Messages in this thread | | | Date | Wed, 7 Mar 2018 11:04:04 +0100 | From | Robert Richter <> | Subject | Re: [PATCH] watchdog: sbsa: use 32-bit read for WCV |
| |
On 28.02.18 02:52:20, Jayachandran C wrote: > According to SBSA spec v3.1 section 5.3: > All registers are 32 bits in size and should be accessed using > 32-bit reads and writes. If an access size other than 32 bits > is used then the results are IMPLEMENTATION DEFINED. > [...] > The Generic Watchdog is little-endian > > The current code uses readq to read the watchdog compare register > which does a 64-bit access. This fails on ThunderX2 which does not > implement 64-bit access to this register. > > Fix this by using lo_hi_readq() that does two 32-bit reads. > > Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Reviewed-by: Robert Richter <rrichter@cavium.com>
I have looked into the non-atomic use of the register access and it looks sane as the WCV register is only incremented by hardware. There is no concurrent (write) access from the kernel.
-Robert
| |