PCI: brcmstb: Split post-link up initialization to brcm_pcie_start_link()

Previously brcm_pcie_setup() initialized the Root Port itself as well as
doing the actual link-up.  Split brcm_pcie_setup() into two functions:

  - brcm_pcie_setup(), which initializes everything that does not require
    the link itself to be up, and

  - brcm_pcie_start_link(), which brings up the link and initializes things
    that depend on the link being up.

[bhelgaas: condense commit log, deferring details for future changes]
Link: https://lore.kernel.org/r/20220725151258.42574-3-jim2101024@gmail.comSigned-off-by: Jim Quinlan <jim2101024@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/pci/controller/pcie-brcmstb.c

@@ -857,17 +857,13 @@ static inline int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
 
 static int brcm_pcie_setup(struct brcm_pcie *pcie)
 {
-	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 	u64 rc_bar2_offset, rc_bar2_size;
 	void __iomem *base = pcie->base;
-	struct device *dev = pcie->dev;
+	struct pci_host_bridge *bridge;
 	struct resource_entry *entry;
-	bool ssc_good = false;
-	struct resource *res;
-	int num_out_wins = 0;
-	u16 nlw, cls, lnksta;
-	int i, ret, memc;
 	u32 tmp, burst, aspm_support;
+	int num_out_wins = 0;
+	int ret, memc;
 
 	/* Reset the bridge */
 	pcie->bridge_sw_init_set(pcie, 1);
@@ -943,6 +939,11 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	else
 		pcie->msi_target_addr = BRCM_MSI_TARGET_ADDR_GT_4GB;
 
+	if (!brcm_pcie_rc_mode(pcie)) {
+		dev_err(pcie->dev, "PCIe RC controller misconfigured as Endpoint\n");
+		return -EINVAL;
+	}
+
 	/* disable the PCIe->GISB memory window (RC_BAR1) */
 	tmp = readl(base + PCIE_MISC_RC_BAR1_CONFIG_LO);
 	tmp &= ~PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK;
@@ -953,31 +954,27 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	tmp &= ~PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK;
 	writel(tmp, base + PCIE_MISC_RC_BAR3_CONFIG_LO);
 
-	if (pcie->gen)
-		brcm_pcie_set_gen(pcie, pcie->gen);
-
-	/* Unassert the fundamental reset */
-	pcie->perst_set(pcie, 0);
+	/* Don't advertise L0s capability if 'aspm-no-l0s' */
+	aspm_support = PCIE_LINK_STATE_L1;
+	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
+		aspm_support |= PCIE_LINK_STATE_L0S;
+	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
+	u32p_replace_bits(&tmp, aspm_support,
+		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
+	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
 	/*
-	 * Give the RC/EP time to wake up, before trying to configure RC.
-	 * Intermittently check status for link-up, up to a total of 100ms.
+	 * For config space accesses on the RC, show the right class for
+	 * a PCIe-PCIe bridge (the default setting is to be EP mode).
 	 */
-	for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)
-		msleep(5);
-
-	if (!brcm_pcie_link_up(pcie)) {
-		dev_err(dev, "link down\n");
-		return -ENODEV;
-	}
-
-	if (!brcm_pcie_rc_mode(pcie)) {
-		dev_err(dev, "PCIe misconfigured; is in EP mode\n");
-		return -EINVAL;
-	}
+	tmp = readl(base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+	u32p_replace_bits(&tmp, 0x060400,
+			  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK);
+	writel(tmp, base + PCIE_RC_CFG_PRIV1_ID_VAL3);
 
+	bridge = pci_host_bridge_from_priv(pcie);
 	resource_list_for_each_entry(entry, &bridge->windows) {
-		res = entry->res;
+		struct resource *res = entry->res;
 
 		if (resource_type(res) != IORESOURCE_MEM)
 			continue;
@@ -1006,23 +1003,41 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 		num_out_wins++;
 	}
 
-	/* Don't advertise L0s capability if 'aspm-no-l0s' */
-	aspm_support = PCIE_LINK_STATE_L1;
-	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
-		aspm_support |= PCIE_LINK_STATE_L0S;
-	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
-	u32p_replace_bits(&tmp, aspm_support,
-		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
-	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
+	/* PCIe->SCB endian mode for BAR */
+	tmp = readl(base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
+	u32p_replace_bits(&tmp, PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN,
+		PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK);
+	writel(tmp, base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
+
+	return 0;
+}
+
+static int brcm_pcie_start_link(struct brcm_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	void __iomem *base = pcie->base;
+	u16 nlw, cls, lnksta;
+	bool ssc_good = false;
+	u32 tmp;
+	int ret, i;
+
+	/* Unassert the fundamental reset */
+	pcie->perst_set(pcie, 0);
 
 	/*
-	 * For config space accesses on the RC, show the right class for
-	 * a PCIe-PCIe bridge (the default setting is to be EP mode).
+	 * Give the RC/EP time to wake up, before trying to configure RC.
+	 * Intermittently check status for link-up, up to a total of 100ms.
 	 */
-	tmp = readl(base + PCIE_RC_CFG_PRIV1_ID_VAL3);
-	u32p_replace_bits(&tmp, 0x060400,
-			  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK);
-	writel(tmp, base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+	for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)
+		msleep(5);
+
+	if (!brcm_pcie_link_up(pcie)) {
+		dev_err(dev, "link down\n");
+		return -ENODEV;
+	}
+
+	if (pcie->gen)
+		brcm_pcie_set_gen(pcie, pcie->gen);
 
 	if (pcie->ssc) {
 		ret = brcm_pcie_set_ssc(pcie);
@@ -1039,12 +1054,6 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 		 pci_speed_string(pcie_link_speed[cls]), nlw,
 		 ssc_good ? "(SSC)" : "(!SSC)");
 
-	/* PCIe->SCB endian mode for BAR */
-	tmp = readl(base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
-	u32p_replace_bits(&tmp, PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN,
-		PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK);
-	writel(tmp, base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
-
 	/*
 	 * Refclk from RC should be gated with CLKREQ# input when ASPM L0s,L1
 	 * is enabled => setting the CLKREQ_DEBUG_ENABLE field to 1.
@@ -1212,6 +1221,10 @@ static int brcm_pcie_resume(struct device *dev)
 	if (ret)
 		goto err_reset;
 
+	ret = brcm_pcie_start_link(pcie);
+	if (ret)
+		goto err_reset;
+
 	if (pcie->msi)
 		brcm_msi_set_regs(pcie->msi);
 
@@ -1401,6 +1414,10 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;
 
+	ret = brcm_pcie_start_link(pcie);
+	if (ret)
+		goto fail;
+
 	pcie->hw_rev = readl(pcie->base + PCIE_MISC_REVISION);
 	if (pcie->type == BCM4908 && pcie->hw_rev >= BRCM_PCIE_HW_REV_3_20) {
 		dev_err(pcie->dev, "hardware revision with unsupported PERST# setup\n");