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.maka...@linaro.org>
> ---
> 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
>
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