Re: [PATCH v8 0/4] ACPI: parse the SPCR table

From: Aleksey Makarov
Date: Mon Jun 20 2016 - 12:10:52 EST


On 05/20/2016 04:03 PM, Aleksey Makarov wrote:

Hi Rafael,

Can you consider this patch set for queuing up please?

You approved ACPI part. I believe it's 2/4 and 3/4.

https://lkml.kernel.org/g/CAJZ5v0hdoLTfjrD8+WxSoxM48dqbZK2KwY_h+63kHKHKgO=JFA@xxxxxxxxxxxxxx

1/4 is ACKed by Rob Herring and Greg Kroah-Hartman

As for 4/4 it had an ACK from Greg but since then I had to make a small
change. For details look at

https://lkml.kernel.org/g/c37d62c7-1e1b-0b10-a083-c5207fbbb820@xxxxxxxxx

Thank you
Aleksey Makarov

> '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
>
> Parse SPCR table, setup earlycon and 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. When
> ACPI_SPCR_TABLE is defined initialization of DT earlycon is deferred until the
> DT/ACPI decision is done.
>
> Implement console_match() for pl011.
>
> Based on the work by Leif Lindholm [3]
> Thanks to Peter Hurley for explaining how this should work.
>
> Should be applied to next-20160520
> Tested on QEMU and ThunderX.
> SPCR support is included in QEMU's ARM64 mach-virt since 2.4 release.
>
> v8:
> - rebase to next-20160520
> - remove the patch "ACPICA: Headers: Add new constants for the DBG2 ACPI table"
> as it have got to linux-next
> - add Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Reviewed-by:
> Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> (but see below)
> - fix the patch "serial: pl011: add console matching function". The patch by
> Christopher Covington [4] specifies that SBSA uart does 32-bit access to
> registers and this breaks the match function. In this series the function
> was changed to match when SPCR specifies both mmio32 and mmio access.
> I removed Acked-by: Greg from this patch because of these changes.
>
> v7:
> https://lkml.kernel.org/g/1459431629-27934-1-git-send-email-aleksey.makarov@xxxxxxxxxx
> - 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@xxxxxxxxxx
> - 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@xxxxxxxxxx
> - 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 [4]
> - 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@xxxxxxxxxx
> - 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@xxxxxxxxxx
>
> 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@xxxxxxxxxx
> - 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@xxxxxxxxxx
>
> [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/1441716217-23786-1-git-send-email-leif.lindholm@xxxxxxxxxx
> [4] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@xxxxxxxxxxxxxx
>
> Aleksey Makarov (3):
> 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/linux/acpi.h | 6 +++
> include/linux/of_fdt.h | 2 +
> include/linux/serial_core.h | 6 +++
> 11 files changed, 214 insertions(+), 13 deletions(-)
> create mode 100644 drivers/acpi/spcr.c
>