[Xen-devel] [PATCH v2 35/41] arm : acpi add helper function to calculate crc32

[Parth Dixit <parth.dixit@xxxxxxxxxx>]

Add helper functions for calculating crc32.
This is required for computing crc of efi table.
These functions are copied from here
http://mirrors.neusoft.edu.cn/rpi-kernel/lib/xz/xz_crc32.c
Original author's are  Lasse Collin and Igor Pavlov.

Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 36b072b..0ad70c1 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1227,6 +1227,39 @@ static int handle_node(struct domain *d, struct 
kernel_info *kinfo,
 }
 #ifdef CONFIG_ACPI
 
+static uint32_t xz_crc32_table[256];
+
+static void xz_crc32_init(void)
+{
+       const uint32_t poly = 0xEDB88320;
+
+       uint32_t i;
+       uint32_t j;
+       uint32_t r;
+
+       for (i = 0; i < 256; ++i) {
+               r = i;
+               for (j = 0; j < 8; ++j)
+                       r = (r >> 1) ^ (poly & ~((r & 1) - 1));
+
+               xz_crc32_table[i] = r;
+       }
+
+       return;
+}
+
+static uint32_t xz_crc32(uint8_t *buf, size_t size, uint32_t crc)
+{
+       crc = ~crc;
+
+       while (size != 0) {
+               crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
+               --size;
+       }
+
+       return ~crc;
+}
+
 static int create_xen_acpi_tables(struct kernel_info *kinfo, struct domain *d,
                                   struct membank tbl_add[])
 {
-- 
1.9.1


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