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 <aleksey.makarov@xxxxxxxxxx> > --- > 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 <linux/sizes.h> > #include <linux/of.h> > #include <linux/of_fdt.h> > +#include <linux/acpi.h> > > #ifdef CONFIG_FIX_EARLYCON_MEM > #include <asm/fixmap.h> > @@ -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. > + > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html