[Xen-devel] [RFC 4/8] x86/hpet: Debug and verbose hpet logging

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This was for debugging purposes, but might perhaps be more useful generally.
I am happy to keep none, some or all of it, depending on how useful people
think it might be.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/arch/x86/hpet.c |   83 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c
index 091e624..4b08381 100644
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -61,6 +61,36 @@ u8 __initdata hpet_blockid;
 static bool_t __initdata force_hpet_broadcast;
 boolean_param("hpetbroadcast", force_hpet_broadcast);
 
+static bool_t __read_mostly hpet_verbose;
+static bool_t __read_mostly hpet_debug;
+static void __init parse_hpet_param(char * s)
+{
+    char *ss;
+    int val;
+
+    do {
+        val = !!strncmp(s, "no-", 3);
+        if ( !val )
+            s += 3;
+
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        if ( !strcmp(s, "verbose") )
+            hpet_verbose = val;
+        else if ( !strcmp(s, "debug") )
+        {
+            hpet_debug = val;
+            if ( val )
+                hpet_verbose = 1;
+        }
+
+        s = ss + 1;
+    } while ( ss );
+}
+custom_param("hpet", parse_hpet_param);
+
 /*
  * Calculate a multiplication factor for scaled math, which is used to convert
  * nanoseconds based values to clock ticks:
@@ -94,6 +124,35 @@ static inline unsigned long ns2ticks(unsigned long nsec, 
int shift,
     return (unsigned long) tmp;
 }
 
+static void __maybe_unused dump_hpet_timer(int timer)
+{
+    u32 cfg = hpet_read32(HPET_Tn_CFG(timer));
+
+    printk(XENLOG_INFO "HPET: Timer %02u CFG: raw 0x%08"PRIx32
+           " Caps: %d %c%c", timer, cfg,
+           cfg & HPET_TN_64BIT_CAP ? 64 : 32,
+           cfg & HPET_TN_FSB_CAP ? 'M' : '-',
+           cfg & HPET_TN_PERIODIC_CAP ? 'P' : '-');
+
+    printk("\n  Setup: ");
+
+    if ( (cfg & HPET_TN_FSB_CAP) && (cfg & HPET_TN_FSB) )
+        printk("FSB ");
+
+    if ( !(cfg & HPET_TN_FSB) )
+        printk("GSI %#x ",
+               (cfg & HPET_TN_ROUTE) >> HPET_TN_ROUTE_SHIFT);
+
+    if ( cfg & HPET_TN_32BIT )
+        printk("32bit ");
+
+    if ( cfg & HPET_TN_PERIODIC )
+        printk("Periodic ");
+
+    printk("%sabled ", cfg & HPET_TN_ENABLE ? "En" : "Dis");
+    printk("%s\n", cfg & HPET_TN_LEVEL ? "Level" : "Edge");
+}
+
 static int hpet_next_event(unsigned long delta, int timer)
 {
     uint32_t cnt, cmp;
@@ -769,7 +828,14 @@ u64 __init hpet_setup(void)
     unsigned int last;
 
     if ( hpet_rate )
+    {
+        if ( hpet_debug )
+            printk(XENLOG_DEBUG "HPET: Skipping re-setup\n");
         return hpet_rate;
+    }
+
+    if ( hpet_debug )
+        printk(XENLOG_DEBUG "HPET: Setting up hpet data\n");
 
     if ( hpet_address == 0 )
         return 0;
@@ -783,6 +849,20 @@ u64 __init hpet_setup(void)
         return 0;
     }
 
+    if ( hpet_verbose )
+    {
+        printk(XENLOG_INFO "HPET: Vendor: %04"PRIx16", Rev: %u, %u timers\n",
+               hpet_id >> HPET_ID_VENDOR_SHIFT,
+               hpet_id & HPET_ID_REV,
+               ((hpet_id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1);
+        printk(XENLOG_INFO "HPET:   Caps: ");
+        if ( hpet_id & HPET_ID_LEGSUP )
+            printk("Legacy ");
+        if ( hpet_id & HPET_ID_64BIT )
+            printk("64bit ");
+        printk("\n");
+    }
+
     /* Check for sane period (100ps <= period <= 100ns). */
     hpet_period = hpet_read32(HPET_PERIOD);
     if ( (hpet_period > 100000000) || (hpet_period < 100000) )
@@ -840,6 +920,9 @@ void hpet_resume(u32 *boot_cfg)
             cfg &= ~HPET_TN_RESERVED;
         }
         hpet_write32(cfg, HPET_Tn_CFG(i));
+
+        if ( hpet_verbose )
+            dump_hpet_timer(i);
     }
 
     cfg = hpet_read32(HPET_CFG);
-- 
1.7.10.4


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