[d-kernel] [PATCH 1/1] pcie-baikal: forced enable dma-coherent for pcie on Baikal-M

[Daniil Gnusarev <gnusarevda@basealt.ru>]

When using the CONFIG_INIT_ON_ALLOC_DEFAULT_ON=Y kernel option or
the init_on_alloc=1 boot parameter, errors are observed when initializing
nvme on the PCIe bus:
    [   71.480815] nvme nvme0: I/O tag 16 (0010) QID 0 timeout, disable controller
    [   71.489912] nvme nvme0: Device not ready; aborting shutdown, CSTS=0x1
    [   71.496838] nvme nvme0: Identify Controller failed (-4)
    [   71.502910] nvme 0000:01:00.0: probe with driver nvme failed with error -5
As a solution, Baikal Electronics proposed to add the 'dma-coherent'
property to the PCIe device description in dts. To support devices with
older firmware versions, this property is forced into the device driver.

Signed-off-by: Daniil Gnusarev <gnusarevda@basealt.ru>
---
 drivers/pci/controller/dwc/pcie-baikal-core.c | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-baikal-core.c b/drivers/pci/controller/dwc/pcie-baikal-core.c
index 9e85edfb656a4..0c1355a22630b 100644
--- a/drivers/pci/controller/dwc/pcie-baikal-core.c
+++ b/drivers/pci/controller/dwc/pcie-baikal-core.c
@@ -2209,11 +2209,32 @@ static int baikal_pcie_probe(struct platform_device *pdev)
 	union baikal_pcie *bp;
 	const struct baikal_pcie_of_data *data;
 	int ret;
+	struct of_changeset ocs;
 
 	data = of_device_get_match_data(dev);
 	if (!data)
 		return -EINVAL;
 
+	if (!of_property_present(dev->of_node,"dma-coherent") &&
+		!of_property_present(dev->of_node,"dma-noncoherent"))
+	{
+		dev->dma_coherent = true;
+
+		of_changeset_init(&ocs);
+
+		ret=of_changeset_add_prop_bool(&ocs,dev->of_node,"dma-coherent");
+		if (ret) {
+			dev_err(dev, "failed to append dma-coherent property\n");
+			return ret;
+		}
+
+		ret=of_changeset_apply(&ocs);
+		if (ret) {
+			dev_err(dev, "failed to append dma-coherent property\n");
+			return ret;
+		}
+	}
+
 	bp = devm_kzalloc(dev, sizeof(*bp), GFP_KERNEL);
 	if (!bp)
 		return -ENOMEM;
-- 
2.42.2