bsps/riscv: Add tm27 support

bsps/riscv/riscv/include/tm27.h

@@ -1 +1,136 @@
-#include <rtems/tm27-default.h>
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsRISCVGeneric
+ *
+ * @brief This header file contains the generic RISC-V tm27 support
+ *   implementation.
+ */
+
+/*
+ * Copyright (C) 2022 embedded brains GmbH
+ *
+ * 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 _RTEMS_TMTEST27
+#error "This is an RTEMS internal file you must not include directly."
+#endif
+
+#ifndef __tm27_h
+#define __tm27_h
+
+#include <bsp/irq-generic.h>
+#include <rtems/score/assert.h>
+#include <rtems/score/riscv-utility.h>
+#include <rtems/score/percpu.h>
+
+#define MUST_WAIT_FOR_INTERRUPT 1
+
+static bool riscv_tm27_can_use_mtime;
+
+static rtems_interrupt_entry riscv_tm27_interrupt_entry;
+
+static inline void Install_tm27_vector(
+  void ( *handler )( rtems_vector_number )
+)
+{
+  rtems_vector_number irq;
+  bool                enabled;
+
+  irq = RISCV_INTERRUPT_VECTOR_TIMER;
+  enabled = false;
+  rtems_interrupt_vector_is_enabled( irq, &enabled );
+
+  if ( enabled ) {
+    irq = RISCV_INTERRUPT_VECTOR_SOFTWARE;
+  } else {
+    riscv_tm27_can_use_mtime = true;
+  }
+
+  rtems_interrupt_entry_initialize(
+    &riscv_tm27_interrupt_entry,
+    (rtems_interrupt_handler) handler,
+    NULL,
+    "tm27"
+  );
+
+  (void) rtems_interrupt_entry_install(
+    irq,
+    RTEMS_INTERRUPT_SHARED,
+    &riscv_tm27_interrupt_entry
+  );
+}
+
+static inline void Cause_tm27_intr( void )
+{
+  if ( riscv_tm27_can_use_mtime ) {
+    rtems_interrupt_level level;
+    Per_CPU_Control      *cpu_self;
+
+    rtems_interrupt_local_disable( level );
+    cpu_self = _Per_CPU_Get();
+    cpu_self->cpu_per_cpu.clint_mtimecmp->val_64 = 0;
+    rtems_interrupt_local_enable( level );
+  } else {
+    (void) rtems_interrupt_raise( RISCV_INTERRUPT_VECTOR_SOFTWARE );
+  }
+}
+
+static inline void Clear_tm27_intr( void )
+{
+  if ( riscv_tm27_can_use_mtime ) {
+    rtems_interrupt_level level;
+    Per_CPU_Control      *cpu_self;
+
+    rtems_interrupt_local_disable( level );
+    cpu_self = _Per_CPU_Get();
+    cpu_self->cpu_per_cpu.clint_mtimecmp->val_64 = UINT64_MAX;
+    rtems_interrupt_local_enable( level );
+  } else {
+    (void) rtems_interrupt_clear( RISCV_INTERRUPT_VECTOR_SOFTWARE );
+  }
+}
+
+static inline void Lower_tm27_intr( void )
+{
+  rtems_vector_number irq;
+
+  /*
+   * This is an ugly hack just to for tm27.  The support for nested interrupts
+   * is currently quite bad on RISC-V.
+   */
+  irq = RISCV_INTERRUPT_VECTOR_SOFTWARE;
+
+  if ( bsp_interrupt_handler_table[ irq ] == NULL ) {
+    _Assert( riscv_tm27_can_use_mtime );
+    bsp_interrupt_handler_table[ irq ] = &riscv_tm27_interrupt_entry;
+    (void) rtems_interrupt_vector_enable( irq );
+  }
+
+  _ISR_Set_level( 0 );
+  (void) rtems_interrupt_raise( irq );
+}
+
+#endif