Add a checksum implementation that can be used with CMOS RAM.
Signed-off-by: Simon Glass <s...@chromium.org>
---
arch/x86/cpu/Makefile | 1 +
arch/x86/cpu/ip_checksum.c | 61 ++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/ip_checksum.h | 16 ++++++++++
3 files changed, 78 insertions(+)
create mode 100644 arch/x86/cpu/ip_checksum.c
create mode 100644 arch/x86/include/asm/ip_checksum.h
diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 62e43c0..eee2289 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_SYS_COREBOOT) += coreboot/
obj-$(CONFIG_NORTHBRIDGE_INTEL_SANDYBRIDGE) += ivybridge/
obj-$(CONFIG_NORTHBRIDGE_INTEL_IVYBRIDGE) += ivybridge/
obj-$(CONFIG_INTEL_QUEENSBAY) += queensbay/
+obj-y += ip_checksum.o
obj-y += lapic.o
obj-y += mtrr.o
obj-$(CONFIG_PCI) += pci.o
diff --git a/arch/x86/cpu/ip_checksum.c b/arch/x86/cpu/ip_checksum.c
new file mode 100644
index 0000000..17f9417
--- /dev/null
+++ b/arch/x86/cpu/ip_checksum.c
@@ -0,0 +1,61 @@
+/*
+ * From Coreboot compute_ip_checksum.c
+ *
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <asm/ip_checksum.h>
+
+/* This function is functionally the same as NetCksum() - should we unify? */
+unsigned long compute_ip_checksum(void *addr, unsigned long length)
+{
+ uint8_t *ptr;
+ union {
+ uint8_t byte[2];
+ uint16_t word;
+ } value;
+ unsigned long sum;
+ unsigned long i;
+
+ sum = 0;
+ ptr = addr;
+ for (i = 0; i < length; i++) {
+ unsigned long v;
+
+ v = ptr[i];
+ if (i & 1)
+ v <<= 8;
+ /* Add the new value */
+ sum += v;
+ /* Wrap around the carry */
+ if (sum > 0xffff)
+ sum = (sum + (sum >> 16)) & 0xffff;
+ }
+ value.byte[0] = sum & 0xff;
+ value.byte[1] = (sum >> 8) & 0xff;
+ return (~value.word) & 0xffff;
+}
+
+unsigned long add_ip_checksums(unsigned long offset, unsigned long sum,
+ unsigned long new)
+{
+ unsigned long checksum;
+
+ sum = ~sum & 0xffff;
+ new = ~new & 0xffff;
+ if (offset & 1) {
+ /*
+ * byte-swap the sum if it came from an odd offset; since the
+ * computation is endian independant this works.
+ */
+ new = ((new >> 8) & 0xff) | ((new << 8) & 0xff00);
+ }
+ checksum = sum + new;
+ if (checksum > 0xffff)
+ checksum -= 0xffff;
+
+ return (~checksum) & 0xffff;
+}
diff --git a/arch/x86/include/asm/ip_checksum.h
b/arch/x86/include/asm/ip_checksum.h
new file mode 100644
index 0000000..6553d7b
--- /dev/null
+++ b/arch/x86/include/asm/ip_checksum.h
@@ -0,0 +1,16 @@
+/*
+ * From Coreboot ip_checksum.h
+ *
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef _IP_CHECKSUM_H
+#define _IP_CHECKSUM_H
+
+unsigned long compute_ip_checksum(void *addr, unsigned long length);
+unsigned long add_ip_checksums(unsigned long offset, unsigned long sum,
+ unsigned long new);
+
+#endif /* IP_CHECKSUM_H */
--
2.2.0.rc0.207.ga3a616c
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