PCI: Make the intel-iommu_wait_op macro work when jiffies are not running

The following patch changes the intel-iommu.c code to use the TSC
instead of jiffies for detecting bad DMAR functionality.  Some systems
with bad bios's have been seen to hang in early boot spinning in the
IOMMU_WAIT_IO macro.  This patch will replace the infinite loop with a call to
panic.
Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/intel-iommu.c

@@ -49,7 +49,7 @@
 
 #define DEFAULT_DOMAIN_ADDRESS_WIDTH 48
 
-#define DMAR_OPERATION_TIMEOUT (HZ*60) /* 1m */
+#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000) /* 10sec */
 
 #define DOMAIN_MAX_ADDR(gaw) ((((u64)1) << gaw) - 1)
 
@@ -490,12 +490,12 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
 
 #define IOMMU_WAIT_OP(iommu, offset, op, cond, sts) \
 {\
-	unsigned long start_time = jiffies;\
+	cycles_t start_time = get_cycles();\
 	while (1) {\
 		sts = op (iommu->reg + offset);\
 		if (cond)\
 			break;\
-		if (time_after(jiffies, start_time + DMAR_OPERATION_TIMEOUT))\
+		if (DMAR_OPERATION_TIMEOUT < (get_cycles() - start_time))\
 			panic("DMAR hardware is malfunctioning\n");\
 		cpu_relax();\
 	}\