p54: enhance rssi->dBm database import

This patch fixes several shortcomings of the
previous implementation. Features of the
rewrite include:

 * handles undocumented "0x0000" word at the
   start of the frequency table.
   (Affected some early? DELL 1450 USB devices
    and my Symbol 5GHz miniPCI card.)

 * supports more than just one reference point
   per band. (Also needed for the Symbol card.)

 * ships with default values in case the eeprom
   data is damaged, absent or unsupported.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 153 insertions, 30 deletions

diff --git a/drivers/net/wireless/p54/eeprom.c b/drivers/net/wireless/p54/eeprom.c
index 360bc7810f93..f54e15fcd623 100644
--- a/drivers/net/wireless/p54/eeprom.c
+++ b/drivers/net/wireless/p54/eeprom.c
@@ -55,6 +55,17 @@ static struct ieee80211_rate p54_arates[] = {
         { .bitrate = 540, .hw_value = 11, },
 };
 
+static struct p54_rssi_db_entry p54_rssi_default = {
+        /*
+         * The defaults are taken from usb-logs of the
+         * vendor driver. So, they should be safe to
+         * use in case we can't get a match from the
+         * rssi <-> dBm conversion database.
+         */
+        .mul = 130,
+        .add = -398,
+};
+
 #define CHAN_HAS_CAL            BIT(0)
 #define CHAN_HAS_LIMIT          BIT(1)
 #define CHAN_HAS_CURVE          BIT(2)
@@ -87,6 +98,11 @@ static int p54_get_band_from_freq(u16 freq)
         return -1;
 }
 
+static int same_band(u16 freq, u16 freq2)
+{
+        return p54_get_band_from_freq(freq) == p54_get_band_from_freq(freq2);
+}
+
 static int p54_compare_channels(const void *_a,
                                 const void *_b)
 {
@@ -96,6 +112,15 @@ static int p54_compare_channels(const void *_a,
         return a->freq - b->freq;
 }
 
+static int p54_compare_rssichan(const void *_a,
+                                const void *_b)
+{
+        const struct p54_rssi_db_entry *a = _a;
+        const struct p54_rssi_db_entry *b = _b;
+
+        return a->freq - b->freq;
+}
+
 static int p54_fill_band_bitrates(struct ieee80211_hw *dev,
                                   struct ieee80211_supported_band *band_entry,
                                   enum ieee80211_band band)
@@ -411,33 +436,118 @@ static int p54_convert_rev1(struct ieee80211_hw *dev,
 static const char *p54_rf_chips[] = { "INVALID-0", "Duette3", "Duette2",
         "Frisbee", "Xbow", "Longbow", "INVALID-6", "INVALID-7" };
 
-static void p54_parse_rssical(struct ieee80211_hw *dev, void *data, int len,
-                             u16 type)
+static int p54_parse_rssical(struct ieee80211_hw *dev,
+                             u8 *data, int len, u16 type)
 {
         struct p54_common *priv = dev->priv;
-        int offset = (type == PDR_RSSI_LINEAR_APPROXIMATION_EXTENDED) ? 2 : 0;
-        int entry_size = sizeof(struct pda_rssi_cal_entry) + offset;
-        int num_entries = (type == PDR_RSSI_LINEAR_APPROXIMATION) ? 1 : 2;
-        int i;
+        struct p54_rssi_db_entry *entry;
+        size_t db_len, entries;
+        int offset = 0, i;
+
+        if (type != PDR_RSSI_LINEAR_APPROXIMATION_EXTENDED) {
+                entries = (type == PDR_RSSI_LINEAR_APPROXIMATION) ? 1 : 2;
+                if (len != sizeof(struct pda_rssi_cal_entry) * entries) {
+                        wiphy_err(dev->wiphy, "rssical size mismatch.\n");
+                        goto err_data;
+                }
+        } else {
+                /*
+                 * Some devices (Dell 1450 USB, Xbow 5GHz card, etc...)
+                 * have an empty two byte header.
+                 */
+                if (*((__le16 *)&data[offset]) == cpu_to_le16(0))
+                        offset += 2;
 
-        if (len != (entry_size * num_entries)) {
-                wiphy_err(dev->wiphy,
-                          "unknown rssi calibration data packing type:(%x) len:%d.\n",
-                          type, len);
+                entries = (len - offset) /
+                        sizeof(struct pda_rssi_cal_ext_entry);
 
-                print_hex_dump_bytes("rssical:", DUMP_PREFIX_NONE,
-                                     data, len);
+                if ((len - offset) % sizeof(struct pda_rssi_cal_ext_entry) ||
+                    entries <= 0) {
+                        wiphy_err(dev->wiphy, "invalid rssi database.\n");
+                        goto err_data;
+                }
+        }
 
-                wiphy_err(dev->wiphy, "please report this issue.\n");
-                return;
+        db_len = sizeof(*entry) * entries;
+        priv->rssi_db = kzalloc(db_len + sizeof(*priv->rssi_db), GFP_KERNEL);
+        if (!priv->rssi_db)
+                return -ENOMEM;
+
+        priv->rssi_db->offset = 0;
+        priv->rssi_db->entries = entries;
+        priv->rssi_db->entry_size = sizeof(*entry);
+        priv->rssi_db->len = db_len;
+
+        entry = (void *)((unsigned long)priv->rssi_db->data + priv->rssi_db->offset);
+        if (type == PDR_RSSI_LINEAR_APPROXIMATION_EXTENDED) {
+                struct pda_rssi_cal_ext_entry *cal = (void *) &data[offset];
+
+                for (i = 0; i < entries; i++) {
+                        entry[i].freq = le16_to_cpu(cal[i].freq);
+                        entry[i].mul = (s16) le16_to_cpu(cal[i].mul);
+                        entry[i].add = (s16) le16_to_cpu(cal[i].add);
+                }
+        } else {
+                struct pda_rssi_cal_entry *cal = (void *) &data[offset];
+
+                for (i = 0; i < entries; i++) {
+                        u16 freq;
+                        switch (i) {
+                        case IEEE80211_BAND_2GHZ:
+                                freq = 2437;
+                                break;
+                        case IEEE80211_BAND_5GHZ:
+                                freq = 5240;
+                                break;
+                        }
+
+                        entry[i].freq = freq;
+                        entry[i].mul = (s16) le16_to_cpu(cal[i].mul);
+                        entry[i].add = (s16) le16_to_cpu(cal[i].add);
+                }
         }
 
-        for (i = 0; i < num_entries; i++) {
-                struct pda_rssi_cal_entry *cal = data +
-                                                 (offset + i * entry_size);
-                priv->rssical_db[i].mul = (s16) le16_to_cpu(cal->mul);
-                priv->rssical_db[i].add = (s16) le16_to_cpu(cal->add);
+        /* sort the list by channel frequency */
+        sort(entry, entries, sizeof(*entry), p54_compare_rssichan, NULL);
+        return 0;
+
+err_data:
+        wiphy_err(dev->wiphy,
+                  "rssi calibration data packing type:(%x) len:%d.\n",
+                  type, len);
+
+        print_hex_dump_bytes("rssical:", DUMP_PREFIX_NONE, data, len);
+
+        wiphy_err(dev->wiphy, "please report this issue.\n");
+        return -EINVAL;
+}
+
+struct p54_rssi_db_entry *p54_rssi_find(struct p54_common *priv, const u16 freq)
+{
+        struct p54_rssi_db_entry *entry = (void *)(priv->rssi_db->data +
+                                                   priv->rssi_db->offset);
+        int i, found = -1;
+
+        for (i = 0; i < priv->rssi_db->entries; i++) {
+                if (!same_band(freq, entry[i].freq))
+                        continue;
+
+                if (found == -1) {
+                        found = i;
+                        continue;
+                }
+
+                /* nearest match */
+                if (abs(freq - entry[i].freq) <
+                    abs(freq - entry[found].freq)) {
+                        found = i;
+                        continue;
+                } else {
+                        break;
+                }
         }
+
+        return found < 0 ? &p54_rssi_default : &entry[found];
 }
 
 static void p54_parse_default_country(struct ieee80211_hw *dev,
@@ -628,21 +738,30 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
                 case PDR_RSSI_LINEAR_APPROXIMATION:
                 case PDR_RSSI_LINEAR_APPROXIMATION_DUAL_BAND:
                 case PDR_RSSI_LINEAR_APPROXIMATION_EXTENDED:
-                        p54_parse_rssical(dev, entry->data, data_len,
-                                          le16_to_cpu(entry->code));
+                        err = p54_parse_rssical(dev, entry->data, data_len,
+                                                le16_to_cpu(entry->code));
+                        if (err)
+                                goto err;
                         break;
-                case PDR_RSSI_LINEAR_APPROXIMATION_CUSTOM: {
-                        __le16 *src = (void *) entry->data;
-                        s16 *dst = (void *) &priv->rssical_db;
+                case PDR_RSSI_LINEAR_APPROXIMATION_CUSTOMV2: {
+                        struct pda_custom_wrapper *pda = (void *) entry->data;
+                        __le16 *src;
+                        u16 *dst;
                         int i;
 
-                        if (data_len != sizeof(priv->rssical_db)) {
-                                err = -EINVAL;
-                                goto err;
-                        }
-                        for (i = 0; i < sizeof(priv->rssical_db) /
-                                        sizeof(*src); i++)
+                        if (priv->rssi_db || data_len < sizeof(*pda))
+                                break;
+
+                        priv->rssi_db = p54_convert_db(pda, data_len);
+                        if (!priv->rssi_db)
+                                break;
+
+                        src = (void *) priv->rssi_db->data;
+                        dst = (void *) priv->rssi_db->data;
+
+                        for (i = 0; i < priv->rssi_db->entries; i++)
                                 *(dst++) = (s16) le16_to_cpu(*(src++));
+
                         }
                         break;
                 case PDR_PRISM_PA_CAL_OUTPUT_POWER_LIMITS_CUSTOM: {
@@ -718,6 +837,8 @@ good_eeprom:
                 SET_IEEE80211_PERM_ADDR(dev, perm_addr);
         }
 
+        priv->cur_rssi = &p54_rssi_default;
+
         wiphy_info(dev->wiphy, "hwaddr %pM, MAC:isl38%02x RF:%s\n",
                    dev->wiphy->perm_addr, priv->version,
                    p54_rf_chips[priv->rxhw]);
@@ -728,9 +849,11 @@ err:
         kfree(priv->iq_autocal);
         kfree(priv->output_limit);
         kfree(priv->curve_data);
+        kfree(priv->rssi_db);
         priv->iq_autocal = NULL;
         priv->output_limit = NULL;
         priv->curve_data = NULL;
+        priv->rssi_db = NULL;
 
         wiphy_err(dev->wiphy, "eeprom parse failed!\n");
         return err;