From: wangwenhu <[email protected]>
When generating .config file with menuconfig on Freescale BOOKE
SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
description in the Kconfig field, which makes it impossible
to support L2Cache-Sram driver. Add a description to make it
configurable.
Signed-off-by: wangwenhu <[email protected]>
---
arch/powerpc/platforms/85xx/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/85xx/Kconfig b/arch/powerpc/platforms/85xx/Kconfig
index fa3d29dcb57e..ee5ba10b98cb 100644
--- a/arch/powerpc/platforms/85xx/Kconfig
+++ b/arch/powerpc/platforms/85xx/Kconfig
@@ -17,7 +17,7 @@ if FSL_SOC_BOOKE
if PPC32
config FSL_85XX_CACHE_SRAM
- bool
+ bool "Freescale Cache-Sram"
select PPC_LIB_RHEAP
help
When selected, this option enables cache-sram support
--
2.23.0
On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
> From: wangwenhu <[email protected]>
>
> When generating .config file with menuconfig on Freescale BOOKE
> SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
> description in the Kconfig field, which makes it impossible
> to support L2Cache-Sram driver. Add a description to make it
> configurable.
>
> Signed-off-by: wangwenhu <[email protected]>
The intent was that drivers using the SRAM API would select the symbol. What
is the use case for selecting it manually?
Since this code was added almost ten years ago and there are still no (in-
tree?) users of the API, we should just remove the sram code (unless this
prods someone to submit such a user very soon).
-Scott
From: Scott Wood <[email protected]>
Date: 2020-01-21 11:25:25
To: wangwenhu <[email protected]>,Kumar Gala <[email protected]>,Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <[email protected]>,Michael Ellerman <[email protected]>,[email protected],[email protected]
Cc: [email protected],[email protected],Rai Harninder <[email protected]>
Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
>> From: wangwenhu <[email protected]>
>>
>> When generating .config file with menuconfig on Freescale BOOKE
>> SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
>> description in the Kconfig field, which makes it impossible
>> to support L2Cache-Sram driver. Add a description to make it
>> configurable.
>>
>> Signed-off-by: wangwenhu <[email protected]>
>
>The intent was that drivers using the SRAM API would select the symbol. What
>is the use case for selecting it manually?
>
With a repository of multiple products(meaning different defconfigs) and multiple
developers, the Kconfigs of the Kernel Source Tree change frequently. So the "make menuconfig"
process is needed for defconfigs' re-generating or updating for the complexity of dependencies
between different features defined in the Kconfigs.
>Since this code was added almost ten years ago and there are still no (in-
>tree?) users of the API, we should just remove the sram code (unless this
>prods someone to submit such a user very soon).
>
Yes, pretty long a time. But we DO really use the API now for PPCE500/Freescale SoC.
Like sometimes we need to reset the whole RAM, then the L2-Cache would be used as
SRAM for backup using. Since it is useful for us now, a re-consideration is recommanded.
>-Scott
>
>
--
Wenhu
vivo
On Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
> From: Scott Wood <[email protected]>
> Date: 2020-01-21 11:25:25
> To: wangwenhu <[email protected]>,Kumar Gala <[email protected]>,
> Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> [email protected]>,Michael Ellerman <[email protected]>,
> [email protected],[email protected]
> Cc: [email protected],[email protected],Rai Harninder <
> [email protected]>
> Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
> configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
> > > From: wangwenhu <[email protected]>
> > >
> > > When generating .config file with menuconfig on Freescale BOOKE
> > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
> > > description in the Kconfig field, which makes it impossible
> > > to support L2Cache-Sram driver. Add a description to make it
> > > configurable.
> > >
> > > Signed-off-by: wangwenhu <[email protected]>
> >
> > The intent was that drivers using the SRAM API would select the
> > symbol. What
> > is the use case for selecting it manually?
> >
>
> With a repository of multiple products(meaning different defconfigs) and
> multiple
> developers, the Kconfigs of the Kernel Source Tree change frequently. So the
> "make menuconfig"
> process is needed for defconfigs' re-generating or updating for the
> complexity of dependencies
> between different features defined in the Kconfigs.
That doesn't answer my question of how the SRAM code would be useful other
than to some other driver that uses the API (which would use "select"). There
is no userspace API. You could use the kernel command line to configure the
SRAM but you need to get the address of it for it to be useful.
> > Since this code was added almost ten years ago and there are still no (in-
> > tree?) users of the API, we should just remove the sram code (unless this
> > prods someone to submit such a user very soon).
> >
>
> Yes, pretty long a time. But we DO really use the API now for
> PPCE500/Freescale SoC.
I do not see any users in the kernel tree. Are you talking about out-of-tree
code, or something that you've submitted or will submit soon? Or are you
accessing it via /dev/mem?
> Like sometimes we need to reset the whole RAM, then the L2-Cache would be
> used as
> SRAM for backup using. Since it is useful for us now, a re-consideration is
> recommanded.
Where is the code that would do this?
-Scott
>
发件人：Scott Wood <[email protected]>
发送日期：2020-01-21 13:49:59
收件人："王文虎" <[email protected]>
抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <[email protected]>,Michael Ellerman <[email protected]>,[email protected],[email protected],[email protected],Rai Harninder <[email protected]>
主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
>> From: Scott Wood <[email protected]>
>> Date: 2020-01-21 11:25:25
>> To: wangwenhu <[email protected]>,Kumar Gala <[email protected]>,
>> Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> [email protected]>,Michael Ellerman <[email protected]>,
>> [email protected],[email protected]
>> Cc: [email protected],[email protected],Rai Harninder <
>> [email protected]>
>> Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
>> configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
>> > > From: wangwenhu <[email protected]>
>> > >
>> > > When generating .config file with menuconfig on Freescale BOOKE
>> > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
>> > > description in the Kconfig field, which makes it impossible
>> > > to support L2Cache-Sram driver. Add a description to make it
>> > > configurable.
>> > >
>> > > Signed-off-by: wangwenhu <[email protected]>
>> >
>> > The intent was that drivers using the SRAM API would select the
>> > symbol. What
>> > is the use case for selecting it manually?
>> >
>>
>> With a repository of multiple products(meaning different defconfigs) and
>> multiple
>> developers, the Kconfigs of the Kernel Source Tree change frequently. So the
>> "make menuconfig"
>> process is needed for defconfigs' re-generating or updating for the
>> complexity of dependencies
>> between different features defined in the Kconfigs.
>
>That doesn't answer my question of how the SRAM code would be useful other
>than to some other driver that uses the API (which would use "select"). There
>is no userspace API. You could use the kernel command line to configure the
>SRAM but you need to get the address of it for it to be useful.
>
Like you've asked below, via /dev/mem or direct calling within the Kernel.
And they are not submitted yes, under development.
>> > Since this code was added almost ten years ago and there are still no (in-
>> > tree?) users of the API, we should just remove the sram code (unless this
>> > prods someone to submit such a user very soon).
>> >
>>
>> Yes, pretty long a time. But we DO really use the API now for
>> PPCE500/Freescale SoC.
>
>I do not see any users in the kernel tree. Are you talking about out-of-tree
>code, or something that you've submitted or will submit soon? Or are you
>accessing it via /dev/mem?
>
Both, but not submitted yet, and partly under development.
>> Like sometimes we need to reset the whole RAM, then the L2-Cache would be
>> used as
>> SRAM for backup using. Since it is useful for us now, a re-consideration is
>> recommanded.
>
>Where is the code that would do this?
>
Currently under development, and not submitted yet.
>-Scott
>>
>
Wenhu
On Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote:
> 发件人：Scott Wood <[email protected]>
> 发送日期：2020-01-21 13:49:59
> 收件人："王文虎" <[email protected]>
> 抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,B
> enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> [email protected]>,Michael Ellerman <[email protected]>,
> [email protected],[email protected],
> [email protected],Rai Harninder <[email protected]>
> 主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
> Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
> > > From: Scott Wood <[email protected]>
> > > Date: 2020-01-21 11:25:25
> > > To: wangwenhu <[email protected]>,Kumar Gala <
> > > [email protected]>,
> > > Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> > > [email protected]>,Michael Ellerman <[email protected]>,
> > > [email protected],[email protected]
> > > Cc: [email protected],[email protected],Rai Harninder <
> > > [email protected]>
> > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
> > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
> > > > > From: wangwenhu <[email protected]>
> > > > >
> > > > > When generating .config file with menuconfig on Freescale BOOKE
> > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
> > > > > description in the Kconfig field, which makes it impossible
> > > > > to support L2Cache-Sram driver. Add a description to make it
> > > > > configurable.
> > > > >
> > > > > Signed-off-by: wangwenhu <[email protected]>
> > > >
> > > > The intent was that drivers using the SRAM API would select the
> > > > symbol. What
> > > > is the use case for selecting it manually?
> > > >
> > >
> > > With a repository of multiple products(meaning different defconfigs) and
> > > multiple
> > > developers, the Kconfigs of the Kernel Source Tree change frequently. So
> > > the
> > > "make menuconfig"
> > > process is needed for defconfigs' re-generating or updating for the
> > > complexity of dependencies
> > > between different features defined in the Kconfigs.
> >
> > That doesn't answer my question of how the SRAM code would be useful other
> > than to some other driver that uses the API (which would use
> > "select"). There
> > is no userspace API. You could use the kernel command line to configure
> > the
> > SRAM but you need to get the address of it for it to be useful.
> >
>
> Like you've asked below, via /dev/mem or direct calling within the Kernel.
> And they are not submitted yes, under development.
If they are calling within the kernel, then whatever driver that is should
select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way for
the kernel to advertise where it is or which parts of SRAM are available for
use sounds like a bad idea.
-Scott
发件人：Scott Wood <[email protected]>
发送日期：2020-03-01 07:12:58
收件人："王文虎" <[email protected]>
抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <[email protected]>,Michael Ellerman <[email protected]>,[email protected],[email protected],[email protected],Rai Harninder <[email protected]>
主题：Re: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote:
>> 发件人：Scott Wood <[email protected]>
>> 发送日期：2020-01-21 13:49:59
>> 收件人："王文虎" <[email protected]>
>> 抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,B
>> enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> [email protected]>,Michael Ellerman <[email protected]>,
>> [email protected],[email protected],
>> [email protected],Rai Harninder <[email protected]>
>> 主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
>> Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
>> > > From: Scott Wood <[email protected]>
>> > > Date: 2020-01-21 11:25:25
>> > > To: wangwenhu <[email protected]>,Kumar Gala <
>> > > [email protected]>,
>> > > Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> > > [email protected]>,Michael Ellerman <[email protected]>,
>> > > [email protected],[email protected]
>> > > Cc: [email protected],[email protected],Rai Harninder <
>> > > [email protected]>
>> > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
>> > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
>> > > > > From: wangwenhu <[email protected]>
>> > > > >
>> > > > > When generating .config file with menuconfig on Freescale BOOKE
>> > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
>> > > > > description in the Kconfig field, which makes it impossible
>> > > > > to support L2Cache-Sram driver. Add a description to make it
>> > > > > configurable.
>> > > > >
>> > > > > Signed-off-by: wangwenhu <[email protected]>
>> > > >
>> > > > The intent was that drivers using the SRAM API would select the
>> > > > symbol. What
>> > > > is the use case for selecting it manually?
>> > > >
>> > >
>> > > With a repository of multiple products(meaning different defconfigs) and
>> > > multiple
>> > > developers, the Kconfigs of the Kernel Source Tree change frequently. So
>> > > the
>> > > "make menuconfig"
>> > > process is needed for defconfigs' re-generating or updating for the
>> > > complexity of dependencies
>> > > between different features defined in the Kconfigs.
>> >
>> > That doesn't answer my question of how the SRAM code would be useful other
>> > than to some other driver that uses the API (which would use
>> > "select"). There
>> > is no userspace API. You could use the kernel command line to configure
>> > the
>> > SRAM but you need to get the address of it for it to be useful.
>> >
>>
>> Like you've asked below, via /dev/mem or direct calling within the Kernel.
>> And they are not submitted yes, under development.
>
>If they are calling within the kernel, then whatever driver that is should
>select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way for
>the kernel to advertise where it is or which parts of SRAM are available for
>use sounds like a bad idea.
>
Yes, definitely. So like we enable the moulde which should selet
FSL_85XX_CACHE_SRAM to build vmlinux, FSL_85XX_CACHE_SRAM
could not be seleted because of the Kconfig definition problem
which I am trying to fix now. So would you please merge the patch
for the convenience of later works depending on the driver.
Wenhu
>-Scott
>
>
On Mon, 2020-03-02 at 12:42 +0800, 王文虎 wrote:
> 发件人：Scott Wood <[email protected]>
> 发送日期：2020-03-01 07:12:58
> 收件人："王文虎" <[email protected]>
> 抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,B
> enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> [email protected]>,Michael Ellerman <[email protected]>,
> [email protected],[email protected],
> [email protected],Rai Harninder <[email protected]>
> 主题：Re: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
> Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote:
> > > 发件人：Scott Wood <[email protected]>
> > > 发送日期：2020-01-21 13:49:59
> > > 收件人："王文虎" <[email protected]>
> > > 抄送人：wangwenhu <[email protected]>,Kumar Gala <
> > > [email protected]>,B
> > > enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> > > [email protected]>,Michael Ellerman <[email protected]>,
> > > [email protected],[email protected],
> > > [email protected],Rai Harninder <[email protected]>
> > > 主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
> > > Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
> > > > > From: Scott Wood <[email protected]>
> > > > > Date: 2020-01-21 11:25:25
> > > > > To: wangwenhu <[email protected]>,Kumar Gala <
> > > > > [email protected]>,
> > > > > Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
> > > > > [email protected]>,Michael Ellerman <[email protected]>,
> > > > > [email protected],[email protected]
> > > > > Cc: [email protected],[email protected],Rai Harninder <
> > > > > [email protected]>
> > > > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
> > > > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
> > > > > > > From: wangwenhu <[email protected]>
> > > > > > >
> > > > > > > When generating .config file with menuconfig on Freescale BOOKE
> > > > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
> > > > > > > description in the Kconfig field, which makes it impossible
> > > > > > > to support L2Cache-Sram driver. Add a description to make it
> > > > > > > configurable.
> > > > > > >
> > > > > > > Signed-off-by: wangwenhu <[email protected]>
> > > > > >
> > > > > > The intent was that drivers using the SRAM API would select the
> > > > > > symbol. What
> > > > > > is the use case for selecting it manually?
> > > > > >
> > > > >
> > > > > With a repository of multiple products(meaning different defconfigs)
> > > > > and
> > > > > multiple
> > > > > developers, the Kconfigs of the Kernel Source Tree change
> > > > > frequently. So
> > > > > the
> > > > > "make menuconfig"
> > > > > process is needed for defconfigs' re-generating or updating for the
> > > > > complexity of dependencies
> > > > > between different features defined in the Kconfigs.
> > > >
> > > > That doesn't answer my question of how the SRAM code would be useful
> > > > other
> > > > than to some other driver that uses the API (which would use
> > > > "select"). There
> > > > is no userspace API. You could use the kernel command line to
> > > > configure
> > > > the
> > > > SRAM but you need to get the address of it for it to be useful.
> > > >
> > >
> > > Like you've asked below, via /dev/mem or direct calling within the
> > > Kernel.
> > > And they are not submitted yes, under development.
> >
> > If they are calling within the kernel, then whatever driver that is should
> > select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way
> > for
> > the kernel to advertise where it is or which parts of SRAM are available
> > for
> > use sounds like a bad idea.
> >
>
> Yes, definitely. So like we enable the moulde which should selet
> FSL_85XX_CACHE_SRAM to build vmlinux, FSL_85XX_CACHE_SRAM
> could not be seleted because of the Kconfig definition problem
> which I am trying to fix now. So would you please merge the patch
> for the convenience of later works depending on the driver.
Sorry, I don't think it's something that should be enabled by itself with
nothing using the allocators. Suppose we took this patch, and people enabled
it and accessed it via /dev/mem. Then suppose a driver is patched to allocate
some sram and use it. They'd be stepping on each others' toes undetected.
If you want to expose it to userspace, add code that allocates some or all of
the sram and make it something userspace can mmap. Or, if nothing's going to
use them, remove the allocators and export the entire thing to userspace
(again via an sram-specific mappable rather than /dev/mem).
-Scott
发件人：Scott Wood <[email protected]>
发送日期：2020-03-02 16:58:52
收件人："王文虎" <[email protected]>
抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <[email protected]>,Michael Ellerman <[email protected]>,[email protected],[email protected],[email protected],Rai Harninder <[email protected]>
主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On Mon, 2020-03-02 at 12:42 +0800, 王文虎 wrote:
>> 发件人：Scott Wood <[email protected]>
>> 发送日期：2020-03-01 07:12:58
>> 收件人："王文虎" <[email protected]>
>> 抄送人：wangwenhu <[email protected]>,Kumar Gala <[email protected]>,B
>> enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> [email protected]>,Michael Ellerman <[email protected]>,
>> [email protected],[email protected],
>> [email protected],Rai Harninder <[email protected]>
>> 主题：Re: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
>> Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote:
>> > > 发件人：Scott Wood <[email protected]>
>> > > 发送日期：2020-01-21 13:49:59
>> > > 收件人："王文虎" <[email protected]>
>> > > 抄送人：wangwenhu <[email protected]>,Kumar Gala <
>> > > [email protected]>,B
>> > > enjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> > > [email protected]>,Michael Ellerman <[email protected]>,
>> > > [email protected],[email protected],
>> > > [email protected],Rai Harninder <[email protected]>
>> > > 主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On
>> > > Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote:
>> > > > > From: Scott Wood <[email protected]>
>> > > > > Date: 2020-01-21 11:25:25
>> > > > > To: wangwenhu <[email protected]>,Kumar Gala <
>> > > > > [email protected]>,
>> > > > > Benjamin Herrenschmidt <[email protected]>,Paul Mackerras <
>> > > > > [email protected]>,Michael Ellerman <[email protected]>,
>> > > > > [email protected],[email protected]
>> > > > > Cc: [email protected],[email protected],Rai Harninder <
>> > > > > [email protected]>
>> > > > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM
>> > > > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote:
>> > > > > > > From: wangwenhu <[email protected]>
>> > > > > > >
>> > > > > > > When generating .config file with menuconfig on Freescale BOOKE
>> > > > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of
>> > > > > > > description in the Kconfig field, which makes it impossible
>> > > > > > > to support L2Cache-Sram driver. Add a description to make it
>> > > > > > > configurable.
>> > > > > > >
>> > > > > > > Signed-off-by: wangwenhu <[email protected]>
>> > > > > >
>> > > > > > The intent was that drivers using the SRAM API would select the
>> > > > > > symbol. What
>> > > > > > is the use case for selecting it manually?
>> > > > > >
>> > > > >
>> > > > > With a repository of multiple products(meaning different defconfigs)
>> > > > > and
>> > > > > multiple
>> > > > > developers, the Kconfigs of the Kernel Source Tree change
>> > > > > frequently. So
>> > > > > the
>> > > > > "make menuconfig"
>> > > > > process is needed for defconfigs' re-generating or updating for the
>> > > > > complexity of dependencies
>> > > > > between different features defined in the Kconfigs.
>> > > >
>> > > > That doesn't answer my question of how the SRAM code would be useful
>> > > > other
>> > > > than to some other driver that uses the API (which would use
>> > > > "select"). There
>> > > > is no userspace API. You could use the kernel command line to
>> > > > configure
>> > > > the
>> > > > SRAM but you need to get the address of it for it to be useful.
>> > > >
>> > >
>> > > Like you've asked below, via /dev/mem or direct calling within the
>> > > Kernel.
>> > > And they are not submitted yes, under development.
>> >
>> > If they are calling within the kernel, then whatever driver that is should
>> > select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way
>> > for
>> > the kernel to advertise where it is or which parts of SRAM are available
>> > for
>> > use sounds like a bad idea.
>> >
>>
>> Yes, definitely. So like we enable the moulde which should selet
>> FSL_85XX_CACHE_SRAM to build vmlinux, FSL_85XX_CACHE_SRAM
>> could not be seleted because of the Kconfig definition problem
>> which I am trying to fix now. So would you please merge the patch
>> for the convenience of later works depending on the driver.
>
>Sorry, I don't think it's something that should be enabled by itself with
>nothing using the allocators. Suppose we took this patch, and people enabled
>it and accessed it via /dev/mem. Then suppose a driver is patched to allocate
>some sram and use it. They'd be stepping on each others' toes undetected.
>
Right, and maybe i did not explain it clear: I mean that we are developing
modules both in kernel which call the interfaces of FSL_85XX_CACHE_SRAM
directly, and in user space which is a further consideration upon the work
we have done. Cause we have not exported the code under developing, it
seems like that nothing uses FSL_85XX_CACHE_SRAM.
>If you want to expose it to userspace, add code that allocates some or all of
>the sram and make it something userspace can mmap. Or, if nothing's going to
>use them, remove the allocators and export the entire thing to userspace
>(again via an sram-specific mappable rather than /dev/mem).
As for /dev/mem, it was one of our choices ever but now a user-space
driver is preferred for further consideration. But currently, the functionality
that directly calls the insterfaces of FSL_85XX_CACHE_SRAM have been
under developing for couples of days and would be exported in the future.
They would be used on hw-platforms like PPCe500.
Just some time it takes.
Do you mean the exporting is a pre-condition? If not, the merge would
do a favor for the convenience.
Wenhu
>
>-Scott
>
>