From 742cabf15bf0ade06f26735f73082f39cacbb816 Mon Sep 17 00:00:00 2001
From: Anna Lyons <Anna.Lyons@data61.csiro.au>
Date: Thu, 23 May 2019 14:22:20 +1000
Subject: [PATCH] mcs: provide tickless api for arm timers
This does not implement the timers for any platforms, but
provides the generic arm arch, and aarch32/aarch64 infrastructure for
tickless timer drivers.
---
.cmake-format.yaml | 4 ++
config.cmake | 3 ++
configs/seL4Config.cmake | 15 ++++++-
include/arch/arm/arch/32/mode/machine/timer.h | 28 ++++++++++++
include/arch/arm/arch/64/mode/machine/timer.h | 23 ++++++++++
include/arch/arm/arch/machine/timer.h | 43 +++++++++++++++++++
src/arch/arm/kernel/boot.c | 4 ++
src/arch/arm/platform_gen.h.in | 14 ++++++
8 files changed, 133 insertions(+), 1 deletion(-)
diff --git a/.cmake-format.yaml b/.cmake-format.yaml
index 77f34a9eb..eb93d3998 100644
--- a/.cmake-format.yaml
+++ b/.cmake-format.yaml
@@ -53,3 +53,7 @@ additional_commands:
NUM_PPI: '*'
INTERRUPT_CONTROLLER: '*'
TIMER: '*'
+ KERNEL_WCET: '*'
+ CLK_MAGIC: '*'
+ CLK_SHIFT: '*'
+ TIMER_PRECISION: '*'
diff --git a/config.cmake b/config.cmake
index 4f825a6f9..7fefcf0a1 100644
--- a/config.cmake
+++ b/config.cmake
@@ -84,6 +84,9 @@ if(DEFINED CONFIGURE_MAX_IRQ)
math(EXPR BITS "${BITS} + 1")
endif()
set(CONFIGURE_IRQ_SLOT_BITS "${BITS}" CACHE INTERNAL "")
+ if(NOT DEFINED ${CONFIGURE_TIMER_PRECISION})
+ set(CONFIGURE_TIMER_PRECISION "0")
+ endif()
configure_file(
src/arch/${KernelArch}/platform_gen.h.in
${CMAKE_CURRENT_BINARY_DIR}/gen_headers/plat/platform_gen.h @ONLY
diff --git a/configs/seL4Config.cmake b/configs/seL4Config.cmake
index 72ea4ed3d..8f5339fe5 100644
--- a/configs/seL4Config.cmake
+++ b/configs/seL4Config.cmake
@@ -102,13 +102,22 @@ unset(CONFIGURE_NUM_PPI CACHE)
unset(CONFIGURE_INTERRUPT_CONTROLLER CACHE)
unset(CONFIGURE_TIMER CACHE)
unset(CONFIGURE_SMMU CACHE)
+unset(CONFIGURE_CLK_SHIFT CACHE)
+unset(CONFIGURE_CLK_MAGIC CACHE)
+unset(CONFIGURE_KERNEL_WCET CACHE)
+unset(CONFIGURE_TIMER_PRECISION CACHE)
+# CLK_SHIFT and CLK_MAGIC are generated from tools/reciprocal.py
+# based on the TIMER_CLK_HZ to simulate division.
+# This could be moved to a cmake function
+# in future to build the values on the first build. Note the calculation
+# can take a long time though.
function(declare_default_headers)
cmake_parse_arguments(
PARSE_ARGV
0
CONFIGURE
""
- "TIMER_FREQUENCY;MAX_IRQ;NUM_PPI;PLIC_MAX_NUM_INT;INTERRUPT_CONTROLLER;TIMER;SMMU"
+ "TIMER_FREQUENCY;MAX_IRQ;NUM_PPI;PLIC_MAX_NUM_INT;INTERRUPT_CONTROLLER;TIMER;SMMU;CLK_SHIFT;CLK_MAGIC;KERNEL_WCET;TIMER_PRECISION"
""
)
set(CONFIGURE_TIMER_FREQUENCY "${CONFIGURE_TIMER_FREQUENCY}" CACHE INTERNAL "")
@@ -118,6 +127,10 @@ function(declare_default_headers)
set(CONFIGURE_INTERRUPT_CONTROLLER "${CONFIGURE_INTERRUPT_CONTROLLER}" CACHE INTERNAL "")
set(CONFIGURE_TIMER "${CONFIGURE_TIMER}" CACHE INTERNAL "")
set(CONFIGURE_SMMU "${CONFIGURE_SMMU}" CACHE INTERNAL "")
+ set(CONFIGURE_CLK_SHIFT "${CONFIGURE_CLK_SHIFT}" CACHE INTERNAL "")
+ set(CONFIGURE_CLK_MAGIC "${CONFIGURE_CLK_MAGIC}" CACHE INTERNAL "")
+ set(CONFIGURE_KERNEL_WCET "${CONFIGURE_KERNEL_WCET}" CACHE INTERNAL "")
+ set(CONFIGURE_TIMER_PRECISION "${CONFIGURE_TIMER_PRECISION}" CACHE INTERNAL "")
endfunction()
# For all of the common variables we set a default value here if they haven't
diff --git a/include/arch/arm/arch/32/mode/machine/timer.h b/include/arch/arm/arch/32/mode/machine/timer.h
index f5d506311..c75b6a320 100644
--- a/include/arch/arm/arch/32/mode/machine/timer.h
+++ b/include/arch/arm/arch/32/mode/machine/timer.h
@@ -30,4 +30,32 @@
#define CNT_CVAL CNTV_CVAL
#endif
+#ifdef CONFIG_KERNEL_MCS
+#include <util.h>
+
+/* timer function definitions that work for all 32bit arm platforms that provide
+ * CLK_MAGIC and TIMER_CLOCK_MHZ -- these definitions might need to move
+ * if we come across an arm platform that does not suit this model */
+
+/* get the max value ticksToUs can be passed without overflowing */
+static inline CONST ticks_t getMaxTicksToUs(void)
+{
+#if USE_KHZ
+ return UINT64_MAX / KHZ_IN_MHZ / CLK_MAGIC;
+#else
+ return UINT64_MAX / CLK_MAGIC;
+#endif
+}
+
+static inline CONST time_t ticksToUs(ticks_t ticks)
+{
+ /* simulate 64bit division using multiplication by reciprocal */
+#if USE_KHZ
+ return (ticks * KHZ_IN_MHZ) * CLK_MAGIC >> CLK_SHIFT;
+#else
+ return (ticks * CLK_MAGIC) >> CLK_SHIFT;
+#endif
+}
+#endif /* CONFIG_KERNEL_MCS */
+
#endif /* __ARCH_MODE_MACHINE_TIMER_H_ */
diff --git a/include/arch/arm/arch/64/mode/machine/timer.h b/include/arch/arm/arch/64/mode/machine/timer.h
index 2444f8b3b..519414965 100644
--- a/include/arch/arm/arch/64/mode/machine/timer.h
+++ b/include/arch/arm/arch/64/mode/machine/timer.h
@@ -26,4 +26,27 @@
#endif
#define CNTFRQ "cntfrq_el0"
+#ifdef CONFIG_KERNEL_MCS
+#include <stdint.h>
+#include <util.h>
+
+/* timer function definitions that work for all 64 bit arm platforms */
+static inline CONST ticks_t getMaxTicksToUs(void)
+{
+#if USE_KHZ
+ return UINT64_MAX / TIMER_CLOCK_KHZ;
+#else
+ return UINT64_MAX;
+#endif
+}
+
+static inline CONST time_t ticksToUs(ticks_t ticks)
+{
+#if USE_KHZ
+ return (ticks * TIMER_CLOCK_KHZ) / TIMER_CLOCK_MHZ;
+#else
+ return ticks / TIMER_CLOCK_MHZ;
+#endif
+}
+#endif /* CONFIG_KERNEL_MCS */
#endif /* __ARCH_MODE_MACHINE_TIMER_H_ */
diff --git a/include/arch/arm/arch/machine/timer.h b/include/arch/arm/arch/machine/timer.h
index 8bb04c8e8..ab546f9af 100644
--- a/include/arch/arm/arch/machine/timer.h
+++ b/include/arch/arm/arch/machine/timer.h
@@ -15,6 +15,48 @@
#include <config.h>
#include <stdint.h>
+
+#ifdef CONFIG_KERNEL_MCS
+#include <types.h>
+#include <util.h>
+#include <mode/util.h>
+
+#define USE_KHZ (TIMER_CLOCK_HZ % HZ_IN_MHZ > 0)
+#define TIMER_CLOCK_KHZ (TIMER_CLOCK_HZ / HZ_IN_KHZ)
+#define TIMER_CLOCK_MHZ (TIMER_CLOCK_HZ / HZ_IN_MHZ)
+
+#include <plat/platform_gen.h>
+#include <mode/machine/timer.h>
+
+void initTimer(void);
+
+/* get the max value usToTicks can be passed without overflowing */
+static inline CONST time_t getMaxUsToTicks(void)
+{
+#if USE_KHZ
+ return UINT64_MAX / TIMER_CLOCK_KHZ;
+#else
+ return UINT64_MAX / TIMER_CLOCK_MHZ;
+#endif
+}
+
+static inline CONST ticks_t usToTicks(time_t us)
+{
+#if USE_KHZ
+ /* reciprocal division overflows too quickly for dividing by KHZ_IN_MHZ.
+ * This operation isn't used frequently or on many platforms, so use manual
+ * division here */
+ return div64(us * TIMER_CLOCK_KHZ, KHZ_IN_MHZ);
+#else
+ return us * TIMER_CLOCK_MHZ;
+#endif
+}
+
+static inline CONST ticks_t getTimerPrecision(void)
+{
+ return usToTicks(TIMER_PRECISION);
+}
+#else /* CONFIG_KERNEL_MCS */
#include <mode/machine/timer.h>
#include <plat/machine/hardware.h>
@@ -29,5 +71,6 @@
#endif
void initTimer(void);
+#endif
#endif /* __ARCH_MACHINE_TIMER_H_ */
diff --git a/src/arch/arm/kernel/boot.c b/src/arch/arm/kernel/boot.c
index 02850890a..058f45c5d 100644
--- a/src/arch/arm/kernel/boot.c
+++ b/src/arch/arm/kernel/boot.c
@@ -487,6 +487,10 @@ static BOOT_CODE bool_t try_init_kernel(
}
write_it_asid_pool(it_ap_cap, it_pd_cap);
+#ifdef CONFIG_KERNEL_MCS
+ NODE_STATE(ksCurTime) = getCurrentTime();
+#endif
+
/* create the idle thread */
if (!create_idle_thread()) {
return false;
diff --git a/src/arch/arm/platform_gen.h.in b/src/arch/arm/platform_gen.h.in
index 6cc74f29c..4a1442e12 100644
--- a/src/arch/arm/platform_gen.h.in
+++ b/src/arch/arm/platform_gen.h.in
@@ -13,7 +13,13 @@
#ifndef __ARM_PLAT_H
#define __ARM_PLAT_H
+#include <autoconf.h>
+
#define TIMER_CLOCK_HZ @CONFIGURE_TIMER_FREQUENCY@
+#define CLK_MAGIC @CONFIGURE_CLK_MAGIC@
+#define CLK_SHIFT @CONFIGURE_CLK_SHIFT@
+#define TIMER_PRECISION @CONFIGURE_TIMER_PRECISION@
+
enum IRQConstants {
maxIRQ = @CONFIGURE_MAX_IRQ@
} platform_interrupt_t;
@@ -27,4 +33,12 @@ enum IRQConstants {
#if (defined(CONFIGURE_SMMU) && defined(CONFIG_ARM_SMMU))
#include CONFIGURE_SMMU
#endif
+
+#ifdef CONFIG_KERNEL_MCS
+static inline CONST time_t getKernelWcetUs(void)
+{
+ return @CONFIGURE_KERNEL_WCET@;
+}
+#endif
+
#endif /* !__ARM_PLAT_H */
--
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