[rtems commit] bsps/shared: Add PSCI SMP startup support

[Joel Sherrill]

Module:    rtems
Branch:    master
Commit:    36477258320f731c3019df6e311a4deab7d1a1bb
Changeset: http://git.rtems.org/rtems/commit/?id=36477258320f731c3019df6e311a4deab7d1a1bb

Author:    Kinsey Moore <kinsey.moore at oarcorp.com>
Date:      Mon Jul 26 15:52:20 2021 -0500

bsps/shared: Add PSCI SMP startup support

This adds the SMP function that supports spinup of additional CPU cores
using the ARM standard PSCI inteface. This interface is provided by QEMU
as well as ARM Trusted Firmware running in monitor mode (EL3) on ARMv7 and
AArch64 CPUs. This supports activation va SMC or HVC instructions
depending on BSP configuration.

---

 bsps/shared/start/bspsmp-arm-psci.c | 92 +++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/bsps/shared/start/bspsmp-arm-psci.c b/bsps/shared/start/bspsmp-arm-psci.c
new file mode 100644
index 0000000..1ff5b7b
--- /dev/null
+++ b/bsps/shared/start/bspsmp-arm-psci.c
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsShared
+ *
+ * @brief PSCI-based BSP CPU start.
+ */
+
+/*
+ * Copyright (C) 2021 On-Line Applications Research Corporation (OAR)
+ * Written by Kinsey Moore <kinsey.moore at oarcorp.com>
+ *
+ * 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.
+ */
+
+#include <rtems/score/smpimpl.h>
+
+#include <bsp/start.h>
+#include <bsp.h>
+#if defined( AARCH64_MULTILIB_ARCH_V8 ) || \
+  defined( AARCH64_MULTILIB_ARCH_V8_ILP32 )
+#include <rtems/score/aarch64-system-registers.h>
+#else
+#include <rtems/score/aarch32-system-registers.h>
+#endif
+
+#if defined( AARCH64_MULTILIB_ARCH_V8 ) || \
+  defined( AARCH64_MULTILIB_ARCH_V8_ILP32 )
+#define REGISTER_PREFIX "x"
+#else
+#define REGISTER_PREFIX "r"
+#endif
+
+bool _CPU_SMP_Start_processor( uint32_t cpu_index )
+{
+#if defined( AARCH64_MULTILIB_ARCH_V8 ) || \
+  defined( AARCH64_MULTILIB_ARCH_V8_ILP32 )
+  uint32_t PSCI_FN_SYSTEM_CPU_ON = 0xC4000003;
+  uint64_t target_cpu = _AArch64_Read_mpidr_el1();
+  uint64_t ret;
+#else
+  uint32_t PSCI_FN_SYSTEM_CPU_ON = 0x84000003;
+  uint32_t target_cpu = _AArch32_Read_mpidr();
+  uint32_t ret;
+#endif
+  target_cpu &= ~( 0xff0000ffUL );
+  target_cpu |= cpu_index;
+
+  __asm__ volatile (
+    "mov " REGISTER_PREFIX "0, %1\n"
+    "mov " REGISTER_PREFIX "1, %2\n"
+    "mov " REGISTER_PREFIX "2, %3\n"
+    "mov " REGISTER_PREFIX "3, #0\n"
+#ifdef BSP_CPU_ON_USES_SMC
+    "smc #0\n"
+#else
+    "hvc #0\n"
+#endif
+    "mov %0, " REGISTER_PREFIX "0\n"
+    : "=r" ( ret ) : "r" ( PSCI_FN_SYSTEM_CPU_ON ), "r" ( target_cpu ),
+    "r" ( _start )
+    : REGISTER_PREFIX "0", REGISTER_PREFIX "1", REGISTER_PREFIX "2",
+    REGISTER_PREFIX "3"
+  );
+
+  if ( ret != 0 ) {
+    return false;
+  }
+
+  return _Per_CPU_State_wait_for_non_initial_state( cpu_index, 0 );
+}