From: Lorenzo Pieralisi Date: Fri, 23 Oct 2015 14:46:50 +0000 (+0100) Subject: drivers: psci: make PSCI 1.0 functions initialization version dependent X-Git-Tag: v4.4-rc1~52^2~5^2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=79b04beb1e0ac7754e667f0aa47b57a197dc343a;p=linux.git drivers: psci: make PSCI 1.0 functions initialization version dependent The PSCI specifications [1] and the SMC calling convention mandate that unimplemented functions ids must return NOT_SUPPORTED (0xffffffff) if a function id is called but it is not implemented. Consequently, PSCI 1.0 function ids that require the 1.0 PSCI_FEATURES call to be initialized: CPU_SUSPEND (psci_init_cpu_suspend()) SYSTEM_SUSPEND (psci_init_system_suspend()) call the PSCI_FEATURES function id independently of the detected PSCI firmware version, since, if the PSCI_FEATURES function id is not implemented, it must return NOT_SUPPORTED according to the PSCI specifications, causing the initialization functions to fail as expected. Some existing PSCI implementations (ie Qemu PSCI emulation), do not comply with the SMC calling convention and fail if function ids that are not implemented are called from the OS, causing boot failures. To solve this issue, this patch adds code that checks the PSCI firmware version before calling PSCI 1.0 initialization functions so that the OS makes sure that it is calling 1.0 functions only if the firmware version detected is 1.0 or greater, therefore avoiding PSCI calls that are bound to fail and might cause system boot failures owing to non-compliant PSCI firmware implementations. [1] http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf Signed-off-by: Lorenzo Pieralisi Cc: Arnd Bergmann Cc: Mark Rutland Tested-by: Kevin Hilman Acked-by: Sudeep Holla Signed-off-by: Olof Johansson --- diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c index 492db42c4e08..d24f35d74b27 100644 --- a/drivers/firmware/psci.c +++ b/drivers/firmware/psci.c @@ -347,9 +347,10 @@ static int __init psci_probe(void) psci_init_migrate(); - psci_init_cpu_suspend(); - - psci_init_system_suspend(); + if (PSCI_VERSION_MAJOR(ver) >= 1) { + psci_init_cpu_suspend(); + psci_init_system_suspend(); + } return 0; }