Re: [PATCH v1] net/axgbe: use PCI root complex device to distinguish AMD hardware

[Awan, Arsalan]

Hi Chandu,

I have tested this in the following configurations and it works very well in 
all cases:

* V1000 with Yocto v3.3.2 & Linux v5.10.47
* E3000 with Yocto v3.3.2 & Linux v5.10.47
* V1000 with Ubuntu Server v20.04.3 LTS
* E3000 with Ubuntu Server v20.04.3 LTS

I think this is a much better approach than scanning the whole PCI bus and 
comparing
each and every device against the PCI Root Complex Device ID of the platform.

This solution looks good to me!

Acked by: Arsalan H. Awan <arsalan_a...@mentor.com>
________________________________________
From: Chandubabu Namburu <cha...@amd.com>
Sent: Friday, November 26, 2021 3:24 PM
To: dev@dpdk.org
Cc: selwin.sebast...@amd.com; Awan, Arsalan; Chandubabu Namburu
Subject: [PATCH v1] net/axgbe: use PCI root complex device to distinguish AMD 
hardware

"bus/pci: optimize bus scan" broke axgbe on V1000/R1000.
RV root complex pci device does not have any kernel driver assigned
so it is removed from pci scan list which is used in
"net/axgbe: add a HW quirk for register definitions"

Get root complex device id directly from pci sysfs instead of
pci scan list

Signed-off-by: Chandubabu Namburu <cha...@amd.com>
---
 drivers/net/axgbe/axgbe_ethdev.c | 39 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/net/axgbe/axgbe_ethdev.c b/drivers/net/axgbe/axgbe_ethdev.c
index 9cd056d04a..26babde354 100644
--- a/drivers/net/axgbe/axgbe_ethdev.c
+++ b/drivers/net/axgbe/axgbe_ethdev.c
@@ -10,6 +10,8 @@
 #include "axgbe_regs.h"
 #include "rte_time.h"

+#include "eal_filesystem.h"
+
 static int eth_axgbe_dev_init(struct rte_eth_dev *eth_dev);
 static int  axgbe_dev_configure(struct rte_eth_dev *dev);
 static int  axgbe_dev_start(struct rte_eth_dev *dev);
@@ -1923,28 +1925,27 @@ static void axgbe_default_config(struct axgbe_port 
*pdata)
        pdata->power_down = 0;
 }

-static int
-pci_device_cmp(const struct rte_device *dev, const void *_pci_id)
+/*
+ * Return PCI root complex device id on success else 0
+ */
+static uint16_t
+get_pci_rc_devid(void)
 {
-       const struct rte_pci_device *pdev = RTE_DEV_TO_PCI_CONST(dev);
-       const struct rte_pci_id *pcid = _pci_id;
+       char pci_sysfs[PATH_MAX];
+       const struct rte_pci_addr pci_rc_addr = {0, 0, 0, 0};
+       unsigned long device_id;

-       if (pdev->id.vendor_id == AMD_PCI_VENDOR_ID &&
-                       pdev->id.device_id == pcid->device_id)
-               return 0;
-       return 1;
-}
+       snprintf(pci_sysfs, sizeof(pci_sysfs), "%s/" PCI_PRI_FMT "/device",
+                rte_pci_get_sysfs_path(), pci_rc_addr.domain,
+                pci_rc_addr.bus, pci_rc_addr.devid, pci_rc_addr.function);

-static bool
-pci_search_device(int device_id)
-{
-       struct rte_bus *pci_bus;
-       struct rte_pci_id dev_id;
+       /* get device id */
+       if (eal_parse_sysfs_value(pci_sysfs, &device_id) < 0) {
+               PMD_INIT_LOG(ERR, "Error in reading PCI sysfs\n");
+               return 0;
+       }

-       dev_id.device_id = device_id;
-       pci_bus = rte_bus_find_by_name("pci");
-       return (pci_bus != NULL) &&
-               (pci_bus->find_device(NULL, pci_device_cmp, &dev_id) != NULL);
+       return (uint16_t)device_id;
 }

 /*
@@ -1986,7 +1987,7 @@ eth_axgbe_dev_init(struct rte_eth_dev *eth_dev)
        /*
         * Use root complex device ID to differentiate RV AXGBE vs SNOWY AXGBE
         */
-       if (pci_search_device(AMD_PCI_RV_ROOT_COMPLEX_ID)) {
+       if ((get_pci_rc_devid()) == AMD_PCI_RV_ROOT_COMPLEX_ID) {
                pdata->xpcs_window_def_reg = PCS_V2_RV_WINDOW_DEF;
                pdata->xpcs_window_sel_reg = PCS_V2_RV_WINDOW_SELECT;
        } else {
--
2.25.1