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Re: [PATCH v7 0/5] ACPI: parse the SPCR table

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  Re: [PATCH v7 0/5] ACPI: parse the SPCR table Mark Salter <msalter@redhat.com> - 2016-04-05 18:30 +0200
    Re: [PATCH v7 0/5] ACPI: parse the SPCR table Aleksey Makarov <aleksey.makarov@linaro.org> - 2016-04-06 12:30 +0200
      Re: [PATCH v7 0/5] ACPI: parse the SPCR table Graeme Gregory <gg@slimlogic.co.uk> - 2016-04-06 13:00 +0200
        Re: [PATCH v7 0/5] ACPI: parse the SPCR table Mark Salter <msalter@redhat.com> - 2016-04-06 16:20 +0200
          Re: [PATCH v7 0/5] ACPI: parse the SPCR table Peter Hurley <peter@hurleysoftware.com> - 2016-04-06 18:30 +0200
            Re: [PATCH v7 0/5] ACPI: parse the SPCR table Mark Salter <msalter@redhat.com> - 2016-04-06 21:10 +0200

#1371774 — Re: [PATCH v7 0/5] ACPI: parse the SPCR table

Could you CC me on future postings of this series, please?

So v3 fixed a problem where platforms using 8250 didn't work.
Then in v5, that fix was lost so 8250 no longer works.

--Mark


On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
> Console Redirection Table) [2] as a mandatory ACPI table that
> specifies the configuration of serial console.
> 
> Move "earlycon" early_param handling to earlycon.c to parse this option once
> 
> *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
> *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
> 
> Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
> for the next patch.  It is taken from ACPICA series [3], but it has not appeared
> in linux-next yet.
> 
> Parse SPCR table, setup earlycon and add register specified console.
> 
> Enable parsing this table on ARM64.  Earlycon should be set up
> as early as possible.  ACPI boot tables are mapped in
> arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
> and that's where we parse spcr.  So it has to be opted-in per-arch.
> 
> Implement console_match() for pl011.
> 
> Based on the work by Leif Lindholm [4]
> Thanks to Peter Hurley for explaining how this should work.
> 
> Should be applied to next-20160331.
> 
> Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
> since 2.4 release.
> 
> v7:
> - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
>   to serial"
> - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
>   (Rafael J. Wysocki)
> - fix a few minor issues (Rafael J. Wysocki)
> 
> v6:
> https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
> - add documentation for parse_spcr() functioin (Yury Norov)
> - don't initialize err variable (Yury Norov)
> - add __initdata for the earlycon_init_is_deferred flag variable
> - rename the function exported in "of/serial: move earlycon early_param handling
>   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
> - defer initialization of DT earlycon until DT/ACPI decision is made
>   (Rob Herring, Peter Hurley)
> - use snprintf instead of sprintf (Andy Shevchenko)
> - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
>   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
>   SPCR earlycon will not work on the kernels before 4.6
> 
> v5:
> https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
> - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
>   it is ugly. Also because Christopher Covington came with a better solution [5]
> - remove error message when the table is not provided by ACPI (Andy Shevchenko)
> - rewrite spcr.c following the suggestions by Peter Hurley
> - add console_match() for pl011 in a separate patch
> - add EARLYCON_DECLARE for pl011 in a separate patch
> - add patch "of/serial: move earlycon early_param handling to serial" from
>   the GDB2 series
> 
> v4:
> https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
> - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
>   ACPI developers work on a new API and asked not to do that.
>   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
>   and cache the result. (Lv Zheng)
> - fix some style issues (Yury Norov)
> 
> v3:
> https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
> 
> Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
> 
> - drop acpi_match() member of struct console
> - drop implementations of this member for pl011 and 8250
> - drop the patch that renames some vars in printk.c as it is not needed anymore
> - drop patch that introduces system wide acpi_table_parse2().
>   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
> 
> Instead of introducing a new match_acpi() member of struct console,
> this patchset introduces a new function acpi_console_check().
> This function is called when a new uart is registered at serial_core.c
> the same way OF code checks for console.  If the registered uart is the
> console specified by SPCR table, this function calls add_preferred_console()
> 
> The restrictions of this approach are:
> 
> - only serial consoles can be set up
> - only consoles specified by the memory/io address can be set up
>   (SPCR can specify devices by PCI id/PCI address)
> 
> v2:
> https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
> - don't use SPCR if user specified console in command line
> - fix initialization order of newcon->index = 0
> - rename some variables at printk.c (Joe Perches, Peter Hurley)
> - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
> - remove the retry loop for console registering (Peter Hurley).
>   Instead, obtain SPCR with acpi_get_table().  That works after
>   call to acpi_early_init() i. e. in any *_initcall()
> - describe design decision behind introducing acpi_match() (Peter Hurley)
> - fix compilation for x86 + ACPI (Graeme Gregory)
> - introduce DBG2 constants in a separate patch (Andy Shevchenko)
> - fix a typo in DBG2 constants (Andy Shevchenko)
> - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
> - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
> - add documentation for functions
> - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
>   accessor functions (Christopher Covington)
> - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
> - introduce acpi_table_parse2() in a separate patch
> - fix fetching the SPCR table early (Mark Salter)
> - add a patch from Mark Salter that introduces support for matching 8250-based
>   consoles
> 
> v1:
> https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
> 
> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
> [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
> [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
> [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
> [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
> 
> Aleksey Makarov (4):
>   ACPICA: Headers: Add new constants for the DBG2 ACPI table
>   ACPI: parse SPCR and enable matching console
>   ARM64: ACPI: enable ACPI_SPCR_TABLE
>   serial: pl011: add console matching function
> 
> Leif Lindholm (1):
>   of/serial: move earlycon early_param handling to serial
> 
>  arch/arm64/Kconfig              |   1 +
>  arch/arm64/kernel/acpi.c        |  11 +++-
>  drivers/acpi/Kconfig            |   3 ++
>  drivers/acpi/Makefile           |   1 +
>  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
>  drivers/of/fdt.c                |  11 +---
>  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
>  drivers/tty/serial/earlycon.c   |  19 ++++++-
>  include/acpi/actbl2.h           |   7 ++-
>  include/linux/acpi.h            |   6 +++
>  include/linux/of_fdt.h          |   2 +
>  include/linux/serial_core.h     |   6 +++
>  12 files changed, 220 insertions(+), 14 deletions(-)
>  create mode 100644 drivers/acpi/spcr.c
> 

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#1372381

On 04/05/2016 07:27 PM, Mark Salter wrote:
> Could you CC me on future postings of this series, please?
> 
> So v3 fixed a problem where platforms using 8250 didn't work.
> Then in v5, that fix was lost so 8250 no longer works.

That fix was dropped because now this is implemented differently.  
Now the code uses the existing match() member of struct console.
It has already been implemented for 8250.  
Probably SPCR table specifies incorrect data.
It was reported that D02 board has similar issue.

Thank you
Aleksey Makarov

> 
> --Mark
> 
> 
> On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
>> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
>> Console Redirection Table) [2] as a mandatory ACPI table that
>> specifies the configuration of serial console.
>>
>> Move "earlycon" early_param handling to earlycon.c to parse this option once
>>
>> *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
>> *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
>>
>> Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
>> for the next patch.  It is taken from ACPICA series [3], but it has not appeared
>> in linux-next yet.
>>
>> Parse SPCR table, setup earlycon and add register specified console.
>>
>> Enable parsing this table on ARM64.  Earlycon should be set up
>> as early as possible.  ACPI boot tables are mapped in
>> arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
>> and that's where we parse spcr.  So it has to be opted-in per-arch.
>>
>> Implement console_match() for pl011.
>>
>> Based on the work by Leif Lindholm [4]
>> Thanks to Peter Hurley for explaining how this should work.
>>
>> Should be applied to next-20160331.
>>
>> Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
>> since 2.4 release.
>>
>> v7:
>> - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
>>   to serial"
>> - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
>>   (Rafael J. Wysocki)
>> - fix a few minor issues (Rafael J. Wysocki)
>>
>> v6:
>> https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
>> - add documentation for parse_spcr() functioin (Yury Norov)
>> - don't initialize err variable (Yury Norov)
>> - add __initdata for the earlycon_init_is_deferred flag variable
>> - rename the function exported in "of/serial: move earlycon early_param handling
>>   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
>> - defer initialization of DT earlycon until DT/ACPI decision is made
>>   (Rob Herring, Peter Hurley)
>> - use snprintf instead of sprintf (Andy Shevchenko)
>> - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
>>   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
>>   SPCR earlycon will not work on the kernels before 4.6
>>
>> v5:
>> https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
>> - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
>>   it is ugly. Also because Christopher Covington came with a better solution [5]
>> - remove error message when the table is not provided by ACPI (Andy Shevchenko)
>> - rewrite spcr.c following the suggestions by Peter Hurley
>> - add console_match() for pl011 in a separate patch
>> - add EARLYCON_DECLARE for pl011 in a separate patch
>> - add patch "of/serial: move earlycon early_param handling to serial" from
>>   the GDB2 series
>>
>> v4:
>> https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
>> - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
>>   ACPI developers work on a new API and asked not to do that.
>>   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
>>   and cache the result. (Lv Zheng)
>> - fix some style issues (Yury Norov)
>>
>> v3:
>> https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
>>
>> Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
>>
>> - drop acpi_match() member of struct console
>> - drop implementations of this member for pl011 and 8250
>> - drop the patch that renames some vars in printk.c as it is not needed anymore
>> - drop patch that introduces system wide acpi_table_parse2().
>>   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
>>
>> Instead of introducing a new match_acpi() member of struct console,
>> this patchset introduces a new function acpi_console_check().
>> This function is called when a new uart is registered at serial_core.c
>> the same way OF code checks for console.  If the registered uart is the
>> console specified by SPCR table, this function calls add_preferred_console()
>>
>> The restrictions of this approach are:
>>
>> - only serial consoles can be set up
>> - only consoles specified by the memory/io address can be set up
>>   (SPCR can specify devices by PCI id/PCI address)
>>
>> v2:
>> https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
>> - don't use SPCR if user specified console in command line
>> - fix initialization order of newcon->index = 0
>> - rename some variables at printk.c (Joe Perches, Peter Hurley)
>> - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
>> - remove the retry loop for console registering (Peter Hurley).
>>   Instead, obtain SPCR with acpi_get_table().  That works after
>>   call to acpi_early_init() i. e. in any *_initcall()
>> - describe design decision behind introducing acpi_match() (Peter Hurley)
>> - fix compilation for x86 + ACPI (Graeme Gregory)
>> - introduce DBG2 constants in a separate patch (Andy Shevchenko)
>> - fix a typo in DBG2 constants (Andy Shevchenko)
>> - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
>> - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
>> - add documentation for functions
>> - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
>>   accessor functions (Christopher Covington)
>> - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
>> - introduce acpi_table_parse2() in a separate patch
>> - fix fetching the SPCR table early (Mark Salter)
>> - add a patch from Mark Salter that introduces support for matching 8250-based
>>   consoles
>>
>> v1:
>> https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
>>
>> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
>> [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
>> [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
>> [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
>> [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
>>
>> Aleksey Makarov (4):
>>   ACPICA: Headers: Add new constants for the DBG2 ACPI table
>>   ACPI: parse SPCR and enable matching console
>>   ARM64: ACPI: enable ACPI_SPCR_TABLE
>>   serial: pl011: add console matching function
>>
>> Leif Lindholm (1):
>>   of/serial: move earlycon early_param handling to serial
>>
>>  arch/arm64/Kconfig              |   1 +
>>  arch/arm64/kernel/acpi.c        |  11 +++-
>>  drivers/acpi/Kconfig            |   3 ++
>>  drivers/acpi/Makefile           |   1 +
>>  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
>>  drivers/of/fdt.c                |  11 +---
>>  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
>>  drivers/tty/serial/earlycon.c   |  19 ++++++-
>>  include/acpi/actbl2.h           |   7 ++-
>>  include/linux/acpi.h            |   6 +++
>>  include/linux/of_fdt.h          |   2 +
>>  include/linux/serial_core.h     |   6 +++
>>  12 files changed, 220 insertions(+), 14 deletions(-)
>>  create mode 100644 drivers/acpi/spcr.c
>>
> 

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#1372400

On Wed, Apr 06, 2016 at 01:24:12PM +0300, Aleksey Makarov wrote:
> 
> 
> On 04/05/2016 07:27 PM, Mark Salter wrote:
> > Could you CC me on future postings of this series, please?
> > 
> > So v3 fixed a problem where platforms using 8250 didn't work.
> > Then in v5, that fix was lost so 8250 no longer works.
> 
> That fix was dropped because now this is implemented differently.  
> Now the code uses the existing match() member of struct console.
> It has already been implemented for 8250.  
> Probably SPCR table specifies incorrect data.
> It was reported that D02 board has similar issue.
> 

The D02 issue referred to is the 8250 implementation they used has 32bit
only MMIO access which there is no manner to represent in SPCR. It also
doesn't use the "standard" 16550 clock rate so supplying a baud rate
makes it change to a random baud rate.

We may need two 8250 subset entries, one just means no clock given, and
one no clock given + mmio32 only.

Graeme


> Thank you
> Aleksey Makarov
> 
> > 
> > --Mark
> > 
> > 
> > On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
> >> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
> >> Console Redirection Table) [2] as a mandatory ACPI table that
> >> specifies the configuration of serial console.
> >>
> >> Move "earlycon" early_param handling to earlycon.c to parse this option once
> >>
> >> *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
> >> *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
> >>
> >> Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
> >> for the next patch.  It is taken from ACPICA series [3], but it has not appeared
> >> in linux-next yet.
> >>
> >> Parse SPCR table, setup earlycon and add register specified console.
> >>
> >> Enable parsing this table on ARM64.  Earlycon should be set up
> >> as early as possible.  ACPI boot tables are mapped in
> >> arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
> >> and that's where we parse spcr.  So it has to be opted-in per-arch.
> >>
> >> Implement console_match() for pl011.
> >>
> >> Based on the work by Leif Lindholm [4]
> >> Thanks to Peter Hurley for explaining how this should work.
> >>
> >> Should be applied to next-20160331.
> >>
> >> Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
> >> since 2.4 release.
> >>
> >> v7:
> >> - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
> >>   to serial"
> >> - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
> >>   (Rafael J. Wysocki)
> >> - fix a few minor issues (Rafael J. Wysocki)
> >>
> >> v6:
> >> https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
> >> - add documentation for parse_spcr() functioin (Yury Norov)
> >> - don't initialize err variable (Yury Norov)
> >> - add __initdata for the earlycon_init_is_deferred flag variable
> >> - rename the function exported in "of/serial: move earlycon early_param handling
> >>   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
> >> - defer initialization of DT earlycon until DT/ACPI decision is made
> >>   (Rob Herring, Peter Hurley)
> >> - use snprintf instead of sprintf (Andy Shevchenko)
> >> - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
> >>   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
> >>   SPCR earlycon will not work on the kernels before 4.6
> >>
> >> v5:
> >> https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
> >> - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
> >>   it is ugly. Also because Christopher Covington came with a better solution [5]
> >> - remove error message when the table is not provided by ACPI (Andy Shevchenko)
> >> - rewrite spcr.c following the suggestions by Peter Hurley
> >> - add console_match() for pl011 in a separate patch
> >> - add EARLYCON_DECLARE for pl011 in a separate patch
> >> - add patch "of/serial: move earlycon early_param handling to serial" from
> >>   the GDB2 series
> >>
> >> v4:
> >> https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
> >> - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
> >>   ACPI developers work on a new API and asked not to do that.
> >>   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
> >>   and cache the result. (Lv Zheng)
> >> - fix some style issues (Yury Norov)
> >>
> >> v3:
> >> https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
> >>
> >> Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
> >>
> >> - drop acpi_match() member of struct console
> >> - drop implementations of this member for pl011 and 8250
> >> - drop the patch that renames some vars in printk.c as it is not needed anymore
> >> - drop patch that introduces system wide acpi_table_parse2().
> >>   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
> >>
> >> Instead of introducing a new match_acpi() member of struct console,
> >> this patchset introduces a new function acpi_console_check().
> >> This function is called when a new uart is registered at serial_core.c
> >> the same way OF code checks for console.  If the registered uart is the
> >> console specified by SPCR table, this function calls add_preferred_console()
> >>
> >> The restrictions of this approach are:
> >>
> >> - only serial consoles can be set up
> >> - only consoles specified by the memory/io address can be set up
> >>   (SPCR can specify devices by PCI id/PCI address)
> >>
> >> v2:
> >> https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
> >> - don't use SPCR if user specified console in command line
> >> - fix initialization order of newcon->index = 0
> >> - rename some variables at printk.c (Joe Perches, Peter Hurley)
> >> - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
> >> - remove the retry loop for console registering (Peter Hurley).
> >>   Instead, obtain SPCR with acpi_get_table().  That works after
> >>   call to acpi_early_init() i. e. in any *_initcall()
> >> - describe design decision behind introducing acpi_match() (Peter Hurley)
> >> - fix compilation for x86 + ACPI (Graeme Gregory)
> >> - introduce DBG2 constants in a separate patch (Andy Shevchenko)
> >> - fix a typo in DBG2 constants (Andy Shevchenko)
> >> - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
> >> - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
> >> - add documentation for functions
> >> - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
> >>   accessor functions (Christopher Covington)
> >> - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
> >> - introduce acpi_table_parse2() in a separate patch
> >> - fix fetching the SPCR table early (Mark Salter)
> >> - add a patch from Mark Salter that introduces support for matching 8250-based
> >>   consoles
> >>
> >> v1:
> >> https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
> >>
> >> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
> >> [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
> >> [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
> >> [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
> >> [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
> >>
> >> Aleksey Makarov (4):
> >>   ACPICA: Headers: Add new constants for the DBG2 ACPI table
> >>   ACPI: parse SPCR and enable matching console
> >>   ARM64: ACPI: enable ACPI_SPCR_TABLE
> >>   serial: pl011: add console matching function
> >>
> >> Leif Lindholm (1):
> >>   of/serial: move earlycon early_param handling to serial
> >>
> >>  arch/arm64/Kconfig              |   1 +
> >>  arch/arm64/kernel/acpi.c        |  11 +++-
> >>  drivers/acpi/Kconfig            |   3 ++
> >>  drivers/acpi/Makefile           |   1 +
> >>  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
> >>  drivers/of/fdt.c                |  11 +---
> >>  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
> >>  drivers/tty/serial/earlycon.c   |  19 ++++++-
> >>  include/acpi/actbl2.h           |   7 ++-
> >>  include/linux/acpi.h            |   6 +++
> >>  include/linux/of_fdt.h          |   2 +
> >>  include/linux/serial_core.h     |   6 +++
> >>  12 files changed, 220 insertions(+), 14 deletions(-)
> >>  create mode 100644 drivers/acpi/spcr.c
> >>
> > 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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#1372556

On Wed, 2016-04-06 at 11:52 +0100, Graeme Gregory wrote:
> On Wed, Apr 06, 2016 at 01:24:12PM +0300, Aleksey Makarov wrote:
> > 
> > 
> > 
> > On 04/05/2016 07:27 PM, Mark Salter wrote:
> > > 
> > > Could you CC me on future postings of this series, please?
> > > 
> > > So v3 fixed a problem where platforms using 8250 didn't work.
> > > Then in v5, that fix was lost so 8250 no longer works.
> > That fix was dropped because now this is implemented differently.  
> > Now the code uses the existing match() member of struct console.
> > It has already been implemented for 8250.  
> > Probably SPCR table specifies incorrect data.
> > It was reported that D02 board has similar issue.
> > 
> The D02 issue referred to is the 8250 implementation they used has 32bit
> only MMIO access which there is no manner to represent in SPCR. It also
> doesn't use the "standard" 16550 clock rate so supplying a baud rate
> makes it change to a random baud rate.

So, the problem with Mustang and m400 was the mmio vs mmio32. Right now,
the kernel only supports mmio32 in the 8250_dw.c driver when probed with
ACPI. Other x86 machines just use legacy 8250 ports which don't need
entries in the DSDT and use legacy io. The 8250_dw driver does support
non-standard clocks specified in the DSDT. That works fine for Mustang
and m400.

So with this quick hack, v7 is working with Mustang/m400:

diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 68ffc33..dade9de 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -37,6 +37,7 @@ int __init parse_spcr(bool earlycon)
 	acpi_status status;
 	char *uart;
 	char *iotype;
+	int mmio;
 	int baud_rate;
 	int err;
 
@@ -56,8 +57,8 @@ int __init parse_spcr(bool earlycon)
 		goto done;
 	}
 
-	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
-			"mmio" : "io";
+	mmio = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY;
+	iotype = mmio ? "mmio" : "io";
 
 	switch (table->interface_type) {
 	case ACPI_DBG2_ARM_SBSA_32BIT:
@@ -71,6 +72,8 @@ int __init parse_spcr(bool earlycon)
 	case ACPI_DBG2_16550_COMPATIBLE:
 	case ACPI_DBG2_16550_SUBSET:
 		uart = "uart";
+		if (mmio)
+			iotype = "mmio32";
 		break;
 	default:
 		err = -ENOENT;

> 
> We may need two 8250 subset entries, one just means no clock given, and
> one no clock given + mmio32 only.
> 
> Graeme
> 
> 
> > 
> > Thank you
> > Aleksey Makarov
> > 
> > > 
> > > 
> > > --Mark
> > > 
> > > 
> > > On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
> > > > 
> > > > 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
> > > > Console Redirection Table) [2] as a mandatory ACPI table that
> > > > specifies the configuration of serial console.
> > > > 
> > > > Move "earlycon" early_param handling to earlycon.c to parse this option once
> > > > 
> > > > *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
> > > > *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
> > > > 
> > > > Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
> > > > for the next patch.  It is taken from ACPICA series [3], but it has not appeared
> > > > in linux-next yet.
> > > > 
> > > > Parse SPCR table, setup earlycon and add register specified console.
> > > > 
> > > > Enable parsing this table on ARM64.  Earlycon should be set up
> > > > as early as possible.  ACPI boot tables are mapped in
> > > > arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
> > > > and that's where we parse spcr.  So it has to be opted-in per-arch.
> > > > 
> > > > Implement console_match() for pl011.
> > > > 
> > > > Based on the work by Leif Lindholm [4]
> > > > Thanks to Peter Hurley for explaining how this should work.
> > > > 
> > > > Should be applied to next-20160331.
> > > > 
> > > > Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
> > > > since 2.4 release.
> > > > 
> > > > v7:
> > > > - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
> > > >   to serial"
> > > > - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
> > > >   (Rafael J. Wysocki)
> > > > - fix a few minor issues (Rafael J. Wysocki)
> > > > 
> > > > v6:
> > > > https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
> > > > - add documentation for parse_spcr() functioin (Yury Norov)
> > > > - don't initialize err variable (Yury Norov)
> > > > - add __initdata for the earlycon_init_is_deferred flag variable
> > > > - rename the function exported in "of/serial: move earlycon early_param handling
> > > >   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
> > > > - defer initialization of DT earlycon until DT/ACPI decision is made
> > > >   (Rob Herring, Peter Hurley)
> > > > - use snprintf instead of sprintf (Andy Shevchenko)
> > > > - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
> > > >   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
> > > >   SPCR earlycon will not work on the kernels before 4.6
> > > > 
> > > > v5:
> > > > https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
> > > > - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
> > > >   it is ugly. Also because Christopher Covington came with a better solution [5]
> > > > - remove error message when the table is not provided by ACPI (Andy Shevchenko)
> > > > - rewrite spcr.c following the suggestions by Peter Hurley
> > > > - add console_match() for pl011 in a separate patch
> > > > - add EARLYCON_DECLARE for pl011 in a separate patch
> > > > - add patch "of/serial: move earlycon early_param handling to serial" from
> > > >   the GDB2 series
> > > > 
> > > > v4:
> > > > https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
> > > > - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
> > > >   ACPI developers work on a new API and asked not to do that.
> > > >   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
> > > >   and cache the result. (Lv Zheng)
> > > > - fix some style issues (Yury Norov)
> > > > 
> > > > v3:
> > > > https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
> > > > 
> > > > Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
> > > > 
> > > > - drop acpi_match() member of struct console
> > > > - drop implementations of this member for pl011 and 8250
> > > > - drop the patch that renames some vars in printk.c as it is not needed anymore
> > > > - drop patch that introduces system wide acpi_table_parse2().
> > > >   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
> > > > 
> > > > Instead of introducing a new match_acpi() member of struct console,
> > > > this patchset introduces a new function acpi_console_check().
> > > > This function is called when a new uart is registered at serial_core.c
> > > > the same way OF code checks for console.  If the registered uart is the
> > > > console specified by SPCR table, this function calls add_preferred_console()
> > > > 
> > > > The restrictions of this approach are:
> > > > 
> > > > - only serial consoles can be set up
> > > > - only consoles specified by the memory/io address can be set up
> > > >   (SPCR can specify devices by PCI id/PCI address)
> > > > 
> > > > v2:
> > > > https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
> > > > - don't use SPCR if user specified console in command line
> > > > - fix initialization order of newcon->index = 0
> > > > - rename some variables at printk.c (Joe Perches, Peter Hurley)
> > > > - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
> > > > - remove the retry loop for console registering (Peter Hurley).
> > > >   Instead, obtain SPCR with acpi_get_table().  That works after
> > > >   call to acpi_early_init() i. e. in any *_initcall()
> > > > - describe design decision behind introducing acpi_match() (Peter Hurley)
> > > > - fix compilation for x86 + ACPI (Graeme Gregory)
> > > > - introduce DBG2 constants in a separate patch (Andy Shevchenko)
> > > > - fix a typo in DBG2 constants (Andy Shevchenko)
> > > > - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
> > > > - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
> > > > - add documentation for functions
> > > > - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
> > > >   accessor functions (Christopher Covington)
> > > > - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
> > > > - introduce acpi_table_parse2() in a separate patch
> > > > - fix fetching the SPCR table early (Mark Salter)
> > > > - add a patch from Mark Salter that introduces support for matching 8250-based
> > > >   consoles
> > > > 
> > > > v1:
> > > > https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
> > > > 
> > > > [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
> > > > [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
> > > > [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
> > > > [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
> > > > [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
> > > > 
> > > > Aleksey Makarov (4):
> > > >   ACPICA: Headers: Add new constants for the DBG2 ACPI table
> > > >   ACPI: parse SPCR and enable matching console
> > > >   ARM64: ACPI: enable ACPI_SPCR_TABLE
> > > >   serial: pl011: add console matching function
> > > > 
> > > > Leif Lindholm (1):
> > > >   of/serial: move earlycon early_param handling to serial
> > > > 
> > > >  arch/arm64/Kconfig              |   1 +
> > > >  arch/arm64/kernel/acpi.c        |  11 +++-
> > > >  drivers/acpi/Kconfig            |   3 ++
> > > >  drivers/acpi/Makefile           |   1 +
> > > >  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
> > > >  drivers/of/fdt.c                |  11 +---
> > > >  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
> > > >  drivers/tty/serial/earlycon.c   |  19 ++++++-
> > > >  include/acpi/actbl2.h           |   7 ++-
> > > >  include/linux/acpi.h            |   6 +++
> > > >  include/linux/of_fdt.h          |   2 +
> > > >  include/linux/serial_core.h     |   6 +++
> > > >  12 files changed, 220 insertions(+), 14 deletions(-)
> > > >  create mode 100644 drivers/acpi/spcr.c
> > > > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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#1372650

On 04/06/2016 07:18 AM, Mark Salter wrote:
> On Wed, 2016-04-06 at 11:52 +0100, Graeme Gregory wrote:
>> On Wed, Apr 06, 2016 at 01:24:12PM +0300, Aleksey Makarov wrote:
>>>
>>>
>>>
>>> On 04/05/2016 07:27 PM, Mark Salter wrote:
>>>>
>>>> Could you CC me on future postings of this series, please?
>>>>
>>>> So v3 fixed a problem where platforms using 8250 didn't work.
>>>> Then in v5, that fix was lost so 8250 no longer works.
>>> That fix was dropped because now this is implemented differently.  
>>> Now the code uses the existing match() member of struct console.
>>> It has already been implemented for 8250.  
>>> Probably SPCR table specifies incorrect data.
>>> It was reported that D02 board has similar issue.
>>>
>> The D02 issue referred to is the 8250 implementation they used has 32bit
>> only MMIO access which there is no manner to represent in SPCR. It also
>> doesn't use the "standard" 16550 clock rate so supplying a baud rate
>> makes it change to a random baud rate.
> 
> So, the problem with Mustang and m400 was the mmio vs mmio32.

Bummer. Maybe that firmware can use a different DBG2 port designation to
indicate it's a DesignWare 8250 (or generically 32-bit mmio).


> Right now,
> the kernel only supports mmio32 in the 8250_dw.c driver when probed with
> ACPI.

While that's true specifically for DesignWare 8250 + ACPI, that's not
true for _all_ 8250 + ACPI.


> Other x86 machines just use legacy 8250 ports which don't need
> entries in the DSDT and use legacy io.

I find that statement hard to believe. I know for a fact ia64 servers didn't,
so the assertion that SPCR + 16550 + MMIO automatically means 32-bit data width
seems unlikely.

In fact, I suspect the opposite is true; that before these arm64 designs,
SPCR + 16550 + MMIO automatically meant 8-bit data width, which is why it's
unspecified in the SPCR table.

Regards,
Peter Hurley


> The 8250_dw driver does support
> non-standard clocks specified in the DSDT. That works fine for Mustang
> and m400.
> 
> So with this quick hack, v7 is working with Mustang/m400:
> 
> diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
> index 68ffc33..dade9de 100644
> --- a/drivers/acpi/spcr.c
> +++ b/drivers/acpi/spcr.c
> @@ -37,6 +37,7 @@ int __init parse_spcr(bool earlycon)
>  	acpi_status status;
>  	char *uart;
>  	char *iotype;
> +	int mmio;
>  	int baud_rate;
>  	int err;
>  
> @@ -56,8 +57,8 @@ int __init parse_spcr(bool earlycon)
>  		goto done;
>  	}
>  
> -	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
> -			"mmio" : "io";
> +	mmio = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY;
> +	iotype = mmio ? "mmio" : "io";
>  
>  	switch (table->interface_type) {
>  	case ACPI_DBG2_ARM_SBSA_32BIT:
> @@ -71,6 +72,8 @@ int __init parse_spcr(bool earlycon)
>  	case ACPI_DBG2_16550_COMPATIBLE:
>  	case ACPI_DBG2_16550_SUBSET:
>  		uart = "uart";
> +		if (mmio)
> +			iotype = "mmio32";
>  		break;
>  	default:
>  		err = -ENOENT;
> 
>>
>> We may need two 8250 subset entries, one just means no clock given, and
>> one no clock given + mmio32 only.
>>
>> Graeme
>>
>>
>>>
>>> Thank you
>>> Aleksey Makarov
>>>
>>>>
>>>>
>>>> --Mark
>>>>
>>>>
>>>> On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
>>>>>
>>>>> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
>>>>> Console Redirection Table) [2] as a mandatory ACPI table that
>>>>> specifies the configuration of serial console.
>>>>>
>>>>> Move "earlycon" early_param handling to earlycon.c to parse this option once
>>>>>
>>>>> *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
>>>>> *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
>>>>>
>>>>> Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
>>>>> for the next patch.  It is taken from ACPICA series [3], but it has not appeared
>>>>> in linux-next yet.
>>>>>
>>>>> Parse SPCR table, setup earlycon and add register specified console.
>>>>>
>>>>> Enable parsing this table on ARM64.  Earlycon should be set up
>>>>> as early as possible.  ACPI boot tables are mapped in
>>>>> arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
>>>>> and that's where we parse spcr.  So it has to be opted-in per-arch.
>>>>>
>>>>> Implement console_match() for pl011.
>>>>>
>>>>> Based on the work by Leif Lindholm [4]
>>>>> Thanks to Peter Hurley for explaining how this should work.
>>>>>
>>>>> Should be applied to next-20160331.
>>>>>
>>>>> Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
>>>>> since 2.4 release.
>>>>>
>>>>> v7:
>>>>> - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
>>>>>   to serial"
>>>>> - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
>>>>>   (Rafael J. Wysocki)
>>>>> - fix a few minor issues (Rafael J. Wysocki)
>>>>>
>>>>> v6:
>>>>> https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
>>>>> - add documentation for parse_spcr() functioin (Yury Norov)
>>>>> - don't initialize err variable (Yury Norov)
>>>>> - add __initdata for the earlycon_init_is_deferred flag variable
>>>>> - rename the function exported in "of/serial: move earlycon early_param handling
>>>>>   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
>>>>> - defer initialization of DT earlycon until DT/ACPI decision is made
>>>>>   (Rob Herring, Peter Hurley)
>>>>> - use snprintf instead of sprintf (Andy Shevchenko)
>>>>> - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
>>>>>   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
>>>>>   SPCR earlycon will not work on the kernels before 4.6
>>>>>
>>>>> v5:
>>>>> https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
>>>>> - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
>>>>>   it is ugly. Also because Christopher Covington came with a better solution [5]
>>>>> - remove error message when the table is not provided by ACPI (Andy Shevchenko)
>>>>> - rewrite spcr.c following the suggestions by Peter Hurley
>>>>> - add console_match() for pl011 in a separate patch
>>>>> - add EARLYCON_DECLARE for pl011 in a separate patch
>>>>> - add patch "of/serial: move earlycon early_param handling to serial" from
>>>>>   the GDB2 series
>>>>>
>>>>> v4:
>>>>> https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
>>>>> - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
>>>>>   ACPI developers work on a new API and asked not to do that.
>>>>>   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
>>>>>   and cache the result. (Lv Zheng)
>>>>> - fix some style issues (Yury Norov)
>>>>>
>>>>> v3:
>>>>> https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
>>>>>
>>>>> Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
>>>>>
>>>>> - drop acpi_match() member of struct console
>>>>> - drop implementations of this member for pl011 and 8250
>>>>> - drop the patch that renames some vars in printk.c as it is not needed anymore
>>>>> - drop patch that introduces system wide acpi_table_parse2().
>>>>>   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
>>>>>
>>>>> Instead of introducing a new match_acpi() member of struct console,
>>>>> this patchset introduces a new function acpi_console_check().
>>>>> This function is called when a new uart is registered at serial_core.c
>>>>> the same way OF code checks for console.  If the registered uart is the
>>>>> console specified by SPCR table, this function calls add_preferred_console()
>>>>>
>>>>> The restrictions of this approach are:
>>>>>
>>>>> - only serial consoles can be set up
>>>>> - only consoles specified by the memory/io address can be set up
>>>>>   (SPCR can specify devices by PCI id/PCI address)
>>>>>
>>>>> v2:
>>>>> https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
>>>>> - don't use SPCR if user specified console in command line
>>>>> - fix initialization order of newcon->index = 0
>>>>> - rename some variables at printk.c (Joe Perches, Peter Hurley)
>>>>> - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
>>>>> - remove the retry loop for console registering (Peter Hurley).
>>>>>   Instead, obtain SPCR with acpi_get_table().  That works after
>>>>>   call to acpi_early_init() i. e. in any *_initcall()
>>>>> - describe design decision behind introducing acpi_match() (Peter Hurley)
>>>>> - fix compilation for x86 + ACPI (Graeme Gregory)
>>>>> - introduce DBG2 constants in a separate patch (Andy Shevchenko)
>>>>> - fix a typo in DBG2 constants (Andy Shevchenko)
>>>>> - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
>>>>> - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
>>>>> - add documentation for functions
>>>>> - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
>>>>>   accessor functions (Christopher Covington)
>>>>> - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
>>>>> - introduce acpi_table_parse2() in a separate patch
>>>>> - fix fetching the SPCR table early (Mark Salter)
>>>>> - add a patch from Mark Salter that introduces support for matching 8250-based
>>>>>   consoles
>>>>>
>>>>> v1:
>>>>> https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
>>>>>
>>>>> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
>>>>> [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
>>>>> [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
>>>>> [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
>>>>> [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
>>>>>
>>>>> Aleksey Makarov (4):
>>>>>   ACPICA: Headers: Add new constants for the DBG2 ACPI table
>>>>>   ACPI: parse SPCR and enable matching console
>>>>>   ARM64: ACPI: enable ACPI_SPCR_TABLE
>>>>>   serial: pl011: add console matching function
>>>>>
>>>>> Leif Lindholm (1):
>>>>>   of/serial: move earlycon early_param handling to serial
>>>>>
>>>>>  arch/arm64/Kconfig              |   1 +
>>>>>  arch/arm64/kernel/acpi.c        |  11 +++-
>>>>>  drivers/acpi/Kconfig            |   3 ++
>>>>>  drivers/acpi/Makefile           |   1 +
>>>>>  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
>>>>>  drivers/of/fdt.c                |  11 +---
>>>>>  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
>>>>>  drivers/tty/serial/earlycon.c   |  19 ++++++-
>>>>>  include/acpi/actbl2.h           |   7 ++-
>>>>>  include/linux/acpi.h            |   6 +++
>>>>>  include/linux/of_fdt.h          |   2 +
>>>>>  include/linux/serial_core.h     |   6 +++
>>>>>  12 files changed, 220 insertions(+), 14 deletions(-)
>>>>>  create mode 100644 drivers/acpi/spcr.c
>>>>>
>>> _______________________________________________
>>> linux-arm-kernel mailing list
>>> linux-arm-kernel@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

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#1372748

On Wed, 2016-04-06 at 09:27 -0700, Peter Hurley wrote:
> On 04/06/2016 07:18 AM, Mark Salter wrote:
> > 
> > On Wed, 2016-04-06 at 11:52 +0100, Graeme Gregory wrote:
> > > 
> > > On Wed, Apr 06, 2016 at 01:24:12PM +0300, Aleksey Makarov wrote:
> > > > 
> > > > 
> > > > 
> > > > 
> > > > On 04/05/2016 07:27 PM, Mark Salter wrote:
> > > > > 
> > > > > 
> > > > > Could you CC me on future postings of this series, please?
> > > > > 
> > > > > So v3 fixed a problem where platforms using 8250 didn't work.
> > > > > Then in v5, that fix was lost so 8250 no longer works.
> > > > That fix was dropped because now this is implemented differently.  
> > > > Now the code uses the existing match() member of struct console.
> > > > It has already been implemented for 8250.  
> > > > Probably SPCR table specifies incorrect data.
> > > > It was reported that D02 board has similar issue.
> > > > 
> > > The D02 issue referred to is the 8250 implementation they used has 32bit
> > > only MMIO access which there is no manner to represent in SPCR. It also
> > > doesn't use the "standard" 16550 clock rate so supplying a baud rate
> > > makes it change to a random baud rate.
> > So, the problem with Mustang and m400 was the mmio vs mmio32.
> Bummer. Maybe that firmware can use a different DBG2 port designation to
> indicate it's a DesignWare 8250 (or generically 32-bit mmio).
> 
> > 
> > Right now,
> > the kernel only supports mmio32 in the 8250_dw.c driver when probed with
> > ACPI.
> While that's true specifically for DesignWare 8250 + ACPI, that's not
> true for _all_ 8250 + ACPI.
> 
> > 
> > Other x86 machines just use legacy 8250 ports which don't need
> > entries in the DSDT and use legacy io.
> I find that statement hard to believe. I know for a fact ia64 servers didn't,
> so the assertion that SPCR + 16550 + MMIO automatically means 32-bit data width
> seems unlikely.

You're right. Other than DesignWare, 8250 ports can be descibed with PNP IDs
which is the bit I was missing. And all of those assume 8-bit width. So it
seems a DBG2 port designation for 8250 with 32-bit mmio is needed.

> 
> In fact, I suspect the opposite is true; that before these arm64 designs,
> SPCR + 16550 + MMIO automatically meant 8-bit data width, which is why it's
> unspecified in the SPCR table.
> 
> Regards,
> Peter Hurley
> 
> 
> > 
> > The 8250_dw driver does support
> > non-standard clocks specified in the DSDT. That works fine for Mustang
> > and m400.
> > 
> > So with this quick hack, v7 is working with Mustang/m400:
> > 
> > diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
> > index 68ffc33..dade9de 100644
> > --- a/drivers/acpi/spcr.c
> > +++ b/drivers/acpi/spcr.c
> > @@ -37,6 +37,7 @@ int __init parse_spcr(bool earlycon)
> >  	acpi_status status;
> >  	char *uart;
> >  	char *iotype;
> > +	int mmio;
> >  	int baud_rate;
> >  	int err;
> >  
> > @@ -56,8 +57,8 @@ int __init parse_spcr(bool earlycon)
> >  		goto done;
> >  	}
> >  
> > -	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
> > -			"mmio" : "io";
> > +	mmio = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY;
> > +	iotype = mmio ? "mmio" : "io";
> >  
> >  	switch (table->interface_type) {
> >  	case ACPI_DBG2_ARM_SBSA_32BIT:
> > @@ -71,6 +72,8 @@ int __init parse_spcr(bool earlycon)
> >  	case ACPI_DBG2_16550_COMPATIBLE:
> >  	case ACPI_DBG2_16550_SUBSET:
> >  		uart = "uart";
> > +		if (mmio)
> > +			iotype = "mmio32";
> >  		break;
> >  	default:
> >  		err = -ENOENT;
> > 
> > > 
> > > 
> > > We may need two 8250 subset entries, one just means no clock given, and
> > > one no clock given + mmio32 only.
> > > 
> > > Graeme
> > > 
> > > 
> > > > 
> > > > 
> > > > Thank you
> > > > Aleksey Makarov
> > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > --Mark
> > > > > 
> > > > > 
> > > > > On Thu, 2016-03-31 at 16:40 +0300, Aleksey Makarov wrote:
> > > > > > 
> > > > > > 
> > > > > > 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
> > > > > > Console Redirection Table) [2] as a mandatory ACPI table that
> > > > > > specifies the configuration of serial console.
> > > > > > 
> > > > > > Move "earlycon" early_param handling to earlycon.c to parse this option once
> > > > > > 
> > > > > > *** PATCH  "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
> > > > > > *** IS JUST TO ENABLE BUILDING THE PATCHSET ON linux-next
> > > > > > 
> > > > > > Patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table" is required
> > > > > > for the next patch.  It is taken from ACPICA series [3], but it has not appeared
> > > > > > in linux-next yet.
> > > > > > 
> > > > > > Parse SPCR table, setup earlycon and add register specified console.
> > > > > > 
> > > > > > Enable parsing this table on ARM64.  Earlycon should be set up
> > > > > > as early as possible.  ACPI boot tables are mapped in
> > > > > > arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
> > > > > > and that's where we parse spcr.  So it has to be opted-in per-arch.
> > > > > > 
> > > > > > Implement console_match() for pl011.
> > > > > > 
> > > > > > Based on the work by Leif Lindholm [4]
> > > > > > Thanks to Peter Hurley for explaining how this should work.
> > > > > > 
> > > > > > Should be applied to next-20160331.
> > > > > > 
> > > > > > Tested on QEMU.  SPCR support is included in QEMU's ARM mach-virt
> > > > > > since 2.4 release.
> > > > > > 
> > > > > > v7:
> > > > > > - add Acked-by: Rob Herring for "of/serial: move earlycon early_param handling
> > > > > >   to serial"
> > > > > > - call DT earlycon initialization from the arch ACPI code, not from parse_spcr()
> > > > > >   (Rafael J. Wysocki)
> > > > > > - fix a few minor issues (Rafael J. Wysocki)
> > > > > > 
> > > > > > v6:
> > > > > > https://lkml.kernel.org/g/1458823925-19560-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > - add documentation for parse_spcr() functioin (Yury Norov)
> > > > > > - don't initialize err variable (Yury Norov)
> > > > > > - add __initdata for the earlycon_init_is_deferred flag variable
> > > > > > - rename the function exported in "of/serial: move earlycon early_param handling
> > > > > >   to serial" to avoid clash with the function from arch/microblaze/kernel/prom.c
> > > > > > - defer initialization of DT earlycon until DT/ACPI decision is made
> > > > > >   (Rob Herring, Peter Hurley)
> > > > > > - use snprintf instead of sprintf (Andy Shevchenko)
> > > > > > - drop patch that adds EARLYCON_DECLARE for pl011 as EARLYCON_DECLARE is
> > > > > >   equivalent to OF_EARLYCON_DECLARE for 4.6+ (Peter Hurley).  This means that
> > > > > >   SPCR earlycon will not work on the kernels before 4.6
> > > > > > 
> > > > > > v5:
> > > > > > https://lkml.kernel.org/g/1458643595-14719-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > - drop patch "serial: pl011: use ACPI SPCR to setup 32-bit access" because
> > > > > >   it is ugly. Also because Christopher Covington came with a better solution [5]
> > > > > > - remove error message when the table is not provided by ACPI (Andy Shevchenko)
> > > > > > - rewrite spcr.c following the suggestions by Peter Hurley
> > > > > > - add console_match() for pl011 in a separate patch
> > > > > > - add EARLYCON_DECLARE for pl011 in a separate patch
> > > > > > - add patch "of/serial: move earlycon early_param handling to serial" from
> > > > > >   the GDB2 series
> > > > > > 
> > > > > > v4:
> > > > > > https://lkml.kernel.org/g/1456747355-15692-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()"
> > > > > >   ACPI developers work on a new API and asked not to do that.
> > > > > >   Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once
> > > > > >   and cache the result. (Lv Zheng)
> > > > > > - fix some style issues (Yury Norov)
> > > > > > 
> > > > > > v3:
> > > > > > https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > 
> > > > > > Greg Kroah-Hartman did not like v2 so I have rewritten this patchset:
> > > > > > 
> > > > > > - drop acpi_match() member of struct console
> > > > > > - drop implementations of this member for pl011 and 8250
> > > > > > - drop the patch that renames some vars in printk.c as it is not needed anymore
> > > > > > - drop patch that introduces system wide acpi_table_parse2().
> > > > > >   Instead introduce a custom acpi_table_parse_spcr() in spcr.c
> > > > > > 
> > > > > > Instead of introducing a new match_acpi() member of struct console,
> > > > > > this patchset introduces a new function acpi_console_check().
> > > > > > This function is called when a new uart is registered at serial_core.c
> > > > > > the same way OF code checks for console.  If the registered uart is the
> > > > > > console specified by SPCR table, this function calls add_preferred_console()
> > > > > > 
> > > > > > The restrictions of this approach are:
> > > > > > 
> > > > > > - only serial consoles can be set up
> > > > > > - only consoles specified by the memory/io address can be set up
> > > > > >   (SPCR can specify devices by PCI id/PCI address)
> > > > > > 
> > > > > > v2:
> > > > > > https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > - don't use SPCR if user specified console in command line
> > > > > > - fix initialization order of newcon->index = 0
> > > > > > - rename some variables at printk.c (Joe Perches, Peter Hurley)
> > > > > > - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko)
> > > > > > - remove the retry loop for console registering (Peter Hurley).
> > > > > >   Instead, obtain SPCR with acpi_get_table().  That works after
> > > > > >   call to acpi_early_init() i. e. in any *_initcall()
> > > > > > - describe design decision behind introducing acpi_match() (Peter Hurley)
> > > > > > - fix compilation for x86 + ACPI (Graeme Gregory)
> > > > > > - introduce DBG2 constants in a separate patch (Andy Shevchenko)
> > > > > > - fix a typo in DBG2 constants (Andy Shevchenko)
> > > > > > - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington)
> > > > > > - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington)
> > > > > > - add documentation for functions
> > > > > > - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit
> > > > > >   accessor functions (Christopher Covington)
> > > > > > - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch
> > > > > > - introduce acpi_table_parse2() in a separate patch
> > > > > > - fix fetching the SPCR table early (Mark Salter)
> > > > > > - add a patch from Mark Salter that introduces support for matching 8250-based
> > > > > >   consoles
> > > > > > 
> > > > > > v1:
> > > > > > https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.makarov@linaro.org
> > > > > > 
> > > > > > [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
> > > > > > [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx
> > > > > > [3] https://lkml.kernel.org/g/cover.1458714002.git.lv.zheng@intel.com
> > > > > > [4] https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindholm@linaro.org
> > > > > > [5] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
> > > > > > 
> > > > > > Aleksey Makarov (4):
> > > > > >   ACPICA: Headers: Add new constants for the DBG2 ACPI table
> > > > > >   ACPI: parse SPCR and enable matching console
> > > > > >   ARM64: ACPI: enable ACPI_SPCR_TABLE
> > > > > >   serial: pl011: add console matching function
> > > > > > 
> > > > > > Leif Lindholm (1):
> > > > > >   of/serial: move earlycon early_param handling to serial
> > > > > > 
> > > > > >  arch/arm64/Kconfig              |   1 +
> > > > > >  arch/arm64/kernel/acpi.c        |  11 +++-
> > > > > >  drivers/acpi/Kconfig            |   3 ++
> > > > > >  drivers/acpi/Makefile           |   1 +
> > > > > >  drivers/acpi/spcr.c             | 111 ++++++++++++++++++++++++++++++++++++++++
> > > > > >  drivers/of/fdt.c                |  11 +---
> > > > > >  drivers/tty/serial/amba-pl011.c |  56 ++++++++++++++++++++
> > > > > >  drivers/tty/serial/earlycon.c   |  19 ++++++-
> > > > > >  include/acpi/actbl2.h           |   7 ++-
> > > > > >  include/linux/acpi.h            |   6 +++
> > > > > >  include/linux/of_fdt.h          |   2 +
> > > > > >  include/linux/serial_core.h     |   6 +++
> > > > > >  12 files changed, 220 insertions(+), 14 deletions(-)
> > > > > >  create mode 100644 drivers/acpi/spcr.c
> > > > > > 
> > > > _______________________________________________
> > > > linux-arm-kernel mailing list
> > > > linux-arm-kernel@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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