iwl3945: update iwl3945_apm_init()

Update iwl3945_apm_init() to set up device registers in sequence most recently
recommended by factory.

Add resets for APMG interrupts and radio chip, formerly done only in
iwl3945_apm_reset(); moving them here assures that apm_init() will do
a complete job of preparing hardware not only after platform boot,
but also after apm_stop() has executed (due to rfkill, ifconfig down,
driver unload, etc.).  This is in preparation to completely remove apm_reset().

Add some comments.

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index 4115672e233834a11275db2c44997b0dd1905128..89f82396a13a9d61fe231fcce4bf1349da57eb69 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -982,23 +982,45 @@ static int iwl3945_txq_ctx_reset(struct iwl_priv *priv)
        return rc;
 }
 
+/*
+ * Start up NIC's basic functionality after it has been reset
+ * (e.g. after platform boot, or shutdown via iwl3945_apm_stop())
+ * NOTE:  This does not load uCode nor start the embedded processor
+ */
 static int iwl3945_apm_init(struct iwl_priv *priv)
 {
        int ret;
 
        iwl_power_initialize(priv);
 
+       /* Configure chip clock phase-lock-loop */
+       iwl_set_bit(priv, CSR_ANA_PLL_CFG, CSR39_ANA_PLL_CFG_VAL);
+
+       /*
+        * Disable L0S exit timer (platform NMI Work/Around)
+        * (does this do anything on 3945, or just 4965 and beyond?)
+        */
        iwl_set_bit(priv, CSR_GIO_CHICKEN_BITS,
                          CSR_GIO_CHICKEN_BITS_REG_BIT_DIS_L0S_EXIT_TIMER);
 
-       /* disable L0s without affecting L1 :don't wait for ICH L0s bug W/A) */
+       /* Disable L0s without affecting L1; don't wait for ICH (L0s bug W/A) */
        iwl_set_bit(priv, CSR_GIO_CHICKEN_BITS,
                          CSR_GIO_CHICKEN_BITS_REG_BIT_L1A_NO_L0S_RX);
 
-       /* set "initialization complete" bit to move adapter
-       * D0U* --> D0A* state */
+       /* Set FH wait threshold to maximum (HW error during stress W/A) */
+       iwl_set_bit(priv, CSR_DBG_HPET_MEM_REG, CSR_DBG_HPET_MEM_REG_VAL);
+
+       /*
+        * Set "initialization complete" bit to move adapter from
+        * D0U* --> D0A* (powered-up active) state.
+        */
        iwl_set_bit(priv, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_INIT_DONE);
 
+       /*
+        * Wait for clock stabilization; once stabilized, access to
+        * device-internal resources is supported, e.g. iwl_write_prph()
+        * and accesses to uCode SRAM.
+        */
        ret = iwl_poll_bit(priv, CSR_GP_CNTRL,
                        CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY,
                        CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY, 25000);
@@ -1007,13 +1029,21 @@ static int iwl3945_apm_init(struct iwl_priv *priv)
                goto out;
        }
 
-       /* enable DMA */
+       /* Enable DMA and BSM clocks, wait for them to stabilize */
        iwl_write_prph(priv, APMG_CLK_CTRL_REG, APMG_CLK_VAL_DMA_CLK_RQT |
                                                APMG_CLK_VAL_BSM_CLK_RQT);
-
        udelay(20);
 
-       /* disable L1-Active */
+       /* Clear APMG (NIC's internal power management) interrupts */
+       iwl_write_prph(priv, APMG_RTC_INT_MSK_REG, 0x0);
+       iwl_write_prph(priv, APMG_RTC_INT_STT_REG, 0xFFFFFFFF);
+
+       /* Reset radio chip */
+       iwl_set_bits_prph(priv, APMG_PS_CTRL_REG, APMG_PS_CTRL_VAL_RESET_REQ);
+       udelay(5);
+       iwl_clear_bits_prph(priv, APMG_PS_CTRL_REG, APMG_PS_CTRL_VAL_RESET_REQ);
+
+       /* Disable L1-Active */
        iwl_set_bits_prph(priv, APMG_PCIDEV_STT_REG,
                          APMG_PCIDEV_STT_VAL_L1_ACT_DIS);