i386: insert HPET firmware resource after PCI enumeration has completed

Insert HPET resources after pci probing has been completed in order to
avoid resource conflicts with PCI resource reservation.  With this change
the HPET firmware resources will be identified, but it should also not
cause issues when the HPET address falls on a BAR in a PCI device, and the
PCI enumeration cannot reserve the resources.
Signed-off-by: NAaron Durbin <adurbin@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/i386/kernel/acpi/boot.c

@@ -618,6 +618,8 @@ static int __init acpi_parse_sbf(struct acpi_table_header *table)
 #ifdef CONFIG_HPET_TIMER
 #include <asm/hpet.h>
 
+static struct __initdata resource *hpet_res;
+
 static int __init acpi_parse_hpet(struct acpi_table_header *table)
 {
 	struct acpi_table_hpet *hpet_tbl;
@@ -638,8 +640,42 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table)
 	printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",
 	       hpet_tbl->id, hpet_address);
 
+	/*
+	 * Allocate and initialize the HPET firmware resource for adding into
+	 * the resource tree during the lateinit timeframe.
+	 */
+#define HPET_RESOURCE_NAME_SIZE 9
+	hpet_res = alloc_bootmem(sizeof(*hpet_res) + HPET_RESOURCE_NAME_SIZE);
+
+	if (!hpet_res)
+		return 0;
+
+	memset(hpet_res, 0, sizeof(*hpet_res));
+	hpet_res->name = (void *)&hpet_res[1];
+	hpet_res->flags = IORESOURCE_MEM;
+	snprintf((char *)hpet_res->name, HPET_RESOURCE_NAME_SIZE, "HPET %u",
+		 hpet_tbl->sequence);
+
+	hpet_res->start = hpet_address;
+	hpet_res->end = hpet_address + (1 * 1024) - 1;
+
 	return 0;
 }
+
+/*
+ * hpet_insert_resource inserts the HPET resources used into the resource
+ * tree.
+ */
+static __init int hpet_insert_resource(void)
+{
+	if (!hpet_res)
+		return 1;
+
+	return insert_resource(&iomem_resource, hpet_res);
+}
+
+late_initcall(hpet_insert_resource);
+
 #else
 #define	acpi_parse_hpet	NULL
 #endif