2018-06-13 12:22:26

by Neil Armstrong

[permalink] [raw]
Subject: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
seems to be dependent on the FCLK_DIV2 to be operationnal.

The issue occured since v4.17-rc1 by freezing the kernel boot when
the 'schedutil' cpufreq governor was selected as default :

[ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
domain-0 init dvfs: 4
[ 12.087757] hctosys: unable to open rtc device (rtc0)
[ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'

But when disabling the MMC driver, the boot finished but cpufreq failed to
change the CPU frequency :

[ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5

A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
the first bad commit.
This commit added support for the missing clock gates before the fixed PLL
fixed dividers (FCLK_DIVx) and the clock framework basically disabled
all the unused fixed dividers, thus disabled a critical clock path for
the SCPI Co-Processor.

This patch simply sets the FCLK_DIV2 gate as critical to ensure
nobody can disable it.

Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
Signed-off-by: Neil Armstrong <[email protected]>
---
drivers/clk/meson/gxbb.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
index b1e4d95..0e053c1 100644
--- a/drivers/clk/meson/gxbb.c
+++ b/drivers/clk/meson/gxbb.c
@@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2 = {
.ops = &clk_regmap_gate_ops,
.parent_names = (const char *[]){ "fclk_div2_div" },
.num_parents = 1,
+ .flags = CLK_IS_CRITICAL,
},
};

--
2.7.4



2018-06-13 12:28:19

by Jerome Brunet

[permalink] [raw]
Subject: Re: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

On Wed, 2018-06-13 at 14:20 +0200, Neil Armstrong wrote:
> On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> seems to be dependent on the FCLK_DIV2 to be operationnal.
>
> The issue occured since v4.17-rc1 by freezing the kernel boot when
> the 'schedutil' cpufreq governor was selected as default :
>
> [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> domain-0 init dvfs: 4
> [ 12.087757] hctosys: unable to open rtc device (rtc0)
> [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
>
> But when disabling the MMC driver, the boot finished but cpufreq failed to
> change the CPU frequency :
>
> [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
>
> A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> the first bad commit.
> This commit added support for the missing clock gates before the fixed PLL
> fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> all the unused fixed dividers, thus disabled a critical clock path for
> the SCPI Co-Processor.
>
> This patch simply sets the FCLK_DIV2 gate as critical to ensure
> nobody can disable it.
>
> Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> Signed-off-by: Neil Armstrong <[email protected]>

Good catch !
We'll probably have to check the axg family as well

> ---
> drivers/clk/meson/gxbb.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
> index b1e4d95..0e053c1 100644
> --- a/drivers/clk/meson/gxbb.c
> +++ b/drivers/clk/meson/gxbb.c
> @@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2 = {
> .ops = &clk_regmap_gate_ops,
> .parent_names = (const char *[]){ "fclk_div2_div" },
> .num_parents = 1,
> + .flags = CLK_IS_CRITICAL,
> },
> };
>


2018-06-13 22:43:30

by Kevin Hilman

[permalink] [raw]
Subject: Re: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

Neil Armstrong <[email protected]> writes:

> On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> seems to be dependent on the FCLK_DIV2 to be operationnal.
>
> The issue occured since v4.17-rc1 by freezing the kernel boot when
> the 'schedutil' cpufreq governor was selected as default :
>
> [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> domain-0 init dvfs: 4
> [ 12.087757] hctosys: unable to open rtc device (rtc0)
> [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
>
> But when disabling the MMC driver, the boot finished but cpufreq failed to
> change the CPU frequency :
>
> [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
>
> A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> the first bad commit.
> This commit added support for the missing clock gates before the fixed PLL
> fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> all the unused fixed dividers, thus disabled a critical clock path for
> the SCPI Co-Processor.
>
> This patch simply sets the FCLK_DIV2 gate as critical to ensure
> nobody can disable it.
>
> Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> Signed-off-by: Neil Armstrong <[email protected]>

Nice! this also fixes the boot hang I had noticed on gxm-nexbox-a1
(though MMC still needs to be disabled to fully boot.)

Tested-by: Kevin Hilman <[email protected]>

Kevin

> ---
> drivers/clk/meson/gxbb.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
> index b1e4d95..0e053c1 100644
> --- a/drivers/clk/meson/gxbb.c
> +++ b/drivers/clk/meson/gxbb.c
> @@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2 = {
> .ops = &clk_regmap_gate_ops,
> .parent_names = (const char *[]){ "fclk_div2_div" },
> .num_parents = 1,
> + .flags = CLK_IS_CRITICAL,
> },
> };

2018-06-19 15:30:39

by Jerome Brunet

[permalink] [raw]
Subject: Re: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

On Wed, 2018-06-13 at 14:26 +0200, Jerome Brunet wrote:
> On Wed, 2018-06-13 at 14:20 +0200, Neil Armstrong wrote:
> > On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> > seems to be dependent on the FCLK_DIV2 to be operationnal.
> >
> > The issue occured since v4.17-rc1 by freezing the kernel boot when
> > the 'schedutil' cpufreq governor was selected as default :
> >
> > [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> > domain-0 init dvfs: 4
> > [ 12.087757] hctosys: unable to open rtc device (rtc0)
> > [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> > [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
> >
> > But when disabling the MMC driver, the boot finished but cpufreq failed to
> > change the CPU frequency :
> >
> > [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
> >
> > A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> > the first bad commit.
> > This commit added support for the missing clock gates before the fixed PLL
> > fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> > all the unused fixed dividers, thus disabled a critical clock path for
> > the SCPI Co-Processor.
> >
> > This patch simply sets the FCLK_DIV2 gate as critical to ensure
> > nobody can disable it.
> >
> > Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> > Signed-off-by: Neil Armstrong <[email protected]>
>
> Good catch !
> We'll probably have to check the axg family as well

SCPI is not enabled on AXG at this time. We'll deal with it when the time comes.

patch applied.
Thx

2018-07-26 15:26:00

by Neil Armstrong

[permalink] [raw]
Subject: Re: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

Hi Stable Team,

On 13/06/2018 14:20, Neil Armstrong wrote:
> On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> seems to be dependent on the FCLK_DIV2 to be operationnal.
>
> The issue occured since v4.17-rc1 by freezing the kernel boot when
> the 'schedutil' cpufreq governor was selected as default :
>
> [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> domain-0 init dvfs: 4
> [ 12.087757] hctosys: unable to open rtc device (rtc0)
> [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
>
> But when disabling the MMC driver, the boot finished but cpufreq failed to
> change the CPU frequency :
>
> [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
>
> A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> the first bad commit.
> This commit added support for the missing clock gates before the fixed PLL
> fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> all the unused fixed dividers, thus disabled a critical clock path for
> the SCPI Co-Processor.
>
> This patch simply sets the FCLK_DIV2 gate as critical to ensure
> nobody can disable it.
>
> Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> Signed-off-by: Neil Armstrong <[email protected]>


This patch hit linux master with commit id c987ac6f1f088663b6dad39281071aeb31d450a8

Could this be backported to the next 4.17 stable release ?

Thanks,
Neil

> ---
> drivers/clk/meson/gxbb.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
> index b1e4d95..0e053c1 100644
> --- a/drivers/clk/meson/gxbb.c
> +++ b/drivers/clk/meson/gxbb.c
> @@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2 = {
> .ops = &clk_regmap_gate_ops,
> .parent_names = (const char *[]){ "fclk_div2_div" },
> .num_parents = 1,
> + .flags = CLK_IS_CRITICAL,
> },
> };
>
>


2018-07-26 15:35:29

by Greg KH

[permalink] [raw]
Subject: Re: [PATCH] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

On Thu, Jul 26, 2018 at 05:24:09PM +0200, Neil Armstrong wrote:
> Hi Stable Team,
>
> On 13/06/2018 14:20, Neil Armstrong wrote:
> > On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> > seems to be dependent on the FCLK_DIV2 to be operationnal.
> >
> > The issue occured since v4.17-rc1 by freezing the kernel boot when
> > the 'schedutil' cpufreq governor was selected as default :
> >
> > [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> > domain-0 init dvfs: 4
> > [ 12.087757] hctosys: unable to open rtc device (rtc0)
> > [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> > [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
> >
> > But when disabling the MMC driver, the boot finished but cpufreq failed to
> > change the CPU frequency :
> >
> > [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
> >
> > A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> > the first bad commit.
> > This commit added support for the missing clock gates before the fixed PLL
> > fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> > all the unused fixed dividers, thus disabled a critical clock path for
> > the SCPI Co-Processor.
> >
> > This patch simply sets the FCLK_DIV2 gate as critical to ensure
> > nobody can disable it.
> >
> > Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> > Signed-off-by: Neil Armstrong <[email protected]>
>
>
> This patch hit linux master with commit id c987ac6f1f088663b6dad39281071aeb31d450a8
>
> Could this be backported to the next 4.17 stable release ?

Now queued up, thanks,

greg k-h