net: ethernet: ti: cpsw: add check for in-band mode setting with RGMII PHY interface
authorSZ Lin (林上智) <sz.lin@moxa.com>
Thu, 15 Mar 2018 16:56:01 +0000 (00:56 +0800)
committerDavid S. Miller <davem@davemloft.net>
Sat, 17 Mar 2018 23:49:34 +0000 (19:49 -0400)
commitf9db50691db4a7d860fce985f080bb3fc23a7ede
tree082364c3645bf37b66ffb4a7f7a9258dd75a5032
parentd61d263c8d82db7c4404a29ebc29674b1c0c05c9
net: ethernet: ti: cpsw: add check for in-band mode setting with RGMII PHY interface

According to AM335x TRM[1] 14.3.6.2, AM437x TRM[2] 15.3.6.2 and
DRA7 TRM[3] 24.11.4.8.7.3.3, in-band mode in EXT_EN(bit18) register is only
available when PHY is configured in RGMII mode with 10Mbps speed. It will
cause some networking issues without RGMII mode, such as carrier sense
errors and low throughput. TI also mentioned this issue in their forum[4].

This patch adds the check mechanism for PHY interface with RGMII interface
type, the in-band mode can only be set in RGMII mode with 10Mbps speed.

References:
[1]: https://www.ti.com/lit/ug/spruh73p/spruh73p.pdf
[2]: http://www.ti.com/lit/ug/spruhl7h/spruhl7h.pdf
[3]: http://www.ti.com/lit/ug/spruic2b/spruic2b.pdf
[4]: https://e2e.ti.com/support/arm/sitara_arm/f/791/p/640765/2392155

Suggested-by: Holsety Chen (陳憲輝) <Holsety.Chen@moxa.com>
Signed-off-by: SZ Lin (林上智) <sz.lin@moxa.com>
Signed-off-by: Schuyler Patton <spatton@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/ti/cpsw.c