[PATCH 1/4] PCI: dwc: Change to use an array to store the structure of functions

[Zhiqiang Hou]

From: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>

As there isn't dynamically adding and deleting a function's structure,
the list_head is not necessary for this case. Array is easier and
more efficient to search.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
---
 .../pci/controller/dwc/pcie-designware-ep.c   | 33 ++++++++-----------
 drivers/pci/controller/dwc/pcie-designware.h  |  3 +-
 2 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index bcd1cd9ba8c8..e583700b5ba3 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -34,12 +34,8 @@ EXPORT_SYMBOL_GPL(dw_pcie_ep_init_notify);
 struct dw_pcie_ep_func *
 dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no)
 {
-	struct dw_pcie_ep_func *ep_func;
-
-	list_for_each_entry(ep_func, &ep->func_list, list) {
-		if (ep_func->func_no == func_no)
-			return ep_func;
-	}
+	if (func_no < ep->epc->max_functions)
+		return ep->funcs + func_no;
 
 	return NULL;
 }
@@ -675,9 +671,9 @@ EXPORT_SYMBOL_GPL(dw_pcie_ep_init_complete);
 
 int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 {
+	u8 i;
 	int ret;
 	void *addr;
-	u8 func_no;
 	struct resource *res;
 	struct pci_epc *epc;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
@@ -685,9 +681,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct device_node *np = dev->of_node;
 	const struct pci_epc_features *epc_features;
-	struct dw_pcie_ep_func *ep_func;
-
-	INIT_LIST_HEAD(&ep->func_list);
+	struct dw_pcie_ep_func *funcs;
 
 	if (!pci->dbi_base) {
 		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
@@ -750,18 +744,19 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	if (ret < 0)
 		epc->max_functions = 1;
 
-	for (func_no = 0; func_no < epc->max_functions; func_no++) {
-		ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
-		if (!ep_func)
-			return -ENOMEM;
+	funcs = devm_kcalloc(dev, epc->max_functions, sizeof(*funcs),
+			     GFP_KERNEL);
+	if (!funcs)
+		return -ENOMEM;
+
+	ep->funcs = funcs;
 
-		ep_func->func_no = func_no;
-		ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
+	for (i = 0; i < epc->max_functions; i++) {
+		funcs[i].func_no = i;
+		funcs[i].msi_cap = dw_pcie_ep_find_capability(ep, i,
 							      PCI_CAP_ID_MSI);
-		ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
+		funcs[i].msix_cap = dw_pcie_ep_find_capability(ep, i,
 							       PCI_CAP_ID_MSIX);
-
-		list_add_tail(&ep_func->list, &ep->func_list);
 	}
 
 	if (ep->ops->ep_init)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 98710bf5ab0e..16d239c4d09b 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -221,7 +221,6 @@ struct dw_pcie_ep_ops {
 };
 
 struct dw_pcie_ep_func {
-	struct list_head	list;
 	u8			func_no;
 	u8			msi_cap;	/* MSI capability offset */
 	u8			msix_cap;	/* MSI-X capability offset */
@@ -229,7 +228,7 @@ struct dw_pcie_ep_func {
 
 struct dw_pcie_ep {
 	struct pci_epc		*epc;
-	struct list_head	func_list;
+	struct dw_pcie_ep_func	*funcs;
 	const struct dw_pcie_ep_ops *ops;
 	phys_addr_t		phys_base;
 	size_t			addr_size;
-- 
2.17.1