From 32aee8415dac5ef71d53cacc28e25a8d312cc47b Mon Sep 17 00:00:00 2001
From: Roberto Vargas <roberto.vargas@arm.com>
Date: Mon, 13 Nov 2017 13:41:58 +0000
Subject: [PATCH] scmi: Optimize bakery locks when HW_ASSISTED_COHERENCY is
enabled
When HW_ASSISTED_COHERENCY is enabled we can use spinlocks
instead of using the more complex and slower bakery algorithm.
Change-Id: I9d791a70050d599241169b9160a67e57d5506564
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
---
bl31/bl31.ld.S | 9 ++++++++-
include/plat/arm/common/plat_arm.h | 9 +++++++++
plat/arm/css/drivers/scmi/scmi.h | 10 +++++++++-
plat/arm/css/drivers/scmi/scmi_common.c | 18 +++++++++++++++---
plat/arm/css/drivers/scp/css_pm_scmi.c | 4 ++--
5 files changed, 43 insertions(+), 7 deletions(-)
diff --git a/bl31/bl31.ld.S b/bl31/bl31.ld.S
index 66cb3f30e..81e7ba3a3 100644
--- a/bl31/bl31.ld.S
+++ b/bl31/bl31.ld.S
@@ -188,8 +188,15 @@ SECTIONS
__PERCPU_BAKERY_LOCK_SIZE__ = ABSOLUTE(. - __BAKERY_LOCK_START__);
. = . + (__PERCPU_BAKERY_LOCK_SIZE__ * (PLATFORM_CORE_COUNT - 1));
__BAKERY_LOCK_END__ = .;
+
+ /*
+ * If BL31 doesn't use any bakery lock then __PERCPU_BAKERY_LOCK_SIZE__
+ * will be zero. For this reason, the only two valid values for
+ * __PERCPU_BAKERY_LOCK_SIZE__ are 0 or the platform defined value
+ * PLAT_PERCPU_BAKERY_LOCK_SIZE.
+ */
#ifdef PLAT_PERCPU_BAKERY_LOCK_SIZE
- ASSERT(__PERCPU_BAKERY_LOCK_SIZE__ == PLAT_PERCPU_BAKERY_LOCK_SIZE,
+ ASSERT((__PERCPU_BAKERY_LOCK_SIZE__ == 0) || (__PERCPU_BAKERY_LOCK_SIZE__ == PLAT_PERCPU_BAKERY_LOCK_SIZE),
"PLAT_PERCPU_BAKERY_LOCK_SIZE does not match bakery lock requirements");
#endif
#endif
diff --git a/include/plat/arm/common/plat_arm.h b/include/plat/arm/common/plat_arm.h
index d543894d7..848f4eea8 100644
--- a/include/plat/arm/common/plat_arm.h
+++ b/include/plat/arm/common/plat_arm.h
@@ -11,6 +11,7 @@
#include <cassert.h>
#include <cpu_data.h>
#include <stdint.h>
+#include <spinlock.h>
#include <tzc_common.h>
#include <utils_def.h>
@@ -80,6 +81,14 @@ void arm_setup_romlib(void);
*/
#define ARM_INSTANTIATE_LOCK static DEFINE_BAKERY_LOCK(arm_lock)
#define ARM_LOCK_GET_INSTANCE (&arm_lock)
+
+#if !HW_ASSISTED_COHERENCY
+#define ARM_SCMI_INSTANTIATE_LOCK DEFINE_BAKERY_LOCK(arm_scmi_lock)
+#else
+#define ARM_SCMI_INSTANTIATE_LOCK spinlock_t arm_scmi_lock
+#endif
+#define ARM_SCMI_LOCK_GET_INSTANCE (&arm_scmi_lock)
+
/*
* These are wrapper macros to the Coherent Memory Bakery Lock API.
*/
diff --git a/plat/arm/css/drivers/scmi/scmi.h b/plat/arm/css/drivers/scmi/scmi.h
index 723fd06ed..71a8c2d02 100644
--- a/plat/arm/css/drivers/scmi/scmi.h
+++ b/plat/arm/css/drivers/scmi/scmi.h
@@ -10,6 +10,7 @@
#include <bakery_lock.h>
#include <stddef.h>
#include <stdint.h>
+#include <spinlock.h>
/* Supported SCMI Protocol Versions */
#define SCMI_AP_CORE_PROTO_VER MAKE_SCMI_VERSION(1, 0)
@@ -116,13 +117,20 @@ typedef struct scmi_channel_plat_info {
void *cookie;
} scmi_channel_plat_info_t;
+
+#if HW_ASSISTED_COHERENCY
+typedef spinlock_t scmi_lock_t;
+#else
+typedef bakery_lock_t scmi_lock_t;
+#endif
+
/*
* Structure to represent an SCMI channel.
*/
typedef struct scmi_channel {
scmi_channel_plat_info_t *info;
/* The lock for channel access */
- bakery_lock_t *lock;
+ scmi_lock_t *lock;
/* Indicate whether the channel is initialized */
int is_initialized;
} scmi_channel_t;
diff --git a/plat/arm/css/drivers/scmi/scmi_common.c b/plat/arm/css/drivers/scmi/scmi_common.c
index 8482d219c..b34178ec3 100644
--- a/plat/arm/css/drivers/scmi/scmi_common.c
+++ b/plat/arm/css/drivers/scmi/scmi_common.c
@@ -10,13 +10,25 @@
#include "scmi.h"
#include "scmi_private.h"
+
+#if HW_ASSISTED_COHERENCY
+#define scmi_lock_init(lock)
+#define scmi_lock_get(lock) spin_lock(lock)
+#define scmi_lock_release(lock) spin_unlock(lock)
+#else
+#define scmi_lock_init(lock) bakery_lock_init(lock)
+#define scmi_lock_get(lock) bakery_lock_get(lock)
+#define scmi_lock_release(lock) bakery_lock_release(lock)
+#endif
+
+
/*
* Private helper function to get exclusive access to SCMI channel.
*/
void scmi_get_channel(scmi_channel_t *ch)
{
assert(ch->lock);
- bakery_lock_get(ch->lock);
+ scmi_lock_get(ch->lock);
/* Make sure any previous command has finished */
assert(SCMI_IS_CHANNEL_FREE(
@@ -68,7 +80,7 @@ void scmi_put_channel(scmi_channel_t *ch)
((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
assert(ch->lock);
- bakery_lock_release(ch->lock);
+ scmi_lock_release(ch->lock);
}
/*
@@ -152,7 +164,7 @@ void *scmi_init(scmi_channel_t *ch)
assert(ch->lock);
- bakery_lock_init(ch->lock);
+ scmi_lock_init(ch->lock);
ch->is_initialized = 1;
diff --git a/plat/arm/css/drivers/scp/css_pm_scmi.c b/plat/arm/css/drivers/scp/css_pm_scmi.c
index d280101d6..9297e9fe4 100644
--- a/plat/arm/css/drivers/scp/css_pm_scmi.c
+++ b/plat/arm/css/drivers/scp/css_pm_scmi.c
@@ -71,7 +71,7 @@ static void *scmi_handle;
/* The SCMI channel global object */
static scmi_channel_t channel;
-ARM_INSTANTIATE_LOCK;
+ARM_SCMI_INSTANTIATE_LOCK;
/*
* Helper function to suspend a CPU power domain and its parent power domains
@@ -331,7 +331,7 @@ static int scmi_ap_core_init(scmi_channel_t *ch)
void __init plat_arm_pwrc_setup(void)
{
channel.info = &plat_css_scmi_plat_info;
- channel.lock = ARM_LOCK_GET_INSTANCE;
+ channel.lock = ARM_SCMI_LOCK_GET_INSTANCE;
scmi_handle = scmi_init(&channel);
if (scmi_handle == NULL) {
ERROR("SCMI Initialization failed\n");
--
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