@@ -21,12 +21,16 @@
#include "hw/sysbus.h"
#include "chardev/char-fe.h"
#include "qom/object.h"
+#include "qemu/fifo32.h"
#define TYPE_IMX_SERIAL "imx.serial"
OBJECT_DECLARE_SIMPLE_TYPE(IMXSerialState, IMX_SERIAL)
+#define FIFO_SIZE 32
+
#define URXD_CHARRDY (1<<15) /* character read is valid */
#define URXD_ERR (1<<14) /* Character has error */
+#define URXD_OVRRUN (1<<13) /* 32nd character in RX FIFO */
#define URXD_FRMERR (1<<12) /* Character has frame error */
#define URXD_BRK (1<<11) /* Break received */
@@ -65,11 +69,13 @@ OBJECT_DECLARE_SIMPLE_TYPE(IMXSerialState, IMX_SERIAL)
#define UCR1_TXMPTYEN (1<<6) /* Tx Empty Interrupt Enable */
#define UCR1_UARTEN (1<<0) /* UART Enable */
+#define UCR2_ATEN (1<<3) /* Ageing Timer Enable */
#define UCR2_TXEN (1<<2) /* Transmitter enable */
#define UCR2_RXEN (1<<1) /* Receiver enable */
#define UCR2_SRST (1<<0) /* Reset complete */
#define UCR4_DREN BIT(0) /* Receive Data Ready interrupt enable */
+#define UCR4_OREN BIT(1) /* Overrun interrupt enable */
#define UCR4_TCEN BIT(3) /* TX complete interrupt enable */
#define UCR4_WKEN BIT(7) /* WAKE interrupt enable */
@@ -78,13 +84,25 @@ OBJECT_DECLARE_SIMPLE_TYPE(IMXSerialState, IMX_SERIAL)
#define UTS1_TXFULL (1<<4)
#define UTS1_RXFULL (1<<3)
+#define TL_MASK 0x3f
+
+ /* Bit time in nanoseconds assuming maximum baud rate of 115200 */
+#define BIT_TIME_NS 8681
+
+/* Assume 8 bits per character */
+#define NUM_BITS 8
+
+/* Ageing timer triggers after 8 characters */
+#define AGE_DURATION_NS (8 * NUM_BITS * BIT_TIME_NS)
+
struct IMXSerialState {
/*< private >*/
SysBusDevice parent_obj;
/*< public >*/
MemoryRegion iomem;
- int32_t readbuff;
+ QEMUTimer ageing_timer;
+ Fifo32 rx_fifo;
uint32_t usr1;
uint32_t usr2;
@@ -26,6 +26,7 @@
#include "migration/vmstate.h"
#include "qemu/log.h"
#include "qemu/module.h"
+#include "qemu/fifo32.h"
#ifndef DEBUG_IMX_UART
#define DEBUG_IMX_UART 0
@@ -41,10 +42,11 @@
static const VMStateDescription vmstate_imx_serial = {
.name = TYPE_IMX_SERIAL,
- .version_id = 2,
- .minimum_version_id = 2,
+ .version_id = 3,
+ .minimum_version_id = 3,
.fields = (const VMStateField[]) {
- VMSTATE_INT32(readbuff, IMXSerialState),
+ VMSTATE_FIFO32(rx_fifo, IMXSerialState),
+ VMSTATE_TIMER(ageing_timer, IMXSerialState),
VMSTATE_UINT32(usr1, IMXSerialState),
VMSTATE_UINT32(usr2, IMXSerialState),
VMSTATE_UINT32(ucr1, IMXSerialState),
@@ -71,6 +73,10 @@ static void imx_update(IMXSerialState *s)
* following:
*/
usr1 = s->usr1 & s->ucr1 & (USR1_TRDY | USR1_RRDY);
+ /*
+ * Interrupt if AGTIM is set (ageing timer interrupt in RxFIFO)
+ */
+ usr1 |= (s->ucr2 & UCR2_ATEN) ? (s->usr1 & USR1_AGTIM) : 0;
/*
* Bits that we want in USR2 are not as conveniently laid out,
* unfortunately.
@@ -78,15 +84,66 @@ static void imx_update(IMXSerialState *s)
mask = (s->ucr1 & UCR1_TXMPTYEN) ? USR2_TXFE : 0;
/*
* TCEN and TXDC are both bit 3
+ * ORE and OREN are both bit 1
* RDR and DREN are both bit 0
*/
- mask |= s->ucr4 & (UCR4_WKEN | UCR4_TCEN | UCR4_DREN);
+ mask |= s->ucr4 & (UCR4_WKEN | UCR4_TCEN | UCR4_DREN | UCR4_OREN);
usr2 = s->usr2 & mask;
qemu_set_irq(s->irq, usr1 || usr2);
}
+static void imx_serial_rx_fifo_push(IMXSerialState *s, uint32_t value)
+{
+ uint32_t pushed_value = value;
+ if (fifo32_is_full(&s->rx_fifo)) {
+ /* Set ORE if FIFO is already full */
+ s->usr2 |= USR2_ORE;
+ } else {
+ if (fifo32_num_used(&s->rx_fifo) == FIFO_SIZE - 1) {
+ /* Set OVRRUN on 32nd character in FIFO */
+ pushed_value |= URXD_ERR | URXD_OVRRUN;
+ }
+ fifo32_push(&s->rx_fifo, pushed_value);
+ }
+}
+
+static uint32_t imx_serial_rx_fifo_pop(IMXSerialState *s)
+{
+ if (fifo32_is_empty(&s->rx_fifo)) {
+ return 0;
+ }
+ return fifo32_pop(&s->rx_fifo);
+}
+
+static void imx_serial_rx_fifo_ageing_timer_int(void *opaque)
+{
+ IMXSerialState *s = (IMXSerialState *) opaque;
+ s->usr1 |= USR1_AGTIM;
+ imx_update(s);
+}
+
+static void imx_serial_rx_fifo_ageing_timer_restart(void *opaque)
+{
+ /*
+ * Ageing timer starts ticking when
+ * RX FIFO is non empty and below trigger level.
+ * Timer is reset if new character is received or
+ * a FIFO read occurs.
+ * Timer triggers an interrupt when duration of
+ * 8 characters has passed (assuming 115200 baudrate).
+ */
+ IMXSerialState *s = (IMXSerialState *) opaque;
+
+ if (!(s->usr1 & USR1_RRDY) && !(s->uts1 & UTS1_RXEMPTY)) {
+ timer_mod_ns(&s->ageing_timer,
+ qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + AGE_DURATION_NS);
+ } else {
+ timer_del(&s->ageing_timer);
+ }
+}
+
static void imx_serial_reset(IMXSerialState *s)
{
@@ -102,7 +159,9 @@ static void imx_serial_reset(IMXSerialState *s)
s->ucr3 = 0x700;
s->ubmr = 0;
s->ubrc = 4;
- s->readbuff = URXD_ERR;
+
+ fifo32_reset(&s->rx_fifo);
+ timer_del(&s->ageing_timer);
}
static void imx_serial_reset_at_boot(DeviceState *dev)
@@ -125,20 +184,28 @@ static uint64_t imx_serial_read(void *opaque, hwaddr offset,
unsigned size)
{
IMXSerialState *s = (IMXSerialState *)opaque;
- uint32_t c;
+ uint32_t c, rx_used;
+ uint8_t rxtl = s->ufcr & TL_MASK;
DPRINTF("read(offset=0x%" HWADDR_PRIx ")\n", offset);
switch (offset >> 2) {
case 0x0: /* URXD */
- c = s->readbuff;
+ c = imx_serial_rx_fifo_pop(s);
if (!(s->uts1 & UTS1_RXEMPTY)) {
/* Character is valid */
c |= URXD_CHARRDY;
- s->usr1 &= ~USR1_RRDY;
- s->usr2 &= ~USR2_RDR;
- s->uts1 |= UTS1_RXEMPTY;
+ rx_used = fifo32_num_used(&s->rx_fifo);
+ /* Clear RRDY if below threshold */
+ if (rx_used < rxtl) {
+ s->usr1 &= ~USR1_RRDY;
+ }
+ if (rx_used == 0) {
+ s->usr2 &= ~USR2_RDR;
+ s->uts1 |= UTS1_RXEMPTY;
+ }
imx_update(s);
+ imx_serial_rx_fifo_ageing_timer_restart(s);
qemu_chr_fe_accept_input(&s->chr);
}
return c;
@@ -300,19 +367,24 @@ static void imx_serial_write(void *opaque, hwaddr offset,
static int imx_can_receive(void *opaque)
{
IMXSerialState *s = (IMXSerialState *)opaque;
- return !(s->usr1 & USR1_RRDY);
+ return s->ucr2 & UCR2_RXEN && fifo32_num_used(&s->rx_fifo) < FIFO_SIZE;
}
static void imx_put_data(void *opaque, uint32_t value)
{
IMXSerialState *s = (IMXSerialState *)opaque;
+ uint8_t rxtl = s->ufcr & TL_MASK;
DPRINTF("received char\n");
+ imx_serial_rx_fifo_push(s, value);
+ if (fifo32_num_used(&s->rx_fifo) >= rxtl) {
+ s->usr1 |= USR1_RRDY;
+ }
+
+ imx_serial_rx_fifo_ageing_timer_restart(s);
- s->usr1 |= USR1_RRDY;
s->usr2 |= USR2_RDR;
s->uts1 &= ~UTS1_RXEMPTY;
- s->readbuff = value;
if (value & URXD_BRK) {
s->usr2 |= USR2_BRCD;
}
@@ -345,6 +417,10 @@ static void imx_serial_realize(DeviceState *dev, Error **errp)
{
IMXSerialState *s = IMX_SERIAL(dev);
+ fifo32_create(&s->rx_fifo, FIFO_SIZE);
+ timer_init_ns(&s->ageing_timer, QEMU_CLOCK_VIRTUAL,
+ imx_serial_rx_fifo_ageing_timer_int, s);
+
DPRINTF("char dev for uart: %p\n", qemu_chr_fe_get_driver(&s->chr));
qemu_chr_fe_set_handlers(&s->chr, imx_can_receive, imx_receive,