PCI: dw-rockchip: Use rockchip_pcie_link_up() to check link up instead of open coding

Some of the callers of rockchip_pcie_link_up() are open coding the
rockchip_pcie_link_up() function, leading to code duplication. So switch
them to use rockchip_pcie_link_up() function.

Also, use the FIELD_GET() macro to simplify the link up check in
rockchip_pcie_link_up().

Signed-off-by: Hans Zhang <18255117159@163.com>
[mani: subject and description rewording]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://patch.msgid.link/20250427125316.99627-4-18255117159@163.com

Author: Hans Zhang

drivers/pci/controller/dwc/pcie-dw-rockchip.c

@@ -8,6 +8,7 @@
  * Author: Simon Xue <xxm@rock-chips.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/gpio/consumer.h>
 #include <linux/irqchip/chained_irq.h>
@@ -60,9 +61,8 @@
 
 /* LTSSM Status Register */
 #define PCIE_CLIENT_LTSSM_STATUS	0x300
-#define  PCIE_SMLH_LINKUP		BIT(16)
-#define  PCIE_RDLH_LINKUP		BIT(17)
-#define  PCIE_LINKUP			(PCIE_SMLH_LINKUP | PCIE_RDLH_LINKUP)
+#define  PCIE_LINKUP			0x3
+#define  PCIE_LINKUP_MASK		GENMASK(17, 16)
 #define  PCIE_LTSSM_STATUS_MASK		GENMASK(5, 0)
 
 struct rockchip_pcie {
@@ -188,10 +188,7 @@ static int rockchip_pcie_link_up(struct dw_pcie *pci)
 	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
 	u32 val = rockchip_pcie_get_ltssm(rockchip);
 
-	if ((val & PCIE_LINKUP) == PCIE_LINKUP)
-		return 1;
-
-	return 0;
+	return FIELD_GET(PCIE_LINKUP_MASK, val) == PCIE_LINKUP;
 }
 
 static void rockchip_pcie_enable_l0s(struct dw_pcie *pci)
@@ -450,7 +447,7 @@ static irqreturn_t rockchip_pcie_rc_sys_irq_thread(int irq, void *arg)
 	struct dw_pcie *pci = &rockchip->pci;
 	struct dw_pcie_rp *pp = &pci->pp;
 	struct device *dev = pci->dev;
-	u32 reg, val;
+	u32 reg;
 
 	reg = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_INTR_STATUS_MISC);
 	rockchip_pcie_writel_apb(rockchip, reg, PCIE_CLIENT_INTR_STATUS_MISC);
@@ -459,8 +456,7 @@ static irqreturn_t rockchip_pcie_rc_sys_irq_thread(int irq, void *arg)
 	dev_dbg(dev, "LTSSM_STATUS: %#x\n", rockchip_pcie_get_ltssm(rockchip));
 
 	if (reg & PCIE_RDLH_LINK_UP_CHGED) {
-		val = rockchip_pcie_get_ltssm(rockchip);
-		if ((val & PCIE_LINKUP) == PCIE_LINKUP) {
+		if (rockchip_pcie_link_up(pci)) {
 			dev_dbg(dev, "Received Link up event. Starting enumeration!\n");
 			/* Rescan the bus to enumerate endpoint devices */
 			pci_lock_rescan_remove();
@@ -477,7 +473,7 @@ static irqreturn_t rockchip_pcie_ep_sys_irq_thread(int irq, void *arg)
 	struct rockchip_pcie *rockchip = arg;
 	struct dw_pcie *pci = &rockchip->pci;
 	struct device *dev = pci->dev;
-	u32 reg, val;
+	u32 reg;
 
 	reg = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_INTR_STATUS_MISC);
 	rockchip_pcie_writel_apb(rockchip, reg, PCIE_CLIENT_INTR_STATUS_MISC);
@@ -491,8 +487,7 @@ static irqreturn_t rockchip_pcie_ep_sys_irq_thread(int irq, void *arg)
 	}
 
 	if (reg & PCIE_RDLH_LINK_UP_CHGED) {
-		val = rockchip_pcie_get_ltssm(rockchip);
-		if ((val & PCIE_LINKUP) == PCIE_LINKUP) {
+		if (rockchip_pcie_link_up(pci)) {
 			dev_dbg(dev, "link up\n");
 			dw_pcie_ep_linkup(&pci->ep);
 		}