diff options
| -rw-r--r-- | include/lib/bakery_lock.h | 28 | ||||
| -rw-r--r-- | lib/locks/bakery/bakery_lock_coherent.c | 26 | ||||
| -rw-r--r-- | lib/locks/bakery/bakery_lock_normal.c | 22 |
3 files changed, 41 insertions, 35 deletions
diff --git a/include/lib/bakery_lock.h b/include/lib/bakery_lock.h index 9736f850..eaefecd9 100644 --- a/include/lib/bakery_lock.h +++ b/include/lib/bakery_lock.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: @@ -38,12 +38,34 @@ #ifndef __ASSEMBLY__ #include <stdint.h> +/***************************************************************************** + * Internal helper macros used by the bakery lock implementation. + ****************************************************************************/ +/* Convert a ticket to priority */ +#define PRIORITY(t, pos) (((t) << 8) | (pos)) + +#define CHOOSING_TICKET 0x1 +#define CHOSEN_TICKET 0x0 + +#define bakery_is_choosing(info) (info & 0x1) +#define bakery_ticket_number(info) ((info >> 1) & 0x7FFF) +#define make_bakery_data(choosing, number) \ + (((choosing & 0x1) | (number << 1)) & 0xFFFF) + +/***************************************************************************** + * External bakery lock interface. + ****************************************************************************/ #if USE_COHERENT_MEM typedef struct bakery_lock { int owner; - volatile char entering[BAKERY_LOCK_MAX_CPUS]; - volatile unsigned number[BAKERY_LOCK_MAX_CPUS]; + /* + * The lock_data is a bit-field of 2 members: + * Bit[0] : choosing. This field is set when the CPU is + * choosing its bakery number. + * Bits[1 - 15] : number. This is the bakery number allocated. + */ + volatile uint16_t lock_data[BAKERY_LOCK_MAX_CPUS]; } bakery_lock_t; #define NO_OWNER (-1) diff --git a/lib/locks/bakery/bakery_lock_coherent.c b/lib/locks/bakery/bakery_lock_coherent.c index 5d538ce2..02d31d64 100644 --- a/lib/locks/bakery/bakery_lock_coherent.c +++ b/lib/locks/bakery/bakery_lock_coherent.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: @@ -63,10 +63,6 @@ assert(entry < BAKERY_LOCK_MAX_CPUS); \ } while (0) -/* Convert a ticket to priority */ -#define PRIORITY(t, pos) (((t) << 8) | (pos)) - - /* Initialize Bakery Lock to reset ownership and all ticket values */ void bakery_lock_init(bakery_lock_t *bakery) { @@ -95,9 +91,9 @@ static unsigned int bakery_get_ticket(bakery_lock_t *bakery, unsigned int me) * value, not the ticket value alone. */ my_ticket = 0; - bakery->entering[me] = 1; + bakery->lock_data[me] = make_bakery_data(CHOOSING_TICKET, my_ticket); for (they = 0; they < BAKERY_LOCK_MAX_CPUS; they++) { - their_ticket = bakery->number[they]; + their_ticket = bakery_ticket_number(bakery->lock_data[they]); if (their_ticket > my_ticket) my_ticket = their_ticket; } @@ -107,8 +103,7 @@ static unsigned int bakery_get_ticket(bakery_lock_t *bakery, unsigned int me) * finish calculating our ticket value that we're done */ ++my_ticket; - bakery->number[me] = my_ticket; - bakery->entering[me] = 0; + bakery->lock_data[me] = make_bakery_data(CHOSEN_TICKET, my_ticket); return my_ticket; } @@ -129,6 +124,7 @@ void bakery_lock_get(bakery_lock_t *bakery) { unsigned int they, me; unsigned int my_ticket, my_prio, their_ticket; + unsigned int their_bakery_data; me = platform_get_core_pos(read_mpidr_el1()); @@ -150,14 +146,15 @@ void bakery_lock_get(bakery_lock_t *bakery) continue; /* Wait for the contender to get their ticket */ - while (bakery->entering[they]) - ; + do { + their_bakery_data = bakery->lock_data[they]; + } while (bakery_is_choosing(their_bakery_data)); /* * If the other party is a contender, they'll have non-zero * (valid) ticket value. If they do, compare priorities */ - their_ticket = bakery->number[they]; + their_ticket = bakery_ticket_number(their_bakery_data); if (their_ticket && (PRIORITY(their_ticket, they) < my_prio)) { /* * They have higher priority (lower value). Wait for @@ -167,7 +164,8 @@ void bakery_lock_get(bakery_lock_t *bakery) */ do { wfe(); - } while (their_ticket == bakery->number[they]); + } while (their_ticket == + bakery_ticket_number(bakery->lock_data[they])); } } @@ -189,7 +187,7 @@ void bakery_lock_release(bakery_lock_t *bakery) * waiting contenders */ bakery->owner = NO_OWNER; - bakery->number[me] = 0; + bakery->lock_data[me] = 0; dsb(); sev(); } diff --git a/lib/locks/bakery/bakery_lock_normal.c b/lib/locks/bakery/bakery_lock_normal.c index a325fd4f..4503ae09 100644 --- a/lib/locks/bakery/bakery_lock_normal.c +++ b/lib/locks/bakery/bakery_lock_normal.c @@ -56,17 +56,6 @@ * accesses regardless of status of address translation. */ -/* Convert a ticket to priority */ -#define PRIORITY(t, pos) (((t) << 8) | (pos)) - -#define CHOOSING_TICKET 0x1 -#define CHOOSING_DONE 0x0 - -#define bakery_is_choosing(info) (info & 0x1) -#define bakery_ticket_number(info) ((info >> 1) & 0x7FFF) -#define make_bakery_data(choosing, number) \ - (((choosing & 0x1) | (number << 1)) & 0xFFFF) - /* This macro assumes that the bakery_info array is located at the offset specified */ #define get_my_bakery_info(offset, id) \ (((bakery_info_t *) (((uint8_t *)_cpu_data()) + offset)) + id) @@ -138,7 +127,7 @@ static unsigned int bakery_get_ticket(int id, unsigned int offset, * finish calculating our ticket value that we're done */ ++my_ticket; - my_bakery_info->lock_data = make_bakery_data(CHOOSING_DONE, my_ticket); + my_bakery_info->lock_data = make_bakery_data(CHOSEN_TICKET, my_ticket); write_cache_op(my_bakery_info, is_cached); @@ -150,7 +139,7 @@ void bakery_lock_get(unsigned int id, unsigned int offset) unsigned int they, me, is_cached; unsigned int my_ticket, my_prio, their_ticket; bakery_info_t *their_bakery_info; - uint16_t their_bakery_data; + unsigned int their_bakery_data; me = platform_get_core_pos(read_mpidr_el1()); @@ -174,15 +163,12 @@ void bakery_lock_get(unsigned int id, unsigned int offset) */ their_bakery_info = get_bakery_info_by_index(offset, id, they); assert(their_bakery_info); - read_cache_op(their_bakery_info, is_cached); - - their_bakery_data = their_bakery_info->lock_data; /* Wait for the contender to get their ticket */ - while (bakery_is_choosing(their_bakery_data)) { + do { read_cache_op(their_bakery_info, is_cached); their_bakery_data = their_bakery_info->lock_data; - } + } while (bakery_is_choosing(their_bakery_data)); /* * If the other party is a contender, they'll have non-zero |