On Tue, 2015-09-08 at 13:43 +0100, Leif Lindholm wrote:
The ACPI DBG2 table defines a debug console. Add support for parsing it and using it to select earlycon destination when no arguments provided.
Signed-off-by: Leif Lindholm leif.lindholm@linaro.org
arch/arm64/kernel/acpi.c | 2 + drivers/acpi/Makefile | 1 + drivers/acpi/console.c | 103 ++++++++++++++++++++++++++++++++++++++++++ drivers/of/fdt.c | 2 +- drivers/tty/serial/earlycon.c | 16 ++++--- include/linux/acpi.h | 4 ++ include/linux/serial_core.h | 9 ++-- 7 files changed, 126 insertions(+), 11 deletions(-) create mode 100644 drivers/acpi/console.c
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index b9a5623..be7600a 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -207,6 +207,8 @@ void __init acpi_boot_table_init(void) if (!param_acpi_force) disable_acpi(); }
- acpi_early_console_probe();
} void __init acpi_gic_init(void) diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index b5e7cd8..a89587d 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -10,6 +10,7 @@ ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT # obj-y += tables.o obj-$(CONFIG_X86) += blacklist.o +obj-y += console.o
obj-$(CONFIG_SERIAL_EARLYCON) += console.o
to eliminate whole-file #ifdef
# # ACPI Core Subsystem (Interpreter) diff --git a/drivers/acpi/console.c b/drivers/acpi/console.c new file mode 100644 index 0000000..a985890 --- /dev/null +++ b/drivers/acpi/console.c @@ -0,0 +1,103 @@ +/*
- Copyright (c) 2012, Intel Corporation
- Copyright (c) 2015, Linaro Ltd.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License version 2 as
- published by the Free Software Foundation.
- */
+#define DEBUG +#define pr_fmt(fmt) "ACPI: " KBUILD_MODNAME ": " fmt
+#include <linux/acpi.h> +#include <linux/kernel.h> +#include <linux/serial_core.h>
+#define NUM_ELEMS(x) (sizeof(x) / sizeof(*x))
+#ifdef CONFIG_SERIAL_EARLYCON +static int use_earlycon __initdata; +static int __init setup_acpi_earlycon(char *buf) +{
- if (!buf)
use_earlycon = 1;
- return 0;
+} +early_param("earlycon", setup_acpi_earlycon);
+extern struct earlycon_id __earlycon_table[];
+static __initdata struct {
- int id;
- const char *name;
+} subtypes[] = {
- {0, "uart8250"},
- {1, "uart8250"},
- {2, NULL},
- {3, "pl011"},
+};
Instead of having a table here, why not have an ACPI_EARLYCON_DECLARE() where individual drivers can provide an id similar to OF_EARLYCON_DECLARE() providing compatible strings?
+static int __init acpi_setup_earlycon(unsigned long addr, const char *driver) +{
- const struct earlycon_id *match;
- for (match = __earlycon_table; match->name[0]; match++)
if (strcmp(driver, match->name) == 0)
return setup_earlycon_driver(addr, match->setup);
- return -ENODEV;
+}
+static int __init acpi_parse_dbg2(struct acpi_table_header *table) +{
- struct acpi_table_dbg2 *dbg2;
- struct acpi_dbg2_device *entry;
- void *tbl_end;
- dbg2 = (struct acpi_table_dbg2 *)table;
- if (!dbg2) {
pr_debug("DBG2 not present.\n");
return -ENODEV;
- }
- tbl_end = (void *)table + table->length;
- entry = (struct acpi_dbg2_device *)((void *)dbg2 + dbg2->info_offset);
- while (((void *)entry) + sizeof(struct acpi_dbg2_device) < tbl_end) {
struct acpi_generic_address *addr;
if (entry->revision != 0) {
pr_debug("DBG2 revision %d not supported.\n",
entry->revision);
return -ENODEV;
}
addr = (void *)entry + entry->base_address_offset;
pr_debug("DBG2 PROBE - console (%04x:%04x).\n",
entry->port_type, entry->port_subtype);
if (use_earlycon &&
(entry->port_type == ACPI_DBG2_SERIAL_PORT) &&
(entry->port_subtype < NUM_ELEMS(subtypes)))
acpi_setup_earlycon(addr->address,
subtypes[entry->port_subtype].name);
Don't we need to handle space_id (and bit width) as well as address?
entry = (struct acpi_dbg2_device *)
((void *)entry + entry->length);
- }
- return 0;
+}
+int __init acpi_early_console_probe(void) +{
- acpi_table_parse(ACPI_SIG_DBG2, acpi_parse_dbg2);
- return 0;
+} +#endif /* CONFIG_SERIAL_EARLYCON */ diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index fcfc4c7..a96209f 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -829,7 +829,7 @@ int __init early_init_dt_scan_chosen_serial(void) if (!addr) return -ENXIO;
of_setup_earlycon(addr, match->data);
return 0; } return -ENODEV;setup_earlycon_driver(addr, match->data);
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index 2bda09a..c063cbb 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -13,6 +13,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/acpi.h> #include <linux/console.h> #include <linux/kernel.h> #include <linux/init.h> @@ -184,12 +185,16 @@ static int __init param_setup_earlycon(char *buf) int err; /*
* Just 'earlycon' is a valid param for devicetree earlycons;
* don't generate a warning from parse_early_params() in that case
* Just 'earlycon' is a valid param for devicetree or ACPI earlycons;
* ACPI cannot be parsed yet, so return without action if enabled.
*/* Otherwise, attempt initialization using DT.
- if (!buf || !buf[0])
if (IS_ENABLED(CONFIG_OF_FLATTREE))
- if (!buf || !buf[0]) {
if (!acpi_disabled)
How do we know for sure that "acpi" has been parsed before "earlycon"?
return 0;
else if (IS_ENABLED(CONFIG_OF_FLATTREE)) return early_init_dt_scan_chosen_serial();
- }
err = setup_earlycon(buf); if (err == -ENOENT || err == -EALREADY) @@ -198,8 +203,7 @@ static int __init param_setup_earlycon(char *buf) } early_param("earlycon", param_setup_earlycon); -int __init of_setup_earlycon(unsigned long addr,
int (*setup)(struct earlycon_device *, const char *))
+int __init setup_earlycon_driver(unsigned long addr, earlycon_initfunc_t setup) { int err; struct uart_port *port = &early_console_dev.port; diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 7235c48..88cb9c1 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -811,4 +811,8 @@ static inline struct acpi_device *acpi_get_next_child(struct device *dev, #endif +#if defined(CONFIG_ACPI) && defined(CONFIG_SERIAL_EARLYCON) +int __init acpi_early_console_probe(void); +#endif
#endif /*_LINUX_ACPI_H*/ diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 297d4fa..39e99b0 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -339,14 +339,15 @@ struct earlycon_device { unsigned int baud; }; +typedef int (*earlycon_initfunc_t)(struct earlycon_device *, const char *);
struct earlycon_id {
- char name[16];
- int (*setup)(struct earlycon_device *, const char *options);
- char name[16];
- earlycon_initfunc_t setup;
} __aligned(32); extern int setup_earlycon(char *buf); -extern int of_setup_earlycon(unsigned long addr,
int (*setup)(struct earlycon_device *, const char *));
+extern int setup_earlycon_driver(unsigned long addr, earlycon_initfunc_t setup); #define EARLYCON_DECLARE(_name, func) \ static const struct earlycon_id __earlycon_##_name \