 acbea54bc2
			
		
	
	acbea54bc2
	
	
	
		
			
			The most noticeable one is fix for RX stopping on high traffic. Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
		
			
				
	
	
		
			120 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From 14b3b46a67f78ade99eafcbf320105615e948569 Mon Sep 17 00:00:00 2001
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| From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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| Date: Fri, 12 Feb 2021 16:21:35 +0100
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| Subject: [PATCH] net: broadcom: bcm4908_enet: set MTU on open & on request
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| MIME-Version: 1.0
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| Content-Type: text/plain; charset=UTF-8
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| Content-Transfer-Encoding: 8bit
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| 
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| Hardware comes up with default max frame size set to 1518. When using it
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| with switch it results in actual Ethernet MTU 1492:
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| 1518 - 14 (Ethernet header) - 4 (Broadcom's tag) - 4 (802.1q) - 4 (FCS)
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| 
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| Above means hardware in its default state can't handle standard Ethernet
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| traffic (MTU 1500).
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| 
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| Define maximum possible Ethernet overhead and always set MAC max frame
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| length accordingly. This change fixes handling Ethernet frames of length
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| 1506 - 1514.
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| 
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| Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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| Signed-off-by: David S. Miller <davem@davemloft.net>
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| ---
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|  drivers/net/ethernet/broadcom/bcm4908_enet.c | 31 ++++++++++++++++----
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|  1 file changed, 25 insertions(+), 6 deletions(-)
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| 
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| --- a/drivers/net/ethernet/broadcom/bcm4908_enet.c
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| +++ b/drivers/net/ethernet/broadcom/bcm4908_enet.c
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| @@ -5,6 +5,7 @@
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|  
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|  #include <linux/delay.h>
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|  #include <linux/etherdevice.h>
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| +#include <linux/if_vlan.h>
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|  #include <linux/interrupt.h>
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|  #include <linux/module.h>
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|  #include <linux/of.h>
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| @@ -29,9 +30,10 @@
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|  						 ENET_DMA_CH_CFG_INT_BUFF_DONE)
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|  #define ENET_DMA_MAX_BURST_LEN			8 /* in 64 bit words */
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|  
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| -#define ENET_MTU_MIN				60
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| -#define ENET_MTU_MAX				1500 /* Is it possible to support 2044? */
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| -#define ENET_MTU_MAX_EXTRA_SIZE			32 /* L2 */
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| +#define ENET_MTU_MAX				ETH_DATA_LEN /* Is it possible to support 2044? */
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| +#define BRCM_MAX_TAG_LEN			6
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| +#define ENET_MAX_ETH_OVERHEAD			(ETH_HLEN + BRCM_MAX_TAG_LEN + VLAN_HLEN + \
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| +						 ETH_FCS_LEN + 4) /* 32 */
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|  
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|  struct bcm4908_enet_dma_ring_bd {
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|  	__le32 ctl;
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| @@ -135,6 +137,11 @@ static void bcm4908_enet_intrs_ack(struc
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|  	enet_write(enet, ENET_DMA_CH_RX_CFG + ENET_DMA_CH_CFG_INT_STAT, ENET_DMA_INT_DEFAULTS);
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|  }
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|  
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| +static void bcm4908_enet_set_mtu(struct bcm4908_enet *enet, int mtu)
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| +{
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| +	enet_umac_write(enet, UMAC_MAX_FRAME_LEN, mtu + ENET_MAX_ETH_OVERHEAD);
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| +}
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| +
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|  /***
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|   * DMA
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|   */
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| @@ -246,7 +253,7 @@ static int bcm4908_enet_dma_alloc_rx_buf
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|  	u32 tmp;
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|  	int err;
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|  
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| -	slot->len = ENET_MTU_MAX + ENET_MTU_MAX_EXTRA_SIZE;
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| +	slot->len = ENET_MTU_MAX + ENET_MAX_ETH_OVERHEAD;
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|  
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|  	slot->skb = netdev_alloc_skb(enet->netdev, slot->len);
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|  	if (!slot->skb)
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| @@ -374,6 +381,8 @@ static void bcm4908_enet_gmac_init(struc
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|  {
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|  	u32 cmd;
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|  
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| +	bcm4908_enet_set_mtu(enet, enet->netdev->mtu);
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| +
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|  	cmd = enet_umac_read(enet, UMAC_CMD);
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|  	enet_umac_write(enet, UMAC_CMD, cmd | CMD_SW_RESET);
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|  	enet_umac_write(enet, UMAC_CMD, cmd & ~CMD_SW_RESET);
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| @@ -559,7 +568,7 @@ static int bcm4908_enet_poll(struct napi
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|  
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|  		len = (ctl & DMA_CTL_LEN_DESC_BUFLENGTH) >> DMA_CTL_LEN_DESC_BUFLENGTH_SHIFT;
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|  
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| -		if (len < ENET_MTU_MIN ||
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| +		if (len < ETH_ZLEN ||
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|  		    (ctl & (DMA_CTL_STATUS_SOP | DMA_CTL_STATUS_EOP)) != (DMA_CTL_STATUS_SOP | DMA_CTL_STATUS_EOP)) {
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|  			enet->netdev->stats.rx_dropped++;
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|  			break;
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| @@ -583,11 +592,21 @@ static int bcm4908_enet_poll(struct napi
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|  	return handled;
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|  }
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|  
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| +static int bcm4908_enet_change_mtu(struct net_device *netdev, int new_mtu)
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| +{
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| +	struct bcm4908_enet *enet = netdev_priv(netdev);
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| +
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| +	bcm4908_enet_set_mtu(enet, new_mtu);
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| +
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| +	return 0;
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| +}
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| +
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|  static const struct net_device_ops bcm4908_enet_netdev_ops = {
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|  	.ndo_open = bcm4908_enet_open,
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|  	.ndo_stop = bcm4908_enet_stop,
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|  	.ndo_start_xmit = bcm4908_enet_start_xmit,
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|  	.ndo_set_mac_address = eth_mac_addr,
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| +	.ndo_change_mtu = bcm4908_enet_change_mtu,
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|  };
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|  
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|  static int bcm4908_enet_probe(struct platform_device *pdev)
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| @@ -625,7 +644,7 @@ static int bcm4908_enet_probe(struct pla
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|  	eth_hw_addr_random(netdev);
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|  	netdev->netdev_ops = &bcm4908_enet_netdev_ops;
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|  	netdev->min_mtu = ETH_ZLEN;
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| -	netdev->mtu = ENET_MTU_MAX;
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| +	netdev->mtu = ETH_DATA_LEN;
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|  	netdev->max_mtu = ENET_MTU_MAX;
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|  	netif_napi_add(netdev, &enet->napi, bcm4908_enet_poll, 64);
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|  
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