From 96cc64020c24060774dbea4f4f201d9e81dad503 Mon Sep 17 00:00:00 2001
From: Akash Kollipara <akashkollipara@gmail.com>
Date: Wed, 10 Jul 2024 19:07:22 +0530
Subject: [PATCH] <locks> Added support for bakerylock

- Added sources for bakerylock
- Moved lock realted files to liblocks for adding more lock sources

Issue: #301
---
 src/lib/build.mk                              |  1 +
 src/lib/liblocks/bakerylock.c                 | 44 +++++++++++++++++++
 src/lib/liblocks/build.mk                     | 20 +++++++++
 src/lib/liblocks/include/lock/bakerylock.h    | 16 +++++++
 src/{ => lib/liblocks}/include/lock/lock.h    |  0
 .../liblocks}/include/lock/spinlock.h         |  0
 6 files changed, 81 insertions(+)
 create mode 100644 src/lib/liblocks/bakerylock.c
 create mode 100644 src/lib/liblocks/build.mk
 create mode 100644 src/lib/liblocks/include/lock/bakerylock.h
 rename src/{ => lib/liblocks}/include/lock/lock.h (100%)
 rename src/{ => lib/liblocks}/include/lock/spinlock.h (100%)

diff --git a/src/lib/build.mk b/src/lib/build.mk
index e65f5ba8..f3658326 100644
--- a/src/lib/build.mk
+++ b/src/lib/build.mk
@@ -16,6 +16,7 @@ include $(LIB_DIR)/libc/build.mk
 include $(LIB_DIR)/libresource/build.mk
 include $(LIB_DIR)/libsyslog/build.mk
 include $(LIB_DIR)/libccfs/build.mk
+include $(LIB_DIR)/liblocks/build.mk
 #==================================================
 
 include $(LIB_DIR)/libnmath/build.mk
diff --git a/src/lib/liblocks/bakerylock.c b/src/lib/liblocks/bakerylock.c
new file mode 100644
index 00000000..dfca1a61
--- /dev/null
+++ b/src/lib/liblocks/bakerylock.c
@@ -0,0 +1,44 @@
+
+#include <status.h>
+#include <stdint.h>
+#include <arch.h>
+#include <lock/bakerylock.h>
+
+void bakerylock_acquire(bakerylock_t *key)
+{
+	unsigned int tid = arch_core_index();
+	key->protect[tid] = 1;
+	arch_dmb();
+
+	unsigned int i, n_cust, n_max = 0;
+	for(i = 0; i < N_CORES; i++)
+	{
+		n_cust = key->thread_count[i];
+		n_max = n_cust > n_max ? n_cust : n_max;
+	}
+
+	key->thread_count[tid] = n_max + 1;
+
+	arch_dmb();
+	key->protect[tid] = 0;
+	arch_dmb();
+
+	for(i = 0; i < N_CORES; i++)
+	{
+		while(key->protect[i]);
+		arch_dmb();
+
+		while(key->thread_count[i] && (
+		      (key->thread_count[i] < key->thread_count[tid]) ||
+		       ((key->thread_count[i] == key->thread_count[tid]) &&
+			(i < tid))));
+	}
+}
+
+void bakerylock_release(bakerylock_t *key)
+{
+	unsigned int tid = arch_core_index();
+	arch_dmb();
+	key->thread_count[tid] = 0;
+}
+
diff --git a/src/lib/liblocks/build.mk b/src/lib/liblocks/build.mk
new file mode 100644
index 00000000..e2c21674
--- /dev/null
+++ b/src/lib/liblocks/build.mk
@@ -0,0 +1,20 @@
+#
+# CYANCORE LICENSE
+# Copyrights (C) 2024, Cyancore Team
+#
+# File Name		: build.mk
+# Description		: This file accumulates sources of locks
+# Primary Author	: Akash Kollipara [akashkollipara@gmail.com]
+# Organisation		: Cyancore Core-Team
+#
+
+LIBLOCKS_PATH	:= $(GET_PATH)
+LIB_OBJS	:=
+
+LIB		+= liblocks.a
+LIB_INCLUDE	+= $(LIBLOCKS_PATH)/include
+DEP_LIBS_ARG	+= -llocks
+
+
+DIR		:= $(LIBLOCKS_PATH)
+include mk/lib.mk
diff --git a/src/lib/liblocks/include/lock/bakerylock.h b/src/lib/liblocks/include/lock/bakerylock.h
new file mode 100644
index 00000000..b22d1bd3
--- /dev/null
+++ b/src/lib/liblocks/include/lock/bakerylock.h
@@ -0,0 +1,16 @@
+
+#pragma once
+#define _BAKERYLOCK_H_
+
+#include <stdbool.h>
+
+#pragma pack(1)
+typedef struct
+{
+	volatile uint8_t thread_count[N_CORES];
+	volatile bool protect[N_CORES];
+} bakerylock_t;
+#pragma pack()
+
+extern void bakerylock_acquire(bakerylock_t *);
+extern void bakerylock_release(bakerylock_t *);
diff --git a/src/include/lock/lock.h b/src/lib/liblocks/include/lock/lock.h
similarity index 100%
rename from src/include/lock/lock.h
rename to src/lib/liblocks/include/lock/lock.h
diff --git a/src/include/lock/spinlock.h b/src/lib/liblocks/include/lock/spinlock.h
similarity index 100%
rename from src/include/lock/spinlock.h
rename to src/lib/liblocks/include/lock/spinlock.h