Merge branch 'pci/endpoint/epf-vntb'

- Return -ENOENT (not -1) if pci_epc_get_next_free_bar() fails (Jerome
  Brunet)

- Align MW (memory window) naming with config names (Jerome Brunet)

- Allow BAR assignment via configfs so platforms have flexibility in
  determining BAR usage (Jerome Brunet)

- Drop incorrect '__iomem' annotation on the return value of
  pci_epf_alloc_space(); this also fixes an sparse warning (Manivannan
  Sadhasivam)

* pci/endpoint/epf-vntb:
  PCI: endpoint: pci-epf-vntb: Fix the incorrect usage of __iomem attribute
  PCI: endpoint: pci-epf-vntb: Allow BAR assignment via configfs
  PCI: endpoint: pci-epf-vntb: Align MW naming with config names
  PCI: endpoint: pci-epf-vntb: Return -ENOENT if pci_epc_get_next_free_bar() fails

Author: bjorn-helgaas

drivers/pci/endpoint/functions/pci-epf-vntb.c

@@ -70,9 +70,11 @@ static struct workqueue_struct *kpcintb_workqueue;
 enum epf_ntb_bar {
 	BAR_CONFIG,
 	BAR_DB,
-	BAR_MW0,
 	BAR_MW1,
 	BAR_MW2,
+	BAR_MW3,
+	BAR_MW4,
+	VNTB_BAR_NUM,
 };
 
 /*
@@ -132,7 +134,7 @@ struct epf_ntb {
 	bool linkup;
 	u32 spad_size;
 
-	enum pci_barno epf_ntb_bar[6];
+	enum pci_barno epf_ntb_bar[VNTB_BAR_NUM];
 
 	struct epf_ntb_ctrl *reg;
 
@@ -510,7 +512,7 @@ static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
 	struct device *dev = &ntb->epf->dev;
 	int ret;
 	struct pci_epf_bar *epf_bar;
-	void __iomem *mw_addr;
+	void *mw_addr;
 	enum pci_barno barno;
 	size_t size = sizeof(u32) * ntb->db_count;
 
@@ -576,7 +578,7 @@ static int epf_ntb_mw_bar_init(struct epf_ntb *ntb)
 
 	for (i = 0; i < ntb->num_mws; i++) {
 		size = ntb->mws_size[i];
-		barno = ntb->epf_ntb_bar[BAR_MW0 + i];
+		barno = ntb->epf_ntb_bar[BAR_MW1 + i];
 
 		ntb->epf->bar[barno].barno = barno;
 		ntb->epf->bar[barno].size = size;
@@ -629,7 +631,7 @@ static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb, int num_mws)
 	int i;
 
 	for (i = 0; i < num_mws; i++) {
-		barno = ntb->epf_ntb_bar[BAR_MW0 + i];
+		barno = ntb->epf_ntb_bar[BAR_MW1 + i];
 		pci_epc_clear_bar(ntb->epf->epc,
 				  ntb->epf->func_no,
 				  ntb->epf->vfunc_no,
@@ -654,6 +656,63 @@ static void epf_ntb_epc_destroy(struct epf_ntb *ntb)
 	pci_epc_put(ntb->epf->epc);
 }
 
+
+/**
+ * epf_ntb_is_bar_used() - Check if a bar is used in the ntb configuration
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @barno: Checked bar number
+ *
+ * Returns: true if used, false if free.
+ */
+static bool epf_ntb_is_bar_used(struct epf_ntb *ntb,
+				enum pci_barno barno)
+{
+	int i;
+
+	for (i = 0; i < VNTB_BAR_NUM; i++) {
+		if (ntb->epf_ntb_bar[i] == barno)
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * epf_ntb_find_bar() - Assign BAR number when no configuration is provided
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @epc_features: The features provided by the EPC specific to this EPF
+ * @bar: NTB BAR index
+ * @barno: Bar start index
+ *
+ * When the BAR configuration was not provided through the userspace
+ * configuration, automatically assign BAR as it has been historically
+ * done by this endpoint function.
+ *
+ * Returns: the BAR number found, if any. -1 otherwise
+ */
+static int epf_ntb_find_bar(struct epf_ntb *ntb,
+			    const struct pci_epc_features *epc_features,
+			    enum epf_ntb_bar bar,
+			    enum pci_barno barno)
+{
+	while (ntb->epf_ntb_bar[bar] < 0) {
+		barno = pci_epc_get_next_free_bar(epc_features, barno);
+		if (barno < 0)
+			break; /* No more BAR available */
+
+		/*
+		 * Verify if the BAR found is not already assigned
+		 * through the provided configuration
+		 */
+		if (!epf_ntb_is_bar_used(ntb, barno))
+			ntb->epf_ntb_bar[bar] = barno;
+
+		barno += 1;
+	}
+
+	return barno;
+}
+
 /**
  * epf_ntb_init_epc_bar() - Identify BARs to be used for each of the NTB
  * constructs (scratchpad region, doorbell, memorywindow)
@@ -676,23 +735,21 @@ static int epf_ntb_init_epc_bar(struct epf_ntb *ntb)
 	epc_features = pci_epc_get_features(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no);
 
 	/* These are required BARs which are mandatory for NTB functionality */
-	for (bar = BAR_CONFIG; bar <= BAR_MW0; bar++, barno++) {
-		barno = pci_epc_get_next_free_bar(epc_features, barno);
+	for (bar = BAR_CONFIG; bar <= BAR_MW1; bar++) {
+		barno = epf_ntb_find_bar(ntb, epc_features, bar, barno);
 		if (barno < 0) {
 			dev_err(dev, "Fail to get NTB function BAR\n");
-			return barno;
+			return -ENOENT;
 		}
-		ntb->epf_ntb_bar[bar] = barno;
 	}
 
 	/* These are optional BARs which don't impact NTB functionality */
-	for (bar = BAR_MW1, i = 1; i < num_mws; bar++, barno++, i++) {
-		barno = pci_epc_get_next_free_bar(epc_features, barno);
+	for (bar = BAR_MW1, i = 1; i < num_mws; bar++, i++) {
+		barno = epf_ntb_find_bar(ntb, epc_features, bar, barno);
 		if (barno < 0) {
 			ntb->num_mws = i;
 			dev_dbg(dev, "BAR not available for > MW%d\n", i + 1);
 		}
-		ntb->epf_ntb_bar[bar] = barno;
 	}
 
 	return 0;
@@ -860,6 +917,37 @@ static ssize_t epf_ntb_##_name##_store(struct config_item *item,	\
 	return len;							\
 }
 
+#define EPF_NTB_BAR_R(_name, _id)					\
+	static ssize_t epf_ntb_##_name##_show(struct config_item *item,	\
+					      char *page)		\
+	{								\
+		struct config_group *group = to_config_group(item);	\
+		struct epf_ntb *ntb = to_epf_ntb(group);		\
+									\
+		return sprintf(page, "%d\n", ntb->epf_ntb_bar[_id]);	\
+	}
+
+#define EPF_NTB_BAR_W(_name, _id)					\
+	static ssize_t epf_ntb_##_name##_store(struct config_item *item, \
+					       const char *page, size_t len) \
+	{								\
+		struct config_group *group = to_config_group(item);	\
+		struct epf_ntb *ntb = to_epf_ntb(group);		\
+		int val;						\
+		int ret;						\
+									\
+		ret = kstrtoint(page, 0, &val);				\
+		if (ret)						\
+			return ret;					\
+									\
+		if (val < NO_BAR || val > BAR_5)			\
+			return -EINVAL;					\
+									\
+		ntb->epf_ntb_bar[_id] = val;				\
+									\
+		return len;						\
+	}
+
 static ssize_t epf_ntb_num_mws_store(struct config_item *item,
 				     const char *page, size_t len)
 {
@@ -899,6 +987,18 @@ EPF_NTB_MW_R(mw3)
 EPF_NTB_MW_W(mw3)
 EPF_NTB_MW_R(mw4)
 EPF_NTB_MW_W(mw4)
+EPF_NTB_BAR_R(ctrl_bar, BAR_CONFIG)
+EPF_NTB_BAR_W(ctrl_bar, BAR_CONFIG)
+EPF_NTB_BAR_R(db_bar, BAR_DB)
+EPF_NTB_BAR_W(db_bar, BAR_DB)
+EPF_NTB_BAR_R(mw1_bar, BAR_MW1)
+EPF_NTB_BAR_W(mw1_bar, BAR_MW1)
+EPF_NTB_BAR_R(mw2_bar, BAR_MW2)
+EPF_NTB_BAR_W(mw2_bar, BAR_MW2)
+EPF_NTB_BAR_R(mw3_bar, BAR_MW3)
+EPF_NTB_BAR_W(mw3_bar, BAR_MW3)
+EPF_NTB_BAR_R(mw4_bar, BAR_MW4)
+EPF_NTB_BAR_W(mw4_bar, BAR_MW4)
 
 CONFIGFS_ATTR(epf_ntb_, spad_count);
 CONFIGFS_ATTR(epf_ntb_, db_count);
@@ -910,6 +1010,12 @@ CONFIGFS_ATTR(epf_ntb_, mw4);
 CONFIGFS_ATTR(epf_ntb_, vbus_number);
 CONFIGFS_ATTR(epf_ntb_, vntb_pid);
 CONFIGFS_ATTR(epf_ntb_, vntb_vid);
+CONFIGFS_ATTR(epf_ntb_, ctrl_bar);
+CONFIGFS_ATTR(epf_ntb_, db_bar);
+CONFIGFS_ATTR(epf_ntb_, mw1_bar);
+CONFIGFS_ATTR(epf_ntb_, mw2_bar);
+CONFIGFS_ATTR(epf_ntb_, mw3_bar);
+CONFIGFS_ATTR(epf_ntb_, mw4_bar);
 
 static struct configfs_attribute *epf_ntb_attrs[] = {
 	&epf_ntb_attr_spad_count,
@@ -922,6 +1028,12 @@ static struct configfs_attribute *epf_ntb_attrs[] = {
 	&epf_ntb_attr_vbus_number,
 	&epf_ntb_attr_vntb_pid,
 	&epf_ntb_attr_vntb_vid,
+	&epf_ntb_attr_ctrl_bar,
+	&epf_ntb_attr_db_bar,
+	&epf_ntb_attr_mw1_bar,
+	&epf_ntb_attr_mw2_bar,
+	&epf_ntb_attr_mw3_bar,
+	&epf_ntb_attr_mw4_bar,
 	NULL,
 };
 
@@ -1048,7 +1160,7 @@ static int vntb_epf_mw_set_trans(struct ntb_dev *ndev, int pidx, int idx,
 	struct device *dev;
 
 	dev = &ntb->ntb.dev;
-	barno = ntb->epf_ntb_bar[BAR_MW0 + idx];
+	barno = ntb->epf_ntb_bar[BAR_MW1 + idx];
 	epf_bar = &ntb->epf->bar[barno];
 	epf_bar->phys_addr = addr;
 	epf_bar->barno = barno;
@@ -1379,6 +1491,7 @@ static int epf_ntb_probe(struct pci_epf *epf,
 {
 	struct epf_ntb *ntb;
 	struct device *dev;
+	int i;
 
 	dev = &epf->dev;
 
@@ -1389,6 +1502,11 @@ static int epf_ntb_probe(struct pci_epf *epf,
 	epf->header = &epf_ntb_header;
 	ntb->epf = epf;
 	ntb->vbus_number = 0xff;
+
+	/* Initially, no bar is assigned */
+	for (i = 0; i < VNTB_BAR_NUM; i++)
+		ntb->epf_ntb_bar[i] = NO_BAR;
+
 	epf_set_drvdata(epf, ntb);
 
 	dev_info(dev, "pci-ep epf driver loaded\n");