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 >>> >> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html