ethernet flow control support

penguin

In drivers/net/ethernet/stmicro/stmmac/stmmac_main.c , there is a flow control module parameter.

1. static int flow_ctrl = FLOW_OFF;                                                                                                                  
   
2. module_param(flow_ctrl, int, S_IRUGO | S_IWUSR);                                                                                                   
   
3. MODULE_PARM_DESC(flow_ctrl, "Flow control ability [on/off]");                                                                                      
   

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It defaults to FLOW_OFF. You can modify it and recompile the kernel to check if it works.

penguin

Or follow the commands below to have a hot fix:

1. cd /sys/bus/platform/drivers/rk_gmac-dwmac
   
2. 
   
3. # unbind the ethernet device from the driver
   
4. echo fe300000.ethernet > unbind
   
5. 
   
6. # turn on flow_ctrl
   
7. echo 1 > /sys/module/stmmac/parameters/flow_ctrl
   
8. 
   
9. # bind the ethernet device back
   
10. echo fe300000.ethernet > bind
    

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After these commands, there're messages from the kernel:

1. 
   
2. [11547.465973] force_sf_dma_mode is ignored if force_thresh_dma_mode is set.[11547.466691] rk_gmac-dwmac fe300000.ethernet: Looking up phy-supply from device tree
   
3. [11547.467826] rk_gmac-dwmac fe300000.ethernet: clock input or output? (input).
   
4. [11547.468510] rk_gmac-dwmac fe300000.ethernet: TX delay(0x28).
   
5. [11547.469033] rk_gmac-dwmac fe300000.ethernet: RX delay(0x1b).
   
6. [11547.469635] rk_gmac-dwmac fe300000.ethernet: integrated PHY? (no).
   
7. [11547.470722] rk_gmac-dwmac fe300000.ethernet: cannot get clock clk_mac_speed
   
8. [11547.471349] rk_gmac-dwmac fe300000.ethernet: clock input from PHY
   
9. [11547.476958] rk_gmac-dwmac fe300000.ethernet: init for RGMII
   
10. [11547.486003] stmmac - user ID: 0x10, Synopsys ID: 0x35
    
11. [11547.486561]  Ring mode enabled
    
12. [11547.486844]  DMA HW capability register supported
    
13. [11547.487250]  Normal descriptors
    
14. [11547.487688]  RX Checksum Offload Engine supported (type 2)
    
15. [11547.488177]  Wake-Up On Lan supported
    
16. [11547.488617]  Enable RX Mitigation via HW Watchdog Timer
    
17. [11547.491855] of_get_named_gpiod_flags: parsed 'snps,reset-gpio' property of node '/ethernet@fe300000[0]' - status (0)
    
18. [11547.492826] gpio-111 (mdio-reset): gpiod_request: status -16
    
19. [11547.509629] libphy: stmmac: probed
    
20. [11547.509949] eth%d: PHY ID 001cc915 at 0 IRQ POLL (stmmac-0:00) active
    
21. [11547.510616] eth%d: PHY ID 001cc915 at 1 IRQ POLL (stmmac-0:01)
    
22. root@firefly:/sys/bus/platform/drivers/rk_gmac-dwmac# [11547.615421] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
    
23. 
    
24. root@firefly:/sys/bus/platform/drivers/rk_gmac-dwmac# [11550.624270] rk_gmac-dwmac fe300000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
    

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The last line is indicating flow control enabled, right?  Plz check