[Qemu-devel] [PATCH v6 4/6] i.MX: Add the Freescale SPI Controller

[Jean-Christophe Dubois]

Signed-off-by: Jean-Christophe Dubois <address@hidden>
---

Changes since V1:
 * Access SPI slave only at a byte level.
 * rework the CS activation to avoid to reset access to SPI slaves.
 
Changes since V2:
 * Added #include "qemu/osdep.h"
 * remove previous_level from state struct
 * save burst_length in VMSTATE
 
Changes since V3:
 * Don't call qemu_set_irq() in reset function

Changes since V4:
 * None

Changes since V5:
 * None

 hw/ssi/Makefile.objs     |   1 +
 hw/ssi/imx_spi.c         | 454 +++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/ssi/imx_spi.h | 103 +++++++++++
 3 files changed, 558 insertions(+)
 create mode 100644 hw/ssi/imx_spi.c
 create mode 100644 include/hw/ssi/imx_spi.h

diff --git a/hw/ssi/Makefile.objs b/hw/ssi/Makefile.objs
index 9555825..fcbb79e 100644
--- a/hw/ssi/Makefile.objs
+++ b/hw/ssi/Makefile.objs
@@ -4,3 +4,4 @@ common-obj-$(CONFIG_XILINX_SPI) += xilinx_spi.o
 common-obj-$(CONFIG_XILINX_SPIPS) += xilinx_spips.o
 
 obj-$(CONFIG_OMAP) += omap_spi.o
+obj-$(CONFIG_IMX) += imx_spi.o
diff --git a/hw/ssi/imx_spi.c b/hw/ssi/imx_spi.c
new file mode 100644
index 0000000..d5dd42a
--- /dev/null
+++ b/hw/ssi/imx_spi.c
@@ -0,0 +1,454 @@
+/*
+ * IMX SPI Controller
+ *
+ * Copyright (c) 2016 Jean-Christophe Dubois <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "hw/ssi/imx_spi.h"
+#include "sysemu/sysemu.h"
+
+#ifndef DEBUG_IMX_SPI
+#define DEBUG_IMX_SPI 0
+#endif
+
+#define DPRINTF(fmt, args...) \
+    do { \
+        if (DEBUG_IMX_SPI) { \
+            fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SPI, \
+                                             __func__, ##args); \
+        } \
+    } while (0)
+
+static char const *imx_spi_reg_name(uint32_t reg)
+{
+    static char unknown[20];
+
+    switch (reg) {
+    case ECSPI_RXDATA:
+        return  "ECSPI_RXDATA";
+    case ECSPI_TXDATA:
+        return  "ECSPI_TXDATA";
+    case ECSPI_CONREG:
+        return  "ECSPI_CONREG";
+    case ECSPI_CONFIGREG:
+        return  "ECSPI_CONFIGREG";
+    case ECSPI_INTREG:
+        return  "ECSPI_INTREG";
+    case ECSPI_DMAREG:
+        return  "ECSPI_DMAREG";
+    case ECSPI_STATREG:
+        return  "ECSPI_STATREG";
+    case ECSPI_PERIODREG:
+        return  "ECSPI_PERIODREG";
+    case ECSPI_TESTREG:
+        return  "ECSPI_TESTREG";
+    case ECSPI_MSGDATA:
+        return  "ECSPI_MSGDATA";
+    default:
+        sprintf(unknown, "%d ?", reg);
+        return unknown;
+    }
+}
+
+static const VMStateDescription vmstate_imx_spi = {
+    .name = TYPE_IMX_SPI,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_FIFO32(tx_fifo, IMXSPIState),
+        VMSTATE_FIFO32(rx_fifo, IMXSPIState),
+        VMSTATE_INT16(burst_length, IMXSPIState),
+        VMSTATE_UINT32_ARRAY(regs, IMXSPIState, ECSPI_MAX),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static void imx_spi_txfifo_reset(IMXSPIState *s)
+{
+    fifo32_reset(&s->tx_fifo);
+    s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
+    s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
+}
+
+static void imx_spi_rxfifo_reset(IMXSPIState *s)
+{
+    fifo32_reset(&s->rx_fifo);
+    s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
+    s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
+    s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RO;
+}
+
+static void imx_spi_update_irq(IMXSPIState *s)
+{
+    int level;
+
+    if (fifo32_is_empty(&s->rx_fifo)) {
+        s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
+    } else {
+        s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RR;
+    }
+
+    if (fifo32_is_full(&s->rx_fifo)) {
+        s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RF;
+    } else {
+        s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
+    }
+
+    if (fifo32_is_empty(&s->tx_fifo)) {
+        s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
+    } else {
+        s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TE;
+    }
+
+    if (fifo32_is_full(&s->tx_fifo)) {
+        s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TF;
+    } else {
+        s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
+    }
+
+    level = s->regs[ECSPI_STATREG] & s->regs[ECSPI_INTREG] ? 1 : 0;
+
+    qemu_set_irq(s->irq, level);
+
+    DPRINTF("IRQ level is %d\n", level);
+}
+
+static uint8_t imx_spi_selected_channel(IMXSPIState *s)
+{
+    return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_SELECT);
+}
+
+static uint32_t imx_spi_burst_length(IMXSPIState *s)
+{
+    return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1;
+}
+
+static bool imx_spi_is_enabled(IMXSPIState *s)
+{
+    return s->regs[ECSPI_CONREG] & ECSPI_CONREG_EN;
+}
+
+static bool imx_spi_channel_is_master(IMXSPIState *s)
+{
+    uint8_t mode = EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_MODE);
+
+    return (mode & (1 << imx_spi_selected_channel(s))) ? true : false;
+}
+
+static bool imx_spi_is_multiple_master_burst(IMXSPIState *s)
+{
+    uint8_t wave = EXTRACT(s->regs[ECSPI_CONFIGREG], ECSPI_CONFIGREG_SS_CTL);
+
+    return imx_spi_channel_is_master(s) &&
+           !(s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC) &&
+           ((wave & (1 << imx_spi_selected_channel(s))) ? true : false);
+}
+
+static void imx_spi_flush_txfifo(IMXSPIState *s)
+{
+    uint32_t tx;
+    uint32_t rx;
+
+    DPRINTF("Begin: TX Fifo Size = %d, RX Fifo Size = %d\n",
+            fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
+
+    while (!fifo32_is_empty(&s->tx_fifo)) {
+        int tx_burst = 0;
+        int index = 0;
+
+        if (s->burst_length <= 0) {
+            s->burst_length = imx_spi_burst_length(s);
+
+            DPRINTF("Burst length = %d\n", s->burst_length);
+
+            if (imx_spi_is_multiple_master_burst(s)) {
+                s->regs[ECSPI_CONREG] |= ECSPI_CONREG_XCH;
+            }
+        }
+
+        tx = fifo32_pop(&s->tx_fifo);
+
+        DPRINTF("data tx:0x%08x\n", tx);
+
+        tx_burst = MIN(s->burst_length, 32);
+
+        rx = 0;
+
+        while (tx_burst) {
+            uint8_t byte = tx & 0xff;
+
+            DPRINTF("writing 0x%02x\n", (uint32_t)byte);
+
+            /* We need to write one byte at a time */
+            byte = ssi_transfer(s->bus, byte);
+
+            DPRINTF("0x%02x read\n", (uint32_t)byte);
+
+            tx = tx >> 8;
+            rx |= (byte << (index * 8));
+
+            /* Remove 8 bits from the actual burst */
+            tx_burst -= 8;
+            s->burst_length -= 8;
+            index++;
+        }
+
+        DPRINTF("data rx:0x%08x\n", rx);
+
+        if (fifo32_is_full(&s->rx_fifo)) {
+            s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RO;
+        } else {
+            fifo32_push(&s->rx_fifo, (uint8_t)rx);
+        }
+
+        if (s->burst_length <= 0) {
+            s->regs[ECSPI_CONREG] &= ~ECSPI_CONREG_XCH;
+
+            if (!imx_spi_is_multiple_master_burst(s)) {
+                s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
+                break;
+            }
+        }
+    }
+
+    if (fifo32_is_empty(&s->tx_fifo)) {
+        s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
+    }
+
+    /* TODO: We should also use TDR and RDR bits */
+
+    DPRINTF("End: TX Fifo Size = %d, RX Fifo Size = %d\n",
+            fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
+}
+
+static void imx_spi_reset(DeviceState *dev)
+{
+    IMXSPIState *s = IMX_SPI(dev);
+
+    DPRINTF("\n");
+
+    memset(s->regs, 0, sizeof(s->regs));
+
+    s->regs[ECSPI_STATREG] = 0x00000003;
+
+    imx_spi_rxfifo_reset(s);
+    imx_spi_txfifo_reset(s);
+
+    imx_spi_update_irq(s);
+
+    s->burst_length = 0;
+}
+
+static uint64_t imx_spi_read(void *opaque, hwaddr offset, unsigned size)
+{
+    uint32_t value = 0;
+    IMXSPIState *s = opaque;
+    uint32_t index = offset >> 2;
+
+    if (index >=  ECSPI_MAX) {
+        qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
+                      HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
+        return 0;
+    }
+
+    switch (index) {
+    case ECSPI_RXDATA:
+        if (!imx_spi_is_enabled(s)) {
+            value = 0;
+        } else if (fifo32_is_empty(&s->rx_fifo)) {
+            /* value is undefined */
+            value = 0xdeadbeef;
+        } else {
+            /* read from the RX FIFO */
+            value = fifo32_pop(&s->rx_fifo);
+        }
+
+        break;
+    case ECSPI_TXDATA:
+        qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from TX FIFO\n",
+                      TYPE_IMX_SPI, __func__);
+
+        /* Reading from TXDATA gives 0 */
+
+        break;
+    case ECSPI_MSGDATA:
+        qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from MSG 
FIFO\n",
+                      TYPE_IMX_SPI, __func__);
+
+        /* Reading from MSGDATA gives 0 */
+
+        break;
+    default:
+        value = s->regs[index];
+        break;
+    }
+
+    DPRINTF("reg[%s] => 0x%" PRIx32 "\n", imx_spi_reg_name(index), value);
+
+    imx_spi_update_irq(s);
+
+    return (uint64_t)value;
+}
+
+static void imx_spi_write(void *opaque, hwaddr offset, uint64_t value,
+                           unsigned size)
+{
+    IMXSPIState *s = opaque;
+    uint32_t index = offset >> 2;
+    uint32_t change_mask;
+
+    if (index >=  ECSPI_MAX) {
+        qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
+                      HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
+        return;
+    }
+
+    DPRINTF("reg[%s] <= 0x%" PRIx32 "\n", imx_spi_reg_name(index),
+            (uint32_t)value);
+
+    change_mask = s->regs[index] ^ value;
+
+    switch (index) {
+    case ECSPI_RXDATA:
+        qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to write to RX FIFO\n",
+                      TYPE_IMX_SPI, __func__);
+        break;
+    case ECSPI_TXDATA:
+    case ECSPI_MSGDATA:
+        /* Is there any difference between TXDATA and MSGDATA ? */
+        /* I'll have to look in the linux driver */
+        if (!imx_spi_is_enabled(s)) {
+            /* Ignore writes if device is disabled */
+            break;
+        } else if (fifo32_is_full(&s->tx_fifo)) {
+            /* Ignore writes if queue is full */
+            break;
+        }
+
+        fifo32_push(&s->tx_fifo, (uint32_t)value);
+
+        if (imx_spi_channel_is_master(s) &&
+            (s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC)) {
+            /*
+             * Start emitting if current channel is master and SMC bit is
+             * set.
+             */
+            imx_spi_flush_txfifo(s);
+        }
+
+        break;
+    case ECSPI_STATREG:
+        /* the RO and TC bits are write-one-to-clear */
+        value &= ECSPI_STATREG_RO | ECSPI_STATREG_TC;
+        s->regs[ECSPI_STATREG] &= ~value;
+
+        break;
+    case ECSPI_CONREG:
+        s->regs[ECSPI_CONREG] = value;
+
+        if (!imx_spi_is_enabled(s)) {
+            /* device is disabled, so this is a reset */
+            imx_spi_reset(DEVICE(s));
+            return;
+        }
+
+        if (imx_spi_channel_is_master(s)) {
+            int i;
+
+            /* We are in master mode */
+
+            for (i = 0; i < 4; i++) {
+                qemu_set_irq(s->cs_lines[i],
+                             i == imx_spi_selected_channel(s) ? 0 : 1);
+            }
+
+            if ((value & change_mask & ECSPI_CONREG_SMC) &&
+                !fifo32_is_empty(&s->tx_fifo)) {
+                /* SMC bit is set and TX FIFO has some slots filled in */
+                imx_spi_flush_txfifo(s);
+            } else if ((value & change_mask & ECSPI_CONREG_XCH) &&
+                !(value & ECSPI_CONREG_SMC)) {
+                /* This is a request to start emitting */
+                imx_spi_flush_txfifo(s);
+            }
+        }
+
+        break;
+    default:
+        s->regs[index] = value;
+
+        break;
+    }
+
+    imx_spi_update_irq(s);
+}
+
+static const struct MemoryRegionOps imx_spi_ops = {
+    .read = imx_spi_read,
+    .write = imx_spi_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        /*
+         * Our device would not work correctly if the guest was doing
+         * unaligned access. This might not be a limitation on the real
+         * device but in practice there is no reason for a guest to access
+         * this device unaligned.
+         */
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+};
+
+static void imx_spi_realize(DeviceState *dev, Error **errp)
+{
+    IMXSPIState *s = IMX_SPI(dev);
+    int i;
+
+    s->bus = ssi_create_bus(dev, "spi");
+
+    memory_region_init_io(&s->iomem, OBJECT(dev), &imx_spi_ops, s,
+                          TYPE_IMX_SPI, 0x1000);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
+    sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
+
+    ssi_auto_connect_slaves(dev, s->cs_lines, s->bus);
+
+    for (i = 0; i < 4; ++i) {
+        sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->cs_lines[i]);
+    }
+
+    s->burst_length = 0;
+
+    fifo32_create(&s->tx_fifo, ECSPI_FIFO_SIZE);
+    fifo32_create(&s->rx_fifo, ECSPI_FIFO_SIZE);
+}
+
+static void imx_spi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = imx_spi_realize;
+    dc->vmsd = &vmstate_imx_spi;
+    dc->reset = imx_spi_reset;
+    dc->desc = "i.MX SPI Controller";
+}
+
+static const TypeInfo imx_spi_info = {
+    .name          = TYPE_IMX_SPI,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IMXSPIState),
+    .class_init    = imx_spi_class_init,
+};
+
+static void imx_spi_register_types(void)
+{
+    type_register_static(&imx_spi_info);
+}
+
+type_init(imx_spi_register_types)
diff --git a/include/hw/ssi/imx_spi.h b/include/hw/ssi/imx_spi.h
new file mode 100644
index 0000000..7103953
--- /dev/null
+++ b/include/hw/ssi/imx_spi.h
@@ -0,0 +1,103 @@
+/*
+ * IMX SPI Controller
+ *
+ * Copyright 2016 Jean-Christophe Dubois <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef IMX_SPI_H
+#define IMX_SPI_H
+
+#include "hw/sysbus.h"
+#include "hw/ssi/ssi.h"
+#include "qemu/bitops.h"
+#include "qemu/fifo32.h"
+
+#define ECSPI_FIFO_SIZE 64
+
+#define ECSPI_RXDATA 0
+#define ECSPI_TXDATA 1
+#define ECSPI_CONREG 2
+#define ECSPI_CONFIGREG 3
+#define ECSPI_INTREG 4
+#define ECSPI_DMAREG 5
+#define ECSPI_STATREG 6
+#define ECSPI_PERIODREG 7
+#define ECSPI_TESTREG 8
+#define ECSPI_MSGDATA 16
+#define ECSPI_MAX 17
+
+/* ECSPI_CONREG */
+#define ECSPI_CONREG_EN (1 << 0)
+#define ECSPI_CONREG_HT (1 << 1)
+#define ECSPI_CONREG_XCH (1 << 2)
+#define ECSPI_CONREG_SMC (1 << 3)
+#define ECSPI_CONREG_CHANNEL_MODE_SHIFT 4
+#define ECSPI_CONREG_CHANNEL_MODE_LENGTH 4
+#define ECSPI_CONREG_DRCTL_SHIFT 16
+#define ECSPI_CONREG_DRCTL_LENGTH 2
+#define ECSPI_CONREG_CHANNEL_SELECT_SHIFT 18
+#define ECSPI_CONREG_CHANNEL_SELECT_LENGTH 2
+#define ECSPI_CONREG_BURST_LENGTH_SHIFT 20
+#define ECSPI_CONREG_BURST_LENGTH_LENGTH 12
+
+/* ECSPI_CONFIGREG */
+#define ECSPI_CONFIGREG_SS_CTL_SHIFT 8
+#define ECSPI_CONFIGREG_SS_CTL_LENGTH 4
+
+/* ECSPI_INTREG */
+#define ECSPI_INTREG_TEEN (1 << 0)
+#define ECSPI_INTREG_TDREN (1 << 1)
+#define ECSPI_INTREG_TFEN (1 << 2)
+#define ECSPI_INTREG_RREN (1 << 3)
+#define ECSPI_INTREG_RDREN (1 << 4)
+#define ECSPI_INTREG_RFEN (1 << 5)
+#define ECSPI_INTREG_ROEN (1 << 6)
+#define ECSPI_INTREG_TCEN (1 << 7)
+
+/* ECSPI_DMAREG */
+#define ECSPI_DMAREG_RXTDEN (1 << 31)
+#define ECSPI_DMAREG_RXDEN (1 << 23)
+#define ECSPI_DMAREG_TEDEN (1 << 7)
+#define ECSPI_DMAREG_RX_THRESHOLD_SHIFT 16
+#define ECSPI_DMAREG_RX_THRESHOLD_LENGTH 6
+
+/* ECSPI_STATREG */
+#define ECSPI_STATREG_TE (1 << 0)
+#define ECSPI_STATREG_TDR (1 << 1)
+#define ECSPI_STATREG_TF (1 << 2)
+#define ECSPI_STATREG_RR (1 << 3)
+#define ECSPI_STATREG_RDR (1 << 4)
+#define ECSPI_STATREG_RF (1 << 5)
+#define ECSPI_STATREG_RO (1 << 6)
+#define ECSPI_STATREG_TC (1 << 7)
+
+#define EXTRACT(value, name) extract32(value, name##_SHIFT, name##_LENGTH)
+
+#define TYPE_IMX_SPI "imx.spi"
+#define IMX_SPI(obj) OBJECT_CHECK(IMXSPIState, (obj), TYPE_IMX_SPI)
+
+typedef struct IMXSPIState {
+    /* <private> */
+    SysBusDevice parent_obj;
+
+    /* <public> */
+    MemoryRegion iomem;
+
+    qemu_irq irq;
+
+    qemu_irq cs_lines[4];
+
+    SSIBus *bus;
+
+    uint32_t regs[ECSPI_MAX];
+
+    Fifo32 rx_fifo;
+    Fifo32 tx_fifo;
+
+    int16_t burst_length;
+} IMXSPIState;
+
+#endif /* IMX_SPI_H */
-- 
2.5.0