* [PATCH] arm: mvebu: Reduce reg-io-width with UARTs
@ 2013-03-01 8:36 Heikki Krogerus
2013-03-01 9:54 ` Gregory CLEMENT
2013-03-01 10:12 ` Masami Hiramatsu
0 siblings, 2 replies; 3+ messages in thread
From: Heikki Krogerus @ 2013-03-01 8:36 UTC (permalink / raw)
To: linux-arm-kernel
Setting the reg-io-width to 1 byte represents more accurate
description of the HW.
This will fix an issue where UART driver causes kernel
panic during bootup. Gregory CLEMENT traced the issue to
autoconfig() in 8250.c, where the existence of FIFO is
checked from UART_IIR register. The register is now read as
32-bit value as the reg-io-width is set to 4-bytes. The
retuned value seems to contain bogus data for bits 31:8,
causing the issue.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
arch/arm/boot/dts/armada-370-xp.dtsi | 4 ++--
arch/arm/boot/dts/armada-xp.dtsi | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
index 6f1acc7..99afca4 100644
--- a/arch/arm/boot/dts/armada-370-xp.dtsi
+++ b/arch/arm/boot/dts/armada-370-xp.dtsi
@@ -54,7 +54,7 @@
reg = <0xd0012000 0x100>;
reg-shift = <2>;
interrupts = <41>;
- reg-io-width = <4>;
+ reg-io-width = <1>;
status = "disabled";
};
serial at d0012100 {
@@ -62,7 +62,7 @@
reg = <0xd0012100 0x100>;
reg-shift = <2>;
interrupts = <42>;
- reg-io-width = <4>;
+ reg-io-width = <1>;
status = "disabled";
};
diff --git a/arch/arm/boot/dts/armada-xp.dtsi b/arch/arm/boot/dts/armada-xp.dtsi
index 1443949..ca00d83 100644
--- a/arch/arm/boot/dts/armada-xp.dtsi
+++ b/arch/arm/boot/dts/armada-xp.dtsi
@@ -46,7 +46,7 @@
reg = <0xd0012200 0x100>;
reg-shift = <2>;
interrupts = <43>;
- reg-io-width = <4>;
+ reg-io-width = <1>;
status = "disabled";
};
serial at d0012300 {
@@ -54,7 +54,7 @@
reg = <0xd0012300 0x100>;
reg-shift = <2>;
interrupts = <44>;
- reg-io-width = <4>;
+ reg-io-width = <1>;
status = "disabled";
};
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH] arm: mvebu: Reduce reg-io-width with UARTs
2013-03-01 8:36 [PATCH] arm: mvebu: Reduce reg-io-width with UARTs Heikki Krogerus
@ 2013-03-01 9:54 ` Gregory CLEMENT
2013-03-01 10:12 ` Masami Hiramatsu
1 sibling, 0 replies; 3+ messages in thread
From: Gregory CLEMENT @ 2013-03-01 9:54 UTC (permalink / raw)
To: linux-arm-kernel
On 03/01/2013 09:36 AM, Heikki Krogerus wrote:
> Setting the reg-io-width to 1 byte represents more accurate
> description of the HW.
>
> This will fix an issue where UART driver causes kernel
> panic during bootup. Gregory CLEMENT traced the issue to
> autoconfig() in 8250.c, where the existence of FIFO is
> checked from UART_IIR register. The register is now read as
> 32-bit value as the reg-io-width is set to 4-bytes. The
> retuned value seems to contain bogus data for bits 31:8,
> causing the issue.
I have tested this patch on the Armada XP based board
DB-MV784MP-GP, and it fixed the issue. I had few doubts
on the fact it worked, but with this test you can add my:
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
and also my
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
as co-maintainer of the mvebu subsystem.
Thanks for your patch.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> ---
> arch/arm/boot/dts/armada-370-xp.dtsi | 4 ++--
> arch/arm/boot/dts/armada-xp.dtsi | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
> index 6f1acc7..99afca4 100644
> --- a/arch/arm/boot/dts/armada-370-xp.dtsi
> +++ b/arch/arm/boot/dts/armada-370-xp.dtsi
> @@ -54,7 +54,7 @@
> reg = <0xd0012000 0x100>;
> reg-shift = <2>;
> interrupts = <41>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
> serial at d0012100 {
> @@ -62,7 +62,7 @@
> reg = <0xd0012100 0x100>;
> reg-shift = <2>;
> interrupts = <42>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
>
> diff --git a/arch/arm/boot/dts/armada-xp.dtsi b/arch/arm/boot/dts/armada-xp.dtsi
> index 1443949..ca00d83 100644
> --- a/arch/arm/boot/dts/armada-xp.dtsi
> +++ b/arch/arm/boot/dts/armada-xp.dtsi
> @@ -46,7 +46,7 @@
> reg = <0xd0012200 0x100>;
> reg-shift = <2>;
> interrupts = <43>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
> serial at d0012300 {
> @@ -54,7 +54,7 @@
> reg = <0xd0012300 0x100>;
> reg-shift = <2>;
> interrupts = <44>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
>
>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH] arm: mvebu: Reduce reg-io-width with UARTs
2013-03-01 8:36 [PATCH] arm: mvebu: Reduce reg-io-width with UARTs Heikki Krogerus
2013-03-01 9:54 ` Gregory CLEMENT
@ 2013-03-01 10:12 ` Masami Hiramatsu
1 sibling, 0 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2013-03-01 10:12 UTC (permalink / raw)
To: linux-arm-kernel
(2013/03/01 17:36), Heikki Krogerus wrote:
> Setting the reg-io-width to 1 byte represents more accurate
> description of the HW.
>
> This will fix an issue where UART driver causes kernel
> panic during bootup. Gregory CLEMENT traced the issue to
> autoconfig() in 8250.c, where the existence of FIFO is
> checked from UART_IIR register. The register is now read as
> 32-bit value as the reg-io-width is set to 4-bytes. The
> retuned value seems to contain bogus data for bits 31:8,
> causing the issue.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
I've tested this patch on Armada-XP based OpenBlocks AX3/4
and fixed the issue.
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Thank you!
> ---
> arch/arm/boot/dts/armada-370-xp.dtsi | 4 ++--
> arch/arm/boot/dts/armada-xp.dtsi | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
> index 6f1acc7..99afca4 100644
> --- a/arch/arm/boot/dts/armada-370-xp.dtsi
> +++ b/arch/arm/boot/dts/armada-370-xp.dtsi
> @@ -54,7 +54,7 @@
> reg = <0xd0012000 0x100>;
> reg-shift = <2>;
> interrupts = <41>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
> serial at d0012100 {
> @@ -62,7 +62,7 @@
> reg = <0xd0012100 0x100>;
> reg-shift = <2>;
> interrupts = <42>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
>
> diff --git a/arch/arm/boot/dts/armada-xp.dtsi b/arch/arm/boot/dts/armada-xp.dtsi
> index 1443949..ca00d83 100644
> --- a/arch/arm/boot/dts/armada-xp.dtsi
> +++ b/arch/arm/boot/dts/armada-xp.dtsi
> @@ -46,7 +46,7 @@
> reg = <0xd0012200 0x100>;
> reg-shift = <2>;
> interrupts = <43>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
> serial at d0012300 {
> @@ -54,7 +54,7 @@
> reg = <0xd0012300 0x100>;
> reg-shift = <2>;
> interrupts = <44>;
> - reg-io-width = <4>;
> + reg-io-width = <1>;
> status = "disabled";
> };
>
>
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt at hitachi.com
^ permalink raw reply [flat|nested] 3+ messages in thread
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