i.MX: Add I2C controller emulator

The slave mode is not implemented.

Signed-off-by: Jean-Christophe Dubois <jcd@tribudubois.net>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 508dbf2ebe26ec383d3a12a1db5a7890ac8acf20.1441057361.git.jcd@tribudubois.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 334 insertions, 0 deletions

diff --git a/hw/i2c/imx_i2c.c b/hw/i2c/imx_i2c.c
new file mode 100644
index 0000000..8474872
--- /dev/null
+++ b/hw/i2c/imx_i2c.c
@@ -0,0 +1,334 @@
+/*
+ *  i.MX I2C Bus Serial Interface Emulation
+ *
+ *  Copyright (C) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net>
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "hw/i2c/imx_i2c.h"
+#include "hw/i2c/i2c.h"
+
+#ifndef IMX_I2C_DEBUG
+#define IMX_I2C_DEBUG                 0
+#endif
+
+#if IMX_I2C_DEBUG
+#define DPRINT(fmt, args...)              \
+    do { fprintf(stderr, "%s: "fmt, __func__, ## args); } while (0)
+
+static const char *imx_i2c_get_regname(unsigned offset)
+{
+    switch (offset) {
+    case IADR_ADDR:
+        return "IADR";
+    case IFDR_ADDR:
+        return "IFDR";
+    case I2CR_ADDR:
+        return "I2CR";
+    case I2SR_ADDR:
+        return "I2SR";
+    case I2DR_ADDR:
+        return "I2DR";
+    default:
+        return "[?]";
+    }
+}
+#else
+#define DPRINT(fmt, args...)              do { } while (0)
+#endif
+
+static inline bool imx_i2c_is_enabled(IMXI2CState *s)
+{
+    return s->i2cr & I2CR_IEN;
+}
+
+static inline bool imx_i2c_interrupt_is_enabled(IMXI2CState *s)
+{
+    return s->i2cr & I2CR_IIEN;
+}
+
+static inline bool imx_i2c_is_master(IMXI2CState *s)
+{
+    return s->i2cr & I2CR_MSTA;
+}
+
+static void imx_i2c_reset(DeviceState *dev)
+{
+    IMXI2CState *s = IMX_I2C(dev);
+
+    if (s->address != ADDR_RESET) {
+        i2c_end_transfer(s->bus);
+    }
+
+    s->address    = ADDR_RESET;
+    s->iadr       = IADR_RESET;
+    s->ifdr       = IFDR_RESET;
+    s->i2cr       = I2CR_RESET;
+    s->i2sr       = I2SR_RESET;
+    s->i2dr_read  = I2DR_RESET;
+    s->i2dr_write = I2DR_RESET;
+}
+
+static inline void imx_i2c_raise_interrupt(IMXI2CState *s)
+{
+    /*
+     * raise an interrupt if the device is enabled and it is configured
+     * to generate some interrupts.
+     */
+    if (imx_i2c_is_enabled(s) && imx_i2c_interrupt_is_enabled(s)) {
+        s->i2sr |= I2SR_IIF;
+        qemu_irq_raise(s->irq);
+    }
+}
+
+static uint64_t imx_i2c_read(void *opaque, hwaddr offset,
+                             unsigned size)
+{
+    uint16_t value;
+    IMXI2CState *s = IMX_I2C(opaque);
+
+    switch (offset) {
+    case IADR_ADDR:
+        value = s->iadr;
+        break;
+    case IFDR_ADDR:
+        value = s->ifdr;
+        break;
+    case I2CR_ADDR:
+        value = s->i2cr;
+        break;
+    case I2SR_ADDR:
+        value = s->i2sr;
+        break;
+    case I2DR_ADDR:
+        value = s->i2dr_read;
+
+        if (imx_i2c_is_master(s)) {
+            int ret = 0xff;
+
+            if (s->address == ADDR_RESET) {
+                /* something is wrong as the address is not set */
+                qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Trying to read "
+                              "without specifying the slave address\n",
+                              TYPE_IMX_I2C, __func__);
+            } else if (s->i2cr & I2CR_MTX) {
+                qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Trying to read "
+                              "but MTX is set\n", TYPE_IMX_I2C, __func__);
+            } else {
+                /* get the next byte */
+                ret = i2c_recv(s->bus);
+
+                if (ret >= 0) {
+                    imx_i2c_raise_interrupt(s);
+                } else {
+                    qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: read failed "
+                                  "for device 0x%02x\n", TYPE_IMX_I2C,
+                                  __func__, s->address);
+                    ret = 0xff;
+                }
+            }
+
+            s->i2dr_read = ret;
+        } else {
+            qemu_log_mask(LOG_UNIMP, "%s[%s]: slave mode not implemented\n",
+                          TYPE_IMX_I2C, __func__);
+        }
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_I2C, __func__, s->address);
+        value = 0;
+        break;
+    }
+
+    DPRINT("read %s [0x%02x] -> 0x%02x\n", imx_i2c_get_regname(offset),
+           (unsigned int)offset, value);
+
+    return (uint64_t)value;
+}
+
+static void imx_i2c_write(void *opaque, hwaddr offset,
+                          uint64_t value, unsigned size)
+{
+    IMXI2CState *s = IMX_I2C(opaque);
+
+    DPRINT("write %s [0x%02x] <- 0x%02x\n", imx_i2c_get_regname(offset),
+           (unsigned int)offset, (int)value);
+
+    value &= 0xff;
+
+    switch (offset) {
+    case IADR_ADDR:
+        s->iadr = value & IADR_MASK;
+        /* i2c_set_slave_address(s->bus, (uint8_t)s->iadr); */
+        break;
+    case IFDR_ADDR:
+        s->ifdr = value & IFDR_MASK;
+        break;
+    case I2CR_ADDR:
+        if (imx_i2c_is_enabled(s) && ((value & I2CR_IEN) == 0)) {
+            /* This is a soft reset. IADR is preserved during soft resets */
+            uint16_t iadr = s->iadr;
+            imx_i2c_reset(DEVICE(s));
+            s->iadr = iadr;
+        } else { /* normal write */
+            s->i2cr = value & I2CR_MASK;
+
+            if (imx_i2c_is_master(s)) {
+                /* set the bus to busy */
+                s->i2sr |= I2SR_IBB;
+            } else { /* slave mode */
+                /* bus is not busy anymore */
+                s->i2sr &= ~I2SR_IBB;
+
+                /*
+                 * if we unset the master mode then it ends the ongoing
+                 * transfer if any
+                 */
+                if (s->address != ADDR_RESET) {
+                    i2c_end_transfer(s->bus);
+                    s->address = ADDR_RESET;
+                }
+            }
+
+            if (s->i2cr & I2CR_RSTA) { /* Restart */
+                /* if this is a restart then it ends the ongoing transfer */
+                if (s->address != ADDR_RESET) {
+                    i2c_end_transfer(s->bus);
+                    s->address = ADDR_RESET;
+                    s->i2cr &= ~I2CR_RSTA;
+                }
+            }
+        }
+        break;
+    case I2SR_ADDR:
+        /*
+         * if the user writes 0 to IIF then lower the interrupt and
+         * reset the bit
+         */
+        if ((s->i2sr & I2SR_IIF) && !(value & I2SR_IIF)) {
+            s->i2sr &= ~I2SR_IIF;
+            qemu_irq_lower(s->irq);
+        }
+
+        /*
+         * if the user writes 0 to IAL, reset the bit
+         */
+        if ((s->i2sr & I2SR_IAL) && !(value & I2SR_IAL)) {
+            s->i2sr &= ~I2SR_IAL;
+        }
+
+        break;
+    case I2DR_ADDR:
+        /* if the device is not enabled, nothing to do */
+        if (!imx_i2c_is_enabled(s)) {
+            break;
+        }
+
+        s->i2dr_write = value & I2DR_MASK;
+
+        if (imx_i2c_is_master(s)) {
+            /* If this is the first write cycle then it is the slave addr */
+            if (s->address == ADDR_RESET) {
+                if (i2c_start_transfer(s->bus, extract32(s->i2dr_write, 1, 7),
+                                       extract32(s->i2dr_write, 0, 1))) {
+                    /* if non zero is returned, the adress is not valid */
+                    s->i2sr |= I2SR_RXAK;
+                } else {
+                    s->address = s->i2dr_write;
+                    s->i2sr &= ~I2SR_RXAK;
+                    imx_i2c_raise_interrupt(s);
+                }
+            } else { /* This is a normal data write */
+                if (i2c_send(s->bus, s->i2dr_write)) {
+                    /* if the target return non zero then end the transfer */
+                    s->i2sr |= I2SR_RXAK;
+                    s->address = ADDR_RESET;
+                    i2c_end_transfer(s->bus);
+                } else {
+                    s->i2sr &= ~I2SR_RXAK;
+                    imx_i2c_raise_interrupt(s);
+                }
+            }
+        } else {
+            qemu_log_mask(LOG_UNIMP, "%s[%s]: slave mode not implemented\n",
+                          TYPE_IMX_I2C, __func__);
+        }
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_I2C, __func__, s->address);
+        break;
+    }
+}
+
+static const MemoryRegionOps imx_i2c_ops = {
+    .read = imx_i2c_read,
+    .write = imx_i2c_write,
+    .valid.min_access_size = 1,
+    .valid.max_access_size = 2,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static const VMStateDescription imx_i2c_vmstate = {
+    .name = TYPE_IMX_I2C,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT16(address, IMXI2CState),
+        VMSTATE_UINT16(iadr, IMXI2CState),
+        VMSTATE_UINT16(ifdr, IMXI2CState),
+        VMSTATE_UINT16(i2cr, IMXI2CState),
+        VMSTATE_UINT16(i2sr, IMXI2CState),
+        VMSTATE_UINT16(i2dr_read, IMXI2CState),
+        VMSTATE_UINT16(i2dr_write, IMXI2CState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void imx_i2c_realize(DeviceState *dev, Error **errp)
+{
+    IMXI2CState *s = IMX_I2C(dev);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &imx_i2c_ops, s, TYPE_IMX_I2C,
+                          IMX_I2C_MEM_SIZE);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
+    sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
+    s->bus = i2c_init_bus(DEVICE(dev), "i2c");
+}
+
+static void imx_i2c_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd = &imx_i2c_vmstate;
+    dc->reset = imx_i2c_reset;
+    dc->realize = imx_i2c_realize;
+}
+
+static const TypeInfo imx_i2c_type_info = {
+    .name = TYPE_IMX_I2C,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IMXI2CState),
+    .class_init = imx_i2c_class_init,
+};
+
+static void imx_i2c_register_types(void)
+{
+    type_register_static(&imx_i2c_type_info);
+}
+
+type_init(imx_i2c_register_types)