[PATCH] pciehp: reduce dependence on ACPI

Reduce the PCI Express hotplug driver's dependence on ACPI.
We don't walk the acpi namespace anymore to build a list of
bridges and devices. We go to ACPI only to run the _OSC or
_OSHP methods to transition control of hotplug hardware from
system BIOS to the hotplug driver, and to run the _HPP
method to get hotplug device parameters like cache line size,
latency timer and SERR/PERR enable from BIOS.

Note that one of the side effects of this patch is that pciehp
does not automatically enable the hot-added device or its DMA
bus mastering capability now. It expects the device driver to
do that. This may break some drivers and we will have to fix
them as they are reported.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 71 insertions, 767 deletions

diff --git a/drivers/pci/hotplug/pciehprm_acpi.c b/drivers/pci/hotplug/pciehprm_acpi.c
index 078550ba270..c823cfa42ee 100644
--- a/drivers/pci/hotplug/pciehprm_acpi.c
+++ b/drivers/pci/hotplug/pciehprm_acpi.c
@@ -39,70 +39,11 @@
 #include <acpi/acpi_bus.h>
 #include <acpi/actypes.h>
 #include "pciehp.h"
-#include "pciehprm.h"
-
-#define	PCI_MAX_BUS		0x100
-#define	ACPI_STA_DEVICE_PRESENT	0x01
 
 #define	METHOD_NAME__SUN	"_SUN"
 #define	METHOD_NAME__HPP	"_HPP"
 #define	METHOD_NAME_OSHP	"OSHP"
 
-/* Status code for running acpi method to gain native control */
-#define NC_NOT_RUN	0
-#define OSC_NOT_EXIST	1
-#define OSC_RUN_FAILED	2
-#define OSHP_NOT_EXIST	3
-#define OSHP_RUN_FAILED	4
-#define NC_RUN_SUCCESS	5
-
-#define	PHP_RES_BUS		0xA0
-#define	PHP_RES_IO		0xA1
-#define	PHP_RES_MEM		0xA2
-#define	PHP_RES_PMEM		0xA3
-
-#define	BRIDGE_TYPE_P2P		0x00
-#define	BRIDGE_TYPE_HOST	0x01
-
-/* this should go to drivers/acpi/include/ */
-struct acpi__hpp {
-	u8	cache_line_size;
-	u8	latency_timer;
-	u8	enable_serr;
-	u8	enable_perr;
-};
-
-struct acpi_php_slot {
-	struct acpi_php_slot	*next;
-	struct acpi_bridge	*bridge;
-	acpi_handle	handle;
-	int	seg;
-	int	bus;
-	int	dev;
-	int	fun;
-	u32	sun;
-	void	*slot_ops;	/* _STA, _EJx, etc */
-	struct slot *slot;
-};		/* per func */
-
-struct acpi_bridge {
-	struct acpi_bridge	*parent;
-	struct acpi_bridge	*next;
-	struct acpi_bridge	*child;
-	acpi_handle	handle;
-	int seg;
-	int pbus;			/* pdev->bus->number		*/
-	int pdevice;			/* PCI_SLOT(pdev->devfn)	*/
-	int pfunction;			/* PCI_DEVFN(pdev->devfn)	*/
-	int bus;			/* pdev->subordinate->number	*/
-	struct acpi__hpp		*_hpp;
-	struct acpi_php_slot	*slots;
-	int scanned;
-	int type;
-};
-
-static struct acpi_bridge *acpi_bridges_head;
-
 static u8 * acpi_path_name( acpi_handle	handle)
 {
 	acpi_status		status;
@@ -118,85 +59,43 @@ static u8 * acpi_path_name( acpi_handle	handle)
 		return path_name;	
 }
 
-static void acpi_get__hpp ( struct acpi_bridge	*ab);
-static int acpi_run_oshp ( struct acpi_bridge	*ab);
-static int osc_run_status = NC_NOT_RUN;
-static int oshp_run_status = NC_NOT_RUN;
-
-static int acpi_add_slot_to_php_slots(
-	struct acpi_bridge	*ab,
-	int			bus_num,
-	acpi_handle		handle,
-	u32			adr,
-	u32			sun
-	)
-{
-	struct acpi_php_slot	*aps;
-	static long	samesun = -1;
-
-	aps = (struct acpi_php_slot *) kmalloc (sizeof(struct acpi_php_slot), GFP_KERNEL);
-	if (!aps) {
-		err ("acpi_pciehprm: alloc for aps fail\n");
-		return -1;
-	}
-	memset(aps, 0, sizeof(struct acpi_php_slot));
-
-	aps->handle = handle;
-	aps->bus = bus_num;
-	aps->dev = (adr >> 16) & 0xffff;
-	aps->fun = adr & 0xffff;
-	aps->sun = sun;
-
-	aps->next = ab->slots;	/* cling to the bridge */
-	aps->bridge = ab;
-	ab->slots = aps;
-
-	ab->scanned += 1;
-	if (!ab->_hpp)
-		acpi_get__hpp(ab);
-	
-	if (osc_run_status == OSC_NOT_EXIST)
-		oshp_run_status = acpi_run_oshp(ab);
-
-	if (sun != samesun) {
-		info("acpi_pciehprm:   Slot sun(%x) at s:b:d:f=0x%02x:%02x:%02x:%02x\n", 
-			aps->sun, ab->seg, aps->bus, aps->dev, aps->fun);
-		samesun = sun;
-	}
-	return 0;
-}
-
-static void acpi_get__hpp ( struct acpi_bridge	*ab)
+static acpi_status
+acpi_run_hpp(acpi_handle handle, struct hotplug_params *hpp)
 {
 	acpi_status		status;
 	u8			nui[4];
 	struct acpi_buffer	ret_buf = { 0, NULL};
 	union acpi_object	*ext_obj, *package;
-	u8			*path_name = acpi_path_name(ab->handle);
+	u8			*path_name = acpi_path_name(handle);
 	int			i, len = 0;
 
 	/* get _hpp */
-	status = acpi_evaluate_object(ab->handle, METHOD_NAME__HPP, NULL, &ret_buf);
+	status = acpi_evaluate_object(handle, METHOD_NAME__HPP, NULL, &ret_buf);
 	switch (status) {
 	case AE_BUFFER_OVERFLOW:
 		ret_buf.pointer = kmalloc (ret_buf.length, GFP_KERNEL);
 		if (!ret_buf.pointer) {
-			err ("acpi_pciehprm:%s alloc for _HPP fail\n", path_name);
-			return;
+			err ("%s:%s alloc for _HPP fail\n", __FUNCTION__,
+					path_name);
+			return AE_NO_MEMORY;
 		}
-		status = acpi_evaluate_object(ab->handle, METHOD_NAME__HPP, NULL, &ret_buf);
+		status = acpi_evaluate_object(handle, METHOD_NAME__HPP,
+				NULL, &ret_buf);
 		if (ACPI_SUCCESS(status))
 			break;
 	default:
 		if (ACPI_FAILURE(status)) {
-			err("acpi_pciehprm:%s _HPP fail=0x%x\n", path_name, status);
-			return;
+			dbg("%s:%s _HPP fail=0x%x\n", __FUNCTION__,
+					path_name, status);
+			return status;
 		}
 	}
 
 	ext_obj = (union acpi_object *) ret_buf.pointer;
 	if (ext_obj->type != ACPI_TYPE_PACKAGE) {
-		err ("acpi_pciehprm:%s _HPP obj not a package\n", path_name);
+		err ("%s:%s _HPP obj not a package\n", __FUNCTION__,
+				path_name);
+		status = AE_ERROR;
 		goto free_and_return;
 	}
 
@@ -209,689 +108,94 @@ static void acpi_get__hpp ( struct acpi_bridge	*ab)
 			nui[i] = (u8)ext_obj->integer.value;
 			break;
 		default:
-			err ("acpi_pciehprm:%s _HPP obj type incorrect\n", path_name);
+			err ("%s:%s _HPP obj type incorrect\n", __FUNCTION__,
+					path_name);
+			status = AE_ERROR;
 			goto free_and_return;
 		}
 	}
 
-	ab->_hpp = kmalloc (sizeof (struct acpi__hpp), GFP_KERNEL);
-	if (!ab->_hpp) {
-		err ("acpi_pciehprm:%s alloc for _HPP failed\n", path_name);
-		goto free_and_return;
-	}
-	memset(ab->_hpp, 0, sizeof(struct acpi__hpp));
+	hpp->cache_line_size = nui[0];
+	hpp->latency_timer = nui[1];
+	hpp->enable_serr = nui[2];
+	hpp->enable_perr = nui[3];
 
-	ab->_hpp->cache_line_size	= nui[0];
-	ab->_hpp->latency_timer		= nui[1];
-	ab->_hpp->enable_serr		= nui[2];
-	ab->_hpp->enable_perr		= nui[3];
-
-	dbg("  _HPP: cache_line_size=0x%x\n", ab->_hpp->cache_line_size);
-	dbg("  _HPP: latency timer  =0x%x\n", ab->_hpp->latency_timer);
-	dbg("  _HPP: enable SERR    =0x%x\n", ab->_hpp->enable_serr);
-	dbg("  _HPP: enable PERR    =0x%x\n", ab->_hpp->enable_perr);
+	dbg("  _HPP: cache_line_size=0x%x\n", hpp->cache_line_size);
+	dbg("  _HPP: latency timer  =0x%x\n", hpp->latency_timer);
+	dbg("  _HPP: enable SERR    =0x%x\n", hpp->enable_serr);
+	dbg("  _HPP: enable PERR    =0x%x\n", hpp->enable_perr);
 
 free_and_return:
 	kfree(ret_buf.pointer);
+	return status;
 }
 
-static int acpi_run_oshp ( struct acpi_bridge	*ab)
+static acpi_status acpi_run_oshp(acpi_handle handle)
 {
 	acpi_status		status;
-	u8			*path_name = acpi_path_name(ab->handle);
+	u8			*path_name = acpi_path_name(handle);
 
 	/* run OSHP */
-	status = acpi_evaluate_object(ab->handle, METHOD_NAME_OSHP, NULL, NULL);
+	status = acpi_evaluate_object(handle, METHOD_NAME_OSHP, NULL, NULL);
 	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:%s OSHP fails=0x%x\n", path_name, status);
-		oshp_run_status = (status == AE_NOT_FOUND) ? OSHP_NOT_EXIST : OSHP_RUN_FAILED;
+		err("%s:%s OSHP fails=0x%x\n", __FUNCTION__, path_name,
+				status);
 	} else {
-		oshp_run_status = NC_RUN_SUCCESS;
-		dbg("acpi_pciehprm:%s OSHP passes =0x%x\n", path_name, status);
-		dbg("acpi_pciehprm:%s oshp_run_status =0x%x\n", path_name, oshp_run_status);
-	}
-	return oshp_run_status;
-}
-
-/* find acpi_bridge downword from ab.  */
-static struct acpi_bridge *
-find_acpi_bridge_by_bus(
-	struct acpi_bridge *ab,
-	int seg,
-	int bus		/* pdev->subordinate->number */
-	)
-{
-	struct acpi_bridge	*lab = NULL;
-
-	if (!ab)
-		return NULL;
-
-	if ((ab->bus == bus) && (ab->seg == seg))
-		return ab;
-
-	if (ab->child)
-		lab = find_acpi_bridge_by_bus(ab->child, seg, bus);
-
-	if (!lab)
-	if (ab->next)
-		lab = find_acpi_bridge_by_bus(ab->next, seg, bus);
-
-	return lab;
-}
-
-/*
- * Build a device tree of ACPI PCI Bridges
- */
-static void pciehprm_acpi_register_a_bridge (
-	struct acpi_bridge	**head,
-	struct acpi_bridge	*pab,	/* parent bridge to which child bridge is added */
-	struct acpi_bridge	*cab	/* child bridge to add */
-	)
-{
-	struct acpi_bridge	*lpab;
-	struct acpi_bridge	*lcab;
-
-	lpab = find_acpi_bridge_by_bus(*head, pab->seg, pab->bus);
-	if (!lpab) {
-		if (!(pab->type & BRIDGE_TYPE_HOST))
-			warn("PCI parent bridge s:b(%x:%x) not in list.\n", pab->seg, pab->bus);
-		pab->next = *head;
-		*head = pab;
-		lpab = pab;
+		dbg("%s:%s OSHP passes\n", __FUNCTION__, path_name);
 	}
-
-	if ((cab->type & BRIDGE_TYPE_HOST) && (pab == cab))
-		return;
-
-	lcab = find_acpi_bridge_by_bus(*head, cab->seg, cab->bus);
-	if (lcab) {
-		if ((pab->bus != lcab->parent->bus) || (lcab->bus != cab->bus))
-			err("PCI child bridge s:b(%x:%x) in list with diff parent.\n", cab->seg, cab->bus);
-		return;
-	} else
-		lcab = cab;
-
-	lcab->parent = lpab;
-	lcab->next = lpab->child;
-	lpab->child = lcab;
+	return status;
 }
 
-static acpi_status pciehprm_acpi_build_php_slots_callback(
-	acpi_handle		handle,
-	u32			Level,
-	void			*context,
-	void			**retval
-	)
+int get_hp_hw_control_from_firmware(struct pci_dev *dev)
 {
-	ulong		bus_num;
-	ulong		seg_num;
-	ulong		sun, adr;
-	ulong		padr = 0;
-	acpi_handle		phandle = NULL;
-	struct acpi_bridge	*pab = (struct acpi_bridge *)context;
-	struct acpi_bridge	*lab;
-	acpi_status		status;
-	u8			*path_name = acpi_path_name(handle);
-
-	/* get _SUN */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__SUN, NULL, &sun);
-	switch(status) {
-	case AE_NOT_FOUND:
-		return AE_OK;
-	default:
-		if (ACPI_FAILURE(status)) {
-			err("acpi_pciehprm:%s _SUN fail=0x%x\n", path_name, status);
-			return status;
-		}
-	}
-
-	/* get _ADR. _ADR must exist if _SUN exists */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
-	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:%s _ADR fail=0x%x\n", path_name, status);
-		return status;
-	}
-
-	dbg("acpi_pciehprm:%s sun=0x%08x adr=0x%08x\n", path_name, (u32)sun, (u32)adr);
-
-	status = acpi_get_parent(handle, &phandle);
-	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:%s get_parent fail=0x%x\n", path_name, status);
-		return (status);
-	}
-
-	bus_num = pab->bus;
-	seg_num = pab->seg;
-
-	if (pab->bus == bus_num) {
-		lab = pab;
-	} else {
-		dbg("WARN: pab is not parent\n");
-		lab = find_acpi_bridge_by_bus(pab, seg_num, bus_num);
-		if (!lab) {
-			dbg("acpi_pciehprm: alloc new P2P bridge(%x) for sun(%08x)\n", (u32)bus_num, (u32)sun);
-			lab = (struct acpi_bridge *)kmalloc(sizeof(struct acpi_bridge), GFP_KERNEL);
-			if (!lab) {
-				err("acpi_pciehprm: alloc for ab fail\n");
-				return AE_NO_MEMORY;
-			}
-			memset(lab, 0, sizeof(struct acpi_bridge));
-
-			lab->handle = phandle;
-			lab->pbus = pab->bus;
-			lab->pdevice = (int)(padr >> 16) & 0xffff;
-			lab->pfunction = (int)(padr & 0xffff);
-			lab->bus = (int)bus_num;
-			lab->scanned = 0;
-			lab->type = BRIDGE_TYPE_P2P;
-
-			pciehprm_acpi_register_a_bridge (&acpi_bridges_head, pab, lab);
-		} else
-			dbg("acpi_pciehprm: found P2P bridge(%x) for sun(%08x)\n", (u32)bus_num, (u32)sun);
+	acpi_status status;
+	/*
+	 * Per PCI firmware specification, we should run the ACPI _OSC
+	 * method to get control of hotplug hardware before using it
+	 */
+	/* Fixme: run _OSC for a specific host bridge, not all of them */
+	status = pci_osc_control_set(OSC_PCI_EXPRESS_NATIVE_HP_CONTROL);
+
+	/* Fixme: fail native hotplug if _OSC does not exist for root ports */
+	if (status == AE_NOT_FOUND) {
+		/*
+		 * Some older BIOS's don't support _OSC but support
+		 * OSHP to do the same thing
+		 */
+		acpi_handle handle = DEVICE_ACPI_HANDLE(&(dev->dev));
+		if (handle)
+			status = acpi_run_oshp(handle);
 	}
-
-	acpi_add_slot_to_php_slots(lab, (int)bus_num, handle, (u32)adr, (u32)sun);
-
-	return (status);
-}
-
-static int pciehprm_acpi_build_php_slots(
-	struct acpi_bridge	*ab,
-	u32			depth
-	)
-{
-	acpi_status	status;
-	u8		*path_name = acpi_path_name(ab->handle);
-
-	/* Walk down this pci bridge to get _SUNs if any behind P2P */
-	status = acpi_walk_namespace ( ACPI_TYPE_DEVICE,
-				ab->handle,
-				depth,
-				pciehprm_acpi_build_php_slots_callback,
-				ab,
-				NULL );
 	if (ACPI_FAILURE(status)) {
-		dbg("acpi_pciehprm:%s walk for _SUN on pci bridge seg:bus(%x:%x) fail=0x%x\n", path_name, ab->seg, ab->bus, status);
+		err("Cannot get control of hotplug hardware\n");
 		return -1;
 	}
 
+	dbg("Sucess getting control of hotplug hardware\n");
 	return 0;
 }
 
-static void build_a_bridge(
-	struct acpi_bridge	*pab,
-	struct acpi_bridge	*ab
-	)
-{
-	u8		*path_name = acpi_path_name(ab->handle);
-
-	pciehprm_acpi_register_a_bridge (&acpi_bridges_head, pab, ab);
-
-	switch (ab->type) {
-	case BRIDGE_TYPE_HOST:
-		dbg("acpi_pciehprm: Registered PCI HOST Bridge(%02x)    on s:b:d:f(%02x:%02x:%02x:%02x) [%s]\n",
-			ab->bus, ab->seg, ab->pbus, ab->pdevice, ab->pfunction, path_name);
-		break;
-	case BRIDGE_TYPE_P2P:
-		dbg("acpi_pciehprm: Registered PCI  P2P Bridge(%02x-%02x) on s:b:d:f(%02x:%02x:%02x:%02x) [%s]\n",
-			ab->pbus, ab->bus, ab->seg, ab->pbus, ab->pdevice, ab->pfunction, path_name);
-		break;
-	};
-
-	/* build any immediate PHP slots under this pci bridge */
-	pciehprm_acpi_build_php_slots(ab, 1);
-}
-
-static struct acpi_bridge * add_p2p_bridge(
-	acpi_handle handle,
-	struct acpi_bridge	*pab,	/* parent */
-	ulong	adr
-	)
-{
-	struct acpi_bridge	*ab;
-	struct pci_dev	*pdev;
-	ulong		devnum, funcnum;
-	u8			*path_name = acpi_path_name(handle);
-
-	ab = (struct acpi_bridge *) kmalloc (sizeof(struct acpi_bridge), GFP_KERNEL);
-	if (!ab) {
-		err("acpi_pciehprm: alloc for ab fail\n");
-		return NULL;
-	}
-	memset(ab, 0, sizeof(struct acpi_bridge));
-
-	devnum = (adr >> 16) & 0xffff;
-	funcnum = adr & 0xffff;
-
-	pdev = pci_find_slot(pab->bus, PCI_DEVFN(devnum, funcnum));
-	if (!pdev || !pdev->subordinate) {
-		err("acpi_pciehprm:%s is not a P2P Bridge\n", path_name);
-		kfree(ab);
-		return NULL;
-	}
-
-	ab->handle = handle;
-	ab->seg = pab->seg;
-	ab->pbus = pab->bus;		/* or pdev->bus->number */
-	ab->pdevice = devnum;		/* or PCI_SLOT(pdev->devfn) */
-	ab->pfunction = funcnum;	/* or PCI_FUNC(pdev->devfn) */
-	ab->bus = pdev->subordinate->number;
-	ab->scanned = 0;
-	ab->type = BRIDGE_TYPE_P2P;
-
-	dbg("acpi_pciehprm: P2P(%x-%x) on pci=b:d:f(%x:%x:%x) acpi=b:d:f(%x:%x:%x) [%s]\n",
-		pab->bus, ab->bus, pdev->bus->number, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
-		pab->bus, (u32)devnum, (u32)funcnum, path_name);
-
-	build_a_bridge(pab, ab);
-
-	return ab;
-}
-
-static acpi_status scan_p2p_bridge(
-	acpi_handle		handle,
-	u32			Level,
-	void			*context,
-	void			**retval
-	)
-{
-	struct acpi_bridge	*pab = (struct acpi_bridge *)context;
-	struct acpi_bridge	*ab;
-	acpi_status		status;
-	ulong			adr = 0;
-	u8			*path_name = acpi_path_name(handle);
-	ulong			devnum, funcnum;
-	struct pci_dev		*pdev;
-
-	/* get device, function */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
-	if (ACPI_FAILURE(status)) {
-		if (status != AE_NOT_FOUND)
-			err("acpi_pciehprm:%s _ADR fail=0x%x\n", path_name, status);
-		return AE_OK;
-	}
-
-	devnum = (adr >> 16) & 0xffff;
-	funcnum = adr & 0xffff;
-
-	pdev = pci_find_slot(pab->bus, PCI_DEVFN(devnum, funcnum));
-	if (!pdev)
-		return AE_OK;
-	if (!pdev->subordinate)
-		return AE_OK;
-
-	ab = add_p2p_bridge(handle, pab, adr);
-	if (ab) {
-		status = acpi_walk_namespace ( ACPI_TYPE_DEVICE,
-					handle,
-					(u32)1,
-					scan_p2p_bridge,
-					ab,
-					NULL);
-		if (ACPI_FAILURE(status))
-			dbg("acpi_pciehprm:%s find_p2p fail=0x%x\n", path_name, status);
-	}
-
-	return AE_OK;
-}
-
-static struct acpi_bridge * add_host_bridge(
-	acpi_handle handle,
-	ulong	segnum,
-	ulong	busnum
-	)
-{
-	ulong			adr = 0;
-	acpi_status		status;
-	struct acpi_bridge	*ab;
-	u8			*path_name = acpi_path_name(handle);
-
-	/* get device, function: host br adr is always 0000 though.  */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
-	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:%s _ADR fail=0x%x\n", path_name, status);
-		return NULL;
-	}
-	dbg("acpi_pciehprm: ROOT PCI seg(0x%x)bus(0x%x)dev(0x%x)func(0x%x) [%s]\n", (u32)segnum, 
-		(u32)busnum, (u32)(adr >> 16) & 0xffff, (u32)adr & 0xffff, path_name);
-
-	ab = (struct acpi_bridge *) kmalloc (sizeof(struct acpi_bridge), GFP_KERNEL);
-	if (!ab) {
-		err("acpi_pciehprm: alloc for ab fail\n");
-		return NULL;
-	}
-	memset(ab, 0, sizeof(struct acpi_bridge));
-
-	ab->handle = handle;
-	ab->seg = (int)segnum;
-	ab->bus = ab->pbus = (int)busnum;
-	ab->pdevice = (int)(adr >> 16) & 0xffff;
-	ab->pfunction = (int)(adr & 0xffff);
-	ab->scanned = 0;
-	ab->type = BRIDGE_TYPE_HOST;
-
-	status = pci_osc_control_set (OSC_PCI_EXPRESS_NATIVE_HP_CONTROL); 
-	if (ACPI_FAILURE(status)) {
-		err("%s: status %x\n", __FUNCTION__, status);
-		osc_run_status = (status == AE_NOT_FOUND) ? OSC_NOT_EXIST : OSC_RUN_FAILED;
-	} else {
-		osc_run_status = NC_RUN_SUCCESS;
-	}	
-	dbg("%s: osc_run_status %x\n", __FUNCTION__, osc_run_status);
-	
-	build_a_bridge(ab, ab);
-
-	return ab;
-}
-
-static acpi_status acpi_scan_from_root_pci_callback (
-	acpi_handle	handle,
-	u32			Level,
-	void		*context,
-	void		**retval
-	)
-{
-	ulong		segnum = 0;
-	ulong		busnum = 0;
-	acpi_status		status;
-	struct acpi_bridge	*ab;
-	u8			*path_name = acpi_path_name(handle);
-
-	/* get bus number of this pci root bridge */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL, &segnum);
-	if (ACPI_FAILURE(status)) {
-		if (status != AE_NOT_FOUND) {
-			err("acpi_pciehprm:%s evaluate _SEG fail=0x%x\n", path_name, status);
-			return status;
-		}
-		segnum = 0;
-	}
-
-	/* get bus number of this pci root bridge */
-	status = acpi_evaluate_integer(handle, METHOD_NAME__BBN, NULL, &busnum);
-	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:%s evaluate _BBN fail=0x%x\n", path_name, status);
-		return (status);
-	}
-
-	ab = add_host_bridge(handle, segnum, busnum);
-	if (ab) {
-		status = acpi_walk_namespace ( ACPI_TYPE_DEVICE,
-					handle,
-					1,
-					scan_p2p_bridge,
-					ab,
-					NULL);
-		if (ACPI_FAILURE(status))
-			dbg("acpi_pciehprm:%s find_p2p fail=0x%x\n", path_name, status);
-	}
-
-	return AE_OK;
-}
-
-static int pciehprm_acpi_scan_pci (void)
+void get_hp_params_from_firmware(struct pci_dev *dev,
+		struct hotplug_params *hpp)
 {
-	acpi_status	status;
+	acpi_status status = AE_NOT_FOUND;
+	struct pci_dev *pdev = dev;
 
 	/*
-	 * TBD: traverse LDM device tree with the help of
-	 *  unified ACPI augmented for php device population.
+	 * _HPP settings apply to all child buses, until another _HPP is
+	 * encountered. If we don't find an _HPP for the input pci dev,
+	 * look for it in the parent device scope since that would apply to
+	 * this pci dev. If we don't find any _HPP, use hardcoded defaults
 	 */
-	status = acpi_get_devices ( PCI_ROOT_HID_STRING,
-				acpi_scan_from_root_pci_callback,
-				NULL,
-				NULL );
-	if (ACPI_FAILURE(status)) {
-		err("acpi_pciehprm:get_device PCI ROOT HID fail=0x%x\n", status);
-		return -1;
-	}
-
-	return 0;
-}
-
-int pciehprm_init(enum php_ctlr_type ctlr_type)
-{
-	int	rc;
-
-	if (ctlr_type != PCI)
-		return -ENODEV;
-
-	dbg("pciehprm ACPI init <enter>\n");
-	acpi_bridges_head = NULL;
-
-	/* construct PCI bus:device tree of acpi_handles */
-	rc = pciehprm_acpi_scan_pci();
-	if (rc)
-		return rc;
-
-	if ((oshp_run_status != NC_RUN_SUCCESS) && (osc_run_status != NC_RUN_SUCCESS)) {
-		err("Fails to gain control of native hot-plug\n");
-		rc = -ENODEV;
-	}
-
-	dbg("pciehprm ACPI init %s\n", (rc)?"fail":"success");
-	return rc;
-}
-
-static void free_a_slot(struct acpi_php_slot *aps)
-{
-	dbg("        free a php func of slot(0x%02x) on PCI b:d:f=0x%02x:%02x:%02x\n", aps->sun, aps->bus, aps->dev, aps->fun);
-
-	kfree(aps);
-}
-
-static void free_a_bridge( struct acpi_bridge	*ab)
-{
-	struct acpi_php_slot	*aps, *next;
-
-	switch (ab->type) {
-	case BRIDGE_TYPE_HOST:
-		dbg("Free ACPI PCI HOST Bridge(%x) [%s] on s:b:d:f(%x:%x:%x:%x)\n",
-			ab->bus, acpi_path_name(ab->handle), ab->seg, ab->pbus, ab->pdevice, ab->pfunction);
-		break;
-	case BRIDGE_TYPE_P2P:
-		dbg("Free ACPI PCI P2P Bridge(%x-%x) [%s] on s:b:d:f(%x:%x:%x:%x)\n",
-			ab->pbus, ab->bus, acpi_path_name(ab->handle), ab->seg, ab->pbus, ab->pdevice, ab->pfunction);
-		break;
-	};
-
-	/* free slots first */
-	for (aps = ab->slots; aps; aps = next) {
-		next = aps->next;
-		free_a_slot(aps);
-	}
-
-	kfree(ab);
-}
-
-static void pciehprm_free_bridges ( struct acpi_bridge	*ab)
-{
-	if (!ab)
-		return;
-
-	if (ab->child)
-		pciehprm_free_bridges (ab->child);
-
-	if (ab->next)
-		pciehprm_free_bridges (ab->next);
-
-	free_a_bridge(ab);
-}
-
-void pciehprm_cleanup(void)
-{
-	pciehprm_free_bridges (acpi_bridges_head);
-}
-
-static int get_number_of_slots (
-	struct acpi_bridge	*ab,
-	int				selfonly
-	)
-{
-	struct acpi_php_slot	*aps;
-	int	prev_slot = -1;
-	int	slot_num = 0;
-
-	for ( aps = ab->slots; aps; aps = aps->next)
-		if (aps->dev != prev_slot) {
-			prev_slot = aps->dev;
-			slot_num++;
-		}
-
-	if (ab->child)
-		slot_num += get_number_of_slots (ab->child, 0);
-
-	if (selfonly)
-		return slot_num;
-
-	if (ab->next)
-		slot_num += get_number_of_slots (ab->next, 0);
-
-	return slot_num;
-}
-
-static struct acpi_php_slot * get_acpi_slot (
-	struct acpi_bridge *ab,
-	u32 sun
-	)
-{
-	struct acpi_php_slot	*aps = NULL;
-
-	for ( aps = ab->slots; aps; aps = aps->next)
-		if (aps->sun == sun)
-			return aps;
-
-	if (!aps && ab->child) {
-		aps = (struct acpi_php_slot *)get_acpi_slot (ab->child, sun);
-		if (aps)
-			return aps;
-	}
-
-	if (!aps && ab->next) {
-		aps = (struct acpi_php_slot *)get_acpi_slot (ab->next, sun);
-		if (aps)
-			return aps;
-	}
-
-	return aps;
-
-}
-
-#if 0
-void * pciehprm_get_slot(struct slot *slot)
-{
-	struct acpi_bridge	*ab = acpi_bridges_head;
-	struct acpi_php_slot	*aps = get_acpi_slot (ab, slot->number);
-
-	aps->slot = slot;
-
-	dbg("Got acpi slot sun(%x): s:b:d:f(%x:%x:%x:%x)\n", aps->sun, aps->seg, aps->bus, aps->dev, aps->fun);
-
-	return (void *)aps;
-}
-#endif
-
-int pciehprm_set_hpp(
-	struct controller *ctrl,
-	struct pci_func *func,
-	u8	card_type
-	)
-{
-	struct acpi_bridge	*ab;
-	struct pci_bus lpci_bus, *pci_bus;
-	int				rc = 0;
-	unsigned int	devfn;
-	u8				cls= 0x08;	/* default cache line size	*/
-	u8				lt = 0x40;	/* default latency timer	*/
-	u8				ep = 0;
-	u8				es = 0;
-
-	memcpy(&lpci_bus, ctrl->pci_bus, sizeof(lpci_bus));
-	pci_bus = &lpci_bus;
-	pci_bus->number = func->bus;
-	devfn = PCI_DEVFN(func->device, func->function);
-
-	ab = find_acpi_bridge_by_bus(acpi_bridges_head, ctrl->seg, ctrl->bus);
-
-	if (ab) {
-		if (ab->_hpp) {
-			lt  = (u8)ab->_hpp->latency_timer;
-			cls = (u8)ab->_hpp->cache_line_size;
-			ep  = (u8)ab->_hpp->enable_perr;
-			es  = (u8)ab->_hpp->enable_serr;
-		} else
-			dbg("_hpp: no _hpp for B/D/F=%#x/%#x/%#x. use default value\n", func->bus, func->device, func->function);
-	} else
-		dbg("_hpp: no acpi bridge for B/D/F = %#x/%#x/%#x. use default value\n", func->bus, func->device, func->function);
-
-
-	if (card_type == PCI_HEADER_TYPE_BRIDGE) {
-		/* set subordinate Latency Timer */
-		rc |= pci_bus_write_config_byte(pci_bus, devfn, PCI_SEC_LATENCY_TIMER, lt);
+	while (pdev && (ACPI_FAILURE(status))) {
+		acpi_handle handle = DEVICE_ACPI_HANDLE(&(pdev->dev));
+		if (!handle)
+			break;
+		status = acpi_run_hpp(handle, hpp);
+		if (!(pdev->bus->parent))
+			break;
+		/* Check if a parent object supports _HPP */
+		pdev = pdev->bus->parent->self;
 	}
-
-	/* set base Latency Timer */
-	rc |= pci_bus_write_config_byte(pci_bus, devfn, PCI_LATENCY_TIMER, lt);
-	dbg("  set latency timer  =0x%02x: %x\n", lt, rc);
-
-	rc |= pci_bus_write_config_byte(pci_bus, devfn, PCI_CACHE_LINE_SIZE, cls);
-	dbg("  set cache_line_size=0x%02x: %x\n", cls, rc);
-
-	return rc;
 }
 
-void pciehprm_enable_card(
-	struct controller *ctrl,
-	struct pci_func *func,
-	u8 card_type)
-{
-	u16 command, cmd, bcommand, bcmd;
-	struct pci_bus lpci_bus, *pci_bus;
-	struct acpi_bridge	*ab;
-	unsigned int devfn;
-	int rc;
-
-	memcpy(&lpci_bus, ctrl->pci_bus, sizeof(lpci_bus));
-	pci_bus = &lpci_bus;
-	pci_bus->number = func->bus;
-	devfn = PCI_DEVFN(func->device, func->function);
-
-	rc = pci_bus_read_config_word(pci_bus, devfn, PCI_COMMAND, &cmd);
-
-	if (card_type == PCI_HEADER_TYPE_BRIDGE) {
-		rc = pci_bus_read_config_word(pci_bus, devfn, PCI_BRIDGE_CONTROL, &bcmd);
-	}
-
-	command  = cmd | PCI_COMMAND_MASTER | PCI_COMMAND_INVALIDATE
-		| PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
-	bcommand  = bcmd | PCI_BRIDGE_CTL_NO_ISA;
-
-	ab = find_acpi_bridge_by_bus(acpi_bridges_head, ctrl->seg, ctrl->bus);
-	if (ab) {
-		if (ab->_hpp) {
-			if (ab->_hpp->enable_perr) {
-				command |= PCI_COMMAND_PARITY;
-				bcommand |= PCI_BRIDGE_CTL_PARITY;
-			} else {
-				command &= ~PCI_COMMAND_PARITY;
-				bcommand &= ~PCI_BRIDGE_CTL_PARITY;
-			}
-			if (ab->_hpp->enable_serr) {
-				command |= PCI_COMMAND_SERR;
-				bcommand |= PCI_BRIDGE_CTL_SERR;
-			} else {
-				command &= ~PCI_COMMAND_SERR;
-				bcommand &= ~PCI_BRIDGE_CTL_SERR;
-			}
-		} else
-			dbg("no _hpp for B/D/F = %#x/%#x/%#x.\n", func->bus, func->device, func->function);
-	} else
-		dbg("no acpi bridge for B/D/F = %#x/%#x/%#x.\n", func->bus, func->device, func->function);
-
-	if (command != cmd) {
-		rc = pci_bus_write_config_word(pci_bus, devfn, PCI_COMMAND, command);
-	}
-	if ((card_type == PCI_HEADER_TYPE_BRIDGE) && (bcommand != bcmd)) {
-		rc = pci_bus_write_config_word(pci_bus, devfn, PCI_BRIDGE_CONTROL, bcommand);
-	}
-}