From nobody Tue Feb 10 05:09:38 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 9333943634A; Thu, 22 Jan 2026 12:10:59 +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=1769083863; cv=none; b=NZU3n4Kj9gqNMtggKXZry7nxPctShVSdBmYoXlAOXqrsG/+w1xS6HG0k+84a6y2PSHuKADdNXdQ0E93GnZ+/K3mq8e9Ti8r3CWZGyK2yBsNmSW7o/xzSYxkZDyb+gKzZobogdwjcLM1Sj6Ekkl53USsv+B3PmJY51Oe9it2OC8A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769083863; c=relaxed/simple; bh=XhfqXG/GA5qfp1zS4RrMnh9Rpl6PePJ2REwVKnmb4Xo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s0JPTDr1oWSc8Vyhw91GYRUPdltpmvfPKHhhCl3FILWBZpatcpQ1+nUCW3ezX7rOF+5v1hz9kkmTdwrIyIRHd2+YnBsNZGzXWv5d1WsKMUOb1oSJAMX5zp0e3eg0oZSZKoAMbdsjDXVyXkVtMThIAUR4qxVBn1nSuMqGo6N5Kks= 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=ovn6rWOr 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="ovn6rWOr" Received: from localhost (localhost [127.0.0.1]) by smtp.simply.com (Simply.com) with ESMTP id 4dxfzG2ty2z1FDXl; Thu, 22 Jan 2026 13:10:50 +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 4dxfzG0kCXz1DHbf; Thu, 22 Jan 2026 13:10:50 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gaisler.com; s=simplycom2; t=1769083850; bh=eUp2qOvFQCwqoiY/xIcrHbhbjUDJgP1zcgG5WtjOJIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ovn6rWOrCI0S+/MUkCxLbgGIc1v8g6r6UCa5cbJf7LZIms7pqtFx379v3sj5Dl1gQ qcQrxe3k4i1FSEagU5ytJp1zeS5V6VxKiktp5+M4b42cmBW0p+ffN5r3jl5HPl0AMc FNYpX6car+ekQp+fbVnp6+Ax8YSRBdA7bOl4CsbMgv8Ti4YlDOUMVuN12xGfw6L0Va x8OJkHwNpA3kNM0/Dq9VYMmndGSb5S95Fz5t114Gkc6VsfBwwinmcjFqfOFyJOEm4a cU2wsIr0GdsVaWBlOBrgZrHz+aTY9da5DElntif2WPyoAMt9gfh9g/bhOzEWlzkI+H SlHcpiZ1lXAWw== 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 v3 13/15] can: grcan: Add CANFD TX support alongside legacy CAN Date: Thu, 22 Jan 2026 13:10:36 +0100 Message-ID: <20260122121038.7910-14-arun.muthusamy@gaisler.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260122121038.7910-1-arun.muthusamy@gaisler.com> References: <20260122121038.7910-1-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 | 102 +++++++++++++++++++++++++++++----------- 1 file changed, 74 insertions(+), 28 deletions(-) diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c index 9fc18064fab1..508ad5320cff 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) =20 #define GRCAN_MSG_SIZE 16 +#define GRCAN_CLASSIC_DATA_SIZE 8 =20 #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 =20 +#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 =20 +#define GRCAN_TX_BRS BIT(25) +#define GRCAN_TX_FDF BIT(26) + /* Hardware capabilities */ struct grcan_hwcap { /* CAN-FD capable, indicates GRCANFD IP. @@ -1218,6 +1226,13 @@ static void grcan_transmit_catch_up(struct net_devic= e *dev) spin_unlock_irqrestore(&priv->lock, flags); } =20 +static int grcan_numbds(int len) +{ + if (len <=3D GRCAN_CLASSIC_DATA_SIZE) + return 1; + return 1 + ((len - GRCAN_CLASSIC_DATA_SIZE + GRCAN_MSG_SIZE) / GRCAN_MSG_= SIZE); +} + static int grcan_receive(struct net_device *dev, int budget) { struct grcan_priv *priv =3D netdev_priv(dev); @@ -1400,15 +1415,22 @@ 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; =20 if (can_dev_dropped_skb(dev, skb)) return NETDEV_TX_OK; @@ -1419,6 +1441,18 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *= skb, if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) return NETDEV_TX_BUSY; =20 + 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. @@ -1427,9 +1461,7 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *s= kb, =20 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); =20 if (unlikely(space =3D=3D 1)) netif_stop_queue(dev); @@ -1445,24 +1477,39 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff = *skb, return NETDEV_TX_BUSY; } =20 - /* 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; + } =20 - 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; + } =20 /* Checking that channel has not been disabled. These cases * should never happen @@ -1504,8 +1551,7 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *s= kb, wmb(); =20 /* 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); =20 return NETDEV_TX_OK; } --=20 2.51.0