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 | 56 +++++++++++++++++++++++++++++++++++++
include/linux/acpi_dbg2.h | 20 +++++++++++++
3 files changed, 79 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9a53c92..4949ebb 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1058,6 +1058,9 @@ 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 05f9e4b..3d11248 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -21,6 +21,7 @@
#include <linux/serial_core.h>
#include <linux/sizes.h>
#include <linux/mod_devicetable.h>
+#include <linux/acpi.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
@@ -186,6 +187,8 @@ 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)
{
@@ -198,6 +201,11 @@ 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;
+ }
+
err = setup_earlycon(buf);
if (err == -ENOENT || err == -EALREADY)
return 0;
@@ -228,3 +236,51 @@ int __init of_setup_earlycon(unsigned long addr,
register_console(early_console_dev.con);
return 0;
}
+
+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;
+}
diff --git a/include/linux/acpi_dbg2.h b/include/linux/acpi_dbg2.h
index 465afcb..9b96de2 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 __init 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
--
2.7.1
--
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