config ACPI_CUSTOM_DSDT_INITRD

	bool "Read Custom DSDT from initramfs"

	depends on BLK_DEV_INITRD

	default y

	help

	  The DSDT (Differentiated System Description Table) often needs to be

	  overridden because of broken BIOS implementations. If this feature is

	  activated you will be able to provide a customized DSDT by adding it

	  to your initramfs.  For now you need to use a special mkinitrd tool.

	  For more details see <file:Documentation/dsdt-initrd.txt> or

	  <http://gaugusch.at/kernel.shtml>. If there is no table found, it

	  will fallback to the custom DSDT in-kernel (if activated) or to the

	  DSDT from the BIOS.

	  Even if you do not need a new one at the moment, you may want to use a

	  better implemented DSDT later. It is safe to say Y here.

#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD

int acpi_must_unregister_table = FALSE;

#endif

#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD

#define MAX_DS_SDTS 10

static struct acpi_table_header *ds_sdt_buffers[MAX_DS_SDTS];

static unsigned int tables_loaded = 0;

void acpi_load_override_tables(void){

	struct file         *firmware_file;

	mm_segment_t        oldfs;

	unsigned long       len, len2;

	struct kstat        stat;

	unsigned int        x, y;

	char *ramfs_ds_sdt_names[MAX_DS_SDTS] = {

		"/DSDT.aml",

		"/SSDT.aml",

		"/SSDT1.aml",

		"/SSDT2.aml",

		"/SSDT3.aml",

		"/SSDT4.aml",

		"/SSDT5.aml",

		"/SSDT6.aml",

		"/SSDT7.aml",

		"/SSDT8.aml",

	};

	/*

	 * Never do this at home, only the user-space is allowed to open a file.

	 * The clean way would be to use the firmware loader. But this code must be run

	 * before there is any userspace available. So we need a static/init firmware

	 * infrastructure, which doesn't exist yet...

	 */

	for (x = 0; x < MAX_DS_SDTS; x++){

		if (vfs_stat(ramfs_ds_sdt_names[x], &stat) < 0) {

			continue;

		}

		len = stat.size;

		/* check especially against empty files */

		if (len <= 4) {

			printk("error file %s is too small, only %lu bytes.\n",

			       ramfs_ds_sdt_names[x], len);

			continue;

		}

		ds_sdt_buffers[x] = kmalloc(len, GFP_KERNEL);

		if (!ds_sdt_buffers[x]) {

			printk("error when allocating %lu bytes of memory.\n",

			       len);

			/* better free all tables again */

			for (y = 0; y < x; y++){

				if (ds_sdt_buffers[y])

					kfree(ds_sdt_buffers[x]);

			}

			acpi_must_unregister_table = FALSE;

			return;

		}

		firmware_file = filp_open(ramfs_ds_sdt_names[x], O_RDONLY, 0);

		if (IS_ERR(firmware_file)) {

			printk("error, could not open file %s.\n",

			       ramfs_ds_sdt_names[x]);

			kfree(ds_sdt_buffers[x]);

			continue;

		}

		oldfs = get_fs();

		set_fs(KERNEL_DS);

		len2 = vfs_read(firmware_file,

				(char __user *)ds_sdt_buffers[x],

				len,

				&firmware_file->f_pos);

		set_fs(oldfs);

		filp_close(firmware_file, NULL);

		if (len2 < len) {

			printk("error trying to read %lu bytes from %s.\n",

			       len, ramfs_ds_sdt_names[x]);

			kfree(ds_sdt_buffers[x]);

			continue;

		}

		printk(PREFIX "successfully read %lu bytes from file %s\n",

		       len, ramfs_ds_sdt_names[x]);

	}

}

struct acpi_table_header * acpi_find_dsdt_initrd(struct acpi_table_header * t)

{

	struct acpi_table_header	*ret = NULL;

	unsigned int                     x;

	for (x = 0; x < MAX_DS_SDTS; x++){

		if (ds_sdt_buffers[x]){

			if (!memcmp(ds_sdt_buffers[x]->signature,

				    t->signature, 4) &&

			    !memcmp(ds_sdt_buffers[x]->oem_table_id,

				    t->oem_table_id, 8)){

				ret = ds_sdt_buffers[x];

				printk(PREFIX "Override [%4.4s-%8.8s]"

				       " from initramfs -"

				       " tainting kernel\n",

				       t->signature,

				       t->oem_table_id);

				add_taint(TAINT_NO_SUPPORT);

				acpi_must_unregister_table = TRUE;

				break;

			}

		}

	}

	return ret;

}

#endif

	*new_table = NULL;

#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD

extern int acpi_must_unregister_table;

#endif

#ifndef CONFIG_ACPI_CUSTOM_DSDT_INITRD

#endif

#ifdef CONFIG_BLK_DEV_INITRD

extern int populate_rootfs(void);

#else

static inline void populate_rootfs(void) {}

#endif

#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD

	populate_rootfs(); /* For DSDT override from initramfs */

#endif