[Qemu-devel] [PATCH 1/2] Add i.MX I2C device emulator.

[Jean-Christophe DUBOIS]

Signed-off-by: Jean-Christophe DUBOIS <address@hidden>
---
 default-configs/arm-softmmu.mak |   2 +
 hw/i2c/Makefile.objs            |   1 +
 hw/i2c/imx_i2c.c                | 374 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 377 insertions(+)
 create mode 100644 hw/i2c/imx_i2c.c

diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index b3a0207..a20f112 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -81,3 +81,5 @@ CONFIG_VERSATILE_PCI=y
 CONFIG_VERSATILE_I2C=y
 
 CONFIG_SDHCI=y
+
+CONFIG_IMX_I2C=y
diff --git a/hw/i2c/Makefile.objs b/hw/i2c/Makefile.objs
index 648278e..d27bbaa 100644
--- a/hw/i2c/Makefile.objs
+++ b/hw/i2c/Makefile.objs
@@ -4,4 +4,5 @@ common-obj-$(CONFIG_ACPI) += smbus_ich9.o
 common-obj-$(CONFIG_APM) += pm_smbus.o
 common-obj-$(CONFIG_BITBANG_I2C) += bitbang_i2c.o
 common-obj-$(CONFIG_EXYNOS4) += exynos4210_i2c.o
+common-obj-$(CONFIG_IMX_I2C) += imx_i2c.o
 obj-$(CONFIG_OMAP) += omap_i2c.o
diff --git a/hw/i2c/imx_i2c.c b/hw/i2c/imx_i2c.c
new file mode 100644
index 0000000..30d3f5c
--- /dev/null
+++ b/hw/i2c/imx_i2c.c
@@ -0,0 +1,374 @@
+/*
+ *  i.MX I2C Bus Serial Interface Emulation
+ *
+ *  Copyright (C) 2013 Jean-Christophe Dubois.
+ *
+ *  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/sysbus.h"
+#include "hw/i2c/i2c.h"
+
+#ifndef IMX_I2C_DEBUG
+#define IMX_I2C_DEBUG                 0
+#endif
+
+#define TYPE_IMX_I2C                  "imx.i2c"
+#define IMX_I2C(obj)                  \
+    OBJECT_CHECK(imx_i2c_state, (obj), TYPE_IMX_I2C)
+
+/* i.MX I2C memory map */
+#define IMX_I2C_MEM_SIZE           0x14
+#define IADR_ADDR                  0x00  /* address register */
+#define IFDR_ADDR                  0x04  /* frequency divider register */
+#define I2CR_ADDR                  0x08  /* control register */
+#define I2SR_ADDR                  0x0c  /* status register */
+#define I2DR_ADDR                  0x10  /* data register */
+
+#define IADR_MASK                  0xFE
+#define IADR_RESET                 0
+
+#define IFDR_MASK                  0x3F
+#define IFDR_RESET                 0
+
+#define I2CR_IEN                   (1 << 7)
+#define I2CR_IIEN                  (1 << 6)
+#define I2CR_MSTA                  (1 << 5)
+#define I2CR_MTX                   (1 << 4)
+#define I2CR_TXAK                  (1 << 3)
+#define I2CR_RSTA                  (1 << 2)
+#define I2CR_MASK                  0xFC
+#define I2CR_RESET                 0
+
+#define I2SR_ICF                   (1 << 7)
+#define I2SR_IAAF                  (1 << 6)
+#define I2SR_IBB                   (1 << 5)
+#define I2SR_IAL                   (1 << 4)
+#define I2SR_SRW                   (1 << 2)
+#define I2SR_IIF                   (1 << 1)
+#define I2SR_RXAK                  (1 << 0)
+#define I2SR_MASK                  0xE9
+#define I2SR_RESET                 0x81
+
+#define I2DR_MASK                  0xFF
+#define I2DR_RESET                 0
+
+#define ADDR_RESET                 0xFF00
+
+#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
+
+typedef struct imx_i2c_state {
+    SysBusDevice busdev;
+    MemoryRegion iomem;
+    i2c_bus *bus;
+    qemu_irq irq;
+
+    uint16_t  address;
+
+    uint16_t iadr;
+    uint16_t ifdr;
+    uint16_t i2cr;
+    uint16_t i2sr;
+    uint16_t i2dr_read;
+    uint16_t i2dr_write;
+} imx_i2c_state;
+
+static inline bool imx_i2c_is_enabled(imx_i2c_state *s)
+{
+    return (s->i2cr & I2CR_IEN);
+}
+
+static inline bool imx_i2c_interrupt_is_enabled(imx_i2c_state *s)
+{
+    return (s->i2cr & I2CR_IIEN);
+}
+
+static inline bool imx_i2c_is_master(imx_i2c_state *s)
+{
+    return (s->i2cr & I2CR_MSTA);
+}
+
+static inline bool imx_i2c_direction_is_tx(imx_i2c_state *s)
+{
+    return (s->i2cr & I2CR_MTX);
+}
+
+static void imx_i2c_reset(DeviceState *d)
+{
+    imx_i2c_state *s = FROM_SYSBUS(imx_i2c_state, SYS_BUS_DEVICE(d));
+
+    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(imx_i2c_state *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)
+{
+    imx_i2c_state *s = (imx_i2c_state *)opaque;
+    uint16_t value;
+
+    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)) { // master mode
+            int ret;
+
+            if (s->address == ADDR_RESET) {
+                // something is wrong as the address is not set
+                DPRINT("Trying to read with specifying the slave address\n");
+            }
+
+            if ((ret = i2c_recv(s->bus)) >= 0) {
+                s->i2dr_read = ret;
+                imx_i2c_raise_interrupt(s);
+            } else {
+                DPRINT("read failed for device 0x%02x\n" s->address);
+                s->i2dr_read = 0xff;
+            }
+        } else { // slave mode
+        }
+        break;
+    default:
+        hw_error("%s: Bad address 0x%x\n", __func__, (int)offset);
+        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)
+{
+    imx_i2c_state *s = (imx_i2c_state *)opaque;
+    uint16_t v = value & 0xff;
+
+    DPRINT("write %s [0x%02x] <- 0x%02x\n", imx_i2c_get_regname(offset),
+           (unsigned int)offset, v);
+
+    switch (offset) {
+    case IADR_ADDR:
+        s->iadr = v & IADR_MASK;
+        //i2c_set_slave_address(s->bus, (uint8_t)s->iadr);
+        break;
+    case IFDR_ADDR:
+        s->ifdr = v & IFDR_MASK;
+        break;
+    case I2CR_ADDR:
+        if (imx_i2c_is_enabled(s) && ((v & I2CR_IEN) == 0)) {
+            /* This is a soft reset. IADR is preserved during soft resets */
+            uint16_t iadr = s->iadr;
+            imx_i2c_reset(&s->busdev.qdev);
+            s->iadr = iadr;
+        } else { // normal write
+            s->i2cr = v & I2CR_MASK;
+
+            if (imx_i2c_is_master(s)) { // master mode
+                // 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) && !(v & 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) && !(v & I2SR_IAL)) {
+            s->i2sr &= ~I2SR_IAL;
+            /* Nothing more to do ? */
+        }
+
+        break;
+    case I2DR_ADDR:
+        /* if the device is not enabled, nothing to do */
+        if (!imx_i2c_is_enabled(s)) {
+            break;
+        }
+
+        s->i2dr_write = v & I2DR_MASK;
+
+        if (imx_i2c_is_master(s)) { // master mode
+            /* If this is the first write cycle then it is the slave addr */
+            if (s->address == ADDR_RESET) {
+                if (!i2c_start_transfer(s->bus, (uint8_t)s->i2dr_write >> 1,
+                                        (int)s->i2dr_write & 0x01)) {
+                    // if 0 is returned, the adress is valid
+                    s->address = s->i2dr_write;
+                    s->i2sr &= ~I2SR_RXAK;
+                    imx_i2c_raise_interrupt(s);
+                } else { // can't start i2c transaction
+                }
+            } 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
+                    i2c_end_transfer(s->bus);
+                }
+                s->i2sr &= ~I2SR_RXAK;
+                imx_i2c_raise_interrupt(s);
+            }
+        } else { // slave mode
+        }
+        break;
+    default:
+        hw_error("%s: Bad address 0x%x\n", __func__, (int)offset);
+        break;
+    }
+}
+
+static const MemoryRegionOps imx_i2c_ops = {
+    .read = imx_i2c_read,
+    .write = imx_i2c_write,
+    .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, imx_i2c_state),
+        VMSTATE_UINT16(iadr, imx_i2c_state),
+        VMSTATE_UINT16(ifdr, imx_i2c_state),
+        VMSTATE_UINT16(i2cr, imx_i2c_state),
+        VMSTATE_UINT16(i2sr, imx_i2c_state),
+        VMSTATE_UINT16(i2dr_read, imx_i2c_state),
+        VMSTATE_UINT16(i2dr_write, imx_i2c_state),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static int imx_i2c_init(SysBusDevice *dev)
+{
+    imx_i2c_state *s = IMX_I2C(dev);
+
+    memory_region_init_io(&s->iomem, &imx_i2c_ops, s, TYPE_IMX_I2C,
+                          IMX_I2C_MEM_SIZE);
+    sysbus_init_mmio(dev, &s->iomem);
+    sysbus_init_irq(dev, &s->irq);
+    s->bus = i2c_init_bus(&dev->qdev, "i2c");
+
+    return 0;
+}
+
+static void imx_i2c_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass);
+
+    dc->vmsd = &imx_i2c_vmstate;
+    dc->reset = imx_i2c_reset;
+    sbdc->init = imx_i2c_init;
+}
+
+static const TypeInfo imx_i2c_type_info = {
+    .name = TYPE_IMX_I2C,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(imx_i2c_state),
+    .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);
-- 
1.8.1.2