diff options
| -rw-r--r-- | arch/arm/mach-bcm/bcm_kona_smc.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/arch/arm/mach-bcm/bcm_kona_smc.c b/arch/arm/mach-bcm/bcm_kona_smc.c index cc81c86f24b5..a55a7ecf146a 100644 --- a/arch/arm/mach-bcm/bcm_kona_smc.c +++ b/arch/arm/mach-bcm/bcm_kona_smc.c @@ -77,16 +77,34 @@ int __init bcm_kona_smc_init(void) } /* - * Since interrupts are disabled in the open mode, we must keep - * interrupts disabled in secure mode by setting R5=0x3. If interrupts - * are enabled in open mode, we can set R5=0x0 to allow interrupts in - * secure mode. If we did this, the secure monitor would return back - * control to the open mode to handle the interrupt prior to completing - * the secure service. If this happened, R12 would not be - * SEC_EXIT_NORMAL and we would need to call SMC again after resetting - * R5 (it gets clobbered by the secure monitor) and setting R4 to - * SSAPI_RET_FROM_INT_SERV to indicate that we want the secure monitor - * to finish up the previous uncompleted secure service. + * int bcm_kona_do_smc(u32 service_id, u32 buffer_addr) + * + * Only core 0 can run the secure monitor code. If an "smc" request + * is initiated on a different core it must be redirected to core 0 + * for execution. We rely on the caller to handle this. + * + * Each "smc" request supplies a service id and the address of a + * buffer containing parameters related to the service to be + * performed. A flags value defines the behavior of the level 2 + * cache and interrupt handling while the secure monitor executes. + * + * Parameters to the "smc" request are passed in r4-r6 as follows: + * r4 service id + * r5 flags (SEC_ROM_*) + * r6 physical address of buffer with other parameters + * + * Execution of an "smc" request produces two distinct results. + * + * First, the secure monitor call itself (regardless of the specific + * service request) can succeed, or can produce an error. When an + * "smc" request completes this value is found in r12; it should + * always be SEC_EXIT_NORMAL. + * + * In addition, the particular service performed produces a result. + * The values that should be expected depend on the service. We + * therefore return this value to the caller, so it can handle the + * request result appropriately. This result value is found in r0 + * when the "smc" request completes. */ static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys) { |