Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753558AbcDFOS1 (ORCPT ); Wed, 6 Apr 2016 10:18:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54260 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750705AbcDFOSY (ORCPT ); Wed, 6 Apr 2016 10:18:24 -0400 Message-ID: <1459952294.10130.32.camel@redhat.com> Subject: Re: [PATCH v7 0/5] ACPI: parse the SPCR table From: Mark Salter To: Graeme Gregory , Aleksey Makarov Cc: Russell King , Peter Hurley , Graeme Gregory , Greg Kroah-Hartman , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, Leif Lindholm , linux-acpi@vger.kernel.org, Andy Shevchenko , Yury Norov , "Zheng, Lv" , linux-serial@vger.kernel.org, Len Brown , Al Stone , linux-arm-kernel@lists.infradead.org, Christopher Covington Date: Wed, 06 Apr 2016 10:18:14 -0400 In-Reply-To: <20160406105252.GB2820@xora-haswell.xora.org.uk> References: <1459431629-27934-1-git-send-email-aleksey.makarov@linaro.org> <1459873627.10130.21.camel@redhat.com> <5704E3CC.8000104@linaro.org> <20160406105252.GB2820@xora-haswell.xora.org.uk> Organization: Red Hat, Inc Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11053 Lines: 236 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