From 1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679 Mon Sep 17 00:00:00 2001
From: Michael Brown
Date: Wed, 13 Mar 2024 15:08:10 +0000
Subject: [mp] Define an API for multiprocessor functions

Define an API for executing very limited functions on application
processors in a multiprocessor system, along with an x86-only
implementation.

The normal iPXE runtime environment is effectively non-existent on
application processors.  There is no ability to make firmware calls
(e.g. to write to a console), and there may be no stack space
available.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/core/mp.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 src/core/mp.c

(limited to 'src/core/mp.c')

diff --git a/src/core/mp.c b/src/core/mp.c
new file mode 100644
index 00000000..146d70a6
--- /dev/null
+++ b/src/core/mp.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * Multiprocessor functions
+ *
+ */
+
+#include <ipxe/timer.h>
+#include <ipxe/mp.h>
+
+/** Time to wait for application processors */
+#define MP_MAX_CPUID_WAIT_MS 10
+
+/**
+ * Get boot CPU identifier
+ *
+ * @ret id		Boot CPU identifier
+ */
+unsigned int mp_boot_cpuid ( void ) {
+	unsigned int max = 0;
+
+	/* Update maximum to accommodate boot processor */
+	mp_exec_boot ( mp_update_max_cpuid, &max );
+	DBGC ( &mp_call, "MP boot processor ID is %#x\n", max );
+
+	return max;
+}
+
+/**
+ * Get maximum CPU identifier
+ *
+ * @ret max		Maximum CPU identifier
+ */
+unsigned int mp_max_cpuid ( void ) {
+	unsigned int max = mp_boot_cpuid();
+
+	/* Update maximum to accommodate application processors */
+	mp_start_all ( mp_update_max_cpuid, &max );
+	mdelay ( MP_MAX_CPUID_WAIT_MS );
+	DBGC ( &mp_call, "MP observed maximum CPU ID is %#x\n", max );
+
+	return max;
+}
-- 
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