[PATCH 1/3] PCI: rockchip: warn of danger of 5.0 GT/s speeds

[Geraldo Nascimento]

Shawn Lin from Rockchip has reiterated that there may be danger in using
their PCIe with 5.0 GT/s speeds. Warn the user if they make a DT change
from the default and at the same time, drive at 2.5 GT/s only, in case
the DT max-link-speed property is invalid or inexistent.

Fixes: 956cd99b35a8 ("PCI: rockchip: Separate common code from RC driver")
Link: https://lore.kernel.org/all/ffd05070-9879-4468-94e3-b88968b4c21b@rock-chips.com/
Reported-by: Shawn Lin <shawn.lin at rock-chips.com>
Signed-off-by: Geraldo Nascimento <geraldogabriel at gmail.com>
---
 drivers/pci/controller/pcie-rockchip.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
index 0f88da378805..ed67886a6d43 100644
--- a/drivers/pci/controller/pcie-rockchip.c
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -66,8 +66,12 @@ int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 	}
 
 	rockchip->link_gen = of_pci_get_max_link_speed(node);
-	if (rockchip->link_gen < 0 || rockchip->link_gen > 2)
-		rockchip->link_gen = 2;
+	if (rockchip->link_gen < 0 || rockchip->link_gen > 2) {
+		rockchip->link_gen = 1;
+		dev_warn(dev, "invalid max-link-speed, set to 2.5 GT/s\n");
+	}
+	else if (rockchip->link_gen == 2)
+		dev_warn(dev, "5.0 GT/s may lead to catastrophic failure\n");
 
 	for (i = 0; i < ROCKCHIP_NUM_PM_RSTS; i++)
 		rockchip->pm_rsts[i].id = rockchip_pci_pm_rsts[i];
-- 
2.49.0