From:   Veerasenareddy Burru <vburru@marvell.com>
To:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <aayarekar@marvell.com>, <sedara@marvell.com>, <sburla@marvell.com>
CC:     <linux-doc@vger.kernel.org>,
        Veerasenareddy Burru <vburru@marvell.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Subject: [PATCH net-next v3 1/7] octeon_ep: defer probe if firmware not ready
Date:   Mon, 13 Feb 2023 21:14:16 -0800
Message-ID: <20230214051422.13705-2-vburru@marvell.com>
In-Reply-To: <20230214051422.13705-1-vburru@marvell.com>
References: <20230214051422.13705-1-vburru@marvell.com>
MIME-Version: 1.0
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Precedence: bulk

Defer probe if firmware is not ready for device usage.

Signed-off-by: Veerasenareddy Burru <vburru@marvell.com>
Signed-off-by: Abhijit Ayarekar <aayarekar@marvell.com>
Signed-off-by: Satananda Burla <sburla@marvell.com>
---
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 5a898fb88e37..5620df4c6d55 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
@@ -1017,6 +1017,26 @@ 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 ? true : false;
+	}
+	return false;
+}
+
 /**
  * octep_probe() - Octeon PCI device probe handler.
  *
@@ -1053,6 +1073,12 @@ static int octep_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	pci_enable_pcie_error_reporting(pdev);
 	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