On 03/01/2016 08:24 AM, Aleksey Makarov wrote: > > > On 03/01/2016 05:49 PM, Peter Hurley wrote: >> On 02/29/2016 04:42 AM, Aleksey Makarov wrote: >>> 'ARM Server Base Boot Requirements' [1] mentions DBG2 (Microsoft Debug >>> Port Table 2) [2] as a mandatory ACPI table that specifies debug ports. >>> >>> - Implement macros >>> >>> ACPI_DBG2_DECLARE(name, type, subtype, setup_fn, data_ptr) >>> >>> that defines a handler for the port of given type and subtype. >>> >>> - For each declared port that is also described in the ACPI DBG2 table >>> call the provided callback. >> >> On 02/22/2016 06:43 AM, Aleksey Makarov wrote: >>> On 02/19/2016 08:20 PM, Christopher Covington wrote: >>>> Can the device specified in DBG2 be used for both earlycon and KGDB? If it >>>> can only be used for one, let's make sure the choice of earlycon vs KGDB >>>> is intentional rather than accidental. >>> >>> I just sent the DBG2 series. It enables an earlycon on DBG2 port with >>> an "earlycon=acpi_dbg2" option (we can discuss particular name). >>> If you need KGDB on that port just support it for that port in the kernel >>> (i. e. add a new instance of ACPI_DBG2_DECLARE() macros for that port, see >>> the patches) >>> and change the command line options. >>> I hope that is OK. We could continue this discussion in the DBG2 thread. >> >> This method will not work for kgdb, since kgdb doesn't actually >> implement the i/o but rather runs on top of a console. > > I see. Thank you for pointing this out. > > I don't have requirements to implement running kgdb over the serial port > specified with DBG2. This feature should be supported separately.
And this takes us back full-circle to my initial point regarding supporting earlycon via ACPI: which is that my view is earlycon should be opt-in for any ACPI-specified console, rather than console via SPCR and earlycon via DBG2. > Thank you > Aleksey Makarov > >>> [1] >>> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html >>> [2] http://go.microsoft.com/fwlink/p/?LinkId=234837 >>> >>> Signed-off-by: Aleksey Makarov <[email protected]> >>> --- >>> drivers/acpi/Kconfig | 3 ++ >>> drivers/acpi/Makefile | 1 + >>> drivers/acpi/dbg2.c | 88 >>> +++++++++++++++++++++++++++++++++++++++ >>> include/asm-generic/vmlinux.lds.h | 1 + >>> include/linux/acpi_dbg2.h | 48 +++++++++++++++++++++ >>> 5 files changed, 141 insertions(+) >>> create mode 100644 drivers/acpi/dbg2.c >>> create mode 100644 include/linux/acpi_dbg2.h >>> >>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig >>> index 65fb483..660666e 100644 >>> --- a/drivers/acpi/Kconfig >>> +++ b/drivers/acpi/Kconfig >>> @@ -57,6 +57,9 @@ config ACPI_SYSTEM_POWER_STATES_SUPPORT >>> config ACPI_CCA_REQUIRED >>> bool >>> >>> +config ACPI_DBG2_TABLE >>> + bool >>> + >>> config ACPI_DEBUGGER >>> bool "AML debugger interface" >>> select ACPI_DEBUG >>> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile >>> index 7395928..3b5f1ea 100644 >>> --- a/drivers/acpi/Makefile >>> +++ b/drivers/acpi/Makefile >>> @@ -83,6 +83,7 @@ obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o >>> obj-$(CONFIG_ACPI_BGRT) += bgrt.o >>> obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o >>> obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o >>> +obj-$(CONFIG_ACPI_DBG2_TABLE) += dbg2.o >>> >>> # processor has its own "processor." module_param namespace >>> processor-y := processor_driver.o >>> diff --git a/drivers/acpi/dbg2.c b/drivers/acpi/dbg2.c >>> new file mode 100644 >>> index 0000000..0f0f6ca >>> --- /dev/null >>> +++ b/drivers/acpi/dbg2.c >>> @@ -0,0 +1,88 @@ >>> +/* >>> + * Copyright (c) 2012, Intel Corporation >>> + * Copyright (c) 2015, 2016 Linaro Ltd. >>> + * >>> + * This program is free software; you can redistribute it and/or modify >>> + * it under the terms of the GNU General Public License version 2 as >>> + * published by the Free Software Foundation. >>> + * >>> + */ >>> + >>> +#define pr_fmt(fmt) "ACPI: DBG2: " fmt >>> + >>> +#include <linux/acpi_dbg2.h> >>> +#include <linux/acpi.h> >>> +#include <linux/kernel.h> >>> + >>> +static const char * __init type2string(u16 type) >>> +{ >>> + switch (type) { >>> + case ACPI_DBG2_SERIAL_PORT: >>> + return "SERIAL"; >>> + case ACPI_DBG2_1394_PORT: >>> + return "1394"; >>> + case ACPI_DBG2_USB_PORT: >>> + return "USB"; >>> + case ACPI_DBG2_NET_PORT: >>> + return "NET"; >>> + default: >>> + return "?"; >>> + } >>> +} >>> + >>> +static const char * __init subtype2string(u16 subtype) >>> +{ >>> + switch (subtype) { >>> + case ACPI_DBG2_16550_COMPATIBLE: >>> + return "16550_COMPATIBLE"; >>> + case ACPI_DBG2_16550_SUBSET: >>> + return "16550_SUBSET"; >>> + case ACPI_DBG2_ARM_PL011: >>> + return "ARM_PL011"; >>> + case ACPI_DBG2_ARM_SBSA_32BIT: >>> + return "ARM_SBSA_32BIT"; >>> + case ACPI_DBG2_ARM_SBSA_GENERIC: >>> + return "ARM_SBSA_GENERIC"; >>> + case ACPI_DBG2_ARM_DCC: >>> + return "ARM_DCC"; >>> + case ACPI_DBG2_BCM2835: >>> + return "BCM2835"; >>> + default: >>> + return "?"; >>> + } >>> +} >>> + >>> +int __init acpi_dbg2_setup(struct acpi_table_header *table, const void >>> *data) >>> +{ >>> + struct acpi_table_dbg2 *dbg2 = (struct acpi_table_dbg2 *)table; >>> + struct acpi_dbg2_data *dbg2_data = (struct acpi_dbg2_data *)data; >>> + struct acpi_dbg2_device *dbg2_device, *dbg2_end; >>> + int i; >>> + >>> + dbg2_device = ACPI_ADD_PTR(struct acpi_dbg2_device, dbg2, >>> + dbg2->info_offset); >>> + dbg2_end = ACPI_ADD_PTR(struct acpi_dbg2_device, dbg2, table->length); >>> + >>> + for (i = 0; i < dbg2->info_count; i++) { >>> + if (dbg2_device + 1 > dbg2_end) { >>> + pr_err("device pointer overflows, bad table\n"); >>> + return 0; >>> + } >>> + >>> + if (dbg2_device->port_type == dbg2_data->port_type && >>> + dbg2_device->port_subtype == dbg2_data->port_subtype) { >>> + if (dbg2_device->port_type == ACPI_DBG2_SERIAL_PORT) >>> + pr_info("debug port: SERIAL; subtype: %s\n", >>> + subtype2string(dbg2_device->port_subtype)); >>> + else >>> + pr_info("debug port: %s\n", >>> + type2string(dbg2_device->port_type)); >>> + dbg2_data->setup(dbg2_device, dbg2_data->data); >>> + } >>> + >>> + dbg2_device = ACPI_ADD_PTR(struct acpi_dbg2_device, dbg2_device, >>> + dbg2_device->length); >>> + } >>> + >>> + return 0; >>> +} >>> diff --git a/include/asm-generic/vmlinux.lds.h >>> b/include/asm-generic/vmlinux.lds.h >>> index 8f5a12a..8cc49ba 100644 >>> --- a/include/asm-generic/vmlinux.lds.h >>> +++ b/include/asm-generic/vmlinux.lds.h >>> @@ -526,6 +526,7 @@ >>> IRQCHIP_OF_MATCH_TABLE() \ >>> ACPI_PROBE_TABLE(irqchip) \ >>> ACPI_PROBE_TABLE(clksrc) \ >>> + ACPI_PROBE_TABLE(dbg2) \ >>> EARLYCON_TABLE() >>> >>> #define INIT_TEXT \ >>> diff --git a/include/linux/acpi_dbg2.h b/include/linux/acpi_dbg2.h >>> new file mode 100644 >>> index 0000000..125ae7e >>> --- /dev/null >>> +++ b/include/linux/acpi_dbg2.h >>> @@ -0,0 +1,48 @@ >>> +#ifndef _ACPI_DBG2_H_ >>> +#define _ACPI_DBG2_H_ >>> + >>> +#ifdef CONFIG_ACPI_DBG2_TABLE >>> + >>> +#include <linux/kernel.h> >>> + >>> +struct acpi_dbg2_device; >>> +struct acpi_table_header; >>> + >>> +struct acpi_dbg2_data { >>> + u16 port_type; >>> + u16 port_subtype; >>> + int (*setup)(struct acpi_dbg2_device *, void *); >>> + void *data; >>> +}; >>> + >>> +int acpi_dbg2_setup(struct acpi_table_header *header, const void *data); >>> + >>> +/** >>> + * ACPI_DBG2_DECLARE() - Define handler for ACPI DBG2 port >>> + * @name: Identifier to compose name of table data >>> + * @type: Type of the port >>> + * @subtype: Subtype of the port >>> + * @setup_fn: Function to be called to setup the port >>> + * (of type int (*)(struct acpi_dbg2_device *, void *);) >>> + * @data_ptr: Sideband data provided back to the driver >>> + */ >>> +#define ACPI_DBG2_DECLARE(name, type, subtype, setup_fn, data_ptr) \ >>> + static const struct acpi_dbg2_data \ >>> + __acpi_dbg2_data_##name __used = { \ >>> + .port_type = type, \ >>> + .port_subtype = subtype, \ >>> + .setup = setup_fn, \ >>> + .data = data_ptr, \ >>> + }; \ >>> + ACPI_DECLARE_PROBE_ENTRY(dbg2, name, ACPI_SIG_DBG2, \ >>> + acpi_dbg2_setup, &__acpi_dbg2_data_##name) >>> + >>> +#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 } >>> + >>> +#endif >>> + >>> +#endif >>> >>
