iwlwifi: Legacy isr only used by legacy devices

Move iwl_isr_legacy function to iwl_legacy.c since it only used
by legacy devices.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-legacy.c b/drivers/net/wireless/iwlwifi/iwl-legacy.c
index b735fef..f49e500 100644
--- a/drivers/net/wireless/iwlwifi/iwl-legacy.c
+++ b/drivers/net/wireless/iwlwifi/iwl-legacy.c
@@ -31,6 +31,7 @@
 
 #include "iwl-dev.h"
 #include "iwl-core.h"
+#include "iwl-helpers.h"
 #include "iwl-legacy.h"
 
 /**
@@ -558,3 +559,64 @@
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 EXPORT_SYMBOL(iwl_legacy_mac_bss_info_changed);
+
+irqreturn_t iwl_isr_legacy(int irq, void *data)
+{
+	struct iwl_priv *priv = data;
+	u32 inta, inta_mask;
+	u32 inta_fh;
+	unsigned long flags;
+	if (!priv)
+		return IRQ_NONE;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/* Disable (but don't clear!) interrupts here to avoid
+	 *    back-to-back ISRs and sporadic interrupts from our NIC.
+	 * If we have something to service, the tasklet will re-enable ints.
+	 * If we *don't* have something, we'll re-enable before leaving here. */
+	inta_mask = iwl_read32(priv, CSR_INT_MASK);  /* just for debug */
+	iwl_write32(priv, CSR_INT_MASK, 0x00000000);
+
+	/* Discover which interrupts are active/pending */
+	inta = iwl_read32(priv, CSR_INT);
+	inta_fh = iwl_read32(priv, CSR_FH_INT_STATUS);
+
+	/* Ignore interrupt if there's nothing in NIC to service.
+	 * This may be due to IRQ shared with another device,
+	 * or due to sporadic interrupts thrown from our NIC. */
+	if (!inta && !inta_fh) {
+		IWL_DEBUG_ISR(priv,
+			"Ignore interrupt, inta == 0, inta_fh == 0\n");
+		goto none;
+	}
+
+	if ((inta == 0xFFFFFFFF) || ((inta & 0xFFFFFFF0) == 0xa5a5a5a0)) {
+		/* Hardware disappeared. It might have already raised
+		 * an interrupt */
+		IWL_WARN(priv, "HARDWARE GONE?? INTA == 0x%08x\n", inta);
+		goto unplugged;
+	}
+
+	IWL_DEBUG_ISR(priv, "ISR inta 0x%08x, enabled 0x%08x, fh 0x%08x\n",
+		      inta, inta_mask, inta_fh);
+
+	inta &= ~CSR_INT_BIT_SCD;
+
+	/* iwl_irq_tasklet() will service interrupts and re-enable them */
+	if (likely(inta || inta_fh))
+		tasklet_schedule(&priv->irq_tasklet);
+
+unplugged:
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return IRQ_HANDLED;
+
+none:
+	/* re-enable interrupts here since we don't have anything to service. */
+	/* only Re-enable if diabled by irq */
+	if (test_bit(STATUS_INT_ENABLED, &priv->status))
+		iwl_enable_interrupts(priv);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return IRQ_NONE;
+}
+EXPORT_SYMBOL(iwl_isr_legacy);