Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752392AbcCAQ6T (ORCPT ); Tue, 1 Mar 2016 11:58:19 -0500 Received: from mail-lb0-f181.google.com ([209.85.217.181]:33776 "EHLO mail-lb0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751696AbcCAQ6R (ORCPT ); Tue, 1 Mar 2016 11:58:17 -0500 Subject: Re: [PATCH v3 5/7] ACPI: serial: implement earlycon on ACPI DBG2 port To: Peter Hurley , linux-acpi@vger.kernel.org References: <1456749726-30261-1-git-send-email-aleksey.makarov@linaro.org> <1456749726-30261-6-git-send-email-aleksey.makarov@linaro.org> <56D5BAFF.6080008@hurleysoftware.com> Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Russell King , Greg Kroah-Hartman , "Rafael J . Wysocki" , Leif Lindholm , Graeme Gregory , Al Stone , Christopher Covington , Matthias Brugger , Jonathan Corbet , Jiri Slaby , linux-doc@vger.kernel.org From: Aleksey Makarov Message-ID: <56D5C9F5.5060301@linaro.org> Date: Tue, 1 Mar 2016 19:57:25 +0300 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: <56D5BAFF.6080008@hurleysoftware.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: 5731 Lines: 171 On 03/01/2016 06:53 PM, Peter Hurley wrote: > On 02/29/2016 04:42 AM, Aleksey Makarov wrote: >> Add ACPI_DBG2_EARLYCON_DECLARE() macros that declares >> an earlycon on the serial port specified in the DBG2 ACPI table. >> >> Pass the string "earlycon=acpi_dbg2" to the kernel to activate it. >> >> Callbacks for EARLYCON_DECLARE() and OF_EARLYCON_DECLARE() >> can also be used for this macros. >> >> Signed-off-by: Aleksey Makarov >> --- >> Documentation/kernel-parameters.txt | 3 ++ >> drivers/tty/serial/earlycon.c | 60 +++++++++++++++++++++++++++++++++++++ >> include/linux/acpi_dbg2.h | 20 +++++++++++++ >> 3 files changed, 83 insertions(+) >> >> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt >> index e0a21e4..19b947b 100644 >> --- a/Documentation/kernel-parameters.txt >> +++ b/Documentation/kernel-parameters.txt >> @@ -1072,6 +1072,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. >> A valid base address must be provided, and the serial >> port must already be setup and configured. >> >> + acpi_dbg2 >> + Use serial port specified by the DBG2 ACPI table. >> + >> earlyprintk= [X86,SH,BLACKFIN,ARM,M68k] >> earlyprintk=vga >> earlyprintk=efi >> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c >> index d217366..9ba3a04 100644 >> --- a/drivers/tty/serial/earlycon.c >> +++ b/drivers/tty/serial/earlycon.c >> @@ -22,6 +22,7 @@ >> #include >> #include >> #include >> +#include >> >> #ifdef CONFIG_FIX_EARLYCON_MEM >> #include >> @@ -200,6 +201,8 @@ int __init setup_earlycon(char *buf) >> return -ENOENT; >> } >> >> +static bool setup_dbg2_earlycon; >> + >> /* early_param wrapper for setup_earlycon() */ >> static int __init param_setup_earlycon(char *buf) >> { >> @@ -212,6 +215,11 @@ static int __init param_setup_earlycon(char *buf) >> if (!buf || !buf[0]) >> return early_init_dt_scan_chosen_serial(); >> >> + if (!strcmp(buf, "acpi_dbg2")) { >> + setup_dbg2_earlycon = true; >> + return 0; >> + } > > So this series doesn't start an ACPI earlycon at early_param time? > That doesn't seem very useful. > > When does the ACPI earlycon actually start? > And don't say "when the DBG2 table is probed"; that much is obvious. ACPI earlycon starts as soon as ACPI tables become accessible (setup_arch()). I think that is still quite early. >> + >> err = setup_earlycon(buf); >> if (err == -ENOENT || err == -EALREADY) >> return 0; >> @@ -286,3 +294,55 @@ int __init of_setup_earlycon(const struct earlycon_id *match, >> } >> >> #endif /* CONFIG_OF_EARLY_FLATTREE */ >> + >> +#ifdef CONFIG_ACPI_DBG2_TABLE >> + >> +int __init acpi_setup_earlycon(struct acpi_dbg2_device *device, void *d) >> +{ >> + int err; >> + struct uart_port *port = &early_console_dev.port; >> + int (*setup)(struct earlycon_device *, const char *) = d; >> + struct acpi_generic_address *reg; >> + >> + if (!setup_dbg2_earlycon) >> + return -ENODEV; >> + >> + if (device->register_count < 1) >> + return -ENODEV; >> + >> + if (device->base_address_offset >= device->length) >> + return -EINVAL; >> + >> + reg = (void *)device + device->base_address_offset; >> + >> + if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY && >> + reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO) >> + return -EINVAL; >> + >> + spin_lock_init(&port->lock); >> + port->uartclk = BASE_BAUD * 16; >> + >> + if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { >> + if (device->port_type == ACPI_DBG2_ARM_SBSA_32BIT) >> + port->iotype = UPIO_MEM32; >> + else >> + port->iotype = UPIO_MEM; >> + port->mapbase = reg->address; >> + port->membase = earlycon_map(reg->address, SZ_4K); >> + } else { >> + port->iotype = UPIO_PORT; >> + port->iobase = reg->address; >> + } >> + >> + early_console_dev.con->data = &early_console_dev; >> + err = setup(&early_console_dev, NULL); >> + if (err < 0) >> + return err; >> + if (!early_console_dev.con->write) >> + return -ENODEV; >> + >> + register_console(early_console_dev.con); >> + return 0; >> +} >> + >> +#endif /* CONFIG_ACPI_DBG2_TABLE */ >> diff --git a/include/linux/acpi_dbg2.h b/include/linux/acpi_dbg2.h >> index 125ae7e..b653752 100644 >> --- a/include/linux/acpi_dbg2.h >> +++ b/include/linux/acpi_dbg2.h >> @@ -37,12 +37,32 @@ int acpi_dbg2_setup(struct acpi_table_header *header, const void *data); >> ACPI_DECLARE_PROBE_ENTRY(dbg2, name, ACPI_SIG_DBG2, \ >> acpi_dbg2_setup, &__acpi_dbg2_data_##name) >> >> +int acpi_setup_earlycon(struct acpi_dbg2_device *device, void *d); >> + >> +/** >> + * ACPI_DBG2_EARLYCON_DECLARE() - Define handler for ACPI GDB2 serial port >> + * @name: Identifier to compose name of table data >> + * @subtype: Subtype of the port >> + * @console_setup: Function to be called to setup the port >> + * >> + * Type of the console_setup() callback is >> + * int (*setup)(struct earlycon_device *, const char *) >> + * It's the type of callback of of_setup_earlycon(). >> + */ >> +#define ACPI_DBG2_EARLYCON_DECLARE(name, subtype, console_setup) \ >> + ACPI_DBG2_DECLARE(name, ACPI_DBG2_SERIAL_PORT, subtype, \ >> + acpi_setup_earlycon, console_setup) >> + >> #else >> >> #define ACPI_DBG2_DECLARE(name, type, subtype, setup_fn, data_ptr) \ >> static const void *__acpi_dbg_data_##name[] \ >> __used __initdata = { (void *)setup_fn, (void *)data_ptr } >> >> +#define ACPI_DBG2_EARLYCON_DECLARE(name, subtype, console_setup) \ >> + static const void *__acpi_dbg_data_serial_##name[] \ >> + __used __initdata = { (void *)console_setup } >> + >> #endif >> >> #endif >> >