1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
new file mode 100644
index 000000000..f9d3d6eed
--- /dev/null
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2015 Qualcomm Atheros, Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <linux/hw_random.h>
+#include <linux/kthread.h>
+
+#include "ath9k.h"
+#include "hw.h"
+#include "ar9003_phy.h"
+
+#define ATH9K_RNG_BUF_SIZE	320
+#define ATH9K_RNG_ENTROPY(x)	(((x) * 8 * 10) >> 5) /* quality: 10/32 */
+
+static DECLARE_WAIT_QUEUE_HEAD(rng_queue);
+
+static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
+{
+	int i, j;
+	u32  v1, v2, rng_last = sc->rng_last;
+	struct ath_hw *ah = sc->sc_ah;
+
+	ath9k_ps_wakeup(sc);
+
+	REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 1);
+	REG_CLR_BIT(ah, AR_PHY_TEST, AR_PHY_TEST_RX_OBS_SEL_BIT5);
+	REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS, AR_PHY_TEST_CTL_RX_OBS_SEL, 0);
+
+	for (i = 0, j = 0; i < buf_size; i++) {
+		v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
+		v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
+
+		/* wait for data ready */
+		if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff &&
+		    v2 != 0xffff)
+			buf[j++] = (v1 << 16) | v2;
+
+		rng_last = v2;
+	}
+
+	ath9k_ps_restore(sc);
+
+	sc->rng_last = rng_last;
+
+	return j << 2;
+}
+
+static u32 ath9k_rng_delay_get(u32 fail_stats)
+{
+	u32 delay;
+
+	if (fail_stats < 100)
+		delay = 10;
+	else if (fail_stats < 105)
+		delay = 1000;
+	else
+		delay = 10000;
+
+	return delay;
+}
+
+static int ath9k_rng_kthread(void *data)
+{
+	int bytes_read;
+	struct ath_softc *sc = data;
+	u32 *rng_buf;
+	u32 delay, fail_stats = 0;
+
+	rng_buf = kmalloc_array(ATH9K_RNG_BUF_SIZE, sizeof(u32), GFP_KERNEL);
+	if (!rng_buf)
+		goto out;
+
+	while (!kthread_should_stop()) {
+		bytes_read = ath9k_rng_data_read(sc, rng_buf,
+						 ATH9K_RNG_BUF_SIZE);
+		if (unlikely(!bytes_read)) {
+			delay = ath9k_rng_delay_get(++fail_stats);
+			wait_event_interruptible_timeout(rng_queue,
+							 kthread_should_stop(),
+							 msecs_to_jiffies(delay));
+			continue;
+		}
+
+		fail_stats = 0;
+
+		/* sleep until entropy bits under write_wakeup_threshold */
+		add_hwgenerator_randomness((void *)rng_buf, bytes_read,
+					   ATH9K_RNG_ENTROPY(bytes_read));
+	}
+
+	kfree(rng_buf);
+out:
+	sc->rng_task = NULL;
+
+	return 0;
+}
+
+void ath9k_rng_start(struct ath_softc *sc)
+{
+	struct ath_hw *ah = sc->sc_ah;
+
+	if (sc->rng_task)
+		return;
+
+	if (!AR_SREV_9300_20_OR_LATER(ah))
+		return;
+
+	sc->rng_task = kthread_run(ath9k_rng_kthread, sc, "ath9k-hwrng");
+	if (IS_ERR(sc->rng_task))
+		sc->rng_task = NULL;
+}
+
+void ath9k_rng_stop(struct ath_softc *sc)
+{
+	if (sc->rng_task) {
+		kthread_stop(sc->rng_task);
+		sc->rng_task = NULL;
+	}
+}