[PATCH net-next v4 1/8] octeon_ep: defer probe if firmware not ready

[Veerasenareddy Burru <vburru@xxxxxxxxxxx>]

Defer probe if firmware is not ready for device usage.

Signed-off-by: Veerasenareddy Burru <vburru@xxxxxxxxxxx>
Signed-off-by: Abhijit Ayarekar <aayarekar@xxxxxxxxxxx>
Signed-off-by: Satananda Burla <sburla@xxxxxxxxxxx>
---
v3 -> v4:
 * address review comments
   https://lore.kernel.org/all/Y+vFlfakHj33DEkt@boxer/
   - fix return statement for get_fw_ready_status().

v2 -> v3:
 * fix review comments
   https://lore.kernel.org/all/Y4chWyR6qTlptkTE@unreal/
   - change get_fw_ready_status() to return bool
   - fix the success oriented flow while looking for
     PCI extended capability

v1 -> v2:
 * was scheduling workqueue task to wait for firmware ready,
   to probe/initialize the device.
 * now, removed the workqueue task; the probe returns EPROBE_DEFER,
   if firmware is not ready.
 * removed device status oct->status, as it is not required with the
   modified implementation.

 .../ethernet/marvell/octeon_ep/octep_main.c   | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
index fdce78ceea87..0a50da52dc27 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
@@ -1016,6 +1016,26 @@ static void octep_device_cleanup(struct octep_device *oct)
 	oct->conf = NULL;
 }
 
+static bool get_fw_ready_status(struct pci_dev *pdev)
+{
+	u32 pos = 0;
+	u16 vsec_id;
+	u8 status;
+
+	while ((pos = pci_find_next_ext_capability(pdev, pos,
+						   PCI_EXT_CAP_ID_VNDR))) {
+		pci_read_config_word(pdev, pos + 4, &vsec_id);
+#define FW_STATUS_VSEC_ID  0xA3
+		if (vsec_id != FW_STATUS_VSEC_ID)
+			continue;
+
+		pci_read_config_byte(pdev, (pos + 8), &status);
+		dev_info(&pdev->dev, "Firmware ready status = %u\n", status);
+		return status;
+	}
+	return false;
+}
+
 /**
  * octep_probe() - Octeon PCI device probe handler.
  *
@@ -1051,6 +1071,12 @@ static int octep_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	pci_set_master(pdev);
 
+	if (!get_fw_ready_status(pdev)) {
+		dev_notice(&pdev->dev, "Firmware not ready; defer probe.\n");
+		err = -EPROBE_DEFER;
+		goto err_alloc_netdev;
+	}
+
 	netdev = alloc_etherdev_mq(sizeof(struct octep_device),
 				   OCTEP_MAX_QUEUES);
 	if (!netdev) {
-- 
2.36.0