[PATCH v3 6/7] net: can: flexcan: split the Message Buffer RAM area

[Pankaj Bansal <pankaj.bansal@xxxxxxx>]

The message buffer RAM area is not a contiguous 1KB area but 2 partitions
of 512 bytes each. Till now, we used Message buffers with payload size 8
bytes, which translates to 32 MBs per partition and no spare space is left
in any partition.
However, in upcoming SOC LX2160A the message buffers can have payload size
64 bytes. This results in less than 32 MBs per partition and some empty
area is left at the end of each partition.This empty area should not be
accessed.
Therefore, split the Message Buffer RAM area into two partitions.

Signed-off-by: Pankaj Bansal <pankaj.bansal@xxxxxxx>
---

Notes:
    V3:
     - No change
    V2:
     - removed mb_count_block1 and mb_count_block2 from priv structure due to
       flexcan_get_mb function introduced in earlier patch

 drivers/net/can/flexcan.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 232b70f371da..c9edfc808f8f 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -224,7 +224,8 @@ struct flexcan_regs {
 	u32 rxfgmask;		/* 0x48 */
 	u32 rxfir;		/* 0x4c */
 	u32 _reserved3[12];	/* 0x50 */
-	u32 mb[256];		/* 0x80 */
+	u32 mb1[128];		/* 0x80 */
+	u32 mb2[128];		/* 0x280 */
 	/* FIFO-mode:
 	 *			MB
 	 * 0x080...0x08f	0	RX message buffer
@@ -357,18 +358,23 @@ static struct flexcan_mb *flexcan_get_mb(const struct flexcan_priv *priv,
 					 u8 mb_index)
 {
 	u8 mb_size;
-	u8 mb_count;
+	u8 mb_count_block;
 
 	if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
 		mb_size = sizeof(struct flexcan_mb) + CANFD_MAX_DLEN;
 	else
 		mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
-	mb_count = (sizeof(priv->regs->mb) / mb_size);
+	mb_count_block = (sizeof(priv->regs->mb1) / mb_size);
 
-	if (mb_index >= mb_count)
+	if (mb_index < mb_count_block)
+		return (struct flexcan_mb __iomem *)((u8 *)&priv->regs->mb1 +
+						     (mb_size * mb_index));
+
+	mb_index -= mb_count_block;
+	if (mb_index >= mb_count_block)
 		return NULL;
 
-	return (struct flexcan_mb __iomem *)((u8 *)&priv->regs->mb +
+	return (struct flexcan_mb __iomem *)((u8 *)&priv->regs->mb2 +
 					     (mb_size * mb_index));
 }
 
@@ -1171,7 +1177,8 @@ static int flexcan_open(struct net_device *dev)
 		u64 imask;
 
 		priv->offload.mb_first = FLEXCAN_RX_MB_OFF_TIMESTAMP_FIRST;
-		priv->offload.mb_last = (sizeof(priv->regs->mb) / mb_size) - 1;
+		priv->offload.mb_last = (sizeof(priv->regs->mb1) / mb_size) +
+					(sizeof(priv->regs->mb2) / mb_size) - 1;
 
 		imask = GENMASK_ULL(priv->offload.mb_last,
 				    priv->offload.mb_first);
-- 
2.17.1

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