Re: [RESEND] Re: [PATCH] PCI: dw-rockchip: Skip waiting for link up

Niklas Cassel
2025-11-10T12:41:47Z

On Mon, Nov 10, 2025 at 01:34:41PM +0100, Niklas Cassel wrote:
> @@ -672,15 +705,13 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
> if (!pp->use_linkup_irq)
> /* Ignore errors, the link may come up later */
> dw_pcie_wait_for_link(pci);
> -
> - ret = pci_host_probe(bridge);
> - if (ret)
> - goto err_stop_link;
> -
> - if (pp->ops->post_init)
> - pp->ops->post_init(pp);
> -
> - dwc_pcie_debugfs_init(pci, DW_PCIE_RC_TYPE);
> + else
> + /*
> + * For platforms with Link Up IRQ, initial scan will be done
> + * on first Link Up IRQ.
> + */
> + if (dw_pcie_host_initial_scan(pp))
> + goto err_stop_link;

Oops.. this condition was inverted, what I meant was:

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index e92513c5bda5..0e04c1d6d260 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -565,6 +565,39 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
return 0;
}

+static int dw_pcie_host_initial_scan(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct pci_host_bridge *bridge = pp->bridge;
+ int ret;
+
+ ret = pci_host_probe(bridge);
+ if (ret)
+ return ret;
+
+ if (pp->ops->post_init)
+ pp->ops->post_init(pp);
+
+ dwc_pcie_debugfs_init(pci, DW_PCIE_RC_TYPE);
+
+ return 0;
+}
+
+void dw_pcie_handle_link_up_irq(struct dw_pcie_rp *pp)
+{
+ if (!pp->initial_linkup_irq_done) {
+ if (dw_pcie_host_initial_scan(pp)) {
+ //TODO: cleanup
+ }
+ pp->initial_linkup_irq_done = true;
+ } else {
+ /* Rescan the bus to enumerate endpoint devices */
+ pci_lock_rescan_remove();
+ pci_rescan_bus(pp->bridge->bus);
+ pci_unlock_rescan_remove();
+ }
+}
+
int dw_pcie_host_init(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -669,18 +702,17 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
* If there is no Link Up IRQ, we should not bypass the delay
* because that would require users to manually rescan for devices.
*/
- if (!pp->use_linkup_irq)
+ if (!pp->use_linkup_irq) {
/* Ignore errors, the link may come up later */
dw_pcie_wait_for_link(pci);

- ret = pci_host_probe(bridge);
- if (ret)
- goto err_stop_link;
-
- if (pp->ops->post_init)
- pp->ops->post_init(pp);
-
- dwc_pcie_debugfs_init(pci, DW_PCIE_RC_TYPE);
+ /*
+ * For platforms with Link Up IRQ, initial scan will be done
+ * on first Link Up IRQ.
+ */
+ if (dw_pcie_host_initial_scan(pp))
+ goto err_stop_link;
+ }

return 0;

diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index e995f692a1ec..a31bd93490dc 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -427,6 +427,7 @@ struct dw_pcie_rp {
int msg_atu_index;
struct resource *msg_res;
bool use_linkup_irq;
+ bool initial_linkup_irq_done;
struct pci_eq_presets presets;
struct pci_config_window *cfg;
bool ecam_enabled;
@@ -807,6 +808,7 @@ void dw_pcie_msi_init(struct dw_pcie_rp *pp);
int dw_pcie_msi_host_init(struct dw_pcie_rp *pp);
void dw_pcie_free_msi(struct dw_pcie_rp *pp);
int dw_pcie_setup_rc(struct dw_pcie_rp *pp);
+void dw_pcie_handle_link_up_irq(struct dw_pcie_rp *pp);
int dw_pcie_host_init(struct dw_pcie_rp *pp);
void dw_pcie_host_deinit(struct dw_pcie_rp *pp);
int dw_pcie_allocate_domains(struct dw_pcie_rp *pp);
@@ -844,6 +846,9 @@ static inline int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
return 0;
}

+static inline void dw_pcie_handle_link_up_irq(struct dw_pcie_rp *pp)
+{ }
+
static inline int dw_pcie_host_init(struct dw_pcie_rp *pp)
{
return 0;
diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 8a882dcd1e4e..042e5845bdd6 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -468,10 +468,7 @@ static irqreturn_t rockchip_pcie_rc_sys_irq_thread(int irq, void *arg)
if (rockchip_pcie_link_up(pci)) {
msleep(PCIE_RESET_CONFIG_WAIT_MS);
dev_dbg(dev, "Received Link up event. Starting enumeration!\n");
- /* Rescan the bus to enumerate endpoint devices */
- pci_lock_rescan_remove();
- pci_rescan_bus(pp->bridge->bus);
- pci_unlock_rescan_remove();
+ dw_pcie_handle_link_up_irq(pp);
}
}