Re: [PATCH v6] ACPI / serial: Add peripheral PnP IDs enumeration support

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On Wed, Apr 03, 2013 at 10:05:49AM +0800, Lv Zheng wrote:
> 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>

Why are these names not on the list below?

> 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.

Please provide more information here.

As this is primarily an ACPI patch, I need an ack from a ACPI maintainer
before I can take this.

> +
>  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");

What is the "uart" part for?  Isn't that kind of obvious?

> +}

You are creating a new sysfs file, you must create a new
Documentation/ABI entry as well.

> +
>  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

I see you never tested this code without the configuration option
enabled :(

{sigh}

greg k-h
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