xilinx_spi: Initial impl. of Xilinx SPI controller

Device model for xilinx XPS SPI controller (v2.0)
Signed-off-by: NPeter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>

hw/microblaze/Makefile.objs

 obj-y = petalogix_s3adsp1800_mmu.o
 obj-y += petalogix_ml605_mmu.o
 obj-y += microblaze_boot.o
+obj-y += xilinx_spi.o
 
 obj-y += microblaze_pic_cpu.o
 obj-y += xilinx_ethlite.o

hw/xilinx_spi.c

+/*
+ * QEMU model of the Xilinx SPI Controller
+ *
+ * Copyright (C) 2010 Edgar E. Iglesias.
+ * Copyright (C) 2012 Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
+ * Copyright (C) 2012 PetaLogix
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "sysbus.h"
+#include "sysemu.h"
+#include "qemu-log.h"
+#include "fifo.h"
+
+#include "ssi.h"
+
+#ifdef XILINX_SPI_ERR_DEBUG
+#define DB_PRINT(...) do { \
+    fprintf(stderr,  ": %s: ", __func__); \
+    fprintf(stderr, ## __VA_ARGS__); \
+    } while (0);
+#else
+    #define DB_PRINT(...)
+#endif
+
+#define R_DGIER     (0x1c / 4)
+#define R_DGIER_IE  (1 << 31)
+
+#define R_IPISR     (0x20 / 4)
+#define IRQ_DRR_NOT_EMPTY    (1 << (31 - 23))
+#define IRQ_DRR_OVERRUN      (1 << (31 - 26))
+#define IRQ_DRR_FULL         (1 << (31 - 27))
+#define IRQ_TX_FF_HALF_EMPTY (1 << 6)
+#define IRQ_DTR_UNDERRUN     (1 << 3)
+#define IRQ_DTR_EMPTY        (1 << (31 - 29))
+
+#define R_IPIER     (0x28 / 4)
+#define R_SRR       (0x40 / 4)
+#define R_SPICR     (0x60 / 4)
+#define R_SPICR_TXFF_RST     (1 << 5)
+#define R_SPICR_RXFF_RST     (1 << 6)
+#define R_SPICR_MTI          (1 << 8)
+
+#define R_SPISR     (0x64 / 4)
+#define SR_TX_FULL    (1 << 3)
+#define SR_TX_EMPTY   (1 << 2)
+#define SR_RX_FULL    (1 << 1)
+#define SR_RX_EMPTY   (1 << 0)
+
+#define R_SPIDTR    (0x68 / 4)
+#define R_SPIDRR    (0x6C / 4)
+#define R_SPISSR    (0x70 / 4)
+#define R_TX_FF_OCY (0x74 / 4)
+#define R_RX_FF_OCY (0x78 / 4)
+#define R_MAX       (0x7C / 4)
+
+#define FIFO_CAPACITY 256
+
+typedef struct XilinxSPI {
+    SysBusDevice busdev;
+    MemoryRegion mmio;
+
+    qemu_irq irq;
+    int irqline;
+
+    uint8_t num_cs;
+    qemu_irq *cs_lines;
+
+    SSIBus *spi;
+
+    Fifo8 rx_fifo;
+    Fifo8 tx_fifo;
+
+    uint32_t regs[R_MAX];
+} XilinxSPI;
+
+static void txfifo_reset(XilinxSPI *s)
+{
+    fifo8_reset(&s->tx_fifo);
+
+    s->regs[R_SPISR] &= ~SR_TX_FULL;
+    s->regs[R_SPISR] |= SR_TX_EMPTY;
+}
+
+static void rxfifo_reset(XilinxSPI *s)
+{
+    fifo8_reset(&s->rx_fifo);
+
+    s->regs[R_SPISR] |= SR_RX_EMPTY;
+    s->regs[R_SPISR] &= ~SR_RX_FULL;
+}
+
+static void xlx_spi_update_cs(XilinxSPI *s)
+{
+   int i;
+
+    for (i = 0; i < s->num_cs; ++i) {
+        qemu_set_irq(s->cs_lines[i], !(~s->regs[R_SPISSR] & 1 << i));
+    }
+}
+
+static void xlx_spi_update_irq(XilinxSPI *s)
+{
+    uint32_t pending;
+
+    s->regs[R_IPISR] |=
+            (!fifo8_is_empty(&s->rx_fifo) ? IRQ_DRR_NOT_EMPTY : 0) |
+            (fifo8_is_full(&s->rx_fifo) ? IRQ_DRR_FULL : 0);
+
+    pending = s->regs[R_IPISR] & s->regs[R_IPIER];
+
+    pending = pending && (s->regs[R_DGIER] & R_DGIER_IE);
+    pending = !!pending;
+
+    /* This call lies right in the data paths so don't call the
+       irq chain unless things really changed.  */
+    if (pending != s->irqline) {
+        s->irqline = pending;
+        DB_PRINT("irq_change of state %d ISR:%x IER:%X\n",
+                    pending, s->regs[R_IPISR], s->regs[R_IPIER]);
+        qemu_set_irq(s->irq, pending);
+    }
+
+}
+
+static void xlx_spi_do_reset(XilinxSPI *s)
+{
+    memset(s->regs, 0, sizeof s->regs);
+
+    rxfifo_reset(s);
+    txfifo_reset(s);
+
+    s->regs[R_SPISSR] = ~0;
+    xlx_spi_update_irq(s);
+    xlx_spi_update_cs(s);
+}
+
+static void xlx_spi_reset(DeviceState *d)
+{
+    xlx_spi_do_reset(DO_UPCAST(XilinxSPI, busdev.qdev, d));
+}
+
+static inline int spi_master_enabled(XilinxSPI *s)
+{
+    return !(s->regs[R_SPICR] & R_SPICR_MTI);
+}
+
+static void spi_flush_txfifo(XilinxSPI *s)
+{
+    uint32_t tx;
+    uint32_t rx;
+
+    while (!fifo8_is_empty(&s->tx_fifo)) {
+        tx = (uint32_t)fifo8_pop(&s->tx_fifo);
+        DB_PRINT("data tx:%x\n", tx);
+        rx = ssi_transfer(s->spi, tx);
+        DB_PRINT("data rx:%x\n", rx);
+        if (fifo8_is_full(&s->rx_fifo)) {
+            s->regs[R_IPISR] |= IRQ_DRR_OVERRUN;
+        } else {
+            fifo8_push(&s->rx_fifo, (uint8_t)rx);
+            if (fifo8_is_full(&s->rx_fifo)) {
+                s->regs[R_SPISR] |= SR_RX_FULL;
+                s->regs[R_IPISR] |= IRQ_DRR_FULL;
+            }
+        }
+
+        s->regs[R_SPISR] &= ~SR_RX_EMPTY;
+        s->regs[R_SPISR] &= ~SR_TX_FULL;
+        s->regs[R_SPISR] |= SR_TX_EMPTY;
+
+        s->regs[R_IPISR] |= IRQ_DTR_EMPTY;
+        s->regs[R_IPISR] |= IRQ_DRR_NOT_EMPTY;
+    }
+
+}
+
+static uint64_t
+spi_read(void *opaque, target_phys_addr_t addr, unsigned int size)
+{
+    XilinxSPI *s = opaque;
+    uint32_t r = 0;
+
+    addr >>= 2;
+    switch (addr) {
+    case R_SPIDRR:
+        if (fifo8_is_empty(&s->rx_fifo)) {
+            DB_PRINT("Read from empty FIFO!\n");
+            return 0xdeadbeef;
+        }
+
+        s->regs[R_SPISR] &= ~SR_RX_FULL;
+        r = fifo8_pop(&s->rx_fifo);
+        if (fifo8_is_empty(&s->rx_fifo)) {
+            s->regs[R_SPISR] |= SR_RX_EMPTY;
+        }
+        break;
+
+    case R_SPISR:
+        r = s->regs[addr];
+        break;
+
+    default:
+        if (addr < ARRAY_SIZE(s->regs)) {
+            r = s->regs[addr];
+        }
+        break;
+
+    }
+    DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr * 4, r);
+    xlx_spi_update_irq(s);
+    return r;
+}
+
+static void
+spi_write(void *opaque, target_phys_addr_t addr,
+            uint64_t val64, unsigned int size)
+{
+    XilinxSPI *s = opaque;
+    uint32_t value = val64;
+
+    DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr, value);
+    addr >>= 2;
+    switch (addr) {
+    case R_SRR:
+        if (value != 0xa) {
+            DB_PRINT("Invalid write to SRR %x\n", value);
+        } else {
+            xlx_spi_do_reset(s);
+        }
+        break;
+
+    case R_SPIDTR:
+        s->regs[R_SPISR] &= ~SR_TX_EMPTY;
+        fifo8_push(&s->tx_fifo, (uint8_t)value);
+        if (fifo8_is_full(&s->tx_fifo)) {
+            s->regs[R_SPISR] |= SR_TX_FULL;
+        }
+        if (!spi_master_enabled(s)) {
+            goto done;
+        } else {
+            DB_PRINT("DTR and master enabled\n");
+        }
+        spi_flush_txfifo(s);
+        break;
+
+    case R_SPISR:
+        DB_PRINT("Invalid write to SPISR %x\n", value);
+        break;
+
+    case R_IPISR:
+        /* Toggle the bits.  */
+        s->regs[addr] ^= value;
+        break;
+
+    /* Slave Select Register.  */
+    case R_SPISSR:
+        s->regs[addr] = value;
+        xlx_spi_update_cs(s);
+        break;
+
+    case R_SPICR:
+        /* FIXME: reset irq and sr state to empty queues.  */
+        if (value & R_SPICR_RXFF_RST) {
+            rxfifo_reset(s);
+        }
+
+        if (value & R_SPICR_TXFF_RST) {
+            txfifo_reset(s);
+        }
+        value &= ~(R_SPICR_RXFF_RST | R_SPICR_TXFF_RST);
+        s->regs[addr] = value;
+
+        if (!(value & R_SPICR_MTI)) {
+            spi_flush_txfifo(s);
+        }
+        break;
+
+    default:
+        if (addr < ARRAY_SIZE(s->regs)) {
+            s->regs[addr] = value;
+        }
+        break;
+    }
+
+done:
+    xlx_spi_update_irq(s);
+}
+
+static const MemoryRegionOps spi_ops = {
+    .read = spi_read,
+    .write = spi_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4
+    }
+};
+
+static int xilinx_spi_init(SysBusDevice *dev)
+{
+    int i;
+    XilinxSPI *s = FROM_SYSBUS(typeof(*s), dev);
+
+    DB_PRINT("\n");
+    sysbus_init_irq(dev, &s->irq);
+    s->cs_lines = g_new(qemu_irq, s->num_cs);
+    for (i = 0; i < s->num_cs; ++i) {
+        sysbus_init_irq(dev, &s->cs_lines[i]);
+    }
+
+    memory_region_init_io(&s->mmio, &spi_ops, s, "xilinx-spi", R_MAX * 4);
+    sysbus_init_mmio(dev, &s->mmio);
+
+    s->irqline = -1;
+
+    s->spi = ssi_create_bus(&dev->qdev, "spi");
+
+    fifo8_create(&s->tx_fifo, FIFO_CAPACITY);
+    fifo8_create(&s->rx_fifo, FIFO_CAPACITY);
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_xilinx_spi = {
+    .name = "xilinx_spi",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_FIFO8(tx_fifo, XilinxSPI),
+        VMSTATE_FIFO8(rx_fifo, XilinxSPI),
+        VMSTATE_UINT32_ARRAY(regs, XilinxSPI, R_MAX),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static Property xilinx_spi_properties[] = {
+    DEFINE_PROP_UINT8("num-ss-bits", XilinxSPI, num_cs, 1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void xilinx_spi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+    k->init = xilinx_spi_init;
+    dc->reset = xlx_spi_reset;
+    dc->props = xilinx_spi_properties;
+    dc->vmsd = &vmstate_xilinx_spi;
+}
+
+static TypeInfo xilinx_spi_info = {
+    .name           = "xlnx.xps-spi",
+    .parent         = TYPE_SYS_BUS_DEVICE,
+    .instance_size  = sizeof(XilinxSPI),
+    .class_init     = xilinx_spi_class_init,
+};
+
+static void xilinx_spi_register_types(void)
+{
+    type_register_static(&xilinx_spi_info);
+}
+
+type_init(xilinx_spi_register_types)