iwlwifi: add comments to EEPROM stuff
Add comments to EEPROM stuff.
Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965.c b/drivers/net/wireless/iwlwifi/iwl-4965.c
index 5dee8e5..7d95de9d0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965.c
+++ b/drivers/net/wireless/iwlwifi/iwl-4965.c
@@ -4687,14 +4687,23 @@
{0}
};
+/*
+ * The device's EEPROM semaphore prevents conflicts between driver and uCode
+ * when accessing the EEPROM; each access is a series of pulses to/from the
+ * EEPROM chip, not a single event, so even reads could conflict if they
+ * weren't arbitrated by the semaphore.
+ */
int iwl4965_eeprom_acquire_semaphore(struct iwl4965_priv *priv)
{
u16 count;
int rc;
for (count = 0; count < EEPROM_SEM_RETRY_LIMIT; count++) {
+ /* Request semaphore */
iwl4965_set_bit(priv, CSR_HW_IF_CONFIG_REG,
CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM);
+
+ /* See if we got it */
rc = iwl4965_poll_bit(priv, CSR_HW_IF_CONFIG_REG,
CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM,
CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM,