From nobody Tue Feb 10 04:16:15 2026 Received: from smtp-out3.simply.com (smtp-out3.simply.com [94.231.106.210]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8B7C30AD1C; Wed, 28 Jan 2026 14:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=94.231.106.210 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769611775; cv=none; b=s6veOCUZmoeY87nnHeYvSwHxMQ7FwNLnAyj3UV9Tn35vDJduk5ujyvJseYBH7HPyVA5gIpcXtWYGH9Q+lFhG5Rsy7yDy47Mb/GRyLwKxB15Oa0kjGtJYL7TsImKwO3w6mVD99cC0fRyp8LbSX9MIqBiqp8CWf0T5cicsStrbgAE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769611775; c=relaxed/simple; bh=hH5mNenLFv2jFXESBsX15fa4OXtKrcjO/eZje/dQ4zU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DexSg3KtTfQTqZ/QktN8ebBHGu5vLU6XyoS/WqXIKScJ6ZSa2Ym3W1AnYeRWZmiMplnwucjrXKjLoPS/HaxGNnqZlY8z9KEjZZAi079G5cbadluRK0T1QYeFzy+hNV1bPw8sOA2PgYrKc/9Q4H/NsTxfLd/p7jrYrLlr7jC3bmk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gaisler.com; spf=pass smtp.mailfrom=gaisler.com; dkim=fail (0-bit key) header.d=gaisler.com header.i=@gaisler.com header.b=QFBAP+eC reason="key not found in DNS"; arc=none smtp.client-ip=94.231.106.210 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gaisler.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gaisler.com Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=gaisler.com header.i=@gaisler.com header.b="QFBAP+eC" Received: from localhost (localhost [127.0.0.1]) by smtp.simply.com (Simply.com) with ESMTP id 4f1QCb2rwnz1FQVX; Wed, 28 Jan 2026 15:49:31 +0100 (CET) Received: from d-5xj5g74.got.gaisler.com.com (h-98-128-223-123.NA.cust.bahnhof.se [98.128.223.123]) by smtp.simply.com (Simply.com) with ESMTPA id 4f1QCb0nVBz1FDXm; Wed, 28 Jan 2026 15:49:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gaisler.com; s=simplycom2; t=1769611771; bh=euBnDk4LZvnk8pPGEi69v5bjXxDOkS3WahwCOi6NLIo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QFBAP+eCO0cdU3T71ad4DLoaImpdd6M+fMQdq37tmiqgzd8/LZa0eY2b+G6YisQnK WudvlLXwIpP1zr/8OB4innlvzhOdU1yEb5E2ugPTGVrzxGwC37USzDEDLKN5LoNcS/ +uy94yqm+42n6dmp+dWIJwd4PVJq6e1f2itXx+4Vu5JXhzxarxuQ1dTvhYrtye+rvN 1FEtkM3A5glQM1UIJaaIyQjeI5jbhAKqWrhCQ9Stp/lcrb/TV3vg+h0FjBBRGhW1+B tlNPsyVaM84ed+ugU39IlDhEwJ5Rxloysfljk2VqWSNjPi7tS91/RDt18pPxKG0O+O QLdOjg6OgQShQ== From: Arun Muthusamy To: robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, mkl@pengutronix.de, mailhol@kernel.org Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-can@vger.kernel.org, Arun Muthusamy Subject: [PATCH v4 12/15] can: grcan: Add CANFD TX support alongside legacy CAN Date: Wed, 28 Jan 2026 15:49:18 +0100 Message-ID: <20260128144921.5458-13-arun.muthusamy@gaisler.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260128144921.5458-1-arun.muthusamy@gaisler.com> References: <20260128144921.5458-1-arun.muthusamy@gaisler.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Include CANFD TX support with the legacy CAN support, enabling support for extended data payloads to provide higher bit rates. Signed-off-by: Arun Muthusamy --- drivers/net/can/grcan.c | 103 +++++++++++++++++++++++++++++----------- 1 file changed, 75 insertions(+), 28 deletions(-) diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c index 3104946071dd..da0b5c129aae 100644 --- a/drivers/net/can/grcan.c +++ b/drivers/net/can/grcan.c @@ -174,6 +174,7 @@ struct grcan_registers { #define GRCAN_IRQ_DEFAULT (GRCAN_IRQ_RX | GRCAN_IRQ_TX | GRCAN_IRQ_ERRORS) #define GRCAN_MSG_SIZE 16 +#define GRCAN_CLASSIC_DATA_SIZE 8 #define GRCAN_MSG_IDE 0x80000000 #define GRCAN_MSG_RTR 0x40000000 @@ -195,6 +196,10 @@ struct grcan_registers { #define GRCAN_MSG_OFF 0x00000002 #define GRCAN_MSG_PASS 0x00000001 +#define GRCAN_MSG_EID_MASK GENMASK(28, 0) +#define GRCAN_MSG_BID_MASK GENMASK(28, 18) +#define GRCAN_MSG_DLC_MASK GENMASK(31, 28) + #define GRCAN_BUFFER_ALIGNMENT 1024 #define GRCAN_DEFAULT_BUFFER_SIZE 1024 #define GRCAN_VALID_TR_SIZE_MASK 0x001fffc0 @@ -227,6 +232,9 @@ struct grcan_registers { #define GRCANFD_FDBTR_PS2_BIT 5 #define GRCANFD_FDBTR_SJW_BIT 0 +#define GRCAN_TX_BRS BIT(25) +#define GRCAN_TX_FDF BIT(26) + /* Hardware capabilities */ struct grcan_hwcap { /* CAN-FD capable, indicates GRCANFD IP. @@ -1207,6 +1215,14 @@ static void grcan_transmit_catch_up(struct net_devic= e *dev) spin_unlock_irqrestore(&priv->lock, flags); } +static int grcan_numbds(int len) +{ + if (len <=3D GRCAN_CLASSIC_DATA_SIZE) + return 1; + + return 1 + DIV_ROUND_UP(len - GRCAN_CLASSIC_DATA_SIZE, GRCAN_MSG_SIZE); +} + static int grcan_receive(struct net_device *dev, int budget) { struct grcan_priv *priv =3D netdev_priv(dev); @@ -1389,15 +1405,22 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff = *skb, struct net_device *dev) { struct grcan_priv *priv =3D netdev_priv(dev); - struct grcan_registers __iomem *regs =3D priv->regs; + struct grcan_registers __iomem *regs; + u32 eff, rtr, dlc, tmp, err, can_id; struct grcan_dma *dma =3D &priv->dma; - struct can_frame *cf =3D (struct can_frame *)skb->data; + u32 bds, copy_len, payload_offset; u32 id, txwr, txrd, space, txctrl; - int slotindex; - u32 *slot; - u32 rtr, eff, dlc, tmp, err; + struct canfd_frame *cfd; + struct can_frame *cf; unsigned long flags; - u32 oneshotmode =3D priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT; + u32 oneshotmode; + u8 *payload; + u32 *slot; + u8 len; + int i; + + regs =3D priv->regs; + oneshotmode =3D priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT; if (can_dev_dropped_skb(dev, skb)) return NETDEV_TX_OK; @@ -1408,6 +1431,18 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *= skb, if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) return NETDEV_TX_BUSY; + cfd =3D (struct canfd_frame *)skb->data; + len =3D cfd->len; + can_id =3D cfd->can_id; + payload =3D cfd->data; + + if (can_is_canfd_skb(skb)) { + dlc =3D can_fd_len2dlc(len); + } else { + cf =3D (struct can_frame *)skb->data; + dlc =3D can_get_cc_dlc(cf, priv->can.ctrlmode); + } + /* Reads of priv->eskbp and shut-downs of the queue needs to * be atomic towards the updates to priv->eskbp and wake-ups * of the queue in the interrupt handler. @@ -1416,9 +1451,7 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *s= kb, txwr =3D grcan_read_reg(®s->txwr); space =3D grcan_txspace(dma->tx.size, txwr, priv->eskbp); - - slotindex =3D txwr / GRCAN_MSG_SIZE; - slot =3D dma->tx.buf + txwr; + bds =3D grcan_numbds(len); if (unlikely(space =3D=3D 1)) netif_stop_queue(dev); @@ -1434,24 +1467,39 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff = *skb, return NETDEV_TX_BUSY; } - /* Convert and write CAN message to DMA buffer */ - eff =3D cf->can_id & CAN_EFF_FLAG; - rtr =3D cf->can_id & CAN_RTR_FLAG; - id =3D cf->can_id & (eff ? CAN_EFF_MASK : CAN_SFF_MASK); - dlc =3D cf->len; - if (eff) - tmp =3D (id << GRCAN_MSG_EID_BIT) & GRCAN_MSG_EID; - else - tmp =3D (id << GRCAN_MSG_BID_BIT) & GRCAN_MSG_BID; - slot[0] =3D (eff ? GRCAN_MSG_IDE : 0) | (rtr ? GRCAN_MSG_RTR : 0) | tmp; + payload_offset =3D 0; + for (i =3D 0; i < bds; i++) { + slot =3D dma->tx.buf + txwr; + memset(slot, 0, GRCAN_MSG_SIZE); + + if (i =3D=3D 0) { + eff =3D can_id & CAN_EFF_FLAG; + rtr =3D can_id & CAN_RTR_FLAG; + id =3D can_id & (eff ? CAN_EFF_MASK : CAN_SFF_MASK); + if (eff) + tmp =3D FIELD_PREP(GRCAN_MSG_EID_MASK, id); + else + tmp =3D FIELD_PREP(GRCAN_MSG_BID_MASK, id); + slot[0] =3D (eff ? GRCAN_MSG_IDE : 0) | (rtr ? GRCAN_MSG_RTR : 0) | tmp; + slot[1] =3D FIELD_PREP(GRCAN_MSG_DLC_MASK, dlc); + if (can_is_canfd_skb(skb)) { + slot[1] |=3D GRCAN_TX_FDF; + if (cfd->flags & CANFD_BRS) + slot[1] |=3D GRCAN_TX_BRS; + } - slot[1] =3D ((dlc << GRCAN_MSG_DLC_BIT) & GRCAN_MSG_DLC); - slot[2] =3D 0; - slot[3] =3D 0; - if (dlc > 0) - memcpy(&slot[2], cf->data, sizeof(u32)); - if (dlc > 4) - memcpy(&slot[3], cf->data + 4, sizeof(u32)); + copy_len =3D min(len, 8); + memcpy(&slot[2], payload, copy_len); + payload_offset +=3D copy_len; + } else { + copy_len =3D min(len - payload_offset, GRCAN_MSG_SIZE); + memcpy(slot, payload + payload_offset, copy_len); + payload_offset +=3D copy_len; + } + txwr +=3D GRCAN_MSG_SIZE; + if (txwr >=3D dma->tx.size) + txwr -=3D dma->tx.size; + } /* Checking that channel has not been disabled. These cases * should never happen @@ -1493,8 +1541,7 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *s= kb, wmb(); /* Update write pointer to start transmission */ - grcan_write_reg(®s->txwr, - grcan_ring_add(txwr, GRCAN_MSG_SIZE, dma->tx.size)); + grcan_write_reg(®s->txwr, txwr); return NETDEV_TX_OK; } -- 2.51.0