x86: Calgary: Convert detect_calgary() to use iommu_init hook

This changes detect_calgary() to set init_calgary() to
iommu_init hook if detect_calgary() finds the Calgary IOMMU.

We can kill the code to check if we found the IOMMU in
init_calgary() since detect_calgary() sets init_calgary() only
when it found the IOMMU.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
LKML-Reference: <1257849980-22640-3-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 971a3be..47bd419 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -46,6 +46,7 @@
 #include <asm/dma.h>
 #include <asm/rio.h>
 #include <asm/bios_ebda.h>
+#include <asm/x86_init.h>
 
 #ifdef CONFIG_CALGARY_IOMMU_ENABLED_BY_DEFAULT
 int use_calgary __read_mostly = 1;
@@ -1344,6 +1345,8 @@
 	return;
 }
 
+int __init calgary_iommu_init(void);
+
 void __init detect_calgary(void)
 {
 	int bus;
@@ -1445,6 +1448,8 @@
 		/* swiotlb for devices that aren't behind the Calgary. */
 		if (max_pfn > MAX_DMA32_PFN)
 			swiotlb = 1;
+
+		x86_init.iommu.iommu_init = calgary_iommu_init;
 	}
 	return;
 
@@ -1461,12 +1466,6 @@
 {
 	int ret;
 
-	if (no_iommu || (swiotlb && !calgary_detected))
-		return -ENODEV;
-
-	if (!calgary_detected)
-		return -ENODEV;
-
 	/* ok, we're trying to use Calgary - let's roll */
 	printk(KERN_INFO "PCI-DMA: Using Calgary IOMMU\n");