift;
-	unsigned int w = ch / 2;
 
 	rcar_canfd_set_bit(gpriv->base, RCANFD_GAFLCFG(w), rnc);
 }
-- 
2.47.2