ARM: at91: sama5d2: Wrap cpu detection to fix macb driver
authorAlexander Dahl <ada@thorsis.com>
Fri, 22 Mar 2019 13:25:54 +0000 (14:25 +0100)
committerEugen Hristev <eugen.hristev@microchip.com>
Tue, 9 Apr 2019 06:28:50 +0000 (09:28 +0300)
commit7dee1848d7e72e23e7c0a45e6342869d81fe1dec
tree9cb0e9e53715b5cfcf4a90a4e5d24c0167a48327
parent3c99166441bf3ea325af2da83cfe65430b49c066
ARM: at91: sama5d2: Wrap cpu detection to fix macb driver

When introducing the SAMA5D27 SoCs, the SAMA5D2 series got an additional
chip id. The check if the cpu is sama5d2 was changed from a preprocessor
definition (inlining a call to 'get_chip_id()') to a C function,
probably to not call get_chip_id twice?

That however broke a check in the macb ethernet driver. That driver is
more generic and also used for other platforms. I suppose this solution
was implemented to use it in 'gem_is_gigabit_capable()', without having
to stricly depend on the at91 platform:

#ifndef cpu_is_sama5d2
#define cpu_is_sama5d2() 0
#endif

That only works as long as cpu_is_sama5d2 is a preprocessor definition.
(The same is still true for sama5d4 by the way.) So this is a straight
forward fix for the workaround.

The not working check on the SAMA5D2 CPU lead to an issue on a custom
board with a LAN8720A ethernet phy connected to the SoC:

=> dhcp
ethernet@f8008000: PHY present at 1
ethernet@f8008000: Starting autonegotiation...
ethernet@f8008000: Autonegotiation complete
ethernet@f8008000: link up, 1000Mbps full-duplex (lpa: 0xffff)
BOOTP broadcast 1
BOOTP broadcast 2
BOOTP broadcast 3
BOOTP broadcast 4
BOOTP broadcast 5
BOOTP broadcast 6
BOOTP broadcast 7
BOOTP broadcast 8
BOOTP broadcast 9
BOOTP broadcast 10
BOOTP broadcast 11
BOOTP broadcast 12
BOOTP broadcast 13
BOOTP broadcast 14
BOOTP broadcast 15
BOOTP broadcast 16
BOOTP broadcast 17

Retry time exceeded; starting again

Notice the wrong reported link speed, although both SoC and phy only
support 100 MBit/s!

The real issue on reliably detecting the features of that cadence
ethernet mac IP block, is probably more complicated, though.

Fixes: 245cbc583d ("ARM: at91: Get the Chip ID of SAMA5D2 SiP")
Signed-off-by: Alexander Dahl <ada@thorsis.com>
arch/arm/mach-at91/armv7/sama5d2_devices.c
arch/arm/mach-at91/include/mach/sama5d2.h