The ARCH_FEATURES function ID is a 32-bit SMC call, which returns
a 32-bit result per the SMCCC spec. Current code is doing a 64-bit
comparison against -1 (SMCCC_RET_NOT_SUPPORTED) to detect that the
feature is unimplemented. That check doesn't work in a Hyper-V VM,
where the upper 32-bits are zero as allowed by the spec.
Cast the result as an 'int' so the comparison works. The change also
makes the code consistent with other similar checks in this file.
Fixes: 821b67fa46 ("firmware: smccc: Add ARCH_SOC_ID support")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
SMCCC v1.2 adds a new optional function SMCCC_ARCH_SOC_ID to obtain a
SiP defined SoC identification value. Add support for the same.
Also using the SoC bus infrastructure, let us expose the platform
specific SoC atrributes under sysfs.
There are various ways in which it can be represented in shortened form
for efficiency and ease of parsing for userspace. The chosen form is
described in the ABI document.
Link: https://lore.kernel.org/r/20200625095939.50861-1-sudeep.holla@arm.com
Cc: Etienne Carriere <etienne.carriere@st.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Michael Kelley