risc-v/qemu-rv: Add LED Driver for QEMU RISC-V 32-bit and 64-bit

- This PR adds the LED Driver for QEMU RISC-V 32-bit and 64-bit (User LEDs and Auto LEDs)
- QEMU RISC-V LED Driver will be used by the Rust Blinky App for Google Summer of Code
- Blinking the LED is probably the most common Embedded Demo, and now it's supported by QEMU RISC-V
- We added NuttX Configs rv-virt:leds and rv-virt:leds64 to support User LEDs for 32-bit and 64-bit RISC-V
- Turning on/off a Simulated User LED will print a log message: "LED 1 set to 1"
- The code is derived from NuttX PinePhone LED Driver

Documentation/platforms/risc-v/qemu-rv/boards/rv-virt/index.rst

@@ -229,6 +229,16 @@ ksmp64
 
 Identical to the `knsh64`_ configuration but with SMP support.
 
+leds
+----
+
+Similar to the `nsh`_ configuration, but with User LEDs support for 32-bit RISC-V.
+
+leds64
+------
+
+Similar to the `nsh64`_ configuration, but with User LEDs support for 64-bit RISC-V.
+
 netnsh
 ------
 

boards/Kconfig

@@ -1993,6 +1993,7 @@ config ARCH_BOARD_RV32M1_VEGA
 config ARCH_BOARD_QEMU_RV_VIRT
 	bool "QEMU RV Virt"
 	depends on ARCH_CHIP_QEMU_RV
+	select ARCH_HAVE_LEDS
 	---help---
 		This is the board configuration for the port of NuttX to the
 		QEMU RV32 Virt board. This board features the QEMU RV32 CPU.

boards/risc-v/qemu-rv/rv-virt/configs/leds/defconfig

@@ -0,0 +1,71 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+# CONFIG_DISABLE_OS_API is not set
+# CONFIG_NSH_DISABLE_LOSMART is not set
+CONFIG_16550_ADDRWIDTH=0
+CONFIG_16550_UART0=y
+CONFIG_16550_UART0_BASE=0x10000000
+CONFIG_16550_UART0_CLOCK=3686400
+CONFIG_16550_UART0_IRQ=37
+CONFIG_16550_UART0_SERIAL_CONSOLE=y
+CONFIG_16550_UART=y
+CONFIG_ARCH="risc-v"
+CONFIG_ARCH_BOARD="rv-virt"
+CONFIG_ARCH_BOARD_QEMU_RV_VIRT=y
+CONFIG_ARCH_CHIP="qemu-rv"
+CONFIG_ARCH_CHIP_QEMU_RV32=y
+CONFIG_ARCH_CHIP_QEMU_RV=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_A=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_C=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_M=y
+CONFIG_ARCH_INTERRUPTSTACK=2048
+CONFIG_ARCH_RISCV=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_BOARDCTL_POWEROFF=y
+CONFIG_BOARD_LATE_INITIALIZE=y
+CONFIG_BOARD_LOOPSPERMSEC=6366
+CONFIG_BUILTIN=y
+CONFIG_DEBUG_FEATURES=y
+CONFIG_DEBUG_FULLOPT=y
+CONFIG_DEBUG_SYMBOLS=y
+CONFIG_DEV_ZERO=y
+CONFIG_ELF=y
+CONFIG_EXAMPLES_HELLO=y
+CONFIG_EXAMPLES_LEDS=y
+CONFIG_FS_HOSTFS=y
+CONFIG_FS_PROCFS=y
+CONFIG_IDLETHREAD_STACKSIZE=2048
+CONFIG_INIT_ENTRYPOINT="nsh_main"
+CONFIG_LIBC_ENVPATH=y
+CONFIG_LIBC_EXECFUNCS=y
+CONFIG_LIBC_PERROR_STDOUT=y
+CONFIG_LIBC_STRERROR=y
+CONFIG_LIBM=y
+CONFIG_NFILE_DESCRIPTORS_PER_BLOCK=6
+CONFIG_NSH_ARCHINIT=y
+CONFIG_NSH_BUILTIN_APPS=y
+CONFIG_NSH_FILEIOSIZE=512
+CONFIG_NSH_READLINE=y
+CONFIG_PATH_INITIAL="/system/bin"
+CONFIG_RAM_SIZE=33554432
+CONFIG_RAM_START=0x80000000
+CONFIG_READLINE_CMD_HISTORY=y
+CONFIG_RISCV_SEMIHOSTING_HOSTFS=y
+CONFIG_RR_INTERVAL=200
+CONFIG_SCHED_WAITPID=y
+CONFIG_SERIAL_UART_ARCH_MMIO=y
+CONFIG_STACK_COLORATION=y
+CONFIG_START_MONTH=12
+CONFIG_START_YEAR=2021
+CONFIG_SYMTAB_ORDEREDBYNAME=y
+CONFIG_SYSTEM_NSH=y
+CONFIG_TESTING_GETPRIME=y
+CONFIG_TESTING_OSTEST=y
+CONFIG_USEC_PER_TICK=1000
+CONFIG_USERLED=y
+CONFIG_USERLED_LOWER=y

boards/risc-v/qemu-rv/rv-virt/configs/leds64/defconfig

@@ -0,0 +1,75 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+# CONFIG_DISABLE_OS_API is not set
+# CONFIG_NSH_DISABLE_LOSMART is not set
+CONFIG_16550_ADDRWIDTH=0
+CONFIG_16550_UART0=y
+CONFIG_16550_UART0_BASE=0x10000000
+CONFIG_16550_UART0_CLOCK=3686400
+CONFIG_16550_UART0_IRQ=37
+CONFIG_16550_UART0_SERIAL_CONSOLE=y
+CONFIG_16550_UART=y
+CONFIG_ARCH="risc-v"
+CONFIG_ARCH_BOARD="rv-virt"
+CONFIG_ARCH_BOARD_QEMU_RV_VIRT=y
+CONFIG_ARCH_CHIP="qemu-rv"
+CONFIG_ARCH_CHIP_QEMU_RV64=y
+CONFIG_ARCH_CHIP_QEMU_RV=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_A=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_C=y
+CONFIG_ARCH_CHIP_QEMU_RV_ISA_M=y
+CONFIG_ARCH_INTERRUPTSTACK=2048
+CONFIG_ARCH_RISCV=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_BCH=y
+CONFIG_BOARDCTL_POWEROFF=y
+CONFIG_BOARD_LATE_INITIALIZE=y
+CONFIG_BOARD_LOOPSPERMSEC=6366
+CONFIG_BUILTIN=y
+CONFIG_DEBUG_FEATURES=y
+CONFIG_DEBUG_FULLOPT=y
+CONFIG_DEBUG_SYMBOLS=y
+CONFIG_DEVICE_TREE=y
+CONFIG_DEV_ZERO=y
+CONFIG_ELF=y
+CONFIG_EXAMPLES_HELLO=y
+CONFIG_EXAMPLES_LEDS=y
+CONFIG_FS_HOSTFS=y
+CONFIG_FS_PROCFS=y
+CONFIG_IDLETHREAD_STACKSIZE=2048
+CONFIG_INIT_ENTRYPOINT="nsh_main"
+CONFIG_INIT_STACKSIZE=3072
+CONFIG_LIBC_ENVPATH=y
+CONFIG_LIBC_EXECFUNCS=y
+CONFIG_LIBC_PERROR_STDOUT=y
+CONFIG_LIBC_STRERROR=y
+CONFIG_LIBM=y
+CONFIG_NFILE_DESCRIPTORS_PER_BLOCK=6
+CONFIG_NSH_ARCHINIT=y
+CONFIG_NSH_BUILTIN_APPS=y
+CONFIG_NSH_FILEIOSIZE=512
+CONFIG_NSH_READLINE=y
+CONFIG_PATH_INITIAL="/system/bin"
+CONFIG_RAM_SIZE=33554432
+CONFIG_RAM_START=0x80000000
+CONFIG_READLINE_CMD_HISTORY=y
+CONFIG_RISCV_SEMIHOSTING_HOSTFS=y
+CONFIG_RR_INTERVAL=200
+CONFIG_SCHED_WAITPID=y
+CONFIG_SERIAL_UART_ARCH_MMIO=y
+CONFIG_STACK_COLORATION=y
+CONFIG_START_MONTH=12
+CONFIG_START_YEAR=2021
+CONFIG_SYMTAB_ORDEREDBYNAME=y
+CONFIG_SYSTEM_NSH=y
+CONFIG_SYSTEM_NSH_STACKSIZE=3072
+CONFIG_TESTING_GETPRIME=y
+CONFIG_TESTING_OSTEST=y
+CONFIG_USEC_PER_TICK=1000
+CONFIG_USERLED=y
+CONFIG_USERLED_LOWER=y

boards/risc-v/qemu-rv/rv-virt/include/board.h

@@ -31,6 +31,24 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* LED definitions **********************************************************/
+
+/* LED index values for use with board_userled() */
+
+typedef enum
+{
+    BOARD_LED1 = 0,
+    BOARD_LED2 = 1,
+    BOARD_LED3 = 2,
+    BOARD_LEDS  /* Number of LEDs */
+} led_typedef_enum;
+
+/* LED bits for use with board_userled_all() */
+
+#define BOARD_LED1_BIT    (1 << BOARD_LED1)
+#define BOARD_LED2_BIT    (1 << BOARD_LED2)
+#define BOARD_LED3_BIT    (1 << BOARD_LED3)
+
 #define LED_STARTED       0  /* N/A */
 #define LED_HEAPALLOCATE  1  /* N/A */
 #define LED_IRQSENABLED   2  /* N/A */

boards/risc-v/qemu-rv/rv-virt/src/Makefile

@@ -30,6 +30,14 @@ CSRCS += $(if $(wildcard romfs_boot.c), romfs_boot.c, romfs_stub.c)
 endif
 endif
 
+ifeq ($(CONFIG_ARCH_LEDS),y)
+CSRCS += qemu_rv_autoleds.c
+endif
+
+ifeq ($(CONFIG_USERLED),y)
+CSRCS += qemu_rv_userleds.c
+endif
+
 include $(TOPDIR)/boards/Board.mk
 
 # don't use single-colon targets as they may coflict with those included ones.

boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c

@@ -43,6 +43,10 @@
 #include "riscv_internal.h"
 #include "romfs.h"
 
+#ifdef CONFIG_USERLED
+#include <nuttx/leds/userled.h>
+#endif
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -181,6 +185,16 @@ void board_late_initialize(void)
   mount(NULL, "/proc", "procfs", 0, NULL);
 
 #endif
+
+#ifdef CONFIG_USERLED
+  /* Register the LED driver */
+
+  int ret = userled_lower_initialize("/dev/userleds");
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: userled_lower_initialize() failed: %d\n", ret);
+    }
+#endif
 }
 
 #ifdef CONFIG_BOARDCTL_POWEROFF

boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_autoleds.c

@@ -0,0 +1,145 @@
+/****************************************************************************
+ * boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_autoleds.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <debug.h>
+
+#include <sys/param.h>
+
+#include <nuttx/board.h>
+#include <arch/board/board.h>
+
+#include "chip.h"
+
+#ifdef CONFIG_ARCH_LEDS
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_autoled_initialize
+ *
+ * Description:
+ *   This function is called very early in initialization to perform board-
+ *   specific initialization of LED-related resources.  This includes such
+ *   things as, for example, configure GPIO pins to drive the LEDs and also
+ *   putting the LEDs in their correct initial state.
+ *
+ *   NOTE: In most architectures, board_autoled_initialize() is called from
+ *   board-specific initialization logic.  But there are a few architectures
+ *   where this initialization function is still called from common chip
+ *   architecture logic.  This interface is not, however, a common board
+ *   interface in any event and, hence, the usage of the name
+ *   board_autoled_initialize is deprecated.
+ *
+ *   WARNING: This interface name will eventually be removed; do not use it
+ *   in new board ports.  New implementations should use the naming
+ *   conventions for "Microprocessor-Specific Interfaces" or the "Board-
+ *   Specific Interfaces" as described above.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void board_autoled_initialize(void)
+{
+}
+
+/****************************************************************************
+ * Name: board_autoled_on
+ *
+ * Description:
+ *   Set the LED configuration into the ON condition for the state provided
+ *   by the led parameter.  This may be one of:
+ *
+ *     LED_STARTED       NuttX has been started
+ *     LED_HEAPALLOCATE  Heap has been allocated
+ *     LED_IRQSENABLED   Interrupts enabled
+ *     LED_STACKCREATED  Idle stack created
+ *     LED_INIRQ         In an interrupt
+ *     LED_SIGNAL        In a signal handler
+ *     LED_ASSERTION     An assertion failed
+ *     LED_PANIC         The system has crashed
+ *     LED_IDLE          MCU is in sleep mode
+ *
+ *   Where these values are defined in a board-specific way in the standard
+ *   board.h header file exported by every architecture.
+ *
+ * Input Parameters:
+ *   led - Identifies the LED state to put in the ON state (which may or may
+ *         not equate to turning an LED on)
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void board_autoled_on(int led)
+{
+  /* This stub is required for supporting User LEDs */
+
+  UNUSED(led);
+}
+
+/****************************************************************************
+ * Name: board_autoled_off
+ *
+ * Description:
+ *   Set the LED configuration into the OFF condition for the state provided
+ *   by the led parameter.  This may be one of:
+ *
+ *     LED_INIRQ         Leaving an interrupt
+ *     LED_SIGNAL        Leaving a signal handler
+ *     LED_ASSERTION     Recovering from an assertion failure
+ *     LED_PANIC         The system has crashed (blinking).
+ *     LED_IDLE          MCU is not in sleep mode
+ *
+ *   Where these values are defined in a board-specific way in the standard
+ *   board.h header file exported by every architecture.
+ *
+ * Input Parameters:
+ *   led - Identifies the LED state to put in the OFF state (which may or may
+ *         not equate to turning an LED off)
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void board_autoled_off(int led)
+{
+  /* This stub is required for supporting User LEDs */
+
+  UNUSED(led);
+}
+
+#endif /* CONFIG_ARCH_LEDS */