PATCH [10/15] qla2xxx: Use readX_relaxed

PATCH Andrew Vasquez 1 participant 1 message May 7, 2004

Subsystems (2)

SCSI QLogic QLA2XXX FC-SCSI driver

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Andrew Vasquez

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2004-05-07 05:54 UTC #0 lore raw

ChangeSet
1.1931 04/04/30 14:32:56 [email protected] +3 -0 Jeremy Higdon <jeremy () sgi ! com>:

For those to whom this is new (it was discussed on linux-kernel and linux-ia64 I believe), normal PCI register reads imply that PCI DMA writes that occured prior to the PCI MMR (memory mapped register) read (on the PCI bus) will be reflected in system memory once the MMR read is complete.

On our platforms, we can speed up the MMR read significantly if that ordering requirement is "relaxed".

So I attempted to find the common register reads that don't have a need for this ordering so that I could make them use this faster read.

 drivers/scsi/qla2xxx/qla_def.h  |    3 +++
 drivers/scsi/qla2xxx/qla_iocb.c |    6 +++---
 drivers/scsi/qla2xxx/qla_isr.c  |    2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

drivers/scsi/qla2xxx/qla_def.h +3 -0

diff -Nru a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
@@ -154,6 +154,9 @@
 #define RD_REG_BYTE(addr)		readb(addr)
 #define RD_REG_WORD(addr)		readw(addr)
 #define RD_REG_DWORD(addr)		readl(addr)
+#define RD_REG_BYTE_RELAXED(addr)	readb_relaxed(addr)
+#define RD_REG_WORD_RELAXED(addr)	readw_relaxed(addr)
+#define RD_REG_DWORD_RELAXED(addr)	readl_relaxed(addr)
 #define WRT_REG_BYTE(addr, data)	writeb(data,addr)
 #define WRT_REG_WORD(addr, data)	writew(data,addr)
 #define WRT_REG_DWORD(addr, data)	writel(data,addr)

drivers/scsi/qla2xxx/qla_iocb.c +3 -3

diff -Nru a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -390,7 +390,7 @@
 
 	if (ha->req_q_cnt < (sp->req_cnt + 2)) {
 		/* Calculate number of free request entries */
-		cnt = RD_REG_WORD(ISP_REQ_Q_OUT(ha, reg));
+		cnt = RD_REG_WORD_RELAXED(ISP_REQ_Q_OUT(ha, reg));
 		if (ha->req_ring_index < cnt)
 			ha->req_q_cnt = cnt - ha->req_ring_index;
 		else

@@ -499,7 +499,7 @@
 
 	/* Set chip new ring index. */
 	WRT_REG_WORD(ISP_REQ_Q_IN(ha, reg), ha->req_ring_index);
-	RD_REG_WORD(ISP_REQ_Q_IN(ha, reg));	/* PCI Posting. */
+	RD_REG_WORD_RELAXED(ISP_REQ_Q_IN(ha, reg));	/* PCI Posting. */
 
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 	return (QLA_SUCCESS);

@@ -748,5 +748,5 @@
 
 	/* Set chip new ring index. */
 	WRT_REG_WORD(ISP_REQ_Q_IN(ha, reg), ha->req_ring_index);
-	RD_REG_WORD(ISP_REQ_Q_IN(ha, reg));	/* PCI Posting. */
+	RD_REG_WORD_RELAXED(ISP_REQ_Q_IN(ha, reg));	/* PCI Posting. */
 }

drivers/scsi/qla2xxx/qla_isr.c +1 -1

diff -Nru a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
@@ -165,7 +165,7 @@
 				break;
 			}
 			WRT_REG_WORD(&reg->hccr, HCCR_CLR_RISC_INT);
-			RD_REG_WORD(&reg->hccr);
+			RD_REG_WORD_RELAXED(&reg->hccr);
 		}
 	}