iwlwifi: implement iwl5000_calc_rssi

This patch implements rssi calculation for 5000 HW.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index 56dbc8144a34..c5b104fd149c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -1459,6 +1459,44 @@ static void iwl5000_temperature(struct iwl_priv *priv)
         priv->temperature = le32_to_cpu(priv->statistics.general.temperature);
 }
 
+/* Calc max signal level (dBm) among 3 possible receivers */
+static int iwl5000_calc_rssi(struct iwl_priv *priv,
+                             struct iwl_rx_phy_res *rx_resp)
+{
+        /* data from PHY/DSP regarding signal strength, etc.,
+         *   contents are always there, not configurable by host
+         */
+        struct iwl5000_non_cfg_phy *ncphy =
+                (struct iwl5000_non_cfg_phy *)rx_resp->non_cfg_phy_buf;
+        u32 val, rssi_a, rssi_b, rssi_c, max_rssi;
+        u8 agc;
+
+        val  = le32_to_cpu(ncphy->non_cfg_phy[IWL50_RX_RES_AGC_IDX]);
+        agc = (val & IWL50_OFDM_AGC_MSK) >> IWL50_OFDM_AGC_BIT_POS;
+
+        /* Find max rssi among 3 possible receivers.
+         * These values are measured by the digital signal processor (DSP).
+         * They should stay fairly constant even as the signal strength varies,
+         *   if the radio's automatic gain control (AGC) is working right.
+         * AGC value (see below) will provide the "interesting" info.
+         */
+        val = le32_to_cpu(ncphy->non_cfg_phy[IWL50_RX_RES_RSSI_AB_IDX]);
+        rssi_a = (val & IWL50_OFDM_RSSI_A_MSK) >> IWL50_OFDM_RSSI_A_BIT_POS;
+        rssi_b = (val & IWL50_OFDM_RSSI_B_MSK) >> IWL50_OFDM_RSSI_B_BIT_POS;
+        val = le32_to_cpu(ncphy->non_cfg_phy[IWL50_RX_RES_RSSI_C_IDX]);
+        rssi_c = (val & IWL50_OFDM_RSSI_C_MSK) >> IWL50_OFDM_RSSI_C_BIT_POS;
+
+        max_rssi = max_t(u32, rssi_a, rssi_b);
+        max_rssi = max_t(u32, max_rssi, rssi_c);
+
+        IWL_DEBUG_STATS("Rssi In A %d B %d C %d Max %d AGC dB %d\n",
+                rssi_a, rssi_b, rssi_c, max_rssi, agc);
+
+        /* dBm = max_rssi dB - agc dB - constant.
+         * Higher AGC (higher radio gain) means lower signal. */
+        return max_rssi - agc - IWL_RSSI_OFFSET;
+}
+
 static struct iwl_hcmd_ops iwl5000_hcmd = {
         .rxon_assoc = iwl5000_send_rxon_assoc,
 };
@@ -1469,6 +1507,7 @@ static struct iwl_hcmd_utils_ops iwl5000_hcmd_utils = {
         .gain_computation = iwl5000_gain_computation,
         .chain_noise_reset = iwl5000_chain_noise_reset,
         .rts_tx_cmd_flag = iwl5000_rts_tx_cmd_flag,
+        .calc_rssi = iwl5000_calc_rssi,
 };
 
 static struct iwl_lib_ops iwl5000_lib = {