Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751599AbcDFQ1h (ORCPT ); Wed, 6 Apr 2016 12:27:37 -0400 Received: from mail-pf0-f173.google.com ([209.85.192.173]:34391 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811AbcDFQ1c (ORCPT ); Wed, 6 Apr 2016 12:27:32 -0400 Subject: Re: [PATCH v7 0/5] ACPI: parse the SPCR table To: Mark Salter 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> <1459952294.10130.32.camel@redhat.com> Cc: Graeme Gregory , Aleksey Makarov , Russell King , 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 From: Peter Hurley Message-ID: <570538F0.1030701@hurleysoftware.com> Date: Wed, 6 Apr 2016 09:27:28 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1459952294.10130.32.camel@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11250 Lines: 264 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 >