ath9k: add noise floor override option

Introduce a debugfs option to manually override the noise floor,
ignoring the automatically tuned noise floor of the driver/hw.

In my tests with a AR9580 based module and a tx99 5 MHz interferer,
I could tune the noisefloor to -95 dBm or above to allow communication
again. The automatic noise floor calibration sometimes could adapt to
the situation as well, but not reliably and permanently.

I would consider this "feature" experimental and interesting for people
debugging the noise floor calibration or other effects of the hardware.

Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index 0f71146b781d12dfcb5907fdecb3843b4260ad4b..13ab6bc467753a93748e7c4def72c0292eeca179 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -254,7 +254,9 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
                        if ((i >= AR5416_MAX_CHAINS) && !IS_CHAN_HT40(chan))
                                continue;
 
-                       if (h)
+                       if (ah->nf_override)
+                               nfval = ah->nf_override;
+                       else if (h)
                                nfval = h[i].privNF;
                        else
                                nfval = default_nf;
@@ -348,6 +350,7 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
 
        return 0;
 }
+EXPORT_SYMBOL(ath9k_hw_loadnf);
 
 
 static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)

diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 43930c336987ee4fc802b3219a65fe33fd98073e..2e64977a8ab664c64d3ece94f5fd57ce0c13f729 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1191,6 +1191,65 @@ static const struct file_operations fops_tpc = {
        .llseek = default_llseek,
 };
 
+static ssize_t read_file_nf_override(struct file *file,
+                                    char __user *user_buf,
+                                    size_t count, loff_t *ppos)
+{
+       struct ath_softc *sc = file->private_data;
+       struct ath_hw *ah = sc->sc_ah;
+       char buf[32];
+       unsigned int len;
+
+       if (ah->nf_override == 0)
+               len = sprintf(buf, "off\n");
+       else
+               len = sprintf(buf, "%d\n", ah->nf_override);
+
+       return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t write_file_nf_override(struct file *file,
+                                     const char __user *user_buf,
+                                     size_t count, loff_t *ppos)
+{
+       struct ath_softc *sc = file->private_data;
+       struct ath_hw *ah = sc->sc_ah;
+       long val;
+       char buf[32];
+       ssize_t len;
+
+       len = min(count, sizeof(buf) - 1);
+       if (copy_from_user(buf, user_buf, len))
+               return -EFAULT;
+
+       buf[len] = '\0';
+       if (strncmp("off", buf, 3) == 0)
+               val = 0;
+       else if (kstrtol(buf, 0, &val))
+               return -EINVAL;
+
+       if (val > 0)
+               return -EINVAL;
+
+       if (val < -120)
+               return -EINVAL;
+
+       ah->nf_override = val;
+
+       if (ah->curchan)
+               ath9k_hw_loadnf(ah, ah->curchan);
+
+       return count;
+}
+
+static const struct file_operations fops_nf_override = {
+       .read = read_file_nf_override,
+       .write = write_file_nf_override,
+       .open = simple_open,
+       .owner = THIS_MODULE,
+       .llseek = default_llseek,
+};
+
 /* Ethtool support for get-stats */
 
 #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
@@ -1402,5 +1461,8 @@ int ath9k_init_debug(struct ath_hw *ah)
        debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
                           sc->debug.debugfs_phy, &sc->airtime_flags);
 
+       debugfs_create_file("nf_override", S_IRUSR | S_IWUSR,
+                           sc->debug.debugfs_phy, sc, &fops_nf_override);
+
        return 0;
 }

diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 9cbca1229bac02862211c14d14048f08197dd39d..4ac70827d142c9739c9987cef5cb20cf5ca58776 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -803,6 +803,7 @@ struct ath_hw {
        u32 rfkill_gpio;
        u32 rfkill_polarity;
        u32 ah_flags;
+       s16 nf_override;
 
        bool reset_power_on;
        bool htc_reset_init;