On 02/29/2016 04:02 AM, 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.
>
> Introduce a new function acpi_console_check(). At the uart port
> registration, this function checks if the ACPI SPCR table specifies
> its argument of type struct uart_port to be a console
> and if so calls add_preferred_console().
How will a user enable an earlycon on the same console as the SPCR
console if there is no DBG2 table?
> Use SPCR to tell if SBSA serial driver should use 32-bit access to registers.
>
> Based on the work by Leif Lindholm [3]
>
> Should be applied to next-20160229.
>
> Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt
> since 2.4 release.
>
> v4:
> - 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/[email protected]
>
> 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/[email protected]
> - 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/[email protected]
>
> [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/[email protected]
>
> Aleksey Makarov (4):
> ACPI: parse SPCR and enable matching console
> ACPI: enable ACPI_SPCR_TABLE on ARM64
> ACPI: add definitions of DBG2 subtypes
> serial: pl011: use ACPI SPCR to setup 32-bit access
>
> arch/arm64/Kconfig | 1 +
> drivers/acpi/Kconfig | 3 +
> drivers/acpi/Makefile | 1 +
> drivers/acpi/spcr.c | 138 +++++++++++++++++++++++++++++++++++++++
> drivers/tty/serial/amba-pl011.c | 2 +
> drivers/tty/serial/serial_core.c | 14 +++-
> include/acpi/actbl2.h | 5 ++
> include/linux/acpi.h | 15 +++++
> 8 files changed, 177 insertions(+), 2 deletions(-)
> create mode 100644 drivers/acpi/spcr.c
>
On 03/01/2016 06:31 PM, Peter Hurley wrote:
> On 02/29/2016 04:02 AM, 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.
>>
>> Introduce a new function acpi_console_check(). At the uart port
>> registration, this function checks if the ACPI SPCR table specifies
>> its argument of type struct uart_port to be a console
>> and if so calls add_preferred_console().
>
> How will a user enable an earlycon on the same console as the SPCR
> console if there is no DBG2 table?
...
[ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
[ 0.000000] bootconsole [pl11] enabled
...
[ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000
...
[ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0]
[ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA
[ 0.319502] console [ttyAMA0] enabled
[ 0.319502] console [ttyAMA0] enabled
[ 0.319933] bootconsole [pl11] disabled
[ 0.319933] bootconsole [pl11] disabled
...
Why?
>
>
>> Use SPCR to tell if SBSA serial driver should use 32-bit access to registers.
>>
>> Based on the work by Leif Lindholm [3]
>>
>> Should be applied to next-20160229.
>>
>> Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt
>> since 2.4 release.
>>
>> v4:
>> - 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/[email protected]
>>
>> 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/[email protected]
>> - 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/[email protected]
>>
>> [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/[email protected]
>>
>> Aleksey Makarov (4):
>> ACPI: parse SPCR and enable matching console
>> ACPI: enable ACPI_SPCR_TABLE on ARM64
>> ACPI: add definitions of DBG2 subtypes
>> serial: pl011: use ACPI SPCR to setup 32-bit access
>>
>> arch/arm64/Kconfig | 1 +
>> drivers/acpi/Kconfig | 3 +
>> drivers/acpi/Makefile | 1 +
>> drivers/acpi/spcr.c | 138 +++++++++++++++++++++++++++++++++++++++
>> drivers/tty/serial/amba-pl011.c | 2 +
>> drivers/tty/serial/serial_core.c | 14 +++-
>> include/acpi/actbl2.h | 5 ++
>> include/linux/acpi.h | 15 +++++
>> 8 files changed, 177 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/acpi/spcr.c
>>
>
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On 03/03/2016 03:59 AM, Aleksey Makarov wrote:
>
>
> On 03/01/2016 06:31 PM, Peter Hurley wrote:
>> On 02/29/2016 04:02 AM, 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.
>>>
>>> Introduce a new function acpi_console_check(). At the uart port
>>> registration, this function checks if the ACPI SPCR table specifies
>>> its argument of type struct uart_port to be a console
>>> and if so calls add_preferred_console().
>>
>> How will a user enable an earlycon on the same console as the SPCR
>> console if there is no DBG2 table?
>
> ...
> [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
> [ 0.000000] bootconsole [pl11] enabled
> ...
> [ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000
> ...
> [ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0]
> [ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA
> [ 0.319502] console [ttyAMA0] enabled
> [ 0.319502] console [ttyAMA0] enabled
> [ 0.319933] bootconsole [pl11] disabled
> [ 0.319933] bootconsole [pl11] disabled
> ...
>
> Why?
That's pretty disingenuous; via command line?
By that measure, none of your patches are required because a user
can already start both console and earlycon without them.
With the console location specified in the SPCR, earlycon should
be opt-in on the command-line simply with "earlycon" command-line
parameter.
On 03/03/2016 06:35 PM, Peter Hurley wrote:
> On 03/03/2016 03:59 AM, Aleksey Makarov wrote:
>>
>>
>> On 03/01/2016 06:31 PM, Peter Hurley wrote:
>>> On 02/29/2016 04:02 AM, 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.
>>>>
>>>> Introduce a new function acpi_console_check(). At the uart port
>>>> registration, this function checks if the ACPI SPCR table specifies
>>>> its argument of type struct uart_port to be a console
>>>> and if so calls add_preferred_console().
>>>
>>> How will a user enable an earlycon on the same console as the SPCR
>>> console if there is no DBG2 table?
>>
>> ...
>> [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
>> [ 0.000000] bootconsole [pl11] enabled
>> ...
>> [ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000
>> ...
>> [ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0]
>> [ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA
>> [ 0.319502] console [ttyAMA0] enabled
>> [ 0.319502] console [ttyAMA0] enabled
>> [ 0.319933] bootconsole [pl11] disabled
>> [ 0.319933] bootconsole [pl11] disabled
>> ...
>>
>> Why?
>
> That's pretty disingenuous; via command line?
>
> By that measure, none of your patches are required because a user
> can already start both console and earlycon without them.
>
> With the console location specified in the SPCR, earlycon should
> be opt-in on the command-line simply with "earlycon" command-line
> parameter.
Yes. That's why we have SPCR *and* DBG2.
DBG2 specifies where we should run earlycon.
>>> How will a user enable an earlycon on the same console as the SPCR
>>> console if there is no DBG2 table?
In no way. You need DBG2 to run earlycon.
(If you don't want to specify it's address etc explicitly)
On 03/04/2016 03:53 AM, Aleksey Makarov wrote:
>
>
> On 03/03/2016 06:35 PM, Peter Hurley wrote:
>> On 03/03/2016 03:59 AM, Aleksey Makarov wrote:
>>>
>>>
>>> On 03/01/2016 06:31 PM, Peter Hurley wrote:
>>>> On 02/29/2016 04:02 AM, 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.
>>>>>
>>>>> Introduce a new function acpi_console_check(). At the uart port
>>>>> registration, this function checks if the ACPI SPCR table specifies
>>>>> its argument of type struct uart_port to be a console
>>>>> and if so calls add_preferred_console().
>>>>
>>>> How will a user enable an earlycon on the same console as the SPCR
>>>> console if there is no DBG2 table?
>>>
>>> ...
>>> [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
>>> [ 0.000000] bootconsole [pl11] enabled
>>> ...
>>> [ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000
>>> ...
>>> [ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0]
>>> [ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA
>>> [ 0.319502] console [ttyAMA0] enabled
>>> [ 0.319502] console [ttyAMA0] enabled
>>> [ 0.319933] bootconsole [pl11] disabled
>>> [ 0.319933] bootconsole [pl11] disabled
>>> ...
>>>
>>> Why?
>>
>> That's pretty disingenuous; via command line?
>>
>> By that measure, none of your patches are required because a user
>> can already start both console and earlycon without them.
>>
>> With the console location specified in the SPCR, earlycon should
>> be opt-in on the command-line simply with "earlycon" command-line
>> parameter.
>
> Yes. That's why we have SPCR *and* DBG2.
> DBG2 specifies where we should run earlycon.
>
>>>> How will a user enable an earlycon on the same console as the SPCR
>>>> console if there is no DBG2 table?
>
> In no way. You need DBG2 to run earlycon.
And that's an entirely arbitrary decision being made by you.
Which I think is unnecessarily limited.
> (If you don't want to specify it's address etc explicitly)
Hi Peter,
You are right, SPCR console should support earlycon.
I will send next version that will try to follow your recommendations in
a week, after I return from vacations.
As we discussed with Christopher, "serial: pl011: use SPCR to setup
32-bit access" will be dropped.
Thank you
Aleksey Makarov
On 04.03.2016 22:47, Peter Hurley wrote:
> On 03/04/2016 03:53 AM, Aleksey Makarov wrote:
>>
>>
>> On 03/03/2016 06:35 PM, Peter Hurley wrote:
>>> On 03/03/2016 03:59 AM, Aleksey Makarov wrote:
>>>>
>>>>
>>>> On 03/01/2016 06:31 PM, Peter Hurley wrote:
>>>>> On 02/29/2016 04:02 AM, 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.
>>>>>>
>>>>>> Introduce a new function acpi_console_check(). At the uart port
>>>>>> registration, this function checks if the ACPI SPCR table specifies
>>>>>> its argument of type struct uart_port to be a console
>>>>>> and if so calls add_preferred_console().
>>>>>
>>>>> How will a user enable an earlycon on the same console as the SPCR
>>>>> console if there is no DBG2 table?
>>>>
>>>> ...
>>>> [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
>>>> [ 0.000000] bootconsole [pl11] enabled
>>>> ...
>>>> [ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000
>>>> ...
>>>> [ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0]
>>>> [ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA
>>>> [ 0.319502] console [ttyAMA0] enabled
>>>> [ 0.319502] console [ttyAMA0] enabled
>>>> [ 0.319933] bootconsole [pl11] disabled
>>>> [ 0.319933] bootconsole [pl11] disabled
>>>> ...
>>>>
>>>> Why?
>>>
>>> That's pretty disingenuous; via command line?
>>>
>>> By that measure, none of your patches are required because a user
>>> can already start both console and earlycon without them.
>>>
>>> With the console location specified in the SPCR, earlycon should
>>> be opt-in on the command-line simply with "earlycon" command-line
>>> parameter.
>>
>> Yes. That's why we have SPCR *and* DBG2.
>> DBG2 specifies where we should run earlycon.
>>
>>>>> How will a user enable an earlycon on the same console as the SPCR
>>>>> console if there is no DBG2 table?
>>
>> In no way. You need DBG2 to run earlycon.
>
> And that's an entirely arbitrary decision being made by you.
> Which I think is unnecessarily limited.
>
>
>> (If you don't want to specify it's address etc explicitly)
>
>