ath9k: gather entropy from raw ADC I/Q samples (use the least significant bit only)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 38486

1 files changed, 200 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/550-ath9k_entropy_from_adc.patch b/package/kernel/mac80211/patches/550-ath9k_entropy_from_adc.patch
new file mode 100644
index 0000000..d633345
--- /dev/null
+++ b/package/kernel/mac80211/patches/550-ath9k_entropy_from_adc.patch
@@ -0,0 +1,200 @@
+--- a/drivers/net/wireless/ath/ath9k/hw.h
++++ b/drivers/net/wireless/ath/ath9k/hw.h
+@@ -676,6 +676,7 @@ struct ath_spec_scan {
+  * @config_pci_powersave:
+  * @calibrate: periodic calibration for NF, ANI, IQ, ADC gain, ADC-DC
+  *
++ * @get_adc_entropy: get entropy from the raw ADC I/Q output
+  * @spectral_scan_config: set parameters for spectral scan and enable/disable it
+  * @spectral_scan_trigger: trigger a spectral scan run
+  * @spectral_scan_wait: wait for a spectral scan run to finish
+@@ -698,6 +699,7 @@ struct ath_hw_ops {
+ 			struct ath_hw_antcomb_conf *antconf);
+ 	void (*antdiv_comb_conf_set)(struct ath_hw *ah,
+ 			struct ath_hw_antcomb_conf *antconf);
++	void (*get_adc_entropy)(struct ath_hw *ah, u8 *buf, size_t len);
+ 	void (*spectral_scan_config)(struct ath_hw *ah,
+ 				     struct ath_spec_scan *param);
+ 	void (*spectral_scan_trigger)(struct ath_hw *ah);
+--- a/drivers/net/wireless/ath/ath9k/ar9003_phy.c
++++ b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
+@@ -1609,6 +1609,26 @@ static void ar9003_hw_spectral_scan_wait
+ 	}
+ }
+ 
++static void ar9003_hw_get_adc_entropy(struct ath_hw *ah, u8 *buf, size_t len)
++{
++	int i, j;
++
++	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);
++
++	memset(buf, 0, len);
++	for (i = 0; i < len; i++) {
++		for (j = 0; j < 4; j++) {
++			u32 regval = REG_READ(ah, AR_PHY_TST_ADC);
++
++			buf[i] <<= 2;
++			buf[i] |= (regval & 1) | ((regval & BIT(10)) >> 9);
++			udelay(1);
++		}
++	}
++}
++
+ void ar9003_hw_attach_phy_ops(struct ath_hw *ah)
+ {
+ 	struct ath_hw_private_ops *priv_ops = ath9k_hw_private_ops(ah);
+@@ -1639,6 +1659,7 @@ void ar9003_hw_attach_phy_ops(struct ath
+ 	priv_ops->set_radar_params = ar9003_hw_set_radar_params;
+ 	priv_ops->fast_chan_change = ar9003_hw_fast_chan_change;
+ 
++	ops->get_adc_entropy = ar9003_hw_get_adc_entropy;
+ 	ops->antdiv_comb_conf_get = ar9003_hw_antdiv_comb_conf_get;
+ 	ops->antdiv_comb_conf_set = ar9003_hw_antdiv_comb_conf_set;
+ 	ops->spectral_scan_config = ar9003_hw_spectral_scan_config;
+--- a/drivers/net/wireless/ath/ath9k/init.c
++++ b/drivers/net/wireless/ath/ath9k/init.c
+@@ -794,7 +794,8 @@ static void ath9k_init_txpower_limits(st
+ 	if (ah->caps.hw_caps & ATH9K_HW_CAP_5GHZ)
+ 		ath9k_init_band_txpower(sc, IEEE80211_BAND_5GHZ);
+ 
+-	ah->curchan = curchan;
++	if (curchan)
++		ah->curchan = curchan;
+ }
+ 
+ void ath9k_reload_chainmask_settings(struct ath_softc *sc)
+@@ -940,6 +941,18 @@ void ath9k_set_hw_capab(struct ath_softc
+ 	SET_IEEE80211_PERM_ADDR(hw, common->macaddr);
+ }
+ 
++static void ath_get_initial_entropy(struct ath_softc *sc)
++{
++	struct ath_hw *ah = sc->sc_ah;
++	char buf[256];
++
++	/* reuse last channel initialized by the tx power test */
++	ath9k_hw_reset(ah, ah->curchan, NULL, false);
++
++	ath9k_hw_get_adc_entropy(ah, buf, sizeof(buf));
++	add_device_randomness(buf, sizeof(buf));
++}
++
+ int ath9k_init_device(u16 devid, struct ath_softc *sc,
+ 		    const struct ath_bus_ops *bus_ops)
+ {
+@@ -985,6 +998,8 @@ int ath9k_init_device(u16 devid, struct 
+ 		ARRAY_SIZE(ath9k_tpt_blink));
+ #endif
+ 
++	ath_get_initial_entropy(sc);
++
+ 	/* Register with mac80211 */
+ 	error = ieee80211_register_hw(hw);
+ 	if (error)
+--- a/drivers/net/wireless/ath/ath9k/hw-ops.h
++++ b/drivers/net/wireless/ath/ath9k/hw-ops.h
+@@ -78,6 +78,12 @@ static inline void ath9k_hw_antdiv_comb_
+ 	ath9k_hw_ops(ah)->antdiv_comb_conf_set(ah, antconf);
+ }
+ 
++static inline void ath9k_hw_get_adc_entropy(struct ath_hw *ah,
++		u8 *buf, size_t len)
++{
++	ath9k_hw_ops(ah)->get_adc_entropy(ah, buf, len);
++}
++
+ #ifdef CPTCFG_ATH9K_BTCOEX_SUPPORT
+ 
+ static inline void ath9k_hw_set_bt_ant_diversity(struct ath_hw *ah, bool enable)
+--- a/drivers/net/wireless/ath/ath9k/link.c
++++ b/drivers/net/wireless/ath/ath9k/link.c
+@@ -342,6 +342,11 @@ void ath_ani_calibrate(unsigned long dat
+ 	unsigned int timestamp = jiffies_to_msecs(jiffies);
+ 	u32 cal_interval, short_cal_interval, long_cal_interval;
+ 	unsigned long flags;
++	char buf[256];
++
++	/* gather entropy */
++	ath9k_hw_get_adc_entropy(ah, buf, sizeof(buf));
++	add_device_randomness(buf, sizeof(buf));
+ 
+ 	if (ah->caldata && ah->caldata->nfcal_interference)
+ 		long_cal_interval = ATH_LONG_CALINTERVAL_INT;
+--- a/drivers/net/wireless/ath/ath9k/ar5008_phy.c
++++ b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
+@@ -1299,9 +1299,30 @@ static void ar5008_hw_set_radar_conf(str
+ 	conf->radar_inband = 8;
+ }
+ 
++static void ar5008_hw_get_adc_entropy(struct ath_hw *ah, u8 *buf, size_t len)
++{
++	int i, j;
++
++	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_TEST2, AR_PHY_TEST2_RX_OBS_SEL, 0);
++
++	memset(buf, 0, len);
++	for (i = 0; i < len; i++) {
++		for (j = 0; j < 4; j++) {
++			u32 regval = REG_READ(ah, AR_PHY_TST_ADC);
++
++			buf[i] <<= 2;
++			buf[i] |= (regval & 1) | ((regval & BIT(9)) >> 8);
++			udelay(1);
++		}
++	}
++}
++
+ int ar5008_hw_attach_phy_ops(struct ath_hw *ah)
+ {
+ 	struct ath_hw_private_ops *priv_ops = ath9k_hw_private_ops(ah);
++	struct ath_hw_ops *ops = ath9k_hw_ops(ah);
+ 	static const u32 ar5416_cca_regs[6] = {
+ 		AR_PHY_CCA,
+ 		AR_PHY_CH1_CCA,
+@@ -1316,6 +1337,8 @@ int ar5008_hw_attach_phy_ops(struct ath_
+ 	if (ret)
+ 	    return ret;
+ 
++	ops->get_adc_entropy = ar5008_hw_get_adc_entropy;
++
+ 	priv_ops->rf_set_freq = ar5008_hw_set_channel;
+ 	priv_ops->spur_mitigate_freq = ar5008_hw_spur_mitigate;
+ 
+--- a/drivers/net/wireless/ath/ath9k/ar9002_phy.h
++++ b/drivers/net/wireless/ath/ath9k/ar9002_phy.h
+@@ -20,6 +20,12 @@
+ #define PHY_AGC_CLR             0x10000000
+ #define RFSILENT_BB             0x00002000
+ 
++#define AR_PHY_TEST_BBB_OBS_SEL       0x780000
++#define AR_PHY_TEST_BBB_OBS_SEL_S     19
++
++#define AR_PHY_TEST_RX_OBS_SEL_BIT5_S 23
++#define AR_PHY_TEST_RX_OBS_SEL_BIT5   (1 << AR_PHY_TEST_RX_OBS_SEL_BIT5_S)
++
+ #define AR_PHY_TURBO                0x9804
+ #define AR_PHY_FC_TURBO_MODE        0x00000001
+ #define AR_PHY_FC_TURBO_SHORT       0x00000002
+@@ -36,6 +42,9 @@
+ 
+ #define AR_PHY_TEST2			0x9808
+ 
++#define AR_PHY_TEST2_RX_OBS_SEL        0x3C00
++#define AR_PHY_TEST2_RX_OBS_SEL_S      10
++
+ #define AR_PHY_TIMING2           0x9810
+ #define AR_PHY_TIMING3           0x9814
+ #define AR_PHY_TIMING3_DSC_MAN   0xFFFE0000
+@@ -390,6 +399,8 @@
+ #define AR_PHY_RFBUS_GRANT       0x9C20
+ #define AR_PHY_RFBUS_GRANT_EN    0x00000001
+ 
++#define AR_PHY_TST_ADC      0x9C24
++
+ #define AR_PHY_CHAN_INFO_GAIN_DIFF             0x9CF4
+ #define AR_PHY_CHAN_INFO_GAIN_DIFF_UPPER_LIMIT 320
+