Commit 929d4342 authored by Kurt Kanzenbach's avatar Kurt Kanzenbach Committed by Paolo Abeni
Browse files

net: stmmac: Disable automatic FCS/Pad stripping 



The stmmac has the possibility to automatically strip the padding/FCS for IEEE
802.3 type frames. This feature is enabled conditionally. Therefore, the stmmac
receive path has to have a determination logic whether the FCS has to be
stripped in software or not.

In fact, for DSA this ACS feature is disabled and the determination logic
doesn't check for it properly. For instance, when using DSA in combination with
an older stmmac (pre version 4), the FCS is not stripped by hardware or software
which is problematic.

So either add another check for DSA to the fast path or simply disable ACS
feature completely. The latter approach has been chosen, because most of the
time the FCS is stripped in software anyway and it removes conditionals from the
receive fast path.

Signed-off-by: default avatarKurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/87v8q8jjgh.fsf@kurt/
Link: https://lore.kernel.org/r/20220905130155.193640-1-kurt@linutronix.de


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 418b0866

drivers/net/ethernet/stmicro/stmmac/dwmac100.h

+1 −1
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ 
#define MAC_CONTROL_TE		0x00000008	/* Transmitter Enable */

#define MAC_CONTROL_RE		0x00000004	/* Receiver Enable */



#define MAC_CORE_INIT (MAC_CONTROL_HBD | MAC_CONTROL_ASTP)

#define MAC_CORE_INIT (MAC_CONTROL_HBD)



/* MAC FLOW CTRL defines */

#define MAC_FLOW_CTRL_PT_MASK	0xffff0000	/* Pause Time Mask */

drivers/net/ethernet/stmicro/stmmac/dwmac1000.h

+1 −1
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ enum inter_frame_gap { 
#define GMAC_CONTROL_TE		0x00000008	/* Transmitter Enable */

#define GMAC_CONTROL_RE		0x00000004	/* Receiver Enable */



#define GMAC_CORE_INIT (GMAC_CONTROL_JD | GMAC_CONTROL_PS | GMAC_CONTROL_ACS | \

#define GMAC_CORE_INIT (GMAC_CONTROL_JD | GMAC_CONTROL_PS | \

			GMAC_CONTROL_BE | GMAC_CONTROL_DCRS)



/* GMAC Frame Filter defines */

drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c

+0 −9
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
#include <linux/crc32.h>

#include <linux/slab.h>

#include <linux/ethtool.h>

#include <net/dsa.h>

#include <asm/io.h>

#include "stmmac.h"

#include "stmmac_pcs.h"
@@ -24,7 +23,6 @@ 
static void dwmac1000_core_init(struct mac_device_info *hw,

				struct net_device *dev)

{

	struct stmmac_priv *priv = netdev_priv(dev);

	void __iomem *ioaddr = hw->pcsr;

	u32 value = readl(ioaddr + GMAC_CONTROL);

	int mtu = dev->mtu;
@@ -32,13 +30,6 @@ static void dwmac1000_core_init(struct mac_device_info *hw, 
	/* Configure GMAC core */

	value |= GMAC_CORE_INIT;



	/* Clear ACS bit because Ethernet switch tagging formats such as

	 * Broadcom tags can look like invalid LLC/SNAP packets and cause the

	 * hardware to truncate packets on reception.

	 */

	if (netdev_uses_dsa(dev) || !priv->plat->enh_desc)

		value &= ~GMAC_CONTROL_ACS;



	if (mtu > 1500)

		value |= GMAC_CONTROL_2K;

	if (mtu > 2000)

drivers/net/ethernet/stmicro/stmmac/dwmac100_core.c

+0 −8
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
*******************************************************************************/



#include <linux/crc32.h>

#include <net/dsa.h>

#include <asm/io.h>

#include "stmmac.h"

#include "dwmac100.h"
@@ -28,13 +27,6 @@ static void dwmac100_core_init(struct mac_device_info *hw, 


	value |= MAC_CORE_INIT;



	/* Clear ASTP bit because Ethernet switch tagging formats such as

	 * Broadcom tags can look like invalid LLC/SNAP packets and cause the

	 * hardware to truncate packets on reception.

	 */

	if (netdev_uses_dsa(dev))

		value &= ~MAC_CONTROL_ASTP;



	writel(value, ioaddr + MAC_CONTROL);



#ifdef STMMAC_VLAN_TAG_USED

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

+0 −1
Original line number Diff line number Diff line
@@ -14,7 +14,6 @@ 
#include <linux/slab.h>

#include <linux/ethtool.h>

#include <linux/io.h>

#include <net/dsa.h>

#include "stmmac.h"

#include "stmmac_pcs.h"

#include "dwmac4.h"