iommu/arm-smmu: Polled IRQs

It's not just Marvin Gaye who wants to know what's going on.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>

drivers/iommu/arm/arm-smmu/arm-smmu.c

@@ -55,6 +55,8 @@
 #define MSI_IOVA_BASE			0x8000000
 #define MSI_IOVA_LENGTH			0x100000
 
+#define ARM_SMMU_TIMER_POLL		ns_to_ktime(NSEC_PER_MSEC)
+
 static int force_stage;
 module_param(force_stage, int, S_IRUGO);
 MODULE_PARM_DESC(force_stage,
@@ -458,6 +460,16 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
+static enum hrtimer_restart arm_smmu_timer_handler(struct hrtimer *hrtimer)
+{
+	struct arm_smmu_device *smmu = container_of(hrtimer, struct arm_smmu_device, hrtimer);
+
+	arm_smmu_global_fault(0, smmu);
+
+	hrtimer_forward_now(hrtimer, ARM_SMMU_TIMER_POLL);
+	return HRTIMER_RESTART;
+}
+
 static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
@@ -1700,6 +1712,8 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
 	/* Push the button */
 	arm_smmu_tlb_sync_global(smmu);
 	arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_sCR0, reg);
+
+	hrtimer_start(&smmu->hrtimer, ARM_SMMU_TIMER_POLL, HRTIMER_MODE_REL);
 }
 
 static int arm_smmu_id_size_to_bits(int size)
@@ -2213,6 +2227,8 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 			return err;
 		}
 	}
+	hrtimer_init(&smmu->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	smmu->hrtimer.function = arm_smmu_timer_handler;
 
 	err = iommu_device_sysfs_add(&smmu->iommu, smmu->dev, NULL,
 				     "smmu.%pa", &ioaddr);

drivers/iommu/arm/arm-smmu/arm-smmu.h

@@ -321,6 +321,7 @@ struct arm_smmu_device {
 	unsigned int			*irqs;
 	struct clk_bulk_data		*clks;
 	int				num_clks;
+	struct hrtimer			hrtimer;
 
 	spinlock_t			global_sync_lock;