[PATCH 0/1] Workaround for timeout error in NETSEC driver

[Ryosuke Saito]

This patch adds the workaround for the timeout error in the NETSEC
driver when sending packets.

The NETSEC driver occasionally shows a "netsec_wait_while_busy" error
and fails to send packets like the below:

====================
U-Boot 2023.01 (Jan 09 2023 - 16:07:33 +0000)

CPU:   SC2A11:Cortex-A53 MPCore 24cores
Model: Socionext Developer Box
DRAM:  1.9 GiB (effective 63.9 GiB)
optee optee: OP-TEE: revision 3.20 (8e74d476)
I/TC: Reserved shared memory is enabled
I/TC: Dynamic shared memory is enabled
I/TC: Normal World virtualization support is disabled
I/TC: Asynchronous notifications are disabled
Core:  24 devices, 19 uclasses, devicetree: separate
MMC:   sdhci at 52300000: 0
Loading Environment from nowhere... OK
PCI: Failed autoconfig bar 14
In:    uart at 2a400000
Out:   uart at 2a400000
Err:   uart at 2a400000
Net:   SF: Detected mx25u51245g with page size 256 Bytes, erase size 4 KiB, total 64 MiB
eth0: ethernet at 522d0000
starting USB...
Bus xhci_pci: Register 8000820 NbrPorts 8
Starting the controller
USB XHCI 1.00
scanning bus xhci_pci for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
scanning bus for devices...
SATA link 0 timeout.
SATA link 1 timeout.
AHCI 0001.0200 32 slots 2 ports 6 Gbps 0x3 impl SATA mode
flags: 64bit ncq stag led clo pmp pio slum part ccc sxs 
Hit any key to stop autoboot:  2  0 
=> setenv serverip 192.168.1.109
=> dhcp
BOOTP broadcast 1
BOOTP broadcast 2
BOOTP broadcast 3
BOOTP broadcast 4
*** Unhandled DHCP Option in OFFER/ACK: 125
*** Unhandled DHCP Option in OFFER/ACK: 125
DHCP client bound to address 192.168.1.111 (2131 ms)
*** Warning: no boot file name; using 'C0A8016F.img'
Using ethernet at 522d0000 device
TFTP from server 192.168.1.109; our IP address is 192.168.1.111
Filename 'C0A8016F.img'.
Load address: 0x80000000
Loading: *
TFTP error: 'File not found' (1)
Not retrying...
=> ping 192.168.1.1
Using ethernet at 522d0000 device
host 192.168.1.1 is alive
=> ping 192.168.1.1
ethernet at 522d0000 Waiting for PHY auto negotiation to complete... done
Using ethernet at 522d0000 device
host 192.168.1.1 is alive
=> ping 192.168.1.1

(...skipping...)

=> ping 192.168.1.1
ethernet at 522d0000 Waiting for PHY auto negotiation to complete... 
done
netsec_wait_while_busy: timeout
Using ethernet at 522d0000 device

ARP Retry count exceeded; starting again
ping failed; host 192.168.1.1 is not alive
====================

This could be occurred by, e.g., tftp and dhcp as well.

After investigation, it turns out it's waiting for MAC_REG_DESC_SOFT_RST
to be cleared to 0 after writing 1. The NETSEC firmware normally clears
it, but sometimes it seems to enter a weird state where it's never been
cleared until the next NETSEC software reset.
The reproducibility seems to vary on the environment (for example, 100
ping tries would cause the issue in my environment.); however, we faced
the issue on at least three different boards in three different
networking environments.

We have already reported the issue to Socionext, the supplier of NETSEC
firmware, but it will take longer to find the root cause and fix the
issue. Meanwhile, we can add a workaround for the problematic state by
software resetting NETSEC.

Ryosuke Saito (1):
  net: sni_netsec: Add workaround for timeout error

 drivers/net/sni_netsec.c | 50 ++++++++++++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 9 deletions(-)

-- 
2.41.0