litex: Working spiflash emulation.

hw/ssi/bitbang_ssi.c

@@ -0,0 +1,258 @@
+/*
+ * Bit-Bang ssi emulation extracted from
+ * Marvell MV88W8618 / Freecom MusicPal emulation.
+ *
+ * Copyright (c) 2008 Jan Kiszka
+ *
+ * This code is licensed under the GNU GPL v2.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+#include "qemu/osdep.h"
+#include "hw/hw.h"
+#include "bitbang_ssi.h"
+#include "hw/sysbus.h"
+
+#define DEBUG_BITBANG_SSI
+
+#ifdef DEBUG_BITBANG_SSI
+#define DPRINTF(fmt, ...) \
+do { printf("bitbang_ssi: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) do {} while(0)
+#endif
+
+typedef enum {
+    ACTIVE = 0,
+    IDLE
+} bitbang_ssi_state;
+
+typedef enum bitbang_ssi_state {
+    ACTIVE2IDLE = 0,
+    IDLE2ACTIVE
+} bitbang_ssi_state;
+
+struct bitbang_ssi_interface {
+    SSIBus *bus;
+
+    // Configuration
+    int transfer_size;
+    bitbang_ssi_cpol_mode cpol_mode;
+    bitbang_ssi_cpol_mode cpha_mode;
+
+    // Pin state
+    int last_sclk;
+    int last_mosi;
+    int last_miso;
+
+    // Data transmission state
+    bitbang_ssi_state state;
+    uint32_t data_miso;
+    int data_miso_count;
+    uint32_t data_mosi;
+    int data_mosi_count;
+
+};
+
+void bitbang_ssi_get_miso(bitbang_ssi_interface *ssi)
+{
+    if (ssi->data_miso_count > 0) {
+        ssi->last_miso = ssi->data_miso & 0x1;
+    	ssi->data_miso = ssi->data_miso >> 1;
+        ssi->data_miso_count -= 1;
+    }
+    DEBUG_BITBANG_SSI("get_miso %d %d %d\n", out_bit, ssi->data_miso, ssi->data_miso_count);
+}
+
+void bitbang_ssi_set_mosi(bitbang_ssi_interface *ssi)
+{
+	ssi->data_mosi = ssi->data_in << 1 | ssi->mosi_level;
+    ssi->data_mosi_count += 1;
+    DEBUG_BITBANG_SSI("set_mosi %d %d %d\n", ssi->mosi_level, ssi->data_mosi, ssi->data_mosi_count);
+}
+
+
+/* Returns MISO line level or -1. */
+int bitbang_ssi_set(bitbang_ssi_interface *ssi, bitbang_ssi_line line, int level)
+{
+    if (level != 0 && level != 1) {
+        abort();
+    }
+
+    switch(line) {
+    case BITBANG_SSI_SCLK:
+	    if (ssi->last_sclk == level)
+		    return s->last_miso;
+        break;
+    case BITBANG_SSI_MOSI:
+        ssi->mosi_level = level;
+		return s->last_miso;
+    case BITBANG_SSI_MISO:
+        return s->last_miso;
+    }
+
+    DEBUG_BITBANG_SSI("sclk %d->%d (state: %s)\n", ssi->last_sclk, level, ssi->state == ACTIVE ? "active" : "idle");
+
+	if (ssi->last_sclk == 0 && level == 1) {
+        switch(ssi->cpol_mode) {
+        case BITBANG_SSI_CPOL0:
+            mode = IDLE2ACTIVE;
+            break;
+        case BITBANG_SSI_CPOL1:
+            mode = ACTIVE2IDLE;
+            break;
+        }
+    } else if (ssi->last_sclk == 1 && level == 0) {
+        switch(ssi->cpol_mode) {
+        case BITBANG_SSI_CPOL0:
+            mode = ACTIVE2IDLE;
+            break;
+        case BITBANG_SSI_CPOL1:
+            mode = IDLE2ACTIVE;
+            break;
+        }
+    } else {
+        abort();
+    }
+    ssi->last_sclk = level;
+
+    if (ssi->state == IDLE) {
+		ssi->state = ACTIVE;
+    	ssi->data_count_mosi = 0;
+
+    	if (ssi->cpha_mode == BITBANG_SSI_CPHA0) {
+		    return s->last_miso;
+        }
+    }
+
+    if (ssi->cpha_mode == BITBANG_SSI_CPHA0) {
+        switch(mode) {
+        case IDLE2ACTIVE:
+            bitbang_ssi_set_mosi(ssi);
+            break;
+        case ACTIVE2IDLE:
+            bitbang_ssi_get_miso(ssi);
+            break;
+        }
+    } else if (ssi->cpha_mode == BITBANG_SSI_CPHA1) {
+        switch(mode) {
+        case IDLE2ACTIVE:
+            bitbang_ssi_get_miso(ssi);
+            break;
+        case ACTIVE2IDLE:
+            bitbang_ssi_set_mosi(ssi);
+            break;
+        }
+    }
+
+    if (ssi->data_mosi_count == ssi->transfer_size) {
+        ssi->data_miso = ssi->bus->transfer(ssi->data_mosi);
+        ssi->data_miso_count = ssi->transfer_size;
+        DEBUG_BITBANG_SSI("transfer(%d) ->%d\n", ssi->data_mosi, data->miso);
+        ssi->state = IDLE;
+    }
+    return s->last_miso;
+}
+
+bitbang_ssi_interface *bitbang_ssi_init(SSIBus *bus, bitbang_ssi_cpol_mode cpol_mode, bitbang_ssi_cpha_mode cpha_mode, int transfer_size)
+{
+    DEBUG_BITBANG_SSI("init(cpol:%d, cpha:%d, size:%d\n", cpol_mode, cpha_mode, transfer_size);
+    bitbang_ssi_interface *s;
+
+    s = g_malloc0(sizeof(bitbang_ssi_interface));
+
+    s->bus = bus;
+
+    // Configuration
+    assert(transfer_size < (sizeof(s->data_miso)*8));
+    s->transfer_size = transfer_size;
+    s->cpol_mode = cpol_mode;
+    s->cpha_mode = cpha_mode;
+
+    // Pin values
+    switch (cpol_mode) {
+    case BITBANG_SSI_CPOL0:
+        s->last_sclk = 0;
+        break;
+    case BITBANG_SSI_CPOL1:
+        s->last_sclk = 1;
+        break;
+    }
+    s->last_mosi = 0;
+    s->last_miso = 0;
+
+    // Data transmission state
+    s->state = IDLE;
+    s->data_miso = 0;
+    s->data_miso_count = 0;
+    s->data_mosi = 0;
+    s->data_mosi_count = 0;
+
+    return s;
+}
+
+/* GPIO interface.  */
+
+#define TYPE_GPIO_SSI "gpio_ssi"
+#define GPIO_SSI(obj) OBJECT_CHECK(GPIOSSIState, (obj), TYPE_GPIO_SSI)
+
+typedef struct GPIOSSIState {
+    SysBusDevice parent_obj;
+
+    MemoryRegion dummy_iomem;
+    bitbang_ssi_interface *bitbang;
+    int last_level;
+    qemu_irq out;
+} GPIOSSIState;
+
+static void bitbang_ssi_gpio_set(void *opaque, int irq, int level)
+{
+    GPIOSSIState *s = opaque;
+
+    level = bitbang_ssi_set(s->bitbang, irq, level);
+    if (level != s->last_level) {
+        s->last_level = level;
+        qemu_set_irq(s->out, level);
+    }
+}
+
+static void gpio_ssi_init(Object *obj)
+{
+    DeviceState *dev = DEVICE(obj);
+    GPIOSSIState *s = GPIO_SSI(obj);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    SSIBus *bus;
+
+    memory_region_init(&s->dummy_iomem, obj, "gpio_ssi", 0);
+    sysbus_init_mmio(sbd, &s->dummy_iomem);
+
+    bus = ssi_init_bus(dev, "ssi");
+    s->bitbang = bitbang_ssi_init(bus);
+
+    qdev_init_gpio_in(dev, bitbang_ssi_gpio_set, 2);
+    qdev_init_gpio_out(dev, &s->out, 1);
+}
+
+static void gpio_ssi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    dc->desc = "Virtual GPIO to SSI bridge";
+}
+
+static const TypeInfo gpio_ssi_info = {
+    .name          = TYPE_GPIO_SSI,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(GPIOSSIState),
+    .instance_init = gpio_ssi_init,
+    .class_init    = gpio_ssi_class_init,
+};
+
+static void bitbang_ssi_register_types(void)
+{
+    type_register_static(&gpio_ssi_info);
+}
+
+type_init(bitbang_ssi_register_types)

hw/ssi/bitbang_ssi.h

@@ -0,0 +1,27 @@
+#ifndef BITBANG_SSI_H
+#define BITBANG_SSI_H
+
+#include "hw/ssi/ssi.h"
+
+typedef struct bitbang_ssi_interface bitbang_ssi_interface;
+
+typedef enum {
+    BITBANG_SSI_SCLK = 0,
+    BITBANG_SSI_MOSI,
+    BITBANG_SSI_MISO,
+} bitbang_ssi_line;
+
+typedef enum {
+   BITBANG_SSI_CPOL0 = 0, // idle == low, active == high
+   BITBANG_SSI_CPOL1 = 1  // idle == high, active == low
+} bitbang_ssi_cpol_mode;
+
+typedef enum {
+   BITBANG_SSI_CPHA0 = 0, // Data on 0th edge
+   BITBANG_SSI_CPHA1 = 1  // Data on 1st edge
+} bitbang_ssi_cpha_mode;
+
+bitbang_ssi_interface *bitbang_ssi_init(SSIBus *bus, bitbang_ssi_cpol_mode cpol_mode, bitbang_ssi_cpha_mode cpha_mode, int transfer_size);
+int bitbang_ssi_set(bitbang_ssi_interface *ssi, int line, int level);
+
+#endif