[PATCH 6.12 055/116] can: rcar_canfd: Fix page entries in the AFL list

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit 1dba0a37644ed3022558165bbb5cb9bda540eaf7 upstream.

There are a total of 96 AFL pages and each page has 16 entries with
registers CFDGAFLIDr, CFDGAFLMr, CFDGAFLP0r, CFDGAFLP1r holding
the rule entries (r = 0..15).

Currently, RCANFD_GAFL* macros use a start variable to find AFL entries,
which is incorrect as the testing on RZ/G3E shows ch1 and ch4
gets a start value of 0 and the register contents are overwritten.

Fix this issue by using rule_entry corresponding to the channel
to find the page entries in the AFL list.

Fixes: dd3bd23eb438 ("can: rcar_canfd: Add Renesas R-Car CAN FD driver")
Cc: stable@vger.kernel.org
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20250307170330.173425-3-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/can/rcar/rcar_canfd.c |   28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -787,22 +787,14 @@ static void rcar_canfd_configure_control
 }
 
 static void rcar_canfd_configure_afl_rules(struct rcar_canfd_global *gpriv,
-					   u32 ch)
+					   u32 ch, u32 rule_entry)
 {
-	u32 cfg;
-	int offset, start, page, num_rules = RCANFD_CHANNEL_NUMRULES;
+	int offset, page, num_rules = RCANFD_CHANNEL_NUMRULES;
+	u32 rule_entry_index = rule_entry % 16;
 	u32 ridx = ch + RCANFD_RFFIFO_IDX;
 
-	if (ch == 0) {
-		start = 0; /* Channel 0 always starts from 0th rule */
-	} else {
-		/* Get number of Channel 0 rules and adjust */
-		cfg = rcar_canfd_read(gpriv->base, RCANFD_GAFLCFG(ch));
-		start = RCANFD_GAFLCFG_GETRNC(gpriv, 0, cfg);
-	}
-
 	/* Enable write access to entry */
-	page = RCANFD_GAFL_PAGENUM(start);
+	page = RCANFD_GAFL_PAGENUM(rule_entry);
 	rcar_canfd_set_bit(gpriv->base, RCANFD_GAFLECTR,
 			   (RCANFD_GAFLECTR_AFLPN(gpriv, page) |
 			    RCANFD_GAFLECTR_AFLDAE));
@@ -818,13 +810,13 @@ static void rcar_canfd_configure_afl_rul
 		offset = RCANFD_C_GAFL_OFFSET;
 
 	/* Accept all IDs */
-	rcar_canfd_write(gpriv->base, RCANFD_GAFLID(offset, start), 0);
+	rcar_canfd_write(gpriv->base, RCANFD_GAFLID(offset, rule_entry_index), 0);
 	/* IDE or RTR is not considered for matching */
-	rcar_canfd_write(gpriv->base, RCANFD_GAFLM(offset, start), 0);
+	rcar_canfd_write(gpriv->base, RCANFD_GAFLM(offset, rule_entry_index), 0);
 	/* Any data length accepted */
-	rcar_canfd_write(gpriv->base, RCANFD_GAFLP0(offset, start), 0);
+	rcar_canfd_write(gpriv->base, RCANFD_GAFLP0(offset, rule_entry_index), 0);
 	/* Place the msg in corresponding Rx FIFO entry */
-	rcar_canfd_set_bit(gpriv->base, RCANFD_GAFLP1(offset, start),
+	rcar_canfd_set_bit(gpriv->base, RCANFD_GAFLP1(offset, rule_entry_index),
 			   RCANFD_GAFLP1_GAFLFDP(ridx));
 
 	/* Disable write access to page */
@@ -1851,6 +1843,7 @@ static int rcar_canfd_probe(struct platf
 	unsigned long channels_mask = 0;
 	int err, ch_irq, g_irq;
 	int g_err_irq, g_recc_irq;
+	u32 rule_entry = 0;
 	bool fdmode = true;			/* CAN FD only mode - default */
 	char name[9] = "channelX";
 	int i;
@@ -2023,7 +2016,8 @@ static int rcar_canfd_probe(struct platf
 		rcar_canfd_configure_tx(gpriv, ch);
 
 		/* Configure receive rules */
-		rcar_canfd_configure_afl_rules(gpriv, ch);
+		rcar_canfd_configure_afl_rules(gpriv, ch, rule_entry);
+		rule_entry += RCANFD_CHANNEL_NUMRULES;
 	}
 
 	/* Configure common interrupts */