ath9k: export HW random number generator

We measured the FFT-based entropy in 3 ways, Shannon entropy,
collision entropy, and directly measured min-entropy. Just to
be conservative, we recommend the estimated min-Entropy to be
10 bits per 16-bit value.

Analysis was done by Jacobson,David(djacobso@qti.qualcomm.com).

Signed-off-by: Miaoqing Pan <miaoqing@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/ath/ath9k/Kconfig b/drivers/net/wireless/ath/ath9k/Kconfig
index fee0cadb0f5ed592fba313f1040b2e1f5ed1ebde..bde62ec98bc7fdda37f996b350adde78e31e8f77 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/Kconfig
+++ b/drivers/net/wireless/ath/ath9k/Kconfig
@@ -176,3 +176,10 @@ 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---
+         Provides a hardware random number generator to the kernel.

diff --git a/drivers/net/wireless/ath/ath9k/Makefile b/drivers/net/wireless/ath/ath9k/Makefile
index ecda613c2d547d4278ac0665c8c0eeaaf594c66a..76f9dc37500b18f70e4de8516b3ecb98ef24b511 100644 (file)
--- 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 a7a81b3969cec7e79b2cb73959c4d8ff1fb7489e..45596e5ae4db38a9084c9aaeadecd418f13551f9 100644 (file)
--- 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 +1042,12 @@ struct ath_softc {
        u32 wow_intr_before_sleep;
        bool force_wow;
 #endif
+
+#ifdef CONFIG_ATH9K_HWRNG
+       struct hwrng rng;
+       bool rng_initialized;
+       u32 rng_last;
+#endif
 };
 
 /********/
@@ -1063,6 +1070,22 @@ static inline int ath9k_tx99_send(struct ath_softc *sc,
 }
 #endif /* CONFIG_ATH9K_TX99 */
 
+/***************************/
+/* Random Number Generator */
+/***************************/
+#ifdef CONFIG_ATH9K_HWRNG
+void ath9k_rng_register(struct ath_softc *sc);
+void ath9k_rng_unregister(struct ath_softc *sc);
+#else
+static inline void ath9k_rng_register(struct ath_softc *sc)
+{
+}
+
+static inline void ath9k_rng_unregister(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 cfd45cb8ccfc13df856bb4bbe07d8e2bef21228f..5916ab2f4a3de9b34d4ab83225e4338741025d9e 100644 (file)
--- 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_register(sc);
+
        return 0;
 }
 
@@ -828,6 +830,8 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 
        ath9k_deinit_channel_context(sc);
 
+       ath9k_rng_unregister(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 (file)
index 0000000..d8fa7a5
--- /dev/null
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -0,0 +1,75 @@
+/*
+ * 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 "ath9k.h"
+#include "hw.h"
+#include "ar9003_phy.h"
+
+static int ath9k_rng_data_read(struct hwrng *rng, u32 *data)
+{
+       u32 v1, v2;
+       struct ath_softc *sc = (struct ath_softc *)rng->priv;
+       struct ath_hw *ah = sc->sc_ah;
+
+       ath9k_ps_wakeup(sc);
+
+       REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 5);
+       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);
+
+       v1 = REG_READ(ah, AR_PHY_TST_ADC);
+       v2 = REG_READ(ah, AR_PHY_TST_ADC);
+
+       ath9k_ps_restore(sc);
+
+       /* wait for data ready */
+       if (v1 && v2 && sc->rng_last != v1 && v1 != v2) {
+               *data = (v1 & 0xffff) | (v2 << 16);
+               sc->rng_last = v2;
+
+               return sizeof(u32);
+       }
+
+       sc->rng_last = v2;
+
+       return 0;
+}
+
+void ath9k_rng_register(struct ath_softc *sc)
+{
+       struct ath_hw *ah = sc->sc_ah;
+
+       if (WARN_ON(sc->rng_initialized))
+               return;
+
+       if (!AR_SREV_9300_20_OR_LATER(ah))
+               return;
+
+       sc->rng.name = "ath9k";
+       sc->rng.data_read = ath9k_rng_data_read;
+       sc->rng.priv = (unsigned long)sc;
+
+       if (!hwrng_register(&sc->rng))
+               sc->rng_initialized = true;
+}
+
+void ath9k_rng_unregister(struct ath_softc *sc)
+{
+       if (sc->rng_initialized) {
+               hwrng_unregister(&sc->rng);
+               sc->rng_initialized = false;
+       }
+}