Re: [PATCH 1/2] libata: implement to get tf's from _GTF and execute them

[Jeff Garzik <jgarzik@pobox.com>]

zhao, forrest wrote:
> 1 update the Makefile, Kconfig, kernel-parameters.txt, and add
> definition of noacpi
> 2 implement core SATA-ACPI functions
> 3 implement the functions for getting tf's from _GTF and executing them
> 4 invoke ata_acpi_exec_tfs in appropriate places
> 
> 
> Signed-off-by: Zhao Forrest <forrest.zhao@intel.com>

It sounds like Randy Dunlap already provided most of the necessary feedback.

My comments will likely echo some of his.


>  Documentation/kernel-parameters.txt |    5 
>  drivers/scsi/Kconfig                |   13 +
>  drivers/scsi/Makefile               |    1 
>  drivers/scsi/libata-acpi.c          |  654 +++++++++++++++++++++++++++++++++++
>  drivers/scsi/libata-core.c          |    7 
>  drivers/scsi/libata.h               |   28 +
>  include/linux/libata.h              |    6 
>  7 files changed, 714 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/scsi/libata-acpi.c
> 
> a960cea106c4aad99a5417818fcdab20b3e68056
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index e11f772..0a57036 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -48,6 +48,7 @@ parameter is applicable:
>  	ISAPNP	ISA PnP code is enabled.
>  	ISDN	Appropriate ISDN support is enabled.
>  	JOY	Appropriate joystick support is enabled.
> +	LIBATA  Libata driver is enabled.
>  	LP	Printer support is enabled.
>  	LOOP	Loopback device support is enabled.
>  	M68k	M68k architecture is enabled.
> @@ -1018,6 +1019,10 @@ running once the system is up.
>  			emulation library even if a 387 maths coprocessor
>  			is present.
>  
> +	noacpi		[LIBATA] Disables use of ACPI in libata suspend/resume
> +			when set.
> +			Format: <int>
> +
>  	noalign		[KNL,ARM]
>  
>  	noapic		[SMP,APIC] Tells the kernel to not make use of any
> diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
> index 96a81cd..364f171 100644
> --- a/drivers/scsi/Kconfig
> +++ b/drivers/scsi/Kconfig
> @@ -619,6 +619,19 @@ config SCSI_SATA_INTEL_COMBINED
>  	depends on IDE=y && !BLK_DEV_IDE_SATA && (SCSI_SATA_AHCI || SCSI_ATA_PIIX)
>  	default y
>  
> +config SCSI_SATA_ACPI
> +	bool
> +	depends on SCSI_SATA && ACPI && PCI
> +	default y
> +	help
> +	  This option adds support for SATA-related ACPI objects.
> +	  These ACPI objects add the ability to retrieve taskfiles
> +	  from the ACPI BIOS and write them to the disk controller.
> +	  These objects may be related to performance, security,
> +	  power management, or other areas.
> +	  You can disable this at kernel boot time by using the
> +	  option 'libata.noacpi'.
> +
>  config SCSI_BUSLOGIC
>  	tristate "BusLogic SCSI support"
>  	depends on (PCI || ISA || MCA) && SCSI && ISA_DMA_API
> diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
> index ebd0cf0..b458b3a 100644
> --- a/drivers/scsi/Makefile
> +++ b/drivers/scsi/Makefile
> @@ -167,6 +167,7 @@ CFLAGS_ncr53c8xx.o	:= $(ncr53c8xx-flags-
>  zalon7xx-objs	:= zalon.o ncr53c8xx.o
>  NCR_Q720_mod-objs	:= NCR_Q720.o ncr53c8xx.o
>  libata-objs	:= libata-core.o libata-scsi.o libata-bmdma.o libata-eh.o
> +libata-$(CONFIG_SCSI_SATA_ACPI) += libata-acpi.o
>  oktagon_esp_mod-objs	:= oktagon_esp.o oktagon_io.o
>  
>  # Files generated that shall be removed upon make clean
> diff --git a/drivers/scsi/libata-acpi.c b/drivers/scsi/libata-acpi.c
> new file mode 100644
> index 0000000..cf7eeb1
> --- /dev/null
> +++ b/drivers/scsi/libata-acpi.c
> @@ -0,0 +1,654 @@
> +/*
> + * libata-acpi.c
> + * Provides ACPI support for PATA/SATA.
> + *
> + * Copyright (C) 2005 Intel Corp.
> + * Copyright (C) 2005 Randy Dunlap

optional: consider updating copyright for 2006?


> +#include <linux/ata.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <acpi/acpi.h>
> +#include "scsi.h"
> +#include <linux/libata.h>
> +#include <linux/pci.h>
> +#include "libata.h"
> +
> +#include <acpi/acpi_bus.h>
> +#include <acpi/acnames.h>
> +#include <acpi/acnamesp.h>
> +#include <acpi/acparser.h>
> +#include <acpi/acexcep.h>
> +#include <acpi/acmacros.h>
> +#include <acpi/actypes.h>
> +
> +#define SATA_ROOT_PORT(x)	(((x) >> 16) & 0xffff)
> +#define SATA_PORT_NUMBER(x)	((x) & 0xffff)	/* or NO_PORT_MULT */
> +#define NO_PORT_MULT		0xffff
> +#define SATA_ADR_RSVD		0xffffffff
> +
> +#define REGS_PER_GTF		7
> +struct taskfile_array {
> +	u8	tfa[REGS_PER_GTF];	/* regs. 0x1f1 - 0x1f7 */
> +};
> +
> +struct GTM_buffer {
> +	__u32	PIO_speed0;
> +	__u32	DMA_speed0;
> +	__u32	PIO_speed1;
> +	__u32	DMA_speed1;
> +	__u32	GTM_flags;
> +};
> +
> +#define DEBUGGING	1
> +/* note: adds function name and KERN_DEBUG */
> +#ifdef DEBUGGING
> +#define DEBPRINT(fmt, args...)	\
> +		printk(KERN_DEBUG "%s: " fmt, __FUNCTION__, ## args)
> +#else
> +#define DEBPRINT(fmt, args...)	do {} while (0)
> +#endif	/* DEBUGGING */

should use normal libata debug/message printing


> +/**
> + * sata_get_dev_handle - finds acpi_handle and PCI device.function
> + * @dev: device to locate
> + * @handle: returned acpi_handle for @dev
> + * @pcidevfn: return PCI device.func for @dev
> + *
> + * This function is somewhat SATA-specific.  Or at least the
> + * IDE and SCSI versions of this function are different,
> + * so it's not entirely generic code.
> + *
> + * Returns 0 on success, <0 on error.
> + */
> +static int sata_get_dev_handle(struct device *dev, acpi_handle *handle,
> +					acpi_integer *pcidevfn)
> +{
> +	struct pci_dev	*pci_dev;
> +	acpi_integer	addr;
> +
> +	pci_dev = to_pci_dev(dev);	/* NOTE: PCI-specific */
> +	/* Please refer to the ACPI spec for the syntax of _ADR. */
> +	addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
> +	*pcidevfn = addr;
> +	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
> +	printk(KERN_DEBUG "%s: SATA dev addr=0x%llx, handle=0x%p\n",
> +		__FUNCTION__, (unsigned long long)addr, *handle);

should not unconditionally print out debug info.  KERN_DEBUG messages 
still fill the dmesg(1) ring buffer.


> +	if (!*handle)
> +		return -ENODEV;
> +	return 0;
> +}
> +
> +/**
> + * pata_get_dev_handle - finds acpi_handle and PCI device.function
> + * @dev: device to locate
> + * @handle: returned acpi_handle for @dev
> + * @pcidevfn: return PCI device.func for @dev
> + *
> + * The PATA and SATA versions of this function are different.
> + *
> + * Returns 0 on success, <0 on error.
> + */
> +static int pata_get_dev_handle(struct device *dev, acpi_handle *handle,
> +					acpi_integer *pcidevfn)
> +{
> +	unsigned int domain, bus, devnum, func;
> +	acpi_integer addr;
> +	acpi_handle dev_handle, parent_handle;
> +	int scanned;
> +	struct acpi_buffer buffer = {.length = ACPI_ALLOCATE_BUFFER,
> +					.pointer = NULL};
> +	acpi_status status;
> +	struct acpi_device_info	*dinfo = NULL;
> +	int ret = -ENODEV;
> +
> +	printk(KERN_DEBUG "%s: ENTER: dev->bus_id='%s'\n",
> +		__FUNCTION__,  dev->bus_id);

ditto


> +	if ((scanned = sscanf(dev->bus_id, "%x:%x:%x.%x",
> +			&domain, &bus, &devnum, &func)) != 4) {
> +		printk("sscanf ret. %d\n", scanned);
> +		goto err;
> +	}
> +
> +	dev_handle = DEVICE_ACPI_HANDLE(dev);
> +	parent_handle = DEVICE_ACPI_HANDLE(dev->parent);
> +
> +	status = acpi_get_object_info(parent_handle, &buffer);
> +	if (ACPI_FAILURE(status)) {
> +		printk("get_object_info for parent failed\n");
> +		goto err;
> +	}
> +	dinfo = buffer.pointer;
> +	if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
> +	    dinfo->address == bus) {
> +		/* ACPI spec for _ADR for PCI bus: */
> +		addr = (acpi_integer)(devnum << 16 | func);
> +		*pcidevfn = addr;
> +		*handle = dev_handle;
> +	} else {
> +		printk("get_object_info for parent has wrong "
> +			" bus: %llu, should be %d\n",
> +			dinfo ? (unsigned long long)dinfo->address : -1ULL,
> +			bus);

printk needs improvement.  Add KERN_ERR, and ata_msg_err() test.


> +		goto err;
> +	}
> +
> +	printk(KERN_DEBUG "%s: dev_handle: 0x%p, parent_handle: 0x%p\n",
> +		__FUNCTION__, dev_handle, parent_handle);
> +	printk(KERN_DEBUG
> +		"%s: for dev=0x%x.%x, addr=0x%llx, parent=0x%p, *handle=0x%p\n",
> +		__FUNCTION__, devnum, func, (unsigned long long)addr,
> +		dev->parent, *handle);

should not unconditionally print debug info in a production system


> +	if (!*handle)
> +		goto err;
> +	ret = 0;
> +err:
> +	kfree(dinfo);
> +	return ret;
> +}
> +
> +struct walk_info {		/* can be trimmed some */
> +	struct device	*dev;
> +	struct acpi_device *adev;
> +	acpi_handle	handle;
> +	acpi_integer	pcidevfn;
> +	unsigned int	drivenum;
> +	acpi_handle	obj_handle;
> +	struct ata_port *ataport;
> +	struct ata_device *atadev;
> +	u32		sata_adr;
> +	int		status;
> +	char		basepath[ACPI_PATHNAME_MAX];
> +	int		basepath_len;
> +};
> +
> +static acpi_status get_devices(acpi_handle handle,
> +				u32 level, void *context, void **return_value)
> +{
> +	acpi_status		status;
> +	struct walk_info	*winfo = context;
> +	struct acpi_buffer	namebuf = {ACPI_ALLOCATE_BUFFER, NULL};
> +	char			*pathname;
> +	struct acpi_buffer	buffer;
> +	struct acpi_device_info	*dinfo;
> +
> +	status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &namebuf);
> +	if (status)
> +		goto ret;
> +	pathname = namebuf.pointer;
> +
> +	buffer.length = ACPI_ALLOCATE_BUFFER;
> +	buffer.pointer = NULL;
> +	status = acpi_get_object_info(handle, &buffer);
> +
> +	if (ACPI_SUCCESS(status)) {

decrease indentation of the below quoted code, by transforming the above 
test into

	if (!ACPI_SUCCESS(status))
		goto out2


> +		dinfo = buffer.pointer;
> +
> +		/* find full device path name for pcidevfn */
> +		if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
> +		    dinfo->address == winfo->pcidevfn) {
> +			if (ata_msg_probe(winfo->ataport))
> +				printk(KERN_DEBUG
> +					":%s: matches pcidevfn (0x%llx)\n",
> +					pathname, winfo->pcidevfn);
> +			strlcpy(winfo->basepath, pathname,
> +				sizeof(winfo->basepath));
> +			winfo->basepath_len = strlen(pathname);
> +			goto out;
> +		}
> +
> +		/* if basepath is not yet known, ignore this object */
> +		if (!winfo->basepath_len)
> +			goto out;
> +
> +		/* if this object is in scope of basepath, maybe use it */
> +		if (strncmp(pathname, winfo->basepath,
> +		    winfo->basepath_len) == 0) {
> +			if (!(dinfo->valid & ACPI_VALID_ADR))
> +				goto out;
> +			if (ata_msg_probe(winfo->ataport))
> +				printk(KERN_DEBUG "GOT ONE: (%s) "
> +					"root_port = 0x%llx, port_num = 0x%llx\n",
> +					pathname,
> +					SATA_ROOT_PORT(dinfo->address),
> +					SATA_PORT_NUMBER(dinfo->address));
> +			/* heuristics: */
> +			if (SATA_PORT_NUMBER(dinfo->address) != NO_PORT_MULT)
> +				if (ata_msg_probe(winfo->ataport))
> +					printk(KERN_DEBUG
> +						"warning: don't know how to handle SATA port multiplier\n");
> +			if (SATA_ROOT_PORT(dinfo->address) ==
> +				winfo->ataport->port_no &&
> +			    SATA_PORT_NUMBER(dinfo->address) == NO_PORT_MULT) {
> +				if (ata_msg_probe(winfo->ataport))
> +					printk(KERN_DEBUG
> +						"THIS ^^^^^ is the requested SATA drive (handle = 0x%p)\n",
> +						handle);

all these printk need to be less verbose (VPRINTK ?)


> +				winfo->sata_adr = dinfo->address;
> +				winfo->obj_handle = handle;
> +			}
> +		}
> +out:
> +		kfree(dinfo);
> +	}
> +	kfree(pathname);
> +
> +ret:
> +	return status;
> +}
> +
> +/* Get the SATA drive _ADR object. */
> +static int get_sata_adr(struct device *dev, acpi_handle handle,
> +			acpi_integer pcidevfn, unsigned int drive,
> +			struct ata_port *ap,
> +			struct ata_device *atadev, u32 *dev_adr)
> +{
> +	acpi_status	status;
> +	struct walk_info *winfo;
> +	int		err = -ENOMEM;
> +
> +	winfo = kzalloc(sizeof(struct walk_info), GFP_KERNEL);
> +	if (!winfo)
> +		goto out;
> +
> +	winfo->dev = dev;
> +	winfo->atadev = atadev;
> +	winfo->ataport = ap;
> +	if (acpi_bus_get_device(handle, &winfo->adev) < 0)
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "acpi_bus_get_device failed\n");
> +	winfo->handle = handle;
> +	winfo->pcidevfn = pcidevfn;
> +	winfo->drivenum = drive;
> +
> +	status = acpi_get_devices(NULL, get_devices, winfo, NULL);
> +	if (ACPI_FAILURE(status)) {
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: acpi_get_devices failed\n",
> +				__FUNCTION__);

ditto


> +		err = -ENODEV;
> +	} else {
> +		*dev_adr = winfo->sata_adr;
> +		atadev->obj_handle = winfo->obj_handle;
> +		err = 0;
> +	}
> +	kfree(winfo);
> +out:
> +	return err;
> +}
> +
> +/**
> + * do_drive_get_GTF - get the drive bootup default taskfile settings
> + * @ap: the ata_port for the drive
> + * @ix: target ata_device (drive) index
> + * @gtf_length: number of bytes of _GTF data returned at @gtf_address
> + * @gtf_address: buffer containing _GTF taskfile arrays
> + *
> + * This applies to both PATA and SATA drives.
> + *
> + * The _GTF method has no input parameters.
> + * It returns a variable number of register set values (registers
> + * hex 1F1..1F7, taskfiles).
> + * The <variable number> is not known in advance, so have ACPI-CA
> + * allocate the buffer as needed and return it, then free it later.
> + *
> + * The returned @gtf_length and @gtf_address are only valid if the
> + * function return value is 0.
> + */
> +int do_drive_get_GTF(struct ata_port *ap, int ix,
> +			unsigned int *gtf_length, unsigned long *gtf_address,
> +			unsigned long *obj_loc)
> +{
> +	acpi_status			status;
> +	acpi_handle			dev_handle = NULL;
> +	acpi_handle			chan_handle, drive_handle;
> +	acpi_integer			pcidevfn = 0;
> +	u32				dev_adr;
> +	struct acpi_buffer		output;
> +	union acpi_object 		*out_obj;
> +	struct device			*dev = ap->host_set->dev;
> +	struct ata_device		*atadev = &ap->device[ix];
> +	int				err = -ENODEV;
> +
> +	*gtf_length = 0;
> +	*gtf_address = 0UL;
> +	*obj_loc = 0UL;
> +
> +	if (noacpi)
> +		return 0;
> +
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG
> +			"%s: ENTER: ap->id: %d, port#: %d, hard_port#: %d\n",
> +			__FUNCTION__, ap->id,
> +		ap->port_no, ap->hard_port_no);

VPRINTK


> +	if (!ata_dev_enabled(atadev) || (ap->flags & ATA_FLAG_DISABLED)) {
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: ERR: "
> +				"ata_dev_present: %d, PORT_DISABLED: %lu\n",
> +				__FUNCTION__, ata_dev_enabled(atadev),
> +				ap->flags & ATA_FLAG_DISABLED);
> +		goto out;

ditto


> +	/* Don't continue if device has no _ADR method.
> +	 * _GTF is intended for known motherboard devices. */
> +	if (!(ap->flags & ATA_FLAG_SATA)) {
> +		err = pata_get_dev_handle(dev, &dev_handle, &pcidevfn);
> +		if (err < 0) {
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG
> +					"%s: pata_get_dev_handle failed (%d)\n",
> +					__FUNCTION__, err);
> +			goto out;
> +		}
> +	} else {
> +		err = sata_get_dev_handle(dev, &dev_handle, &pcidevfn);
> +		if (err < 0) {
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG
> +					"%s: sata_get_dev_handle failed (%d\n",
> +					__FUNCTION__, err);
> +			goto out;

the above prints needless messages for devices which don't have 
associated objects


> +	/* Get this drive's _ADR info. if not already known. */
> +	if (!atadev->obj_handle) {
> +		if (!(ap->flags & ATA_FLAG_SATA)) {
> +			/* get child objects of dev_handle == channel objects,
> +	 		 * + _their_ children == drive objects */
> +			/* channel is ap->hard_port_no */
> +			chan_handle = acpi_get_child(dev_handle,
> +						ap->hard_port_no);
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG
> +					"%s: chan adr=%d: chan_handle=0x%p\n",
> +					__FUNCTION__, ap->hard_port_no,
> +					chan_handle);

VPRINTK?

> +			if (!chan_handle) {
> +				err = -ENODEV;
> +				goto out;
> +			}
> +			/* TBD: could also check ACPI object VALID bits */
> +			drive_handle = acpi_get_child(chan_handle, ix);
> +			printk(KERN_DEBUG "%s:   drive w/ adr=%d: %c: 0x%p\n",
> +				__FUNCTION__, ix,
> +				!ata_dev_enabled(atadev) ? 'n' : 'v',
> +				drive_handle);

ditto


> +			if (!drive_handle) {
> +				err = -ENODEV;
> +				goto out;
> +			}
> +			dev_adr = ix;
> +			atadev->obj_handle = drive_handle;
> +		} else {	/* for SATA mode */
> +			dev_adr = SATA_ADR_RSVD;
> +			err = get_sata_adr(dev, dev_handle, pcidevfn, 0,
> +					ap, atadev, &dev_adr);
> +		}
> +		if (err < 0 || dev_adr == SATA_ADR_RSVD ||
> +		    !atadev->obj_handle) {
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG
> +					"%s: get_sata/pata_adr failed: "
> +					"err=%d, dev_adr=%u, obj_handle=0x%p\n",
> +					__FUNCTION__, err, dev_adr,
> +					atadev->obj_handle);

ditto


> +			goto out;
> +		}
> +	}
> +
> +	/* Setting up output buffer */
> +	output.length = ACPI_ALLOCATE_BUFFER;
> +	output.pointer = NULL;	/* ACPI-CA sets this; save/free it later */
> +
> +	/* _GTF has no input parameters */
> +	err = -EIO;
> +	status = acpi_evaluate_object(atadev->obj_handle, "_GTF",
> +					NULL, &output);
> +	if (ACPI_FAILURE(status)) {
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG
> +				"%s: Run _GTF error: status = 0x%x\n",
> +				__FUNCTION__, status);
> +		goto out;
> +	}
> +
> +	if (!output.length || !output.pointer) {
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: Run _GTF: "
> +				"length or ptr is NULL (0x%llx, 0x%p)\n",
> +				__FUNCTION__,
> +				(unsigned long long)output.length,
> +				output.pointer);
> +		kfree(output.pointer);
> +		goto out;
> +	}

ditto x 2


> +	out_obj = output.pointer;
> +	if (out_obj->type != ACPI_TYPE_BUFFER) {
> +		kfree(output.pointer);
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: Run _GTF: error: "
> +				"expected object type of ACPI_TYPE_BUFFER, "
> +				"got 0x%x\n",
> +				__FUNCTION__, out_obj->type);
> +		err = -ENOENT;
> +		goto out;
> +	}
> +
> +	if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
> +	    out_obj->buffer.length % REGS_PER_GTF) {
> +		if (ata_msg_drv(ap))
> +			printk(KERN_ERR
> +				"%s: unexpected GTF length (%d) or addr (0x%p)\n",
> +				__FUNCTION__, out_obj->buffer.length,
> +				out_obj->buffer.pointer);
> +		err = -ENOENT;
> +		goto out;
> +	}
> +
> +	*gtf_length = out_obj->buffer.length;
> +	*gtf_address = (unsigned long)out_obj->buffer.pointer;
> +	*obj_loc = (unsigned long)out_obj;
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG "%s: returning "
> +			"gtf_length=%d, gtf_address=0x%lx, obj_loc=0x%lx\n",
> +			__FUNCTION__, *gtf_length, *gtf_address, *obj_loc);
> +	err = 0;
> +out:
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(do_drive_get_GTF);
> +
> +/**
> + * taskfile_load_raw - send taskfile registers to host controller
> + * @ap: Port to which output is sent
> + * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
> + *
> + * Outputs ATA taskfile to standard ATA host controller using MMIO
> + * or PIO as indicated by the ATA_FLAG_MMIO flag.
> + * Writes the control, feature, nsect, lbal, lbam, and lbah registers.
> + * Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
> + * hob_lbal, hob_lbam, and hob_lbah.
> + *
> + * This function waits for idle (!BUSY and !DRQ) after writing
> + * registers.  If the control register has a new value, this
> + * function also waits for idle after writing control and before
> + * writing the remaining registers.
> + *
> + * LOCKING: TBD:
> + * Inherited from caller.
> + */
> +static void taskfile_load_raw(struct ata_port *ap,
> +				struct ata_device *atadev,
> +				const struct taskfile_array *gtf)
> +{
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG "%s: (0x1f1-1f7): hex: "
> +			"%02x %02x %02x %02x %02x %02x %02x\n",
> +			__FUNCTION__,
> +			gtf->tfa[0], gtf->tfa[1], gtf->tfa[2],
> +			gtf->tfa[3], gtf->tfa[4], gtf->tfa[5], gtf->tfa[6]);
> +
> +	if ((gtf->tfa[0] == 0) && (gtf->tfa[1] == 0) && (gtf->tfa[2] == 0)
> +	    && (gtf->tfa[3] == 0) && (gtf->tfa[4] == 0) && (gtf->tfa[5] == 0)
> +	    && (gtf->tfa[6] == 0))
> +		return;
> +
> +	if (ap->ops->qc_issue) {
> +		struct ata_taskfile tf;
> +		unsigned int err;
> +
> +		ata_tf_init(atadev, &tf);
> +
> +		/* convert gtf to tf */
> +		tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; /* TBD */
> +		tf.protocol = atadev->class == ATA_DEV_ATAPI ?
> +			ATA_PROT_ATAPI_NODATA : ATA_PROT_NODATA;
> +		tf.feature = gtf->tfa[0];	/* 0x1f1 */
> +		tf.nsect   = gtf->tfa[1];	/* 0x1f2 */
> +		tf.lbal    = gtf->tfa[2];	/* 0x1f3 */
> +		tf.lbam    = gtf->tfa[3];	/* 0x1f4 */
> +		tf.lbah    = gtf->tfa[4];	/* 0x1f5 */
> +		tf.device  = gtf->tfa[5];	/* 0x1f6 */
> +		tf.command = gtf->tfa[6];	/* 0x1f7 */
> +
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "call ata_exec_internal:\n");
> +		err = ata_exec_internal(atadev, &tf, NULL, DMA_NONE, NULL, 0);
> +		if (err && ata_msg_probe(ap))
> +			printk(KERN_ERR "%s: ata_exec_internal failed: %u\n",
> +				__FUNCTION__, err);
> +	} else
> +		if (ata_msg_warn(ap))
> +			printk(KERN_WARNING
> +				"%s: SATA driver is missing qc_issue function entry points\n",
> +				__FUNCTION__);
> +}
> +
> +/**
> + * do_drive_set_taskfiles - write the drive taskfile settings from _GTF
> + * @ap: the ata_port for the drive
> + * @atadev: target ata_device
> + * @gtf_length: total number of bytes of _GTF taskfiles
> + * @gtf_address: location of _GTF taskfile arrays
> + *
> + * This applies to both PATA and SATA drives.
> + *
> + * Write {gtf_address, length gtf_length} in groups of
> + * REGS_PER_GTF bytes.
> + */
> +int do_drive_set_taskfiles(struct ata_port *ap, struct ata_device *atadev,
> +			unsigned int gtf_length, unsigned long gtf_address)
> +{
> +	int			err = -ENODEV;
> +	int			gtf_count = gtf_length / REGS_PER_GTF;
> +	int			ix;
> +	struct taskfile_array	*gtf;
> +
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG
> +			"%s: ENTER: ap->id: %d, port#: %d, hard_port#: %d\n",
> +			__FUNCTION__, ap->id,
> +			ap->port_no, ap->hard_port_no);
> +
> +	if (noacpi)
> +		return 0;
> +
> +	if (!ata_dev_enabled(atadev) || (ap->flags & ATA_FLAG_DISABLED))
> +		goto out;
> +	if (!gtf_count)		/* shouldn't be here */
> +		goto out;
> +
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG
> +			"%s: total GTF bytes=%u (0x%x), gtf_count=%d, addr=0x%lx\n",
> +			__FUNCTION__, gtf_length, gtf_length, gtf_count,
> +			gtf_address);
> +	if (gtf_length % REGS_PER_GTF) {
> +		if (ata_msg_drv(ap))
> +			printk(KERN_ERR "%s: unexpected GTF length (%d)\n",
> +				__FUNCTION__, gtf_length);
> +		goto out;
> +	}
> +
> +	for (ix = 0; ix < gtf_count; ix++) {
> +		gtf = (struct taskfile_array *)
> +			(gtf_address + ix * REGS_PER_GTF);
> +
> +		/* send all TaskFile registers (0x1f1-0x1f7) *in*that*order* */
> +		taskfile_load_raw(ap, atadev, gtf);
> +	}
> +
> +	err = 0;
> +out:
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(do_drive_set_taskfiles);
> +
> +/**
> + * ata_acpi_exec_tfs - get then write drive taskfile settings
> + * @ap: the ata_port for the drive
> + *
> + * This applies to both PATA and SATA drives.
> + */
> +int ata_acpi_exec_tfs(struct ata_port *ap)
> +{
> +	int		ix;
> +	int		ret =0;
> +	unsigned int	gtf_length;
> +	unsigned long	gtf_address;
> +	unsigned long	obj_loc;
> +
> +	if (noacpi)
> +		return 0;
> +
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG "%s: ENTER:\n", __FUNCTION__);
> +
> +	for (ix = 0; ix < ATA_MAX_DEVICES; ix++) {
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: call get_GTF, ix=%d\n",
> +				__FUNCTION__, ix);
> +
> +		if (!ata_dev_enabled(&ap->device[ix]))
> +			continue;
> +
> +		ret = do_drive_get_GTF(ap, ix,
> +				&gtf_length, &gtf_address, &obj_loc);
> +		if (ret < 0) {
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG "%s: get_GTF error (%d)\n",
> +					__FUNCTION__, ret);
> +			break;
> +		}
> +
> +		if (ata_msg_probe(ap))
> +			printk(KERN_DEBUG "%s: call set_taskfiles, ix=%d\n",
> +				__FUNCTION__, ix);
> +		ret = do_drive_set_taskfiles(ap, &ap->device[ix],
> +				gtf_length, gtf_address);
> +		kfree((void *)obj_loc);
> +		if (ret < 0) {
> +			if (ata_msg_probe(ap))
> +				printk(KERN_DEBUG
> +					"%s: set_taskfiles error (%d)\n",
> +					__FUNCTION__, ret);
> +			break;
> +		}
> +	}
> +
> +	if (ata_msg_probe(ap))
> +		printk(KERN_DEBUG "%s: ret=%d\n", __FUNCTION__, ret);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(ata_acpi_exec_tfs);
> +
> diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
> index 386e5f2..cd4cf97 100644
> --- a/drivers/scsi/libata-core.c
> +++ b/drivers/scsi/libata-core.c
> @@ -91,6 +91,10 @@ static int ata_probe_timeout = ATA_TMOUT
>  module_param(ata_probe_timeout, int, 0444);
>  MODULE_PARM_DESC(ata_probe_timeout, "Set ATA probing timeout (seconds)");
>  
> +int noacpi = 0;
> +module_param(noacpi, int, 0444);
> +MODULE_PARM_DESC(noacpi, "Disables use of ACPI in suspend/resume when set");
> +
>  MODULE_AUTHOR("Jeff Garzik");
>  MODULE_DESCRIPTION("Library module for ATA devices");
>  MODULE_LICENSE("GPL");
> @@ -1592,6 +1596,9 @@ static int ata_bus_probe(struct ata_port
>  		goto fail;
>  	}
>  
> +	/* retrieve and execute the ATA task file of _GTF */
> +	ata_acpi_exec_tfs(ap);
> +
>  	for (i = 0; i < ATA_MAX_DEVICES; i++)
>  		if (ata_dev_enabled(&ap->device[i]))
>  			return 0;
> diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
> index c325679..d9743e0 100644
> --- a/drivers/scsi/libata.h
> +++ b/drivers/scsi/libata.h
> @@ -43,6 +43,7 @@ extern struct workqueue_struct *ata_aux_
>  extern int atapi_enabled;
>  extern int atapi_dmadir;
>  extern int libata_fua;
> +extern int noacpi;
>  extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
>  extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
>  extern void ata_dev_disable(struct ata_device *dev);
> @@ -114,4 +115,31 @@ extern void ata_scsi_error(struct Scsi_H
>  extern void ata_port_wait_eh(struct ata_port *ap);
>  extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc);
>  
> +/* libata-acpi.c */
> +#ifdef CONFIG_SCSI_SATA_ACPI
> +extern int do_drive_get_GTF(struct ata_port *ap, int ix,
> +			unsigned int *gtf_length, unsigned long *gtf_address,
> +			unsigned long *obj_loc);
> +extern int do_drive_set_taskfiles(struct ata_port *ap, struct ata_device *atadev,
> +			unsigned int gtf_length, unsigned long gtf_address);
> +extern int ata_acpi_exec_tfs(struct ata_port *ap);
> +#else
> +static inline int do_drive_get_GTF(struct ata_port *ap, int ix,
> +			unsigned int *gtf_length, unsigned long *gtf_address,
> +			unsigned long *obj_loc)
> +{
> +	return 0;
> +}
> +static inline int do_drive_set_taskfiles(struct ata_port *ap,
> +			struct ata_device *atadev,
> +			unsigned int gtf_length, unsigned long gtf_address)
> +{
> +	return 0;
> +}
> +static inline int ata_acpi_exec_tfs(struct ata_port *ap)
> +{
> +	return 0;
> +}
> +#endif
> +
>  #endif /* __LIBATA_H__ */
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 66c3100..5e1cbbb 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -35,6 +35,7 @@
>  #include <linux/ata.h>
>  #include <linux/workqueue.h>
>  #include <scsi/scsi_host.h>
> +#include <acpi/acpi.h>
>  
>  /*
>   * compile-time options: to be removed as soon as all the drivers are
> @@ -468,6 +469,11 @@ struct ata_device {
>  
>  	/* error history */
>  	struct ata_ering	ering;
> +
> +#ifdef CONFIG_SCSI_SATA_ACPI
> +	/* ACPI objects info */
> +	acpi_handle		obj_handle;
> +#endif
>  };
>  
>  /* Offset into struct ata_device.  Fields above it are maintained