[PATCH] DRIVER: request_firmware() hotplug interface

drivers/base/Kconfig.lib

+#
+# To be sourced from lib/Kconfig
+#
+
+config FW_LOADER
+	tristate "Hotplug firmware loading support"
+	---help---
+	  This option is provided for the case where no in-kernel-tree modules
+	  require hotplug firmware loading support, but a module built outside
+	  the kernel tree does.
+

drivers/base/Makefile

@@ -3,4 +3,5 @@
 obj-y			:= core.o sys.o interface.o power.o bus.o \
 			   driver.o class.o platform.o \
 			   cpu.o firmware.o init.o map.o
+obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o  memblk.o

drivers/base/firmware_class.c

+/*
+ * firmware_class.c - Multi purpose firmware loading support
+ *
+ * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org>
+ *
+ * Please see Documentation/firmware_class/ for more information.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/timer.h>
+#include <asm/hardirq.h>
+
+#include <linux/firmware.h>
+#include "base.h"
+
+MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
+MODULE_DESCRIPTION("Multi purpose firmware loading support");
+MODULE_LICENSE("GPL");
+
+static int loading_timeout = 10;	/* In seconds */
+
+struct firmware_priv {
+	char fw_id[FIRMWARE_NAME_MAX];
+	struct completion completion;
+	struct bin_attribute attr_data;
+	struct firmware *fw;
+	int loading;
+	int abort;
+	int alloc_size;
+	struct timer_list timeout;
+};
+
+static ssize_t
+firmware_timeout_show(struct class *class, char *buf)
+{
+	return sprintf(buf, "%d\n", loading_timeout);
+}
+
+/**
+ * firmware_timeout_store:
+ * Description:
+ *	Sets the number of seconds to wait for the firmware.  Once
+ *	this expires an error will be return to the driver and no
+ *	firmware will be provided.
+ *
+ *	Note: zero means 'wait for ever'
+ *  
+ **/
+static ssize_t
+firmware_timeout_store(struct class *class, const char *buf, size_t count)
+{
+	loading_timeout = simple_strtol(buf, NULL, 10);
+	return count;
+}
+
+CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
+
+static void  fw_class_dev_release(struct class_device *class_dev);
+int firmware_class_hotplug(struct class_device *dev, char **envp,
+			   int num_envp, char *buffer, int buffer_size);
+
+struct class firmware_class = {
+	.name		= "firmware",
+	.hotplug	= firmware_class_hotplug,
+	.release	= fw_class_dev_release,
+};
+
+int
+firmware_class_hotplug(struct class_device *class_dev, char **envp,
+		       int num_envp, char *buffer, int buffer_size)
+{
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+	int i = 0;
+	char *scratch = buffer;
+
+	if (buffer_size < (FIRMWARE_NAME_MAX + 10))
+		return -ENOMEM;
+	if (num_envp < 1)
+		return -ENOMEM;
+
+	envp[i++] = scratch;
+	scratch += sprintf(scratch, "FIRMWARE=%s", fw_priv->fw_id) + 1;
+	return 0;
+}
+
+static ssize_t
+firmware_loading_show(struct class_device *class_dev, char *buf)
+{
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+	return sprintf(buf, "%d\n", fw_priv->loading);
+}
+
+/**
+ * firmware_loading_store: - loading control file
+ * Description:
+ *	The relevant values are: 
+ *
+ *	 1: Start a load, discarding any previous partial load.
+ *	 0: Conclude the load and handle the data to the driver code.
+ *	-1: Conclude the load with an error and discard any written data.
+ **/
+static ssize_t
+firmware_loading_store(struct class_device *class_dev,
+		       const char *buf, size_t count)
+{
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+	int prev_loading = fw_priv->loading;
+
+	fw_priv->loading = simple_strtol(buf, NULL, 10);
+
+	switch (fw_priv->loading) {
+	case -1:
+		fw_priv->abort = 1;
+		wmb();
+		complete(&fw_priv->completion);
+		break;
+	case 1:
+		kfree(fw_priv->fw->data);
+		fw_priv->fw->data = NULL;
+		fw_priv->fw->size = 0;
+		fw_priv->alloc_size = 0;
+		break;
+	case 0:
+		if (prev_loading == 1)
+			complete(&fw_priv->completion);
+		break;
+	}
+
+	return count;
+}
+
+CLASS_DEVICE_ATTR(loading, 0644,
+		  firmware_loading_show, firmware_loading_store);
+
+static ssize_t
+firmware_data_read(struct kobject *kobj,
+		   char *buffer, loff_t offset, size_t count)
+{
+	struct class_device *class_dev = to_class_dev(kobj);
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+	struct firmware *fw = fw_priv->fw;
+
+	if (offset > fw->size)
+		return 0;
+	if (offset + count > fw->size)
+		count = fw->size - offset;
+
+	memcpy(buffer, fw->data + offset, count);
+	return count;
+}
+static int
+fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
+{
+	u8 *new_data;
+
+	if (min_size <= fw_priv->alloc_size)
+		return 0;
+
+	new_data = kmalloc(fw_priv->alloc_size + PAGE_SIZE, GFP_KERNEL);
+	if (!new_data) {
+		printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
+		/* Make sure that we don't keep incomplete data */
+		fw_priv->abort = 1;
+		return -ENOMEM;
+	}
+	fw_priv->alloc_size += PAGE_SIZE;
+	if (fw_priv->fw->data) {
+		memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
+		kfree(fw_priv->fw->data);
+	}
+	fw_priv->fw->data = new_data;
+	BUG_ON(min_size > fw_priv->alloc_size);
+	return 0;
+}
+
+/**
+ * firmware_data_write:
+ *
+ * Description:
+ *
+ *	Data written to the 'data' attribute will be later handled to
+ *	the driver as a firmware image.
+ **/
+static ssize_t
+firmware_data_write(struct kobject *kobj,
+		    char *buffer, loff_t offset, size_t count)
+{
+	struct class_device *class_dev = to_class_dev(kobj);
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+	struct firmware *fw = fw_priv->fw;
+	int retval;
+
+	retval = fw_realloc_buffer(fw_priv, offset + count);
+	if (retval)
+		return retval;
+
+	memcpy(fw->data + offset, buffer, count);
+
+	fw->size = max_t(size_t, offset + count, fw->size);
+
+	return count;
+}
+static struct bin_attribute firmware_attr_data_tmpl = {
+	.attr = {.name = "data", .mode = 0644},
+	.size = 0,
+	.read = firmware_data_read,
+	.write = firmware_data_write,
+};
+
+static void
+fw_class_dev_release(struct class_device *class_dev)
+{
+	kfree(class_dev);
+}
+
+static void
+firmware_class_timeout(u_long data)
+{
+	struct firmware_priv *fw_priv = (struct firmware_priv *) data;
+	fw_priv->abort = 1;
+	wmb();
+	complete(&fw_priv->completion);
+}
+static inline void
+fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
+{
+#warning we should watch out for name collisions
+	strncpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
+	class_dev->class_id[BUS_ID_SIZE - 1] = '\0';
+}
+static int
+fw_setup_class_device(struct class_device **class_dev_p,
+		      const char *fw_name, struct device *device)
+{
+	int retval = 0;
+	struct firmware_priv *fw_priv = kmalloc(sizeof (struct firmware_priv),
+						GFP_KERNEL);
+	struct class_device *class_dev = kmalloc(sizeof (struct class_device),
+						 GFP_KERNEL);
+
+	if (!fw_priv || !class_dev) {
+		retval = -ENOMEM;
+		goto error_kfree;
+	}
+	memset(fw_priv, 0, sizeof (*fw_priv));
+	memset(class_dev, 0, sizeof (*class_dev));
+
+	init_completion(&fw_priv->completion);
+	memcpy(&fw_priv->attr_data, &firmware_attr_data_tmpl,
+	       sizeof (firmware_attr_data_tmpl));
+
+	strncpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
+	fw_priv->fw_id[FIRMWARE_NAME_MAX - 1] = '\0';
+
+	fw_setup_class_device_id(class_dev, device);
+	class_dev->dev = device;
+
+	fw_priv->timeout.function = firmware_class_timeout;
+	fw_priv->timeout.data = (u_long) fw_priv;
+	init_timer(&fw_priv->timeout);
+
+	class_dev->class = &firmware_class;
+	class_set_devdata(class_dev, fw_priv);
+	retval = class_device_register(class_dev);
+	if (retval) {
+		printk(KERN_ERR "%s: class_device_register failed\n",
+		       __FUNCTION__);
+		goto error_kfree;
+	}
+
+	retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
+	if (retval) {
+		printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
+		       __FUNCTION__);
+		goto error_unreg_class_dev;
+	}
+
+	retval = class_device_create_file(class_dev,
+					  &class_device_attr_loading);
+	if (retval) {
+		printk(KERN_ERR "%s: class_device_create_file failed\n",
+		       __FUNCTION__);
+		goto error_remove_data;
+	}
+
+	fw_priv->fw = kmalloc(sizeof (struct firmware), GFP_KERNEL);
+	if (!fw_priv->fw) {
+		printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
+		       __FUNCTION__);
+		retval = -ENOMEM;
+		goto error_remove_loading;
+	}
+	memset(fw_priv->fw, 0, sizeof (*fw_priv->fw));
+
+	goto out;
+
+error_remove_loading:
+	class_device_remove_file(class_dev, &class_device_attr_loading);
+error_remove_data:
+	sysfs_remove_bin_file(&class_dev->kobj, &fw_priv->attr_data);
+error_unreg_class_dev:
+	class_device_unregister(class_dev);
+error_kfree:
+	kfree(fw_priv);
+	kfree(class_dev);
+	*class_dev_p = NULL;
+out:
+	*class_dev_p = class_dev;
+	return retval;
+}
+static void
+fw_remove_class_device(struct class_device *class_dev)
+{
+	struct firmware_priv *fw_priv = class_get_devdata(class_dev);
+
+	class_device_remove_file(class_dev, &class_device_attr_loading);
+	sysfs_remove_bin_file(&class_dev->kobj, &fw_priv->attr_data);
+	class_device_unregister(class_dev);
+}
+
+/** 
+ * request_firmware: - request firmware to hotplug and wait for it
+ * Description:
+ *	@firmware will be used to return a firmware image by the name
+ *	of @name for device @device.
+ *
+ *	Should be called from user context where sleeping is allowed.
+ *
+ *	@name will be use as $FIRMWARE in the hotplug environment and
+ *	should be distinctive enough not to be confused with any other
+ *	firmware image for this or any other device.
+ **/
+int
+request_firmware(const struct firmware **firmware, const char *name,
+		 struct device *device)
+{
+	struct class_device *class_dev;
+	struct firmware_priv *fw_priv;
+	int retval;
+
+	if (!firmware)
+		return -EINVAL;
+
+	*firmware = NULL;
+
+	retval = fw_setup_class_device(&class_dev, name, device);
+	if (retval)
+		goto out;
+
+	fw_priv = class_get_devdata(class_dev);
+
+	if (loading_timeout) {
+		fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
+		add_timer(&fw_priv->timeout);
+	}
+
+	wait_for_completion(&fw_priv->completion);
+
+	del_timer(&fw_priv->timeout);
+	fw_remove_class_device(class_dev);
+
+	if (fw_priv->fw->size && !fw_priv->abort) {
+		*firmware = fw_priv->fw;
+	} else {
+		retval = -ENOENT;
+		kfree(fw_priv->fw->data);
+		kfree(fw_priv->fw);
+	}
+	kfree(fw_priv);
+out:
+	return retval;
+}
+
+/**
+ * release_firmware: - release the resource associated with a firmware image
+ **/
+void
+release_firmware(const struct firmware *fw)
+{
+	if (fw) {
+		kfree(fw->data);
+		kfree(fw);
+	}
+}
+
+/**
+ * register_firmware: - provide a firmware image for later usage
+ * 
+ * Description:
+ *	Make sure that @data will be available by requesting firmware @name.
+ *
+ *	Note: This will not be possible until some kind of persistence
+ *	is available.
+ **/
+void
+register_firmware(const char *name, const u8 *data, size_t size)
+{
+	/* This is meaningless without firmware caching, so until we
+	 * decide if firmware caching is reasonable just leave it as a
+	 * noop */
+}
+
+/* Async support */
+struct firmware_work {
+	struct work_struct work;
+	struct module *module;
+	const char *name;
+	struct device *device;
+	void *context;
+	void (*cont)(const struct firmware *fw, void *context);
+};
+
+static void
+request_firmware_work_func(void *arg)
+{
+	struct firmware_work *fw_work = arg;
+	const struct firmware *fw;
+	if (!arg)
+		return;
+	request_firmware(&fw, fw_work->name, fw_work->device);
+	fw_work->cont(fw, fw_work->context);
+	release_firmware(fw);
+	module_put(fw_work->module);
+	kfree(fw_work);
+}
+
+/**
+ * request_firmware_nowait:
+ *
+ * Description:
+ *	Asynchronous variant of request_firmware() for contexts where
+ *	it is not possible to sleep.
+ *
+ *	@cont will be called asynchronously when the firmware request is over.
+ *
+ *	@context will be passed over to @cont.
+ *
+ *	@fw may be %NULL if firmware request fails.
+ *
+ **/
+int
+request_firmware_nowait(
+	struct module *module,
+	const char *name, struct device *device, void *context,
+	void (*cont)(const struct firmware *fw, void *context))
+{
+	struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
+						GFP_ATOMIC);
+	if (!fw_work)
+		return -ENOMEM;
+	if (!try_module_get(module)) {
+		kfree(fw_work);
+		return -EFAULT;
+	}
+
+	*fw_work = (struct firmware_work) {
+		.module = module,
+		.name = name,
+		.device = device,
+		.context = context,
+		.cont = cont,
+	};
+	INIT_WORK(&fw_work->work, request_firmware_work_func, fw_work);
+
+	schedule_work(&fw_work->work);
+	return 0;
+}
+
+static int __init
+firmware_class_init(void)
+{
+	int error;
+	error = class_register(&firmware_class);
+	if (error) {
+		printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
+	}
+	error = class_create_file(&firmware_class, &class_attr_timeout);
+	if (error) {
+		printk(KERN_ERR "%s: class_create_file failed\n",
+		       __FUNCTION__);
+		class_unregister(&firmware_class);
+	}
+	return error;
+
+}
+static void __exit
+firmware_class_exit(void)
+{
+	class_remove_file(&firmware_class, &class_attr_timeout);
+	class_unregister(&firmware_class);
+}
+
+module_init(firmware_class_init);
+module_exit(firmware_class_exit);
+
+EXPORT_SYMBOL(release_firmware);
+EXPORT_SYMBOL(request_firmware);
+EXPORT_SYMBOL(request_firmware_nowait);
+EXPORT_SYMBOL(register_firmware);
+EXPORT_SYMBOL(firmware_class);

include/linux/firmware.h

+#ifndef _LINUX_FIRMWARE_H
+#define _LINUX_FIRMWARE_H
+#include <linux/module.h>
+#include <linux/types.h>
+#define FIRMWARE_NAME_MAX 30 
+struct firmware {
+	size_t size;
+	u8 *data;
+};
+int request_firmware(const struct firmware **fw, const char *name,
+		     struct device *device);
+int request_firmware_nowait(
+	struct module *module,
+	const char *name, struct device *device, void *context,
+	void (*cont)(const struct firmware *fw, void *context));
+/* Maybe 'device' should be 'struct device *' */
+
+void release_firmware(const struct firmware *fw);
+void register_firmware(const char *name, const u8 *data, size_t size);
+#endif

lib/Kconfig

@@ -26,5 +26,7 @@ config ZLIB_DEFLATE
 		(PPP_DEFLATE=m || JFFS2_FS=m || CRYPTO_DEFLATE=m)
 	default y if PPP_DEFLATE=y || JFFS2_FS=y || CRYPTO_DEFLATE=y
 
+source "drivers/base/Kconfig.lib"
+
 endmenu