ACPI 5.0 specification introduces mechanisms of enumerating the peripherals
connected on the serial buses. It will look like:
Device (BTH0)
{
Name (_HID, "IBMF001") // _HID: Hardware ID
Name (_CID, "PNPF001") // _CID: Compatible ID
Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings
{
Name (UBUF, ResourceTemplate ()
{
UartSerialBus (0x0001C200, DataBitsEight, StopBitsOne,
0xC0, LittleEndian, ParityTypeNone, FlowControlHardware,
0x0020, 0x0020, "\\_SB.PCI0.UA00",
0x00, ResourceConsumer, ,
)
}
Return (UBUF)
}
}
This patch follows the specification, implementing such UART enumeration
machanism by exporting current peripheral HID/CIDs for the UART devices.
A userspace udev rule may look like:
SUBSYSTEM=tty, ATTR{peripheral_type}=="*:IBMF001:*",
RUN+="/bin/userprog --devpath=%p"
Thanks for the internal composers:
Mika Westerberg <mika.westerberg@xxxxxxxxx>
Huang Ying <ying.huang@xxxxxxxxx>
Zhang Rui <rui.zhang@xxxxxxxxx>
Thanks for the internal reviewers:
Alan Cox <alan@xxxxxxxxxxxxxxx>
Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Heikki Krogerus <heikki.krogerus@xxxxxxxxx>
Andriy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Fengguang Wu <fengguang.wu@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Acked-by: Huang Ying <ying.huang@xxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/acpi/Kconfig | 6 ++
drivers/acpi/Makefile | 1 +
drivers/acpi/acpi_uart.c | 135 ++++++++++++++++++++++++++++++++++++++
drivers/acpi/internal.h | 2 +
drivers/acpi/scan.c | 8 +--
drivers/tty/serial/serial_core.c | 15 +++++
include/linux/tty.h | 11 ++++
7 files changed, 174 insertions(+), 4 deletions(-)
create mode 100644 drivers/acpi/acpi_uart.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 92ed969..42233f6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -186,6 +186,12 @@ config ACPI_I2C
help
ACPI I2C enumeration support.
+config ACPI_UART
+ def_tristate TTY
+ depends on TTY
+ help
+ ACPI UART enumeration support.
+
config ACPI_PROCESSOR
tristate "Processor"
select THERMAL
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 474fcfe..4db5470 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -72,6 +72,7 @@ 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_I2C) += acpi_i2c.o
+obj-$(CONFIG_ACPI_UART) += acpi_uart.o
# processor has its own "processor." module_param namespace
processor-y := processor_driver.o processor_throttling.o
diff --git a/drivers/acpi/acpi_uart.c b/drivers/acpi/acpi_uart.c
new file mode 100644
index 0000000..dd5ac2e
--- /dev/null
+++ b/drivers/acpi/acpi_uart.c
@@ -0,0 +1,135 @@
+/*
+ * acpi_uart.c - ACPI UART enumeration support
+ *
+ * Copyright (c) 2013, Intel Corporation
+ * Author: Lv Zheng <lv.zheng@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/init.h>
+#include <linux/tty.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+
+#include "internal.h"
+
+struct acpi_uart_buf {
+ char *buf;
+ size_t size;
+ int *len;
+};
+
+struct acpi_uart_enum {
+ void *context;
+ acpi_status status;
+
+ struct acpi_device *adev;
+};
+
+static acpi_status
+acpi_uart_enum_pnpids(struct acpi_device *adev,
+ struct acpi_resource_uart_serialbus *sb,
+ void *context);
+
+static int acpi_uart_enum_resources(struct acpi_resource *ares,
+ void *context)
+{
+ struct acpi_uart_enum *ctx = context;
+ struct acpi_resource_uart_serialbus *sb;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+ return 1;
+ sb = &ares->data.uart_serial_bus;
+ if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_UART)
+ return 1;
+
+ ctx->status = acpi_uart_enum_pnpids(ctx->adev, sb, ctx->context);
+ return 1;
+}
+
+static acpi_status acpi_uart_enum_devices(acpi_handle handle, u32 level,
+ void *context,
+ void **return_value)
+{
+ struct acpi_uart_enum *ctx = context;
+ struct acpi_device *adev;
+ struct list_head resource_list;
+
+ if (acpi_bus_get_device(handle, &adev))
+ return AE_OK;
+ if (acpi_bus_get_status(adev) || !adev->status.present)
+ return AE_OK;
+
+ /* Enumerate resources. */
+ ctx->adev = adev;
+ ctx->status = AE_OK;
+ INIT_LIST_HEAD(&resource_list);
+ acpi_dev_get_resources(adev, &resource_list,
+ acpi_uart_enum_resources, ctx);
+ acpi_dev_free_resource_list(&resource_list);
+
+ return ctx->status;
+}
+
+static int acpi_uart_walk_port(struct device *parent,
+ void *context)
+{
+ acpi_handle handle;
+ acpi_status status;
+ struct acpi_uart_enum ctx;
+
+ handle = parent ? ACPI_HANDLE(parent) : NULL;
+ if (!handle)
+ return -ENODEV;
+
+ ctx.context = context;
+
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+ acpi_uart_enum_devices, NULL,
+ &ctx, NULL);
+ if (ACPI_FAILURE(status))
+ return -EINVAL;
+
+ return 0;
+}
+
+static acpi_status
+acpi_uart_enum_pnpids(struct acpi_device *adev,
+ struct acpi_resource_uart_serialbus *sb,
+ void *context)
+{
+ int len;
+ struct acpi_uart_buf *ctx = context;
+
+ len = acpi_device_create_modalias(adev, ctx->buf, ctx->size);
+ *ctx->len = len;
+
+ return len < 0 ? AE_CTRL_DEPTH : AE_OK;
+}
+
+/**
+ * acpi_uart_get_peripheral_type - get peripheral HID/CIDs
+ * @dev: the tty class device
+ * @buf: the string buffer containing HID/CIDs
+ * @size: the size of the string buffer
+ *
+ * Obtain UART peripheral HID/CIDs. Return buffer size on success,
+ * -errno on failure.
+ */
+int acpi_uart_get_peripheral_type(struct device *dev,
+ char *buf, size_t size)
+{
+ int ret;
+ int len = 0;
+ struct acpi_uart_buf ctx = { buf, size, &len };
+
+ ret = acpi_uart_walk_port(dev->parent, &ctx);
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(acpi_uart_get_peripheral_type);
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 3c94a73..30d7440 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -61,6 +61,8 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
int type, unsigned long long sta);
void acpi_device_add_finalize(struct acpi_device *device);
void acpi_free_ids(struct acpi_device *device);
+int acpi_device_create_modalias(struct acpi_device *acpi_dev,
+ char *modalias, int size);
/* --------------------------------------------------------------------------
Power Resource
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 5e7e991..0d7d49f 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -68,8 +68,8 @@ int acpi_scan_add_handler(struct acpi_scan_handler *handler)
* e.g. on a device with hid:IBM0001 and cid:ACPI0001 you get:
* char *modalias: "acpi:IBM0001:ACPI0001"
*/
-static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
- int size)
+int acpi_device_create_modalias(struct acpi_device *acpi_dev,
+ char *modalias, int size)
{
int len;
int count;
@@ -99,7 +99,7 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
int len;
/* Device has no HID and no CID or string is >1024 */
- len = create_modalias(acpi_dev, buf, 1024);
+ len = acpi_device_create_modalias(acpi_dev, buf, 1024);
if (len <= 0)
return 0;
buf[len++] = '\n';
@@ -567,7 +567,7 @@ static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
- len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
+ len = acpi_device_create_modalias(acpi_dev, &env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen);
if (len >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index a400002..17e104e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2515,6 +2515,19 @@ static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
}
+static ssize_t uart_get_attr_peripheral_type(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int len;
+
+ len = acpi_uart_get_peripheral_type(dev, buf, 1024);
+ if (len > 0) {
+ buf[len++] = '\n';
+ return len;
+ }
+ return snprintf(buf, PAGE_SIZE, "uart\n");
+}
+
static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
@@ -2528,6 +2541,7 @@ static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divis
static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
+static DEVICE_ATTR(peripheral_type, S_IRUSR | S_IRGRP, uart_get_attr_peripheral_type, NULL);
static struct attribute *tty_dev_attrs[] = {
&dev_attr_type.attr,
@@ -2543,6 +2557,7 @@ static struct attribute *tty_dev_attrs[] = {
&dev_attr_io_type.attr,
&dev_attr_iomem_base.attr,
&dev_attr_iomem_reg_shift.attr,
+ &dev_attr_peripheral_type.attr,
NULL,
};
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 367a9df..723fdd01 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -692,4 +692,15 @@ do { \
} while (0)
+#ifdef CONFIG_ACPI_UART
+int acpi_uart_get_peripheral_type(struct device *dev,
+ char *buf, size_t size);
+#else
+static inline int acpi_uart_get_peripheral_type(struct device *dev,
+ char *buf, size_t size)
+{
+ return -ENODEV;
+}
+#endif
+
#endif
--
1.7.10
--
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