* [PATCH] fsi: aspeed: Emit fewer barriers in opb operations
@ 2021-02-23 4:17 Joel Stanley
2021-02-23 6:02 ` Jeremy Kerr
2021-04-13 20:08 ` Eddie James
0 siblings, 2 replies; 3+ messages in thread
From: Joel Stanley @ 2021-02-23 4:17 UTC (permalink / raw)
To: Jeremy Kerr, Eddie James, Andrew Jeffery
Cc: linux-aspeed, linux-arm-kernel, linux-fsi
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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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fsi: aspeed: Emit fewer barriers in opb operations
2021-02-23 4:17 [PATCH] fsi: aspeed: Emit fewer barriers in opb operations Joel Stanley
@ 2021-02-23 6:02 ` Jeremy Kerr
2021-04-13 20:08 ` Eddie James
1 sibling, 0 replies; 3+ messages in thread
From: Jeremy Kerr @ 2021-02-23 6:02 UTC (permalink / raw)
To: Joel Stanley, Eddie James, Andrew Jeffery
Cc: linux-aspeed, linux-arm-kernel, linux-fsi
Hey Joel,
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);
Future-joel is going to be angry at you if you don't add a comment
about the ordering requirements there.
Otherwise,
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Cheers,
Jeremy
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fsi: aspeed: Emit fewer barriers in opb operations
2021-02-23 4:17 [PATCH] fsi: aspeed: Emit fewer barriers in opb operations Joel Stanley
2021-02-23 6:02 ` Jeremy Kerr
@ 2021-04-13 20:08 ` Eddie James
1 sibling, 0 replies; 3+ messages in thread
From: Eddie James @ 2021-04-13 20:08 UTC (permalink / raw)
To: Joel Stanley, Jeremy Kerr, Andrew Jeffery
Cc: linux-fsi, linux-arm-kernel, linux-aspeed
On Tue, 2021-02-23 at 14:47 +1030, Joel Stanley wrote:
> 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.
Reviewed-by: Eddie James <eajames@linux.ibm.com>
I have also tested this patch on hardware, so
Tested-by: Eddie James <eajames@linux.ibm.com>
>
> 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,
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2021-02-23 6:02 ` Jeremy Kerr
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