[PATCH v4 2/4] PCI: cadence-host: Introduce cdns_pcie_host_disable helper for cleanup

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

Introduce the helper function cdns_pcie_host_disable() which will undo
the configuration performed by cdns_pcie_host_setup(). Also, export it
for use by existing callers of cdns_pcie_host_setup(), thereby allowing
them to cleanup on their exit path.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---

v3 patch is at:
https://lore.kernel.org/r/20250410104426.463453-3-s-vadapalli@ti.com/
No changes since v3.

Regards,
Siddharth.

 .../controller/cadence/pcie-cadence-host.c    | 104 ++++++++++++++++++
 drivers/pci/controller/cadence/pcie-cadence.h |   5 +
 2 files changed, 109 insertions(+)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
index 96055edeb099..741508738f88 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -152,6 +152,14 @@ static int cdns_pcie_retrain(struct cdns_pcie *pcie)
 	return ret;
 }
 
+static void cdns_pcie_host_disable_ptm_response(struct cdns_pcie *pcie)
+{
+	u32 val;
+
+	val = cdns_pcie_readl(pcie, CDNS_PCIE_LM_PTM_CTRL);
+	cdns_pcie_writel(pcie, CDNS_PCIE_LM_PTM_CTRL, val & ~CDNS_PCIE_LM_TPM_CTRL_PTMRSEN);
+}
+
 static void cdns_pcie_host_enable_ptm_response(struct cdns_pcie *pcie)
 {
 	u32 val;
@@ -177,6 +185,26 @@ static int cdns_pcie_host_start_link(struct cdns_pcie_rc *rc)
 	return ret;
 }
 
+static void cdns_pcie_host_deinit_root_port(struct cdns_pcie_rc *rc)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+	u32 value, ctrl;
+
+	cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, 0xffff);
+	cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0xff);
+	cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0xff);
+	cdns_pcie_writel(pcie, CDNS_PCIE_LM_ID, 0xffffffff);
+	cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, 0xffff);
+	ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
+	value = ~(CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
+		CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
+		CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
+		CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
+		CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
+		CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS);
+	cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
+}
+
 static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
@@ -393,6 +421,32 @@ static int cdns_pcie_host_dma_ranges_cmp(void *priv, const struct list_head *a,
         return resource_size(entry2->res) - resource_size(entry1->res);
 }
 
+static void cdns_pcie_host_unmap_dma_ranges(struct cdns_pcie_rc *rc)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+	enum cdns_pcie_rp_bar bar;
+	u32 value;
+
+	/* Reset inbound configuration for all BARs which were being used */
+	for (bar = RP_BAR0; bar <= RP_NO_BAR; bar++) {
+		if (rc->avail_ib_bar[bar])
+			continue;
+
+		cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(bar), 0);
+		cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(bar), 0);
+
+		if (bar == RP_NO_BAR)
+			continue;
+
+		value = ~(LM_RC_BAR_CFG_CTRL_MEM_64BITS(bar) |
+			  LM_RC_BAR_CFG_CTRL_PREF_MEM_64BITS(bar) |
+			  LM_RC_BAR_CFG_CTRL_MEM_32BITS(bar) |
+			  LM_RC_BAR_CFG_CTRL_PREF_MEM_32BITS(bar) |
+			  LM_RC_BAR_CFG_APERTURE(bar, bar_aperture_mask[bar] + 2));
+		cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
+	}
+}
+
 static int cdns_pcie_host_map_dma_ranges(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
@@ -430,6 +484,29 @@ static int cdns_pcie_host_map_dma_ranges(struct cdns_pcie_rc *rc)
 	return 0;
 }
 
+static void cdns_pcie_host_deinit_address_translation(struct cdns_pcie_rc *rc)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(rc);
+	struct resource_entry *entry;
+	int r;
+
+	cdns_pcie_host_unmap_dma_ranges(rc);
+
+	/*
+	 * Reset outbound region 0 which was reserved for configuration space
+	 * accesses.
+	 */
+	cdns_pcie_reset_outbound_region(pcie, 0);
+
+	/* Reset rest of the outbound regions */
+	r = 1;
+	resource_list_for_each_entry(entry, &bridge->windows) {
+		cdns_pcie_reset_outbound_region(pcie, r);
+		r++;
+	}
+}
+
 static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
@@ -487,6 +564,12 @@ static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
 	return cdns_pcie_host_map_dma_ranges(rc);
 }
 
+static void cdns_pcie_host_deinit(struct cdns_pcie_rc *rc)
+{
+	cdns_pcie_host_deinit_address_translation(rc);
+	cdns_pcie_host_deinit_root_port(rc);
+}
+
 int cdns_pcie_host_init(struct cdns_pcie_rc *rc)
 {
 	int err;
@@ -499,6 +582,14 @@ int cdns_pcie_host_init(struct cdns_pcie_rc *rc)
 }
 EXPORT_SYMBOL_GPL(cdns_pcie_host_init);
 
+static void cdns_pcie_host_link_disable(struct cdns_pcie_rc *rc)
+{
+	struct cdns_pcie *pcie = &rc->pcie;
+
+	cdns_pcie_stop_link(pcie);
+	cdns_pcie_host_disable_ptm_response(pcie);
+}
+
 int cdns_pcie_host_link_setup(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
@@ -524,6 +615,19 @@ int cdns_pcie_host_link_setup(struct cdns_pcie_rc *rc)
 }
 EXPORT_SYMBOL_GPL(cdns_pcie_host_link_setup);
 
+void cdns_pcie_host_disable(struct cdns_pcie_rc *rc)
+{
+	struct pci_host_bridge *bridge;
+
+	bridge = pci_host_bridge_from_priv(rc);
+	pci_stop_root_bus(bridge->bus);
+	pci_remove_root_bus(bridge->bus);
+
+	cdns_pcie_host_deinit(rc);
+	cdns_pcie_host_link_disable(rc);
+}
+EXPORT_SYMBOL_GPL(cdns_pcie_host_disable);
+
 int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 {
 	struct device *dev = rc->pcie.dev;
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index 4b7f295e24e7..0b6bed1ac146 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -523,6 +523,7 @@ static inline bool cdns_pcie_link_up(struct cdns_pcie *pcie)
 int cdns_pcie_host_link_setup(struct cdns_pcie_rc *rc);
 int cdns_pcie_host_init(struct cdns_pcie_rc *rc);
 int cdns_pcie_host_setup(struct cdns_pcie_rc *rc);
+void cdns_pcie_host_disable(struct cdns_pcie_rc *rc);
 void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
 			       int where);
 #else
@@ -541,6 +542,10 @@ static inline int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 	return 0;
 }
 
+static inline void cdns_pcie_host_disable(struct cdns_pcie_rc *rc)
+{
+}
+
 static inline void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
 					     int where)
 {
-- 
2.34.1