[RFC PATCH v2 3/3] lspci: Add function to display cxl1.1 device link status

["Kobayashi,Daisuke" <kobayashi.da-06@xxxxxxxxxxx>]

This patch adds a function to output the link status of the CXL1.1 device
when it is connected.

In CXL1.1, the link status of the device is included in the RCRB mapped to
the memory mapped register area. The value of that register is outputted
to sysfs, and based on that, displays the link status information.


Signed-off-by: "Kobayashi,Daisuke" <kobayashi.da-06@xxxxxxxxxxx>
---
 ls-caps.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)

diff --git a/ls-caps.c b/ls-caps.c
index 1b63262..5c60321 100644
--- a/ls-caps.c
+++ b/ls-caps.c
@@ -10,6 +10,8 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <fcntl.h>
+#include <stdlib.h>
 
 #include "lspci.h"
 
@@ -1381,6 +1383,97 @@ static void cap_express_slot2(struct device *d UNUSED, int where UNUSED)
   /* No capabilities that require this field in PCIe rev2.0 spec. */
 }
 
+#define OBJNAMELEN 1024
+#define OBJBUFSIZE 64
+static int
+get_rcd_sysfs_obj_file(struct pci_dev *d, char *object, char *result)
+{
+  char namebuf[OBJNAMELEN];
+  int n = snprintf(namebuf, OBJNAMELEN, "%s/devices/%04x:%02x:%02x.%d/%s",
+		   pci_get_param(d->access, "sysfs.path"),
+       d->domain, d->bus, d->dev, d->func, object);
+  if (n < 0 || n >= OBJNAMELEN){
+    d->access->error("Failed to get filename");
+    return -1;
+    }
+  int fd = open(namebuf, O_RDONLY);
+  if(fd < 0)
+    return -1;
+  n = read(fd, result, OBJBUFSIZE);
+  if (n < 0 || n >= OBJBUFSIZE){
+    d->access->error("Failed to read the file");
+    return -1;
+  }
+  return 0;
+}
+
+static void cap_express_link_rcd(struct device *d){
+  u32 t, aspm, cap_speed, cap_width, sta_speed, sta_width;
+  u16 w;
+  struct pci_dev *pdev = d->dev;
+  char buf[OBJBUFSIZE];
+
+  if(get_rcd_sysfs_obj_file(pdev, "rcd_link_cap", buf))
+    return;
+  t = (u32)strtoul(buf, NULL, 16);
+
+  aspm = (t & PCI_EXP_LNKCAP_ASPM) >> 10;
+  cap_speed = t & PCI_EXP_LNKCAP_SPEED;
+  cap_width = (t & PCI_EXP_LNKCAP_WIDTH) >> 4;
+  printf("\t\tLnkCap:\tPort #%d, Speed %s, Width x%d, ASPM %s",
+	t >> 24,
+	link_speed(cap_speed), cap_width,
+	aspm_support(aspm));
+  if (aspm)
+    {
+      printf(", Exit Latency ");
+      if (aspm & 1)
+	printf("L0s %s", latency_l0s((t & PCI_EXP_LNKCAP_L0S) >> 12));
+      if (aspm & 2)
+	printf("%sL1 %s", (aspm & 1) ? ", " : "",
+	    latency_l1((t & PCI_EXP_LNKCAP_L1) >> 15));
+    }
+  printf("\n");
+  printf("\t\t\tClockPM%c Surprise%c LLActRep%c BwNot%c ASPMOptComp%c\n",
+	FLAG(t, PCI_EXP_LNKCAP_CLOCKPM),
+	FLAG(t, PCI_EXP_LNKCAP_SURPRISE),
+	FLAG(t, PCI_EXP_LNKCAP_DLLA),
+	FLAG(t, PCI_EXP_LNKCAP_LBNC),
+	FLAG(t, PCI_EXP_LNKCAP_AOC));
+
+  if(!get_rcd_sysfs_obj_file(pdev, "rcd_link_ctrl", buf)){
+    w = (u16)strtoul(buf, NULL, 16);    
+    printf("\t\tLnkCtl:\tASPM %s;", aspm_enabled(w & PCI_EXP_LNKCTL_ASPM));
+    printf(" Disabled%c CommClk%c\n\t\t\tExtSynch%c ClockPM%c AutWidDis%c BWInt%c AutBWInt%c\n",
+    FLAG(w, PCI_EXP_LNKCTL_DISABLE),
+    FLAG(w, PCI_EXP_LNKCTL_CLOCK),
+    FLAG(w, PCI_EXP_LNKCTL_XSYNCH),
+    FLAG(w, PCI_EXP_LNKCTL_CLOCKPM),
+    FLAG(w, PCI_EXP_LNKCTL_HWAUTWD),
+    FLAG(w, PCI_EXP_LNKCTL_BWMIE),
+    FLAG(w, PCI_EXP_LNKCTL_AUTBWIE));
+  }
+
+  if(!get_rcd_sysfs_obj_file(pdev, "rcd_link_status", buf)){
+    w = (u16)strtoul(buf, NULL, 16);    
+    sta_speed = w & PCI_EXP_LNKSTA_SPEED;
+    sta_width = (w & PCI_EXP_LNKSTA_WIDTH) >> 4;
+    printf("\t\tLnkSta:\tSpeed %s%s, Width x%d%s\n",
+    link_speed(sta_speed),
+    link_compare(PCI_EXP_TYPE_ROOT_INT_EP, sta_speed, cap_speed),
+    sta_width,
+    link_compare(PCI_EXP_TYPE_ROOT_INT_EP, sta_width, cap_width));
+    printf("\t\t\tTrErr%c Train%c SlotClk%c DLActive%c BWMgmt%c ABWMgmt%c\n",
+    FLAG(w, PCI_EXP_LNKSTA_TR_ERR),
+    FLAG(w, PCI_EXP_LNKSTA_TRAIN),
+    FLAG(w, PCI_EXP_LNKSTA_SL_CLK),
+    FLAG(w, PCI_EXP_LNKSTA_DL_ACT),
+    FLAG(w, PCI_EXP_LNKSTA_BWMGMT),
+    FLAG(w, PCI_EXP_LNKSTA_AUTBW));
+  }
+  return;
+}
+
 static int
 cap_express(struct device *d, int where, int cap)
 {
@@ -1445,6 +1538,9 @@ cap_express(struct device *d, int where, int cap)
   cap_express_dev(d, where, type);
   if (link)
     cap_express_link(d, where, type);
+  else if (type == PCI_EXP_TYPE_ROOT_INT_EP)
+    cap_express_link_rcd(d);
+   
   if (slot)
     cap_express_slot(d, where);
   if (type == PCI_EXP_TYPE_ROOT_PORT || type == PCI_EXP_TYPE_ROOT_EC)
-- 
2.43.0