can: rcar_canfd: Add rnc_field_width variable to struct rcar_canfd_hw_info

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@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20250417054320.14100-10-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index fded4da50103183c510ff250a3951761a5271a0b..558291a3604332e30877922f56716ae994a84d87 100644 (file)
--- 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);
 }