Re: [PATCH] ftgmac100: Disable HW checksum generation on AST2500

On Wed, 2019-10-09 at 14:18 -0400, Oskar Senft wrote:

Does HW in the AST2500 actually perform the HW checksum calculation,
or would that be the responsibility of the NIC that it's talking to
via NC-SI?

I wouldn't rely on the NC-SI NIC for UDP/TCP checksums. We should be
providing it with well formed traffic.

Cheers,
Ben.

Oskar.

On Wed, Oct 9, 2019 at 12:38 AM Benjamin Herrenschmidt <
benh@kernel.crashing.org> wrote:

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On Wed, 2019-09-11 at 14:48 +0000, Joel Stanley wrote:

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Hi Ben,

On Tue, 10 Sep 2019 at 22:05, Florian Fainelli <

f.fainelli@gmail.com>

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wrote:

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On 9/10/19 2:37 PM, Vijay Khemka wrote:

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HW checksum generation is not working for AST2500, specially

with

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IPV6
over NCSI. All TCP packets with IPv6 get dropped. By

disabling

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this
it works perfectly fine with IPV6.

Verified with IPV6 enabled and can do ssh.

How about IPv4, do these packets have problem? If not, can you
continue
advertising NETIF_F_IP_CSUM but take out NETIF_F_IPV6_CSUM?

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Signed-off-by: Vijay Khemka <redacted>
---
 drivers/net/ethernet/faraday/ftgmac100.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c

b/drivers/net/ethernet/faraday/ftgmac100.c
index 030fed65393e..591c9725002b 100644

--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c

@@ -1839,8 +1839,9 @@ static int ftgmac100_probe(struct

platform_device *pdev)
      if (priv->use_ncsi)
              netdev->hw_features |=

NETIF_F_HW_VLAN_CTAG_FILTER;

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-     /* AST2400  doesn't have working HW checksum generation

*/

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-     if (np && (of_device_is_compatible(np, "aspeed,ast2400-
mac")))
+     /* AST2400  and AST2500 doesn't have working HW

checksum

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generation */
+     if (np && (of_device_is_compatible(np, "aspeed,ast2400-
mac") ||
+                of_device_is_compatible(np, "aspeed,ast2500-
mac")))

Do you recall under what circumstances we need to disable

hardware

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checksumming?

Any news on this ? AST2400 has no HW checksum logic in HW, AST2500
should work for IPV4 fine, we should only selectively disable it
for
IPV6.

Can you do an updated patch ?

Cheers,
Ben.