[Qemu-devel] [RFC PATCH v2 1/4] cadence_uart: initial version of device model

["Peter A. G. Crosthwaite" <peter.crosthwaite@petalogix.com>]

Implemented cadence UART serial controller

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
Signed-off-by: John Linn <john.linn@xilinx.com>
---
changes from v1:
converted register file to array
added vmsd state save/load support
removed read side effects from CISR register

 Makefile.target   |    1 +
 hw/cadence_uart.c |  561 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 562 insertions(+), 0 deletions(-)
 create mode 100644 hw/cadence_uart.c

diff --git a/Makefile.target b/Makefile.target
index 68481a3..620a91d 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -337,6 +337,7 @@ endif
 obj-arm-y = integratorcp.o versatilepb.o arm_pic.o arm_timer.o
 obj-arm-y += arm_boot.o pl011.o pl031.o pl050.o pl080.o pl110.o pl181.o pl190.o
 obj-arm-y += versatile_pci.o
+obj-arm-y += cadence_uart.o
 obj-arm-y += realview_gic.o realview.o arm_sysctl.o arm11mpcore.o a9mpcore.o
 obj-arm-y += arm_l2x0.o
 obj-arm-y += arm_mptimer.o
diff --git a/hw/cadence_uart.c b/hw/cadence_uart.c
new file mode 100644
index 0000000..1a57519
--- /dev/null
+++ b/hw/cadence_uart.c
@@ -0,0 +1,561 @@
+/*
+ * Device model for Cadence UART
+ *
+ * Copyright (c) 2010 Xilinx Inc.
+ * Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
+ * Copyright (c) 2012 PetaLogix Pty Ltd.
+ * Written by Haibing Ma
+ *            M.Habib
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
+ * 02139, USA.
+ */
+
+#include "sysbus.h"
+#include "qemu-char.h"
+#include "qemu-timer.h"
+
+#ifdef CADENCE_UART_ERR_DEBUG
+#define qemu_debug(...) do { \
+    fprintf(stderr,  ": %s: ", __func__); \
+    fprintf(stderr, ## __VA_ARGS__); \
+    fflush(stderr); \
+    } while (0);
+#else
+    #define qemu_debug(...)
+#endif
+
+#define UART_INTR_RTRIG     0x00000001
+#define UART_INTR_REMPTY    0x00000002
+#define UART_INTR_RFUL      0x00000004
+#define UART_INTR_TEMPTY    0x00000008
+#define UART_INTR_TFUL      0x00000010
+#define UART_INTR_ROVR      0x00000020
+#define UART_INTR_FRAME     0x00000040
+#define UART_INTR_PARE      0x00000080
+#define UART_INTR_TIMEOUT   0x00000100
+#define UART_INTR_DMSI      0x00000200
+#define UART_INTR_TTRIG     0x00000400
+#define UART_INTR_TNFUL     0x00000800
+#define UART_INTR_TOVR      0x00001000
+
+#define UART_CSR_RTRIG      0x00000001
+#define UART_CSR_REMPTY     0x00000002
+#define UART_CSR_RFUL       0x00000004
+#define UART_CSR_TEMPTY     0x00000008
+#define UART_CSR_TFUL       0x00000010
+#define UART_CSR_ROVR       0x00000020
+#define UART_CSR_FRAME      0x00000040
+#define UART_CSR_PARE       0x00000080
+#define UART_CSR_TIMEOUT    0x00000100
+#define UART_CSR_DMSI       0x00000200
+#define UART_CSR_RACTIVE    0x00000400
+#define UART_CSR_TACTIVE    0x00000800
+#define UART_CSR_FDELT      0x00001000
+#define UART_CSR_TTRIG      0x00002000
+#define UART_CSR_TNFUL      0x00004000
+
+#define UART_CR_STOPBRK     0x00000100
+#define UART_CR_STARTBRK    0x00000080
+#define UART_CR_RST_TO      0x00000040
+#define UART_CR_TX_DIS      0x00000020
+#define UART_CR_TX_EN       0x00000010
+#define UART_CR_RX_DIS      0x00000008
+#define UART_CR_RX_EN       0x00000004
+#define UART_CR_TXRST       0x00000002
+#define UART_CR_RXRST       0x00000001
+
+#define UART_MR_CLKS            0x00000001
+#define UART_MR_CHRL            0x00000006
+#define UART_MR_PAR             0x00000038
+#define UART_MR_NBSTOP          0x000000C0
+#define UART_MR_CHMODE          0x00000300
+#define UART_MR_UCLKEN          0x00000400
+#define UART_MR_IRMODE          0x00000800
+
+#define UART_PARITY_ODD        0x001
+#define UART_PARITY_EVEN       0x000
+#define UART_DATA_BITS_6       0x003
+#define UART_DATA_BITS_7       0x002
+#define UART_STOP_BITS_1       0x003
+#define UART_STOP_BITS_2       0x002
+#define RX_FIFO_SIZE           16
+#define TX_FIFO_SIZE           16
+#define UARK_INPUT_CLK         50000000
+
+#define NORMAL_MODE            0
+#define ECHO_MODE              1
+#define LOCAL_LOOPBACK         2
+#define REMOTE_LOOPBACK        3
+
+#define R_CR       (0x00/4)
+#define R_MR       (0x04/4)
+#define R_IER      (0x08/4)
+#define R_IDR      (0x0C/4)
+#define R_IMR      (0x10/4)
+#define R_CISR     (0x14/4)
+#define R_BRGR     (0x18/4)
+#define R_RTOR     (0x1C/4)
+#define R_RTRIG    (0x20/4)
+#define R_MCR      (0x24/4)
+#define R_MSR      (0x28/4)
+#define R_CSR      (0x2C/4)
+#define R_TX_RX    (0x30/4)
+#define R_BDIV     (0x34/4)
+#define R_FDEL     (0x38/4)
+#define R_PMIN     (0x3C/4)
+#define R_PWID     (0x40/4)
+#define R_TTRIG    (0x44/4)
+
+#define R_MAX (R_TTRIG + 1)
+
+typedef struct {
+    SysBusDevice busdev;
+    MemoryRegion iomem;
+    uint32_t r[R_MAX];
+    uint8_t r_fifo[RX_FIFO_SIZE];
+    uint32_t rx_wpos;
+    uint32_t rx_count;
+    uint64_t char_tx_time;
+    CharDriverState *chr;
+    qemu_irq irq;
+    struct QEMUTimer *fifo_trigger_handle;
+    struct QEMUTimer *tx_time_handle;
+} UartState;
+
+static void uart_update_status(UartState *s)
+{
+    qemu_set_irq(s->irq, !!(s->r[R_IMR] & s->r[R_CISR]));
+}
+
+static void fifo_trigger_update(void *opaque)
+{
+    UartState *s = (UartState *)opaque;
+
+    s->r[R_CSR] |= UART_CSR_TIMEOUT;
+    s->r[R_CISR] |= UART_INTR_TIMEOUT;
+
+    uart_update_status(s);
+}
+
+static void uart_tx_redo(UartState *s)
+{
+    uint64_t new_tx_time = qemu_get_clock_ns(vm_clock);
+
+    qemu_mod_timer(s->tx_time_handle, new_tx_time + s->char_tx_time);
+
+    s->r[R_CSR] |= UART_CSR_TEMPTY;
+    s->r[R_CISR] |= UART_INTR_TEMPTY;
+
+    uart_update_status(s);
+}
+
+static void uart_tx_write(void *opaque)
+{
+    UartState *s = (UartState *)opaque;
+
+    uart_tx_redo(s);
+}
+
+static void uart_rx_reset(UartState *s)
+{
+    s->rx_wpos = 0;
+    s->rx_count = 0;
+
+    s->r[R_CSR] |= UART_CSR_REMPTY;
+    s->r[R_CSR] &= ~UART_CSR_RFUL;
+    s->r[R_CSR] &= ~UART_CSR_ROVR;
+    s->r[R_CSR] &= ~UART_CSR_TIMEOUT;
+
+    s->r[R_CISR] &= ~UART_INTR_REMPTY;
+    s->r[R_CISR] &= ~UART_INTR_RFUL;
+    s->r[R_CISR] &= ~UART_INTR_ROVR;
+    s->r[R_CISR] &= ~UART_INTR_TIMEOUT;
+}
+
+static void uart_tx_reset(UartState *s)
+{
+    s->r[R_CSR] |= UART_CSR_TEMPTY;
+    s->r[R_CSR] &= ~UART_CSR_TFUL;
+
+    s->r[R_CISR] &= ~UART_INTR_TEMPTY;
+    s->r[R_CISR] &= ~UART_INTR_TFUL;
+}
+
+static void uart_send_breaks(UartState *s)
+{
+    int break_enabled = 1;
+
+    qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
+                               &break_enabled);
+}
+
+static inline uint32_t mask_and_right_justify(uint32_t value, uint32_t mask)
+{
+    while (!mask & 0x1) {
+        mask >>= 1;
+        value >>= 1;
+    }
+    return value & mask;
+}
+
+static void uart_parameters_setup(UartState *s)
+{
+    QEMUSerialSetParams ssp;
+    unsigned int baud_rate, packet_size;
+
+    baud_rate = (s->r[R_MR] & UART_MR_CLKS) ?
+            UARK_INPUT_CLK / 8 : UARK_INPUT_CLK;
+
+    ssp.speed = baud_rate / (s->r[R_BRGR] * (s->r[R_BDIV] + 1));
+    packet_size = 1;
+
+    switch (mask_and_right_justify(s->r[R_MR], UART_MR_PAR)) {
+    case UART_PARITY_EVEN:
+        ssp.parity = 'E';
+        packet_size++;
+        break;
+    case UART_PARITY_ODD:
+        ssp.parity = 'O';
+        packet_size++;
+        break;
+    default:
+        ssp.parity = 'N';
+        break;
+    }
+
+    switch (mask_and_right_justify(s->r[R_MR], UART_MR_CHRL)) {
+    case UART_DATA_BITS_6:
+        ssp.data_bits = 6;
+        break;
+    case UART_DATA_BITS_7:
+        ssp.data_bits = 7;
+        break;
+    default:
+        ssp.data_bits = 8;
+        break;
+    }
+
+    switch (mask_and_right_justify(s->r[R_MR], UART_MR_NBSTOP)) {
+    case UART_STOP_BITS_1:
+        ssp.stop_bits = 1;
+        break;
+    default:
+        ssp.stop_bits = 2;
+        break;
+    }
+
+    packet_size += ssp.data_bits + ssp.stop_bits;
+    s->char_tx_time =  (get_ticks_per_sec() / ssp.speed) * packet_size;
+    qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
+}
+
+static void uart_stop_breaks(UartState *s)
+{
+    int break_enabled = 0;
+    qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
+                               &break_enabled);
+}
+
+static int uart_can_receive(void *opaque)
+{
+    UartState *s = (UartState *)opaque;
+
+    return RX_FIFO_SIZE - s->rx_count;
+}
+
+static void uart_ctrl_update(UartState *s, uint32_t value)
+{
+    if (value & UART_CR_TXRST) {
+        uart_tx_reset(s);
+    }
+
+    if (value & UART_CR_RXRST) {
+        uart_rx_reset(s);
+    }
+
+    s->r[R_CR] &= ~(UART_CR_TXRST | UART_CR_RXRST);
+
+    if ((value & UART_CR_TX_EN) && !(s->r[R_CR] & UART_CR_TX_DIS)) {
+            uart_tx_redo(s);
+    }
+
+    if (value & UART_CR_STARTBRK) {
+        if (!(s->r[R_CR] & UART_CR_STOPBRK)) {
+            uart_send_breaks(s);
+        }
+    }
+    if (value & UART_CR_STARTBRK) {
+        uart_stop_breaks(s);
+    }
+}
+
+static void uart_write_rx_fifo(void *opaque, const uint8_t *buf, int size)
+{
+    UartState *s = (UartState *)opaque;
+    uint64_t new_rx_time = qemu_get_clock_ns(vm_clock);
+    int i;
+
+    if ((s->r[R_CR] & UART_CR_RX_DIS) || !(s->r[R_CR] & UART_CR_RX_EN)) {
+        return;
+    }
+
+    s->r[R_CSR] &= ~UART_CSR_REMPTY;
+    s->r[R_CISR] &= ~UART_INTR_REMPTY;
+
+    if (s->rx_count == RX_FIFO_SIZE) {
+        s->r[R_CISR] |= UART_INTR_ROVR;
+        s->r[R_CSR] |= UART_CSR_ROVR;
+    } else {
+        for (i = 0; i < size; i++) {
+            s->r_fifo[s->rx_wpos] = buf[i];
+            s->rx_wpos = (s->rx_wpos + 1) % RX_FIFO_SIZE;
+            s->rx_count++;
+
+            if (s->rx_count == RX_FIFO_SIZE) {
+                s->r[R_CSR] |= UART_CSR_RFUL;
+                s->r[R_CISR] |= UART_INTR_RFUL;
+                break;
+            }
+
+            if (s->rx_count >= s->r[R_RTRIG]) {
+                s->r[R_CISR] |= UART_INTR_RTRIG;
+                s->r[R_CSR] |= UART_CSR_RTRIG;
+            }
+        }
+        qemu_mod_timer(s->fifo_trigger_handle, new_rx_time +
+                                                (s->char_tx_time * 4));
+    }
+    uart_update_status(s);
+}
+
+static void uart_write_tx_fifo(UartState *s, unsigned  char *c)
+{
+    unsigned  char ch = *c;
+
+    if ((s->r[R_CR] & UART_CR_TX_DIS) || !(s->r[R_CR] & UART_CR_TX_EN)) {
+        return;
+    }
+
+    while (!qemu_chr_fe_write(s->chr, &ch, 1)) {
+    }
+}
+
+static void uart_receive(void *opaque, const uint8_t *buf, int size)
+{
+    UartState *s = (UartState *)opaque;
+    uint32_t ch_mode = mask_and_right_justify(s->r[R_MR], UART_MR_CHMODE);
+
+    if (ch_mode == NORMAL_MODE || ch_mode == ECHO_MODE) {
+        uart_write_rx_fifo(opaque, buf, size);
+    }
+    if (ch_mode == REMOTE_LOOPBACK || ch_mode == ECHO_MODE) {
+        uart_write_tx_fifo(s, (unsigned char *)buf);
+    }
+}
+
+static void uart_event(void *opaque, int event)
+{
+    UartState *s = (UartState *)opaque;
+    uint8_t buf = '\0';
+
+    if (event == CHR_EVENT_BREAK) {
+        uart_write_rx_fifo(opaque, &buf, 1);
+    }
+
+    uart_update_status(s);
+}
+
+static void uart_read_rx_fifo(UartState *s, uint32_t *c)
+{
+    if ((s->r[R_CR] & UART_CR_RX_DIS) || !(s->r[R_CR] & UART_CR_RX_EN)) {
+        return;
+    }
+
+    s->r[R_CSR] &= ~UART_CSR_RFUL;
+    s->r[R_CSR] &= ~UART_CSR_ROVR;
+    s->r[R_CISR] &= ~UART_INTR_ROVR;
+    s->r[R_CISR] &= ~UART_INTR_RFUL;
+
+    if (s->rx_count) {
+        uint32_t rx_rpos =
+                (RX_FIFO_SIZE + s->rx_wpos - s->rx_count) % RX_FIFO_SIZE;
+        *c = s->r_fifo[rx_rpos];
+        s->rx_count--;
+
+        if (!s->rx_count) {
+            s->r[R_CISR] |= UART_INTR_REMPTY;
+            s->r[R_CSR] |= UART_CSR_REMPTY;
+        }
+    } else {
+        *c = 0;
+        s->r[R_CISR] |= UART_INTR_REMPTY;
+        s->r[R_CSR] |= UART_CSR_REMPTY;
+    }
+
+    if (s->rx_count < s->r[R_RTRIG]) {
+        s->r[R_CSR] &= ~UART_CSR_RTRIG;
+        s->r[R_CISR] &= ~UART_INTR_RTRIG;
+    }
+    uart_update_status(s);
+}
+
+static void uart_write(void *opaque, target_phys_addr_t offset,
+                          uint64_t value, unsigned size)
+{
+    UartState *s = (UartState *)opaque;
+
+    qemu_debug(" offset:%x data:%08x\n", offset, (unsigned)value);
+    offset >>= 2;
+    switch (offset) {
+    case R_IER: /* ier (wts imr) */
+        s->r[R_IMR] |= value;
+        break;
+    case R_IDR: /* idr (wtc imr) */
+        s->r[R_IMR] &= ~value;
+        break;
+    case R_IMR: /* imr (read only) */
+        break;
+    case R_CISR: /* cisr (wtc) */
+        s->r[R_CISR] &= ~value;
+        break;
+    case R_TX_RX: /* UARTDR */
+        switch (mask_and_right_justify(s->r[R_MR], UART_MR_CHMODE)) {
+        case NORMAL_MODE:
+            uart_write_tx_fifo(s, (unsigned  char *) &value);
+            break;
+        case LOCAL_LOOPBACK:
+            uart_write_rx_fifo(opaque, (unsigned  char *) &value, 1);
+            break;
+        }
+        break;
+    default:
+        s->r[offset] = value;
+    }
+
+    switch (offset) {
+    case R_CR:
+        uart_ctrl_update(s, value);
+        break;
+    case R_MR:
+        uart_parameters_setup(s);
+        break;
+    }
+}
+
+static uint64_t uart_read(void *opaque, target_phys_addr_t offset,
+        unsigned size)
+{
+    UartState *s = (UartState *)opaque;
+    uint32_t c = 0;
+
+    offset >>= 2;
+    if (offset > R_MAX) {
+        return 0;
+    } else if (offset == R_TX_RX) {
+        uart_read_rx_fifo(s, &c);
+        return c;
+    }
+    return s->r[offset];
+}
+
+static const MemoryRegionOps uart_ops = {
+    .read = uart_read,
+    .write = uart_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static int cadence_uart_init(SysBusDevice *dev)
+{
+    UartState *s = FROM_SYSBUS(UartState, dev);
+
+    memory_region_init_io(&s->iomem, &uart_ops, s, "uart", 0x1000);
+    sysbus_init_mmio(dev, &s->iomem);
+    sysbus_init_irq(dev, &s->irq);
+
+    s->fifo_trigger_handle = qemu_new_timer_ns(vm_clock,
+            (QEMUTimerCB *)fifo_trigger_update, s);
+
+    s->tx_time_handle = qemu_new_timer_ns(vm_clock,
+            (QEMUTimerCB *)uart_tx_write, s);
+
+    s->char_tx_time = (get_ticks_per_sec() / 9600) * 10;
+
+    s->chr = qemu_char_get_next_serial();
+
+    s->r[R_CR] = 0x00000128;
+    s->r[R_IMR] = 0;
+    s->r[R_CISR] = 0;
+    s->r[R_RTRIG] = 0x00000020;
+    s->r[R_BRGR] = 0x0000000F;
+    s->r[R_TTRIG] = 0x00000020;
+
+    uart_rx_reset(s);
+    uart_tx_reset(s);
+
+    s->rx_count = 0;
+    s->rx_wpos = 0;
+
+    if (s->chr) {
+        qemu_chr_add_handlers(s->chr, uart_can_receive, uart_receive,
+                              uart_event, s);
+    }
+
+    return 0;
+}
+
+static int cadence_uart_post_load(void *opaque, int version_id)
+{
+    UartState *s = opaque;
+
+    uart_parameters_setup(s);
+    uart_update_status(s);
+    return 0;
+}
+
+static const VMStateDescription vmstate_cadence_uart = {
+    .name = "cadence_uart",
+    .version_id = 3,
+    .minimum_version_id = 2,
+    .minimum_version_id_old = 2,
+    .post_load = cadence_uart_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(r, UartState, R_MAX),
+        VMSTATE_UINT8_ARRAY(r_fifo, UartState, RX_FIFO_SIZE),
+        VMSTATE_UINT32(rx_count, UartState),
+        VMSTATE_UINT32(rx_wpos, UartState),
+        VMSTATE_TIMER(fifo_trigger_handle, UartState),
+        VMSTATE_TIMER(tx_time_handle, UartState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void cadence_uart_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
+
+    sdc->init = cadence_uart_init;
+    dc->vmsd = &vmstate_cadence_uart;
+}
+
+static TypeInfo cadence_uart_info = {
+    .name          = "cadence_uart",
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(UartState),
+    .class_init    = cadence_uart_class_init,
+};
+
+static void cadence_uart_register(void)
+{
+    type_register_static(&cadence_uart_info);
+}
+
+device_init(cadence_uart_register)
-- 
1.7.3.2