On 03/01/2016 08:57 AM, Aleksey Makarov wrote:
>
>
> 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 <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.
>
> ACPI earlycon starts as soon as ACPI tables become accessible (setup_arch()).
> I think that is still quite early.
I see now; the probe is in patch 6/7.
setup_arch()
acpi_boot_table_init()
acpi_probe_device_table()
...
acpi_dbg2_setup()
->setup()
acpi_setup_earlycon()
>>> +
>>> 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 }
console_setup is a terrible macro argument name; console_setup() is an
actual kernel function (although file-scope).
Please change it to something short and generic.
Honestly, I'd just prefer you skip all this apparatus that makes
ACPI earlycon appear to be like OF earlycon code-wise, but without any of
the real underpinning or flexibility.
This would be trivial to parse the ACPI table and invoke
setup_earlycon() with a string specifier instead.
For example,
int __init acpi_earlycon_setup(struct acpi_dbg2_device *dbg2)
{
char opts[64];
struct acpi_generic_addr *addr = (void*)dbg2 + dbg2->base_address_offset;
int mmio = addr->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY;
if (dbg2->port_type != ACPI_DBG2_SERIAL_PORT)
return 0;
switch (dbg2->port_subtype) {
case ACPI_DBG2_ARM_PL011:
case ACPI_DBG2_ARM_SBSA_GENERIC:
case ACPI_DBG2_BCM2835:
sprintf(opts, "pl011,%s,0x%llx", mmio, addr->address);
break;
case ACPI_DBG2_ARM_SBSA_32BIT:
sprintf(opts, "pl011,mmio32,0x%llx", addr->address);
break;
case ACPI_DBG2_16550_COMPATIBLE:
case ACPI_DBG2_16550_SUBSET:
sprintf(opts, "uart,%s,0x%llx", mmio, addr->address);
break;
default:
return 0;
}
return setup_earlycon(opts);
}
This supports every earlycon ACPI DBG2 declares, not just the ARM_PL011
subtype of your series.
>>> +
>>> #endif
>>>
>>> #endif
>>>
>>
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