s390/pci: Use topology ID for multi-function devices

The newly introduced topology ID (TID) field in the CLP Query PCI
Function explicitly identifies groups of PCI functions whose RIDs belong
to the same (sub-)topology. When available use the TID instead of the
PCHID to match zPCI busses/domains for multi-function devices. Note that
currently only a single PCI bus per TID is supported. This change is
required because in future machines the PCHID will not identify a PCI
card but a specific port in the case of some multi-port NICs while from
a PCI point of view the entire card is a subtopology.

Reviewed-by: Gerd Bayer <[email protected]>
Signed-off-by: Niklas Schnelle <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>

Author: niklas88

arch/s390/include/asm/pci.h

@@ -107,9 +107,10 @@ struct zpci_bus {
 	struct list_head	resources;
 	struct list_head	bus_next;
 	struct resource		bus_resource;
-	int			pchid;
+	int			topo;		/* TID if topo_is_tid, PCHID otherwise */
 	int			domain_nr;
-	bool			multifunction;
+	u8			multifunction	: 1;
+	u8			topo_is_tid	: 1;
 	enum pci_bus_speed	max_bus_speed;
 };
 
@@ -131,6 +132,7 @@ struct zpci_dev {
 	u16		pchid;		/* physical channel ID */
 	u16		maxstbl;	/* Maximum store block size */
 	u16		rid;		/* RID as supplied by firmware */
+	u16		tid;		/* Topology for which RID is valid */
 	u8		pfgid;		/* function group ID */
 	u8		pft;		/* pci function type */
 	u8		port;
@@ -141,7 +143,8 @@ struct zpci_dev {
 	u8		is_physfn	: 1;
 	u8		util_str_avail	: 1;
 	u8		irqs_registered	: 1;
-	u8		reserved	: 2;
+	u8		tid_avail	: 1;
+	u8		reserved	: 1;
 	unsigned int	devfn;		/* DEVFN part of the RID*/
 
 	u8 pfip[CLP_PFIP_NR_SEGMENTS];	/* pci function internal path */

arch/s390/include/asm/pci_clp.h

@@ -110,7 +110,8 @@ struct clp_req_query_pci {
 struct clp_rsp_query_pci {
 	struct clp_rsp_hdr hdr;
 	u16 vfn;			/* virtual fn number */
-	u16			:  3;
+	u16			:  2;
+	u16 tid_avail		:  1;
 	u16 rid_avail		:  1;
 	u16 is_physfn		:  1;
 	u16 reserved1		:  1;
@@ -130,8 +131,9 @@ struct clp_rsp_query_pci {
 	u64 edma;			/* end dma as */
 #define ZPCI_RID_MASK_DEVFN 0x00ff
 	u16 rid;			/* BUS/DEVFN PCI address */
-	u16 reserved0;
-	u32 reserved[10];
+	u32 reserved0;
+	u16 tid;
+	u32 reserved[9];
 	u32 uid;			/* user defined id */
 	u8 util_str[CLP_UTIL_STR_LEN];	/* utility string */
 	u32 reserved2[16];

arch/s390/pci/pci_bus.c

@@ -232,13 +232,13 @@ static void zpci_bus_put(struct zpci_bus *zbus)
 	kref_put(&zbus->kref, zpci_bus_release);
 }
 
-static struct zpci_bus *zpci_bus_get(int pchid)
+static struct zpci_bus *zpci_bus_get(int topo, bool topo_is_tid)
 {
 	struct zpci_bus *zbus;
 
 	mutex_lock(&zbus_list_lock);
 	list_for_each_entry(zbus, &zbus_list, bus_next) {
-		if (pchid == zbus->pchid) {
+		if (topo_is_tid == zbus->topo_is_tid && topo == zbus->topo) {
 			kref_get(&zbus->kref);
 			goto out_unlock;
 		}
@@ -249,15 +249,16 @@ static struct zpci_bus *zpci_bus_get(int pchid)
 	return zbus;
 }
 
-static struct zpci_bus *zpci_bus_alloc(int pchid)
+static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
 {
 	struct zpci_bus *zbus;
 
 	zbus = kzalloc(sizeof(*zbus), GFP_KERNEL);
 	if (!zbus)
 		return NULL;
 
-	zbus->pchid = pchid;
+	zbus->topo = topo;
+	zbus->topo_is_tid = topo_is_tid;
 	INIT_LIST_HEAD(&zbus->bus_next);
 	mutex_lock(&zbus_list_lock);
 	list_add_tail(&zbus->bus_next, &zbus_list);
@@ -321,8 +322,9 @@ static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
 
 int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
 {
+	bool topo_is_tid = zdev->tid_avail;
 	struct zpci_bus *zbus = NULL;
-	int rc = -EBADF;
+	int topo, rc = -EBADF;
 
 	if (zpci_nb_devices == ZPCI_NR_DEVICES) {
 		pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
@@ -333,11 +335,12 @@ int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
 	if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
 		return -EINVAL;
 
+	topo = topo_is_tid ? zdev->tid : zdev->pchid;
 	if (!s390_pci_no_rid && zdev->rid_available)
-		zbus = zpci_bus_get(zdev->pchid);
+		zbus = zpci_bus_get(topo, topo_is_tid);
 
 	if (!zbus) {
-		zbus = zpci_bus_alloc(zdev->pchid);
+		zbus = zpci_bus_alloc(topo, topo_is_tid);
 		if (!zbus)
 			return -ENOMEM;
 	}

arch/s390/pci/pci_clp.c

@@ -170,6 +170,9 @@ static int clp_store_query_pci_fn(struct zpci_dev *zdev,
 		zdev->rid = response->rid;
 	if (!s390_pci_no_rid && zdev->rid_available)
 		zdev->devfn = response->rid & ZPCI_RID_MASK_DEVFN;
+	zdev->tid_avail = response->tid_avail;
+	if (zdev->tid_avail)
+		zdev->tid = response->tid;
 
 	memcpy(zdev->pfip, response->pfip, sizeof(zdev->pfip));
 	if (response->util_str_avail) {