5 files changed, 145 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/Kconfig b/drivers/net/wireless/ath/ath9k/Kconfig
index fee0cadb0f5e..40fa915d6f35 100644
--- a/drivers/net/wireless/ath/ath9k/Kconfig
+++ b/drivers/net/wireless/ath/ath9k/Kconfig
@@ -176,3 +176,14 @@ config ATH9K_HTC_DEBUGFS
 	depends on ATH9K_HTC && DEBUG_FS
 	---help---
 	  Say Y, if you need access to ath9k_htc's statistics.
+
+config ATH9K_HWRNG
+	bool "Random number generator support"
+	depends on ATH9K && (HW_RANDOM = y || HW_RANDOM = ATH9K)
+	default y
+	---help---
+	  This option incorporates the ADC register output as a source of
+	  randomness into Linux entropy pool (/dev/urandom and /dev/random)
+
+	  Say Y, feeds the entropy directly from the WiFi driver to the input
+	  pool.
diff --git a/drivers/net/wireless/ath/ath9k/Makefile b/drivers/net/wireless/ath/ath9k/Makefile
index ecda613c2d54..76f9dc37500b 100644
--- a/drivers/net/wireless/ath/ath9k/Makefile
+++ b/drivers/net/wireless/ath/ath9k/Makefile
@@ -15,6 +15,7 @@ ath9k-$(CONFIG_ATH9K_DFS_DEBUGFS) += dfs_debug.o
 ath9k-$(CONFIG_ATH9K_DFS_CERTIFIED) += dfs.o
 ath9k-$(CONFIG_ATH9K_TX99) += tx99.o
 ath9k-$(CONFIG_ATH9K_WOW) += wow.o
+ath9k-$(CONFIG_ATH9K_HWRNG) += rng.o
 
 ath9k-$(CONFIG_ATH9K_DEBUGFS) += debug.o
 
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index acc21f60f36b..5294595da5a7 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -23,6 +23,7 @@
 #include <linux/leds.h>
 #include <linux/completion.h>
 #include <linux/time.h>
+#include <linux/hw_random.h>
 
 #include "common.h"
 #include "debug.h"
@@ -1041,6 +1042,11 @@ struct ath_softc {
 	u32 wow_intr_before_sleep;
 	bool force_wow;
 #endif
+
+#ifdef CONFIG_ATH9K_HWRNG
+	u32 rng_last;
+	struct task_struct *rng_task;
+#endif
 };
 
 /********/
@@ -1063,6 +1069,22 @@ static inline int ath9k_tx99_send(struct ath_softc *sc,
 }
 #endif /* CONFIG_ATH9K_TX99 */
 
+/***************************/
+/* Random Number Generator */
+/***************************/
+#ifdef CONFIG_ATH9K_HWRNG
+void ath9k_rng_start(struct ath_softc *sc);
+void ath9k_rng_stop(struct ath_softc *sc);
+#else
+static inline void ath9k_rng_start(struct ath_softc *sc)
+{
+}
+
+static inline void ath9k_rng_stop(struct ath_softc *sc)
+{
+}
+#endif
+
 static inline void ath_read_cachesize(struct ath_common *common, int *csz)
 {
 	common->bus_ops->read_cachesize(common, csz);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index d184e682e636..c1b33fdcca08 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -739,6 +739,8 @@ static int ath9k_start(struct ieee80211_hw *hw)
 
 	ath9k_ps_restore(sc);
 
+	ath9k_rng_start(sc);
+
 	return 0;
 }
 
@@ -828,6 +830,8 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 
 	ath9k_deinit_channel_context(sc);
 
+	ath9k_rng_stop(sc);
+
 	mutex_lock(&sc->mutex);
 
 	ath_cancel_work(sc);
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
new file mode 100644
index 000000000000..c9cb2aad7b6f
--- /dev/null
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -0,0 +1,107 @@
+/*
+ * 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 * 320) >> 10) /* quality: 320/1024 */
+
+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 int ath9k_rng_kthread(void *data)
+{
+	int bytes_read;
+	struct ath_softc *sc = data;
+	u32 *rng_buf;
+
+	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)) {
+			msleep_interruptible(10);
+			continue;
+		}
+
+		/* 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);
+}