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-rw-r--r--drivers/iommu/amd_iommu.c33
1 files changed, 13 insertions, 20 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index d81c895..1efbef7 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1045,7 +1045,7 @@ static int __iommu_queue_command_sync(struct amd_iommu *iommu,
struct iommu_cmd *cmd,
bool sync)
{
- bool read_head = true;
+ unsigned int count = 0;
u32 left, next_tail;
next_tail = (iommu->cmd_buf_tail + sizeof(*cmd)) % CMD_BUFFER_SIZE;
@@ -1053,33 +1053,26 @@ again:
left = (iommu->cmd_buf_head - next_tail) % CMD_BUFFER_SIZE;
if (left <= 0x20) {
- struct iommu_cmd sync_cmd;
- int ret;
-
- if (read_head) {
- /* Update head and recheck remaining space */
- iommu->cmd_buf_head = readl(iommu->mmio_base +
- MMIO_CMD_HEAD_OFFSET);
- read_head = false;
- goto again;
- }
-
- read_head = true;
-
- iommu->cmd_sem = 0;
+ /* Skip udelay() the first time around */
+ if (count++) {
+ if (count == LOOP_TIMEOUT) {
+ pr_err("AMD-Vi: Command buffer timeout\n");
+ return -EIO;
+ }
- build_completion_wait(&sync_cmd, (u64)&iommu->cmd_sem);
- copy_cmd_to_buffer(iommu, &sync_cmd);
+ udelay(1);
+ }
- if ((ret = wait_on_sem(&iommu->cmd_sem)) != 0)
- return ret;
+ /* Update head and recheck remaining space */
+ iommu->cmd_buf_head = readl(iommu->mmio_base +
+ MMIO_CMD_HEAD_OFFSET);
goto again;
}
copy_cmd_to_buffer(iommu, cmd);
- /* We need to sync now to make sure all commands are processed */
+ /* Do we need to make sure all commands are processed? */
iommu->need_sync = sync;
return 0;
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