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-rw-r--r--src/lib/Makefile.inc3
-rw-r--r--src/lib/ramdetect.c78
2 files changed, 81 insertions, 0 deletions
diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 7492b162dc..9deb5bf377 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -65,6 +65,7 @@ verstage-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
verstage-$(CONFIG_GENERIC_UDELAY) += timer.c
verstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
+romstage-$(CONFIG_VENDOR_EMULATION) += ramdetect.c
romstage-y += prog_loaders.c
romstage-y += prog_ops.c
romstage-y += memchr.c
@@ -105,6 +106,7 @@ endif
romstage-$(CONFIG_GENERIC_UDELAY) += timer.c
+ramstage-$(CONFIG_VENDOR_EMULATION) += ramdetect.c
ramstage-y += prog_loaders.c
ramstage-y += prog_ops.c
ramstage-y += hardwaremain.c
@@ -155,6 +157,7 @@ ramstage-y += cbmem_common.c
ramstage-y += imd_cbmem.c
ramstage-y += imd.c
+postcar-$(CONFIG_VENDOR_EMULATION) += ramdetect.c
postcar-y += cbmem_common.c
postcar-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
postcar-y += imd_cbmem.c
diff --git a/src/lib/ramdetect.c b/src/lib/ramdetect.c
new file mode 100644
index 0000000000..5416a580dd
--- /dev/null
+++ b/src/lib/ramdetect.c
@@ -0,0 +1,78 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * 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 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 <types.h>
+#include <symbols.h>
+#include <device/mmio.h>
+#include <ramdetect.h>
+#include <console/console.h>
+
+#define OVERLAP(a, b, s, e) ((b) > (s) && (a) < (e))
+
+static int probe_mb(const uintptr_t dram_start, const uintptr_t size)
+{
+ uintptr_t addr = dram_start + (size * MiB) - sizeof(uint32_t);
+ static const uint32_t patterns[] = {
+ 0x55aa55aa,
+ 0x12345678
+ };
+ void *ptr = (void *) addr;
+ size_t i;
+
+ /* Don't accidentally clober oneself. */
+ if (OVERLAP(addr, addr + sizeof(uint32_t), (uintptr_t)_program, (uintptr_t) _eprogram))
+ return 1;
+
+ uint32_t old = read32(ptr);
+ for (i = 0; i < ARRAY_SIZE(patterns); i++) {
+ write32(ptr, patterns[i]);
+ if (read32(ptr) != patterns[i])
+ break;
+ }
+
+ write32(ptr, old);
+ return i == ARRAY_SIZE(patterns);
+}
+
+/* - 20 as probe_size is in MiB, - 1 as i is signed */
+#define MAX_ADDRESSABLE_SPACE (sizeof(size_t) * 8 - 20 - 1)
+
+/* Probe an area if it's read/writable. */
+size_t probe_ramsize(const uintptr_t dram_start, const size_t probe_size)
+{
+ ssize_t i;
+ size_t msb = 0;
+ size_t discovered = 0;
+
+ static size_t saved_result;
+ if (saved_result)
+ return saved_result;
+
+ /* Find the MSB + 1. */
+ size_t tmp = probe_size;
+ do {
+ msb++;
+ } while (tmp >>= 1);
+
+ /* Limit search to accessible address space */
+ msb = MIN(msb, MAX_ADDRESSABLE_SPACE);
+
+ /* Compact binary search. */
+ for (i = msb; i >= 0; i--)
+ if (probe_mb(dram_start, (discovered | (1ULL << i))))
+ discovered |= (1ULL << i);
+
+ saved_result = discovered;
+ printk(BIOS_DEBUG, "RAMDETECT: Found %zu MiB RAM\n", discovered);
+ return discovered;
+}