[PATCH v6] PCI: keystone: Fix pci_ops for AM654x SoC

[Siddharth Vadapalli <s-vadapalli@ti.com>]

In the process of converting .scan_bus() callbacks to .add_bus(), the
ks_pcie_v3_65_scan_bus() function was changed to ks_pcie_v3_65_add_bus().
The .scan_bus() method belonged to ks_pcie_host_ops which was specific
to controller version 3.65a, while the .add_bus() method had been added
to ks_pcie_ops which is shared between the controller versions 3.65a and
4.90a. Neither the older ks_pcie_v3_65_scan_bus() method, nor the newer
ks_pcie_v3_65_add_bus() method is applicable to the controller version
4.90a which is present in AM654x SoCs.

Thus, as a fix, move the contents of "ks_pcie_v3_65_add_bus()" to the
.msi_init callback "ks_pcie_msi_host_init()" which is specific to the
3.65a controller. Also, move the definitions of ks_pcie_set_dbi_mode()
and ks_pcie_clear_dbi_mode() above ks_pcie_msi_host_init() in order to
avoid forward declaration.

Fixes: 6ab15b5e7057 ("PCI: dwc: keystone: Convert .scan_bus() callback to use add_bus")
Suggested-by: Serge Semin <fancer.lancer@gmail.com>
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Suggested-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

Hello,

This patch is based on linux-next tagged next-20240326.

v5:
https://lore.kernel.org/r/20240326111905.2369778-1-s-vadapalli@ti.com/
Changes since v5:
- Fixed indentation of comment as pointed out by:
  Niklas Cassel <cassel@kernel.org>
  at:
  https://lore.kernel.org/r/ZgLUCqh12RMApzyr@x1-carbon/
- Collected Reviewed-by tag from:
  Niklas Cassel <cassel@kernel.org>

Regards,
Siddharth.

 drivers/pci/controller/dwc/pci-keystone.c | 136 ++++++++++------------
 1 file changed, 60 insertions(+), 76 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 844de4418724..6cb3a4713009 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -245,8 +245,68 @@ static struct irq_chip ks_pcie_msi_irq_chip = {
 	.irq_unmask = ks_pcie_msi_unmask,
 };
 
+/**
+ * ks_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask registers
+ * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
+ *	     PCIe host controller driver information.
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_pcie_set_dbi_mode(struct keystone_pcie *ks_pcie)
+{
+	u32 val;
+
+	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	val |= DBI_CS2;
+	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
+
+	do {
+		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	} while (!(val & DBI_CS2));
+}
+
+/**
+ * ks_pcie_clear_dbi_mode() - Disable DBI mode
+ * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
+ *	     PCIe host controller driver information.
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_pcie_clear_dbi_mode(struct keystone_pcie *ks_pcie)
+{
+	u32 val;
+
+	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	val &= ~DBI_CS2;
+	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
+
+	do {
+		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	} while (val & DBI_CS2);
+}
+
 static int ks_pcie_msi_host_init(struct dw_pcie_rp *pp)
 {
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
+
+	/* Configure and set up BAR0 */
+	ks_pcie_set_dbi_mode(ks_pcie);
+
+	/* Enable BAR0 */
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 1);
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, SZ_4K - 1);
+
+	ks_pcie_clear_dbi_mode(ks_pcie);
+
+	/*
+	 * For BAR0, just setting bus address for inbound writes (MSI) should
+	 * be sufficient.  Use physical address to avoid any conflicts.
+	 */
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, ks_pcie->app.start);
+
 	pp->msi_irq_chip = &ks_pcie_msi_irq_chip;
 	return dw_pcie_allocate_domains(pp);
 }
@@ -340,48 +400,6 @@ static const struct irq_domain_ops ks_pcie_intx_irq_domain_ops = {
 	.xlate = irq_domain_xlate_onetwocell,
 };
 
-/**
- * ks_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask registers
- * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
- *	     PCIe host controller driver information.
- *
- * Since modification of dbi_cs2 involves different clock domain, read the
- * status back to ensure the transition is complete.
- */
-static void ks_pcie_set_dbi_mode(struct keystone_pcie *ks_pcie)
-{
-	u32 val;
-
-	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	val |= DBI_CS2;
-	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
-
-	do {
-		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	} while (!(val & DBI_CS2));
-}
-
-/**
- * ks_pcie_clear_dbi_mode() - Disable DBI mode
- * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
- *	     PCIe host controller driver information.
- *
- * Since modification of dbi_cs2 involves different clock domain, read the
- * status back to ensure the transition is complete.
- */
-static void ks_pcie_clear_dbi_mode(struct keystone_pcie *ks_pcie)
-{
-	u32 val;
-
-	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	val &= ~DBI_CS2;
-	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
-
-	do {
-		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	} while (val & DBI_CS2);
-}
-
 static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
 {
 	u32 val;
@@ -445,44 +463,10 @@ static struct pci_ops ks_child_pcie_ops = {
 	.write = pci_generic_config_write,
 };
 
-/**
- * ks_pcie_v3_65_add_bus() - keystone add_bus post initialization
- * @bus: A pointer to the PCI bus structure.
- *
- * This sets BAR0 to enable inbound access for MSI_IRQ register
- */
-static int ks_pcie_v3_65_add_bus(struct pci_bus *bus)
-{
-	struct dw_pcie_rp *pp = bus->sysdata;
-	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
-
-	if (!pci_is_root_bus(bus))
-		return 0;
-
-	/* Configure and set up BAR0 */
-	ks_pcie_set_dbi_mode(ks_pcie);
-
-	/* Enable BAR0 */
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 1);
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, SZ_4K - 1);
-
-	ks_pcie_clear_dbi_mode(ks_pcie);
-
-	 /*
-	  * For BAR0, just setting bus address for inbound writes (MSI) should
-	  * be sufficient.  Use physical address to avoid any conflicts.
-	  */
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, ks_pcie->app.start);
-
-	return 0;
-}
-
 static struct pci_ops ks_pcie_ops = {
 	.map_bus = dw_pcie_own_conf_map_bus,
 	.read = pci_generic_config_read,
 	.write = pci_generic_config_write,
-	.add_bus = ks_pcie_v3_65_add_bus,
 };
 
 /**
-- 
2.40.1