iommu/riscv: Add command queue lock

Add a raw spinlock to the RISC-V IOMMU queue state so command queue
publishing can be serialized by a later change.

Fixes: 856c0cfe5c ("iommu/riscv: Command and fault queue support")
Signed-off-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

drivers/iommu/riscv/iommu.c

@@ -1560,6 +1560,7 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
 	int rc;
 
 	RISCV_IOMMU_QUEUE_INIT(&iommu->cmdq, CQ);
+	raw_spin_lock_init(&iommu->cmdq.lock);
 	RISCV_IOMMU_QUEUE_INIT(&iommu->fltq, FQ);
 
 	rc = riscv_iommu_init_check(iommu);

drivers/iommu/riscv/iommu.h

@@ -12,6 +12,7 @@
 #define _RISCV_IOMMU_H_
 
 #include <linux/iommu.h>
+#include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/iopoll.h>
 
@@ -23,6 +24,7 @@ struct riscv_iommu_queue {
 	atomic_t prod;				/* unbounded producer allocation index */
 	atomic_t head;				/* unbounded shadow ring buffer consumer index */
 	atomic_t tail;				/* unbounded shadow ring buffer producer index */
+	raw_spinlock_t lock;			/* serialize queue publishing */
 	unsigned int mask;			/* index mask, queue length - 1 */
 	unsigned int irq;			/* allocated interrupt number */
 	struct riscv_iommu_device *iommu;	/* iommu device handling the queue when active */