[coreboot-gerrit] New patch to review for coreboot: qemu/vexpress-a9: Discover RAM size.

[Vladimir Serbinenko (phcoder@gmail.com)]

Vladimir Serbinenko (phcoder at gmail.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13754

-gerrit

commit 6bfa3b2255665443cc792e815b17f15f9ed73991
Author: Vladimir Serbinenko <phcoder at gmail.com>
Date:   Fri Feb 19 22:50:50 2016 +0100

    qemu/vexpress-a9: Discover RAM size.
    
    Probe RAM to find its size instead of hardcoding 1024M.
    Also properly export it to memory map.
    
    Change-Id: Ib411f0a068bd247a9e0cd0a59689a3896921483e
    Signed-off-by: Vladimir Serbinenko <phcoder at gmail.com>
---
 src/mainboard/emulation/qemu-armv7/Kconfig     |  4 ---
 src/mainboard/emulation/qemu-armv7/cbmem.c     | 42 +++++++++++++++++++++++++-
 src/mainboard/emulation/qemu-armv7/mainboard.c | 40 ++++++++++++++++++++++++
 src/mainboard/emulation/qemu-armv7/mainboard.h | 21 +++++++++++++
 4 files changed, 102 insertions(+), 5 deletions(-)

diff --git a/src/mainboard/emulation/qemu-armv7/Kconfig b/src/mainboard/emulation/qemu-armv7/Kconfig
index 2654f0f..f30dcd1 100644
--- a/src/mainboard/emulation/qemu-armv7/Kconfig
+++ b/src/mainboard/emulation/qemu-armv7/Kconfig
@@ -48,8 +48,4 @@ config MAINBOARD_VENDOR
 	string
 	default "ARM Ltd."
 
-config DRAM_SIZE_MB
-	int
-	default 1024
-
 endif #  BOARD_EMULATION_QEMU_ARMV7
diff --git a/src/mainboard/emulation/qemu-armv7/cbmem.c b/src/mainboard/emulation/qemu-armv7/cbmem.c
index a626ec6..b634bf6 100644
--- a/src/mainboard/emulation/qemu-armv7/cbmem.c
+++ b/src/mainboard/emulation/qemu-armv7/cbmem.c
@@ -14,8 +14,48 @@
 #include <stddef.h>
 #include <cbmem.h>
 #include <symbols.h>
+#include "mainboard.h"
+
+/* Returns 1 if megabyte mb is present and 0 otherwise.  */
+static int probe_mb(int mb)
+{
+	volatile char *ptr = (char *) 0x60000000 + (mb << 20) + 0xfffff;
+	char old;
+	if (ptr < (volatile char *) &_eprogram) {
+		/* Don't probe below _end to avoid accidentally clobering
+		   oneself.
+		 */
+		return 1;
+	}
+
+	old = *ptr;
+	*ptr = 0x55;
+	if (*ptr != 0x55)
+		return 0;
+	*ptr = 0xaa;
+	if (*ptr != 0xaa)
+		return 0;
+	*ptr = old;
+	return 1;
+}
+
+int probe_ramsize(void)
+{
+	int i;
+	int discovered = 0;
+	static int saved_result;
+	if (saved_result)
+		return saved_result;
+	/* Compact binary search.  */
+	for (i = 9; i >= 0; i--)
+		if (probe_mb(discovered | (1 << i)))
+			discovered |= (1 << i);
+	discovered++;
+	saved_result = discovered;
+	return discovered;
+}
 
 void *cbmem_top(void)
 {
-	return _dram + (CONFIG_DRAM_SIZE_MB << 20);
+	return _dram + (probe_ramsize() << 20);
 }
diff --git a/src/mainboard/emulation/qemu-armv7/mainboard.c b/src/mainboard/emulation/qemu-armv7/mainboard.c
new file mode 100644
index 0000000..d2ce62e
--- /dev/null
+++ b/src/mainboard/emulation/qemu-armv7/mainboard.c
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Vladimir Serbinenko <phcoder at gmail.com>
+ *
+ * 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; version 2 or, at your option, any later
+ * version of the License.
+ *
+ * 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.
+ */
+
+#include <console/console.h>
+#include <device/device.h>
+#include <cbmem.h>
+#include <string.h>
+#include "mainboard.h"
+
+static void mainboard_enable(device_t dev)
+{
+	int discovered;
+	if (!dev) {
+		printk(BIOS_EMERG, "No dev0; die\n");
+		while (1);
+	}
+
+	discovered = probe_ramsize();
+	printk(BIOS_DEBUG, "%d MiB of RAM discovered\n", discovered);
+	ram_resource(dev, 0, 0x60000000 >> 10, discovered << 10);
+	cbmem_recovery(0);
+	init_gfx();
+}
+
+struct chip_operations mainboard_ops = {
+	.enable_dev = mainboard_enable,
+};
diff --git a/src/mainboard/emulation/qemu-armv7/mainboard.h b/src/mainboard/emulation/qemu-armv7/mainboard.h
new file mode 100644
index 0000000..3691c36
--- /dev/null
+++ b/src/mainboard/emulation/qemu-armv7/mainboard.h
@@ -0,0 +1,21 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Vladimir Serbinenko <phcoder at gmail.com>
+ *
+ * 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; version 2 or, at your option, any later
+ * version of the License.
+ *
+ * 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.
+ */
+
+#ifndef QEMU_ARMV7_MAINBOARD_H
+#define QEMU_ARMV7_MAINBOARD_H
+
+int probe_ramsize(void);
+#endif