[PATCH v3 2/5] ACPI: parse SPCR and enable matching console
Aleksey Makarov
aleksey.makarov at linaro.org
Mon Feb 15 10:05:26 PST 2016
'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port
Console Redirection Table) [2] as a mandatory ACPI table that
specifies the configuration of serial console.
Parse this table and check if any registered console match the
description. If it does, enable that console.
Introduce a new function acpi_console_check(). At the uart port
registration, this function checks if the ACPI SPCR table specifies
its argument of type struct uart_port to be a console
and if so calls add_preferred_console().
[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
[2] http://msdn.microsoft.com/en-us/library/windows/hardware/dn639131(v=vs.85).aspx
Signed-off-by: Aleksey Makarov <aleksey.makarov at linaro.org>
---
drivers/acpi/Kconfig | 3 ++
drivers/acpi/Makefile | 1 +
drivers/acpi/spcr.c | 97 ++++++++++++++++++++++++++++++++++++++++
drivers/tty/serial/serial_core.c | 14 +++++-
include/linux/acpi.h | 10 +++++
5 files changed, 123 insertions(+), 2 deletions(-)
create mode 100644 drivers/acpi/spcr.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 65fb483..5611eb6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER
endif
+config ACPI_SPCR_TABLE
+ bool
+
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 346101c..708b143 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
+obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
# processor has its own "processor." module_param namespace
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
new file mode 100644
index 0000000..a1eca91
--- /dev/null
+++ b/drivers/acpi/spcr.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2012, Intel Corporation
+ * Copyright (c) 2015, Red Hat, Inc.
+ * Copyright (c) 2015, 2016 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 pr_fmt(fmt) "ACPI: SPCR: " fmt
+
+#include <linux/acpi.h>
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/serial_core.h>
+
+static int acpi_table_parse_spcr(int (*handler)(struct acpi_table_spcr *table,
+ void *data), void *data)
+{
+ struct acpi_table_spcr *table = NULL;
+ acpi_size table_size;
+ acpi_status status;
+ int err;
+
+ status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
+ (struct acpi_table_header **)&table,
+ &table_size);
+
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ err = handler(table, data);
+
+ early_acpi_os_unmap_memory(table, table_size);
+
+ return err;
+}
+
+static int spcr_table_handler_check(struct acpi_table_spcr *table, void *data)
+{
+ struct uart_port *uport = data;
+ char *options;
+
+ if (table->header.revision < 2)
+ return -EOPNOTSUPP;
+
+ switch (table->baud_rate) {
+ case 3:
+ options = "9600";
+ break;
+ case 4:
+ options = "19200";
+ break;
+ case 6:
+ options = "57600";
+ break;
+ case 7:
+ options = "115200";
+ break;
+ default:
+ options = "";
+ break;
+ }
+
+ if ((table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
+ table->serial_port.address == (u64)uport->mapbase) ||
+ (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_IO &&
+ table->serial_port.address == (u64)uport->iobase)) {
+ pr_info("adding preferred console [%s%d]\n", uport->cons->name,
+ uport->line);
+ add_preferred_console(uport->cons->name, uport->line, options);
+ return 1;
+
+ }
+
+ return 0;
+}
+
+/**
+ * acpi_console_check - Check if uart matches the console specified by SPCR.
+ *
+ * @uport: uart port to check
+ *
+ * This function checks if the ACPI SPCR table specifies @uport to be a console
+ * and if so calls add_preferred_console()
+ *
+ * Return: a non-error value if the console matches.
+ */
+bool acpi_console_check(struct uart_port *uport)
+{
+ if (acpi_disabled || console_set_on_cmdline)
+ return false;
+
+ return acpi_table_parse_spcr(spcr_table_handler_check, uport) > 0;
+}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index a126a60..459ab54 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -34,6 +34,7 @@
#include <linux/serial_core.h>
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/acpi.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
@@ -2654,8 +2655,17 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
spin_lock_init(&uport->lock);
lockdep_set_class(&uport->lock, &port_lock_key);
}
- if (uport->cons && uport->dev)
- of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
+
+ /*
+ * Support both open FW and ACPI access to console definitions.
+ * Both of_console_check() and acpi_console_check() will call
+ * add_preferred_console() if a console definition is found.
+ */
+ if (uport->cons && uport->dev) {
+ if (!acpi_console_check(uport))
+ of_console_check(uport->dev->of_node, uport->cons->name,
+ uport->line);
+ }
uart_configure_port(drv, state, uport);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 06ed7e5..ea0c297 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1004,4 +1004,14 @@ static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
#define acpi_probe_device_table(t) ({ int __r = 0; __r;})
#endif
+struct uart_port;
+#ifdef CONFIG_ACPI_SPCR_TABLE
+bool acpi_console_check(struct uart_port *uport);
+#else
+static inline bool acpi_console_check(struct uart_port *uport)
+{
+ return FALSE;
+}
+#endif
+
#endif /*_LINUX_ACPI_H*/
--
2.7.1
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