Code includes barrier() followed by writel(). writel() already has a
barrier
on some architectures like arm64.
This ends up CPU observing two barriers back to back before executing the
register write.
Create a new wrapper function with relaxed write operator. Use the new
wrapper when a write is following a barrier().
Since code already has an explicit barrier call, changing writel() to
writel_relaxed().
Signed-off-by: Sinan Kaya <[email protected]>
---
drivers/scsi/megaraid/megaraid_mbox.c | 8 ++++----
drivers/scsi/megaraid/megaraid_mbox.h | 2 ++
drivers/scsi/megaraid/megaraid_sas_fusion.c | 4 ++--
3 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c
index 530358c..8c4fc6e 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -1439,7 +1439,7 @@ mbox_post_cmd(adapter_t *adapter, scb_t *scb)
mbox->ack = 0;
wmb();
- WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);
+ WRINDOOR_RELAXED(raid_dev, raid_dev->mbox_dma | 0x1);
spin_unlock_irqrestore(MAILBOX_LOCK(raid_dev), flags);
@@ -2752,7 +2752,7 @@ mbox_post_sync_cmd(adapter_t *adapter, uint8_t raw_mbox[])
mbox->status = 0xFF;
wmb();
- WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);
+ WRINDOOR_RELAXED(raid_dev, raid_dev->mbox_dma | 0x1);
// wait for maximum 1 second for status to post. If the status is not
// available within 1 second, assume FW is initializing and wait
@@ -2877,7 +2877,7 @@ mbox_post_sync_cmd_fast(adapter_t *adapter, uint8_t raw_mbox[])
mbox->status = 0xFF;
wmb();
- WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);
+ WRINDOOR_RELAXED(raid_dev, raid_dev->mbox_dma | 0x1);
for (i = 0; i < MBOX_SYNC_WAIT_CNT; i++) {
if (mbox->numstatus != 0xFF) break;
@@ -3329,7 +3329,7 @@ megaraid_mbox_fire_sync_cmd(adapter_t *adapter)
mbox->status = 0;
wmb();
- WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);
+ WRINDOOR_RELAXED(raid_dev, raid_dev->mbox_dma | 0x1);
/* Wait for maximum 1 min for status to post.
* If the Firmware SUPPORTS the ABOVE COMMAND,
diff --git a/drivers/scsi/megaraid/megaraid_mbox.h b/drivers/scsi/megaraid/megaraid_mbox.h
index c1d86d9..641cbd4 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.h
+++ b/drivers/scsi/megaraid/megaraid_mbox.h
@@ -230,6 +230,8 @@ typedef struct {
#define RDINDOOR(rdev) readl((rdev)->baseaddr + 0x20)
#define RDOUTDOOR(rdev) readl((rdev)->baseaddr + 0x2C)
+#define WRINDOOR_RELAXED(rdev, value) \
+ writel_relaxed(value, (rdev)->baseaddr + 0x20)
#define WRINDOOR(rdev, value) writel(value, (rdev)->baseaddr + 0x20)
#define WROUTDOOR(rdev, value) writel(value, (rdev)->baseaddr + 0x2C)
diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c
index 073ced0..f560496 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
@@ -3479,11 +3479,11 @@ complete_cmd_fusion(struct megasas_instance *instance, u32 MSIxIndex)
wmb();
if (instance->msix_combined)
- writel(((MSIxIndex & 0x7) << 24) |
+ writel_relaxed(((MSIxIndex & 0x7) << 24) |
fusion->last_reply_idx[MSIxIndex],
instance->reply_post_host_index_addr[MSIxIndex/8]);
else
- writel((MSIxIndex << 24) |
+ writel_relaxed((MSIxIndex << 24) |
fusion->last_reply_idx[MSIxIndex],
instance->reply_post_host_index_addr[0]);
megasas_check_and_restore_queue_depth(instance);
--
2.7.4