ARM: bcm: rewrite commentary for bcm_kona_do_smc()

}

/*

 * 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)

{