On certain chipsets AT keyboard controller isn't present and is

emulated by BIOS using SMI interrupt. On those chipsets reading
from the status port may be thousand times slower than usually.
Sometimes this emilation is not working properly resulting in
commands timing out and since we assume that inb() operation
takes very little time to complete we need to adjust number of
retries to keep waiting time within a designed limits (100ms).
Measure time it takes to make read_status() call and adjust
number of retries accordingly.

To keep it simple, use TSC to measure inb() performance and
keep it to amd64-only, since TSC may not available on older
CPUs.

Also enable detection of the AT controller absence on amd64.

Reviewed by:	jhb
MFC after:	1 month

1 files changed, 62 insertions, 14 deletions

diff --git a/sys/dev/atkbdc/atkbdc.c b/sys/dev/atkbdc/atkbdc.c
index df1f28e..f8e856a 100644
--- a/sys/dev/atkbdc/atkbdc.c
+++ b/sys/dev/atkbdc/atkbdc.c
@@ -44,6 +44,10 @@ __FBSDID("$FreeBSD$");
 #include <machine/resource.h>
 #include <sys/rman.h>
 
+#if defined(__amd64__)
+#include <machine/clock.h>
+#endif
+
 #include <dev/atkbdc/atkbdcreg.h>
 
 #ifdef __sparc64__
@@ -153,7 +157,7 @@ atkbdc_configure(void)
 	bus_space_tag_t tag;
 	bus_space_handle_t h0;
 	bus_space_handle_t h1;
-#if defined(__i386__)
+#if defined(__i386__) || defined(__amd64__)
 	volatile int i;
 	register_t flags;
 #endif
@@ -222,7 +226,7 @@ atkbdc_configure(void)
 #endif
 #endif
 
-#if defined(__i386__)
+#if defined(__i386__) || defined(__amd64__)
 	/*
 	 * Check if we really have AT keyboard controller. Poll status
 	 * register until we get "all clear" indication. If no such
@@ -248,6 +252,11 @@ static int
 atkbdc_setup(atkbdc_softc_t *sc, bus_space_tag_t tag, bus_space_handle_t h0,
 	     bus_space_handle_t h1)
 {
+#if defined(__amd64__)
+	u_int64_t tscval[3], read_delay;
+	register_t flags;
+#endif
+
 	if (sc->ioh0 == 0) {	/* XXX */
 	    sc->command_byte = -1;
 	    sc->command_mask = 0;
@@ -264,6 +273,33 @@ atkbdc_setup(atkbdc_softc_t *sc, bus_space_tag_t tag, bus_space_handle_t h0,
 	sc->iot = tag;
 	sc->ioh0 = h0;
 	sc->ioh1 = h1;
+
+#if defined(__amd64__)
+	/*
+	 * On certain chipsets AT keyboard controller isn't present and is
+	 * emulated by BIOS using SMI interrupt. On those chipsets reading
+	 * from the status port may be thousand times slower than usually.
+	 * Sometimes this emilation is not working properly resulting in
+	 * commands timing our and since we assume that inb() operation 
+	 * takes very little time to complete we need to adjust number of
+	 * retries to keep waiting time within a designed limits (100ms).
+	 * Measure time it takes to make read_status() call and adjust
+	 * number of retries accordingly.
+	 */
+	flags = intr_disable();
+	tscval[0] = rdtsc();
+	read_status(sc);
+	tscval[1] = rdtsc();
+	DELAY(1000);
+	tscval[2] = rdtsc();
+	intr_restore(flags);
+	read_delay = tscval[1] - tscval[0];
+	read_delay /= (tscval[2] - tscval[1]) / 1000;
+	sc->retry = 100000 / ((KBDD_DELAYTIME * 2) + read_delay);
+#else
+	sc->retry = 5000;
+#endif
+
 	return 0;
 }
 
@@ -380,10 +416,12 @@ removeq(kqueue *q)
 static int
 wait_while_controller_busy(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 100msec at most */
-    int retry = 5000;
+    int retry;
     int f;
 
+    /* CPU will stay inside the loop for 100msec at most */
+    retry = kbdc->retry;
+
     while ((f = read_status(kbdc)) & KBDS_INPUT_BUFFER_FULL) {
 	if ((f & KBDS_BUFFER_FULL) == KBDS_KBD_BUFFER_FULL) {
 	    DELAY(KBDD_DELAYTIME);
@@ -406,10 +444,12 @@ wait_while_controller_busy(struct atkbdc_softc *kbdc)
 static int
 wait_for_data(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 200msec at most */
-    int retry = 10000;
+    int retry;
     int f;
 
+    /* CPU will stay inside the loop for 200msec at most */
+    retry = kbdc->retry * 2;
+
     while ((f = read_status(kbdc) & KBDS_ANY_BUFFER_FULL) == 0) {
         DELAY(KBDC_DELAYTIME);
         if (--retry < 0)
@@ -423,10 +463,12 @@ wait_for_data(struct atkbdc_softc *kbdc)
 static int
 wait_for_kbd_data(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 200msec at most */
-    int retry = 10000;
+    int retry;
     int f;
 
+    /* CPU will stay inside the loop for 200msec at most */
+    retry = kbdc->retry * 2;
+
     while ((f = read_status(kbdc) & KBDS_BUFFER_FULL)
 	    != KBDS_KBD_BUFFER_FULL) {
         if (f == KBDS_AUX_BUFFER_FULL) {
@@ -448,11 +490,13 @@ wait_for_kbd_data(struct atkbdc_softc *kbdc)
 static int
 wait_for_kbd_ack(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 200msec at most */
-    int retry = 10000;
+    int retry;
     int f;
     int b;
 
+    /* CPU will stay inside the loop for 200msec at most */
+    retry = kbdc->retry * 2;
+
     while (retry-- > 0) {
         if ((f = read_status(kbdc)) & KBDS_ANY_BUFFER_FULL) {
 	    DELAY(KBDD_DELAYTIME);
@@ -475,10 +519,12 @@ wait_for_kbd_ack(struct atkbdc_softc *kbdc)
 static int
 wait_for_aux_data(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 200msec at most */
-    int retry = 10000;
+    int retry;
     int f;
 
+    /* CPU will stay inside the loop for 200msec at most */
+    retry = kbdc->retry * 2;
+
     while ((f = read_status(kbdc) & KBDS_BUFFER_FULL)
 	    != KBDS_AUX_BUFFER_FULL) {
         if (f == KBDS_KBD_BUFFER_FULL) {
@@ -500,11 +546,13 @@ wait_for_aux_data(struct atkbdc_softc *kbdc)
 static int
 wait_for_aux_ack(struct atkbdc_softc *kbdc)
 {
-    /* CPU will stay inside the loop for 200msec at most */
-    int retry = 10000;
+    int retry;
     int f;
     int b;
 
+    /* CPU will stay inside the loop for 200msec at most */
+    retry = kbdc->retry * 2;
+
     while (retry-- > 0) {
         if ((f = read_status(kbdc)) & KBDS_ANY_BUFFER_FULL) {
 	    DELAY(KBDD_DELAYTIME);