[PATCH v3 3/3] Add function to display cxl1.1 device link status

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

From: KobayashiDaisuke <kobayashi.da-06@fujitsu.com>

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: "KobayashiDaisuke" <kobayashi.da-06@fujitsu.com>
---
 lib/access.c | 29 +++++++++++++++++++++
 lib/pci.h    |  2 ++
 ls-caps.c    | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+)

diff --git a/lib/access.c b/lib/access.c
index 7d66123..bc75a84 100644
--- a/lib/access.c
+++ b/lib/access.c
@@ -12,6 +12,7 @@
 #include <stdlib.h>
 #include <stdarg.h>
 #include <string.h>
+#include <fcntl.h>
 
 #include "internal.h"
 
@@ -268,3 +269,31 @@ pci_get_string_property(struct pci_dev *d, u32 prop)
 
   return NULL;
 }
+
+#define OBJNAMELEN 1024
+#define OBJBUFSIZE 64
+int
+get_rcd_sysfs_obj_file(struct pci_dev *d, char *object, char *result)
+{
+#ifdef PCI_HAVE_PM_LINUX_SYSFS
+  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;
+#else
+  return -1;
+#endif
+}
diff --git a/lib/pci.h b/lib/pci.h
index 2322bf7..fb25069 100644
--- a/lib/pci.h
+++ b/lib/pci.h
@@ -187,6 +187,8 @@ int pci_write_long(struct pci_dev *, int pos, u32 data) PCI_ABI;
 int pci_read_block(struct pci_dev *, int pos, u8 *buf, int len) PCI_ABI;
 int pci_write_block(struct pci_dev *, int pos, u8 *buf, int len) PCI_ABI;
 
+int get_rcd_sysfs_obj_file(struct pci_dev *d, char *object, char *result) PCI_ABI;
+
 /*
  * Most device properties take some effort to obtain, so libpci does not
  * initialize them during default bus scan. Instead, you have to call
diff --git a/ls-caps.c b/ls-caps.c
index 1b63262..12c9f34 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 +1383,74 @@ static void cap_express_slot2(struct device *d UNUSED, int where UNUSED)
   /* No capabilities that require this field in PCIe rev2.0 spec. */
 }
 
+#define OBJBUFSIZE 64
+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 +1515,9 @@ 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