[PATCH v2 2/8] PCI: cadence: LGA: Add max_link_speed field and 100 ms delay after link training

[Hans Zhang <18255117159@163.com>]

The Cadence LGA (Legacy Architecture IP) PCIe host controller currently
lacks the mandatory 100 ms delay after link training completes for speeds
> 5.0 GT/s, as required by PCIe r6.0 sec 6.6.1.

Add a 'max_link_speed' field to struct cdns_pcie to record the maximum
supported link speed (or the currently configured speed). In the common
host layer function cdns_pcie_host_start_link(), after the link has been
successfully established, call pcie_wait_after_link_train() to insert the
required delay if max_link_speed > 2.

Glue drivers must set max_link_speed appropriately (e.g., from the device
tree property "max-link-speed") to enable the delay.

Signed-off-by: Hans Zhang <18255117159@163.com>
---
 drivers/pci/controller/cadence/pcie-cadence-host-common.c | 4 ++++
 drivers/pci/controller/cadence/pcie-cadence.h             | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-host-common.c b/drivers/pci/controller/cadence/pcie-cadence-host-common.c
index 2b0211870f02..51376f69d007 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host-common.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host-common.c
@@ -14,6 +14,7 @@
 
 #include "pcie-cadence.h"
 #include "pcie-cadence-host-common.h"
+#include "../../pci.h"
 
 #define LINK_RETRAIN_TIMEOUT HZ
 
@@ -115,6 +116,9 @@ int cdns_pcie_host_start_link(struct cdns_pcie_rc *rc,
 	if (!ret && rc->quirk_retrain_flag)
 		ret = cdns_pcie_retrain(pcie, pcie_link_up);
 
+	if (!ret)
+		pcie_wait_after_link_train(pcie->max_link_speed);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cdns_pcie_host_start_link);
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index 574e9cf4d003..e222b095d2b6 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -86,6 +86,7 @@ struct cdns_plat_pcie_of_data {
  * @ops: Platform-specific ops to control various inputs from Cadence PCIe
  *       wrapper
  * @cdns_pcie_reg_offsets: Register bank offsets for different SoC
+ * @max_link_speed: maximum supported link speed
  */
 struct cdns_pcie {
 	void __iomem		             *reg_base;
@@ -98,6 +99,7 @@ struct cdns_pcie {
 	struct device_link	             **link;
 	const  struct cdns_pcie_ops          *ops;
 	const  struct cdns_plat_pcie_of_data *cdns_pcie_reg_offsets;
+	int				     max_link_speed;
 };
 
 /**
-- 
2.34.1