d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add support for the PIT 'readback' command -- based on a patch by grehan@.

Browse Source 
Approved by:	grehan (co-mentor)
This commit is contained in:
Tycho Nightingale 2014-04-18 16:05:12 +00:00
parent 1d6be92ac6
commit c46ff7fa0b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=264651
1 changed files with 74 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
sys/amd64/vmm/io/vatpit.c
View File

@ -56,6 +56,15 @@ static MALLOC_DEFINE(M_VATPIT, "atpit", "bhyve virtual atpit (8254)");
#define TIMER_MODE_MASK 0x0f
#define TIMER_SEL_READBACK 0xc0
#define TIMER_STS_OUT 0x80
#define TIMER_STS_NULLCNT 0x40
#define TIMER_RB_LCTR 0x20
#define TIMER_RB_LSTATUS 0x10
#define TIMER_RB_CTR_2 0x08
#define TIMER_RB_CTR_1 0x04
#define TIMER_RB_CTR_0 0x02
#define TMR2_OUT_STS 0x20
#define PIT_8254_FREQ 1193182
@ -73,6 +82,8 @@ struct channel {
sbintime_t now_sbt; /* uptime when counter was loaded */
uint8_t cr[2];
uint8_t ol[2];
bool slatched; /* status latched */
uint8_t status;
int crbyte;
int olbyte;
int frbyte;
@ -198,6 +209,7 @@ pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
*/
c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
c->now_sbt = sbinuptime();
c->status &= ~TIMER_STS_NULLCNT;
}
delta_ticks = (sbinuptime() - c->now_sbt) / vatpit->freq_sbt;
@ -213,6 +225,57 @@ pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
return (lval);
}
static int
pit_readback1(struct vatpit *vatpit, int channel, uint8_t cmd)
{
struct channel *c;
c = &vatpit->channel[channel];
/*
* Latch the count/status of the timer if not already latched.
* N.B. that the count/status latch-select bits are active-low.
*/
if (!(cmd & TIMER_RB_LCTR) && !c->olbyte) {
(void) pit_update_counter(vatpit, c, true);
}
if (!(cmd & TIMER_RB_LSTATUS) && !c->slatched) {
c->slatched = true;
/*
* For mode 0, see if the elapsed time is greater
* than the initial value - this results in the
* output pin being set to 1 in the status byte.
*/
if (c->mode == TIMER_INTTC && vatpit_get_out(vatpit, channel))
c->status |= TIMER_STS_OUT;
else
c->status &= ~TIMER_STS_OUT;
}
return (0);
}
static int
pit_readback(struct vatpit *vatpit, uint8_t cmd)
{
int error;
/*
* The readback command can apply to all timers.
*/
error = 0;
if (cmd & TIMER_RB_CTR_0)
error = pit_readback1(vatpit, 0, cmd);
if (!error && cmd & TIMER_RB_CTR_1)
error = pit_readback1(vatpit, 1, cmd);
if (!error && cmd & TIMER_RB_CTR_2)
error = pit_readback1(vatpit, 2, cmd);
return (error);
}
static int
vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
{
@ -224,7 +287,7 @@ vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
mode = val & TIMER_MODE_MASK;
if (sel == TIMER_SEL_READBACK)
return (-1);
return (pit_readback(vatpit, val));
if (rw != TIMER_LATCH && rw != TIMER_16BIT)
return (-1);
@ -247,6 +310,7 @@ vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
else {
c->mode = mode;
c->olbyte = 0; /* reset latch after reprogramming */
c->status |= TIMER_STS_NULLCNT;
}
return (0);
@ -287,7 +351,14 @@ vatpit_handler(void *vm, int vcpuid, bool in, int port, int bytes,
c = &vatpit->channel[port - TIMER_CNTR0];
VATPIT_LOCK(vatpit);
if (in) {
if (in && c->slatched) {
/*
* Return the status byte if latched
*/
*eax = c->status;
c->slatched = false;
c->status = 0;
} else if (in) {
/*
* The spec says that once the output latch is completely
* read it should revert to "following" the counter. Use
@ -309,6 +380,7 @@ vatpit_handler(void *vm, int vcpuid, bool in, int port, int bytes,
} else {
c->cr[c->crbyte++] = *eax;
if (c->crbyte == 2) {
c->status &= ~TIMER_STS_NULLCNT;
c->frbyte = 0;
c->crbyte = 0;
c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;