ath9k: add TX99 support

TX99 support enables Specific Absorption Rate (SAR) testing.
SAR is the unit of measurement for the amount of radio frequency(RF)
absorbed by the body when using a wireless device. The RF
exposure limits used are expressed in the terms of SAR, which is a
measure of the electric and magnetic field strength and power density
for transmitters operating at frequencies from 300 kHz to 100 GHz.

Regulatory bodies around the world require that wireless device
be evaluated to meet the RF exposure limits set forth in the
governmental SAR regulations.

In the examples below, for more bit rate options see the iw TX bitrate
setting documentation:

http://wireless.kernel.org/en/users/Documentation/iw#Modifying_transmit_bitrates

Example usage:

iw phy phy0 interface add moni0 type monitor
ip link set dev moni0 up

iw dev moni0 set channel 36 HT40+
iw set bitrates mcs-5 4

echo 10 > /sys/kernel/debug/ieee80211/phy0/ath9k/tx99_power
echo 1  > /sys/kernel/debug/ieee80211/phy0/ath9k/tx99

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 118 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 1be2c78..83a2c59 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1050,6 +1050,9 @@ static ssize_t write_file_spec_scan_ctl(struct file *file,
 	char buf[32];
 	ssize_t len;
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return -EOPNOTSUPP;
+
 	len = min(count, sizeof(buf) - 1);
 	if (copy_from_user(buf, user_buf, len))
 		return -EFAULT;
@@ -1775,6 +1778,111 @@ void ath9k_deinit_debug(struct ath_softc *sc)
 	}
 }
 
+static ssize_t read_file_tx99(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	char buf[3];
+	unsigned int len;
+
+	len = sprintf(buf, "%d\n", sc->tx99_state);
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t write_file_tx99(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
+	char buf[32];
+	bool start;
+	ssize_t len;
+	int r;
+
+	if (sc->nvifs > 1)
+		return -EOPNOTSUPP;
+
+	len = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, len))
+		return -EFAULT;
+
+	if (strtobool(buf, &start))
+		return -EINVAL;
+
+	if (start == sc->tx99_state) {
+		if (!start)
+			return count;
+		ath_dbg(common, XMIT, "Resetting TX99\n");
+		ath9k_tx99_deinit(sc);
+	}
+
+	if (!start) {
+		ath9k_tx99_deinit(sc);
+		return count;
+	}
+
+	r = ath9k_tx99_init(sc);
+	if (r)
+		return r;
+
+	return count;
+}
+
+static const struct file_operations fops_tx99 = {
+	.read = read_file_tx99,
+	.write = write_file_tx99,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+static ssize_t read_file_tx99_power(struct file *file,
+				    char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	char buf[32];
+	unsigned int len;
+
+	len = sprintf(buf, "%d (%d dBm)\n",
+		      sc->tx99_power,
+		      sc->tx99_power / 2);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t write_file_tx99_power(struct file *file,
+				     const char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	int r;
+	u8 tx_power;
+
+	r = kstrtou8_from_user(user_buf, count, 0, &tx_power);
+	if (r)
+		return r;
+
+	if (tx_power > MAX_RATE_POWER)
+		return -EINVAL;
+
+	sc->tx99_power = tx_power;
+
+	ath9k_ps_wakeup(sc);
+	ath9k_hw_tx99_set_txpower(sc->sc_ah, sc->tx99_power);
+	ath9k_ps_restore(sc);
+
+	return count;
+}
+
+static const struct file_operations fops_tx99_power = {
+	.read = read_file_tx99_power,
+	.write = write_file_tx99_power,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
 int ath9k_init_debug(struct ath_hw *ah)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
@@ -1866,5 +1974,15 @@ int ath9k_init_debug(struct ath_hw *ah)
 	debugfs_create_file("btcoex", S_IRUSR, sc->debug.debugfs_phy, sc,
 			    &fops_btcoex);
 #endif
+	if (config_enabled(CONFIG_ATH9K_TX99) &&
+	    AR_SREV_9300_20_OR_LATER(ah)) {
+		debugfs_create_file("tx99", S_IRUSR | S_IWUSR,
+				    sc->debug.debugfs_phy, sc,
+				    &fops_tx99);
+		debugfs_create_file("tx99_power", S_IRUSR | S_IWUSR,
+				    sc->debug.debugfs_phy, sc,
+				    &fops_tx99_power);
+	}
+
 	return 0;
 }