[PATCH] bsps/aarch64/raspberrypi: Add system timer support

Ning Yang yangn0 at qq.com
Wed Apr 10 14:23:47 UTC 2024


The clock from the ARM timer is derived from the system clock. This clock can change dynamically e.g. if the system goes into reduced power or in low power mode. Thus the clock speed adapts to the overall system performance capabilities. For accurate timing it is recommended to use the system timers.

if BSP_CLOCK_USE_SYSTEMTIMER = 1, use the System Timer, otherwise use the ARM Timer.
---
 .../aarch64/raspberrypi/include/bsp/bcm2711.h | 28 ++++++++++++
 .../raspberrypi/include/bsp/raspberrypi.h     | 43 +++++++++++++++++++
 bsps/aarch64/raspberrypi/start/bspstartmmu.c  |  8 ++++
 spec/build/bsps/aarch64/raspberrypi/bsp4b.yml |  1 +
 spec/build/bsps/aarch64/raspberrypi/obj.yml   |  3 ++
 .../bsps/aarch64/raspberrypi/objclock.yml     |  4 +-
 .../aarch64/raspberrypi/objsystemtimer.yml    | 22 ++++++++++
 .../aarch64/raspberrypi/optsystemtimer.yml    | 24 +++++++++++
 8 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h
 create mode 100644 spec/build/bsps/aarch64/raspberrypi/objsystemtimer.yml
 create mode 100644 spec/build/bsps/aarch64/raspberrypi/optsystemtimer.yml

diff --git a/bsps/aarch64/raspberrypi/include/bsp/bcm2711.h b/bsps/aarch64/raspberrypi/include/bsp/bcm2711.h
index e6c77fa025..8707582ebb 100644
--- a/bsps/aarch64/raspberrypi/include/bsp/bcm2711.h
+++ b/bsps/aarch64/raspberrypi/include/bsp/bcm2711.h
@@ -11,6 +11,7 @@
 /*
  * Copyright (C) 2022 Mohd Noor Aman
  * Copyright (C) 2023 Utkarsh Verma
+ * Copyright (C) 2024 Ning Yang
  *
  *
  * Redistribution and use in source and binary forms, with or without
@@ -91,6 +92,27 @@
 #define BCM2711_UART5_BASE (BCM2711_PL011_BASE + 0xa00)
 #define BCM2711_UART5_SIZE BCM2711_PL011_DEVICE_SIZE
 
+/* System Timer */
+/**
+ * NOTE: The GPU uses Compare registers 0 and 2 for
+ *       it's own RTOS. 1 and 3 are available for use in
+ *       RTEMS.
+ */
+#define BCM2835_GPU_TIMER_BASE    (BCM2711_PERIPHERAL_BASE + 0x2000000+ 0x3000)
+#define BCM2835_GPU_TIMER_SIZE    0x1C
+
+#define BCM2835_GPU_TIMER_CS      (BCM2835_GPU_TIMER_BASE + 0x00)
+#define BCM2835_GPU_TIMER_CS_M0   0x00000001
+#define BCM2835_GPU_TIMER_CS_M1   0x00000002
+#define BCM2835_GPU_TIMER_CS_M2   0x00000004
+#define BCM2835_GPU_TIMER_CS_M3   0x00000008
+#define BCM2835_GPU_TIMER_CLO     (BCM2835_GPU_TIMER_BASE + 0x04)
+#define BCM2835_GPU_TIMER_CHI     (BCM2835_GPU_TIMER_BASE + 0x08)
+#define BCM2835_GPU_TIMER_C0      (BCM2835_GPU_TIMER_BASE + 0x0C)
+#define BCM2835_GPU_TIMER_C1      (BCM2835_GPU_TIMER_BASE + 0x10)
+#define BCM2835_GPU_TIMER_C2      (BCM2835_GPU_TIMER_BASE + 0x14)
+#define BCM2835_GPU_TIMER_C3      (BCM2835_GPU_TIMER_BASE + 0x18)
+
 /* ARM Local */
 #define BCM2711_ARM_LOCAL_BASE 0xff800000LL
 #define BCM2711_ARM_LOCAL_SIZE 0x800000
@@ -114,4 +136,10 @@
 #define BCM2711_IRQ_AUX                (BCM2711_IRQ_VC_PERIPHERAL_BASE + 29)
 #define BCM2711_IRQ_PL011_UART         (BCM2711_IRQ_VC_PERIPHERAL_BASE + 57)
 
+/* Interrupt Vectors: System Timer */
+#define BCM2835_IRQ_ID_GPU_TIMER_M0    (BCM2711_IRQ_VC_PERIPHERAL_BASE + 0)
+#define BCM2835_IRQ_ID_GPU_TIMER_M1    (BCM2711_IRQ_VC_PERIPHERAL_BASE + 1)
+#define BCM2835_IRQ_ID_GPU_TIMER_M2    (BCM2711_IRQ_VC_PERIPHERAL_BASE + 2)
+#define BCM2835_IRQ_ID_GPU_TIMER_M3    (BCM2711_IRQ_VC_PERIPHERAL_BASE + 3)
+
 #endif /* LIBBSP_AARCH64_RASPBERRYPI_BSP_BCM2711_H */
diff --git a/bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h b/bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h
new file mode 100644
index 0000000000..2e1c673bfb
--- /dev/null
+++ b/bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsAArch64RaspberryPi
+ *
+ * @brief RaspberryPi shared Register Definitions
+ */
+
+/*
+ * Copyright (C) 2024 Ning Yang
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LIBBSP_AARCH64_RASPBERRYPI_RASPBERRYPI_H
+#define LIBBSP_AARCH64_RASPBERRYPI_RASPBERRYPI_H
+
+#include <bsp/bcm2711.h>
+#define BCM2835_REG(addr)          *(volatile uint32_t*)(addr)
+
+#endif /* LIBBSP_AARCH64_RASPBERRYPI_RASPBERRYPI_H */
\ No newline at end of file
diff --git a/bsps/aarch64/raspberrypi/start/bspstartmmu.c b/bsps/aarch64/raspberrypi/start/bspstartmmu.c
index d5d1381357..eb59b8f31b 100644
--- a/bsps/aarch64/raspberrypi/start/bspstartmmu.c
+++ b/bsps/aarch64/raspberrypi/start/bspstartmmu.c
@@ -11,6 +11,7 @@
 /*
  * Copyright (C) 2022 Mohd Noor Aman
  * Copyright (C) 2023 Utkarsh Verma
+ * Copyright (C) 2024 Ning Yang
  *
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,6 +46,7 @@
 #include "bsp/irq.h"
 #include "bsp/mbox.h"
 #include "bsp/rpi-gpio.h"
+#include "bsp/bcm2711.h"
 
 #define CONSOLE_DEVICE_MMU_CONFIG(_port, _file, base, size, ...) \
     {.begin = base, .end = base + size, .flags = AARCH64_MMU_DEVICE},
@@ -52,6 +54,12 @@
 BSP_START_DATA_SECTION static const aarch64_mmu_config_entry
     bsp_mmu_config_table[] = {
         AARCH64_MMU_DEFAULT_SECTIONS,
+        {
+            /* System Timer */
+            .begin = BCM2835_GPU_TIMER_BASE,
+            .end   = BCM2835_GPU_TIMER_BASE + BCM2835_GPU_TIMER_SIZE,
+            .flags = AARCH64_MMU_DEVICE,
+        },
 
         /* clang-format off */
         CONSOLE_DEVICES(CONSOLE_DEVICE_MMU_CONFIG)
diff --git a/spec/build/bsps/aarch64/raspberrypi/bsp4b.yml b/spec/build/bsps/aarch64/raspberrypi/bsp4b.yml
index 4347235208..fd1f1ab33f 100644
--- a/spec/build/bsps/aarch64/raspberrypi/bsp4b.yml
+++ b/spec/build/bsps/aarch64/raspberrypi/bsp4b.yml
@@ -17,6 +17,7 @@ includes: []
 install:
   - destination: ${BSP_INCLUDEDIR}/bsp
     source:
+      - bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h
       - bsps/aarch64/raspberrypi/include/bsp/bcm2711.h
 
 source: []
diff --git a/spec/build/bsps/aarch64/raspberrypi/obj.yml b/spec/build/bsps/aarch64/raspberrypi/obj.yml
index 4a320336b7..9692cc955f 100644
--- a/spec/build/bsps/aarch64/raspberrypi/obj.yml
+++ b/spec/build/bsps/aarch64/raspberrypi/obj.yml
@@ -2,6 +2,7 @@ SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
 copyrights:
   - Copyright (C) 2022 Mohd Noor Aman
   - Copyright (C) 2023 Utkarsh Verma
+  - Copyright (C) 2024 Ning Yang
 
 type: build
 enabled-by: true
@@ -31,6 +32,8 @@ links:
     uid: objcache
   - role: build-dependency
     uid: objclock
+  - role: build-dependency
+    uid: objsystemtimer
   - role: build-dependency
     uid: objconsole
   - role: build-dependency
diff --git a/spec/build/bsps/aarch64/raspberrypi/objclock.yml b/spec/build/bsps/aarch64/raspberrypi/objclock.yml
index 550df8029a..317919026e 100644
--- a/spec/build/bsps/aarch64/raspberrypi/objclock.yml
+++ b/spec/build/bsps/aarch64/raspberrypi/objclock.yml
@@ -2,9 +2,11 @@ SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
 copyrights:
   - Copyright (C) 2022 Mohd Noor Aman
   - Copyright (C) 2023 Utkarsh Verma
+  - Copyright (C) 2024 Ning Yang
 
 type: build
-enabled-by: true
+enabled-by:
+  not: BSP_CLOCK_USE_SYSTEMTIMER
 
 build-type: objects
 cflags: []
diff --git a/spec/build/bsps/aarch64/raspberrypi/objsystemtimer.yml b/spec/build/bsps/aarch64/raspberrypi/objsystemtimer.yml
new file mode 100644
index 0000000000..7fc4118d0e
--- /dev/null
+++ b/spec/build/bsps/aarch64/raspberrypi/objsystemtimer.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+  - Copyright (C) 2024 Ning Yang
+
+type: build
+enabled-by: 
+- BSP_CLOCK_USE_SYSTEMTIMER
+
+build-type: objects
+cflags: []
+cppflags: []
+cxxflags: []
+includes: []
+install: []
+
+source:
+  - bsps/shared/dev/clock/bcm2835-system-timer.c
+  - bsps/shared/dev/cpucounter/cpucounterfrequency.c
+  - bsps/shared/dev/cpucounter/cpucounterread.c
+  - bsps/shared/dev/getentropy/getentropy-cpucounter.c
+
+links: []
\ No newline at end of file
diff --git a/spec/build/bsps/aarch64/raspberrypi/optsystemtimer.yml b/spec/build/bsps/aarch64/raspberrypi/optsystemtimer.yml
new file mode 100644
index 0000000000..1cceebf22b
--- /dev/null
+++ b/spec/build/bsps/aarch64/raspberrypi/optsystemtimer.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+  - Copyright (C) 2024 Ning Yang
+
+type: build
+build-type: option
+
+enabled-by: true
+name: BSP_CLOCK_USE_SYSTEMTIMER
+description: |
+  The clock from the ARM timer is derived from the system clock. This clock can change dynamically e.g. if the system
+  goes into reduced power or in low power mode. Thus the clock speed adapts to the overall system performance
+  capabilities. For accurate timing it is recommended to use the system timers.
+
+actions:
+  - get-boolean: null
+  - define-condition: null
+  - env-enable: null
+default:
+  - enabled-by: 
+    - aarch64/raspberrypi4b
+    value: false
+
+links: []
\ No newline at end of file
-- 
2.34.1



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