[Feature][T106]ZXW P56U09 code
Only Configure: Yes
Affected branch: master
Affected module: unknow
Is it affected on both ZXIC and MTK: only ZXIC
Self-test: No
Doc Update: No
Change-Id: I3cbd8b420271eb20c2b40ebe5c78f83059cd42f3
diff --git a/ap/os/linux/linux-3.4.x/lib/random32.c b/ap/os/linux/linux-3.4.x/lib/random32.c
new file mode 100644
index 0000000..aa95712
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/lib/random32.c
@@ -0,0 +1,150 @@
+/*
+ This is a maximally equidistributed combined Tausworthe generator
+ based on code from GNU Scientific Library 1.5 (30 Jun 2004)
+
+ x_n = (s1_n ^ s2_n ^ s3_n)
+
+ s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
+ s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
+ s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
+
+ The period of this generator is about 2^88.
+
+ From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
+ Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
+
+ This is available on the net from L'Ecuyer's home page,
+
+ http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
+ ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
+
+ There is an erratum in the paper "Tables of Maximally
+ Equidistributed Combined LFSR Generators", Mathematics of
+ Computation, 68, 225 (1999), 261--269:
+ http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
+
+ ... the k_j most significant bits of z_j must be non-
+ zero, for each j. (Note: this restriction also applies to the
+ computer code given in [4], but was mistakenly not mentioned in
+ that paper.)
+
+ This affects the seeding procedure by imposing the requirement
+ s1 > 1, s2 > 7, s3 > 15.
+
+*/
+
+#include <linux/types.h>
+#include <linux/percpu.h>
+#include <linux/export.h>
+#include <linux/jiffies.h>
+#include <linux/random.h>
+
+static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
+
+/**
+ * prandom32 - seeded pseudo-random number generator.
+ * @state: pointer to state structure holding seeded state.
+ *
+ * This is used for pseudo-randomness with no outside seeding.
+ * For more random results, use random32().
+ */
+u32 prandom32(struct rnd_state *state)
+{
+#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
+
+ state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
+ state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
+ state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
+
+ return (state->s1 ^ state->s2 ^ state->s3);
+}
+EXPORT_SYMBOL(prandom32);
+
+/**
+ * random32 - pseudo random number generator
+ *
+ * A 32 bit pseudo-random number is generated using a fast
+ * algorithm suitable for simulation. This algorithm is NOT
+ * considered safe for cryptographic use.
+ */
+u32 random32(void)
+{
+ unsigned long r;
+ struct rnd_state *state = &get_cpu_var(net_rand_state);
+ r = prandom32(state);
+ put_cpu_var(state);
+ return r;
+}
+EXPORT_SYMBOL(random32);
+
+/**
+ * srandom32 - add entropy to pseudo random number generator
+ * @seed: seed value
+ *
+ * Add some additional seeding to the random32() pool.
+ */
+void srandom32(u32 entropy)
+{
+ int i;
+ /*
+ * No locking on the CPUs, but then somewhat random results are, well,
+ * expected.
+ */
+ for_each_possible_cpu (i) {
+ struct rnd_state *state = &per_cpu(net_rand_state, i);
+ state->s1 = __seed(state->s1 ^ entropy, 2);
+ }
+}
+EXPORT_SYMBOL(srandom32);
+
+/*
+ * Generate some initially weak seeding values to allow
+ * to start the random32() engine.
+ */
+static int __init random32_init(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct rnd_state *state = &per_cpu(net_rand_state,i);
+
+#define LCG(x) ((x) * 69069) /* super-duper LCG */
+ state->s1 = __seed(LCG(i + jiffies), 2);
+ state->s2 = __seed(LCG(state->s1), 8);
+ state->s3 = __seed(LCG(state->s2), 16);
+
+ /* "warm it up" */
+ prandom32(state);
+ prandom32(state);
+ prandom32(state);
+ prandom32(state);
+ prandom32(state);
+ prandom32(state);
+ }
+ return 0;
+}
+core_initcall(random32_init);
+
+/*
+ * Generate better values after random number generator
+ * is fully initialized.
+ */
+static int __init random32_reseed(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct rnd_state *state = &per_cpu(net_rand_state,i);
+ u32 seeds[3];
+
+ get_random_bytes(&seeds, sizeof(seeds));
+ state->s1 = __seed(seeds[0], 2);
+ state->s2 = __seed(seeds[1], 8);
+ state->s3 = __seed(seeds[2], 16);
+
+ /* mix it in */
+ prandom32(state);
+ }
+ return 0;
+}
+late_initcall(random32_reseed);