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Diffstat (limited to 'drivers/net/wireless/ath/ath9k/rng.c')
-rw-r--r--drivers/net/wireless/ath/ath9k/rng.c107
1 files changed, 107 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 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);
+}