From: Joel Stanley <joel@jms.id.au>
To: Jeremy Kerr <jk@ozlabs.org>, Eddie James <eajames@linux.ibm.com>,
Andrew Jeffery <andrew@aj.id.au>
Cc: linux-aspeed@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org, linux-fsi@lists.ozlabs.org
Subject: [PATCH] fsi: aspeed: Emit fewer barriers in opb operations
Date: Tue, 23 Feb 2021 14:47:37 +1030 [thread overview]
Message-ID: <20210223041737.171274-1-joel@jms.id.au> (raw)
When setting up a read or write to the OPB memory space, we must perform
five or six AHB writes. The ordering of these up until the trigger write
does not matter, so use writel_relaxed.
The generated code goes from (Debian GCC 10.2.1-6):
mov r8, r3
mcr 15, 0, sl, cr7, cr10, {4}
str sl, [r6, #20]
mcr 15, 0, sl, cr7, cr10, {4}
str r3, [r6, #24]
mcr 15, 0, sl, cr7, cr10, {4}
str r1, [r6, #28]
mcr 15, 0, sl, cr7, cr10, {4}
str r2, [r6, #32]
mcr 15, 0, sl, cr7, cr10, {4}
mov r1, #1
str r1, [r6, #64] ; 0x40
mcr 15, 0, sl, cr7, cr10, {4}
str r1, [r6, #4]
to this:
str r3, [r7, #20]
str r2, [r7, #24]
str r1, [r7, #28]
str r3, [r7, #64]
mov r8, #0
mcr 15, 0, r8, cr7, cr10, {4}
str r3, [r7, #4]
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
drivers/fsi/fsi-master-aspeed.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
index 90dbe58ca1ed..09fff86b2bac 100644
--- a/drivers/fsi/fsi-master-aspeed.c
+++ b/drivers/fsi/fsi-master-aspeed.c
@@ -101,11 +101,11 @@ static int __opb_write(struct fsi_master_aspeed *aspeed, u32 addr,
u32 reg, status;
int ret;
- writel(CMD_WRITE, base + OPB0_RW);
- writel(transfer_size, base + OPB0_XFER_SIZE);
- writel(addr, base + OPB0_FSI_ADDR);
- writel(val, base + OPB0_FSI_DATA_W);
- writel(0x1, base + OPB_IRQ_CLEAR);
+ writel_relaxed(CMD_WRITE, base + OPB0_RW);
+ writel_relaxed(transfer_size, base + OPB0_XFER_SIZE);
+ writel_relaxed(addr, base + OPB0_FSI_ADDR);
+ writel_relaxed(val, base + OPB0_FSI_DATA_W);
+ writel_relaxed(0x1, base + OPB_IRQ_CLEAR);
writel(0x1, base + OPB_TRIGGER);
ret = readl_poll_timeout(base + OPB_IRQ_STATUS, reg,
@@ -149,10 +149,10 @@ static int __opb_read(struct fsi_master_aspeed *aspeed, uint32_t addr,
u32 result, reg;
int status, ret;
- writel(CMD_READ, base + OPB0_RW);
- writel(transfer_size, base + OPB0_XFER_SIZE);
- writel(addr, base + OPB0_FSI_ADDR);
- writel(0x1, base + OPB_IRQ_CLEAR);
+ writel_relaxed(CMD_READ, base + OPB0_RW);
+ writel_relaxed(transfer_size, base + OPB0_XFER_SIZE);
+ writel_relaxed(addr, base + OPB0_FSI_ADDR);
+ writel_relaxed(0x1, base + OPB_IRQ_CLEAR);
writel(0x1, base + OPB_TRIGGER);
ret = readl_poll_timeout(base + OPB_IRQ_STATUS, reg,
--
2.30.1
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next reply other threads:[~2021-02-23 4:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 4:17 Joel Stanley [this message]
2021-02-23 6:02 ` [PATCH] fsi: aspeed: Emit fewer barriers in opb operations Jeremy Kerr
2021-04-13 20:08 ` Eddie James
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