[Qemu-devel] [PATCH 06/12] i2c: add mpc8540 i2c controller

[Michael Davidsaver <mdavidsaver@gmail.com>]

Signed-off-by: Michael Davidsaver <mdavidsaver@gmail.com>
---
 hw/i2c/Makefile.objs |   1 +
 hw/i2c/mpc8540_i2c.c | 287 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 288 insertions(+)
 create mode 100644 hw/i2c/mpc8540_i2c.c

diff --git a/hw/i2c/Makefile.objs b/hw/i2c/Makefile.objs
index 0594dea3ae..79af1dd901 100644
--- a/hw/i2c/Makefile.objs
+++ b/hw/i2c/Makefile.objs
@@ -9,3 +9,4 @@ common-obj-$(CONFIG_IMX_I2C) += imx_i2c.o
 common-obj-$(CONFIG_ASPEED_SOC) += aspeed_i2c.o
 obj-$(CONFIG_OMAP) += omap_i2c.o
 obj-$(CONFIG_PPC4XX) += ppc4xx_i2c.o
+obj-$(CONFIG_E500) += mpc8540_i2c.o
diff --git a/hw/i2c/mpc8540_i2c.c b/hw/i2c/mpc8540_i2c.c
new file mode 100644
index 0000000000..884052cc9b
--- /dev/null
+++ b/hw/i2c/mpc8540_i2c.c
@@ -0,0 +1,287 @@
+/*
+ * MPC8540 I2C bus interface
+ * As described in
+ * MPC8540 PowerQUICC III Integrated Host Processor Reference Manual, Rev. 1
+ * Part 2 chapter 11
+ *
+ * Copyright (c) 2015 Michael Davidsaver
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the LICENSE file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "hw/hw.h"
+#include "hw/registerfields.h"
+#include "hw/i2c/i2c.h"
+#include "hw/sysbus.h"
+
+/* #define DEBUG_LVL 0 */
+
+#ifdef DEBUG_LVL
+#define DPRINTK(LVL, FMT, ...) do { if ((LVL) <= DEBUG_LVL) { \
+    printf(TYPE_MPC8540_I2C " : " FMT, ## __VA_ARGS__); } } while (0)
+#else
+#define DPRINTK(LVL, FMT, ...) do {} while (0)
+#endif
+
+#define LOG(MSK, FMT, ...) qemu_log_mask(MSK, TYPE_MPC8540_I2C \
+    " : " FMT, ## __VA_ARGS__)
+
+#define TYPE_MPC8540_I2C "mpc8540-i2c"
+#define MPC8540_I2C(obj) OBJECT_CHECK(I2CState, (obj), TYPE_MPC8540_I2C)
+
+/* offsets relative to CCSR offset 0x3000 */
+#define R_I2CADR (0)
+#define R_I2CFDR (4)
+#define R_I2CCR  (8)
+#define R_I2CSR  (0xc)
+#define R_I2CDR  (0x10)
+#define R_I2CDFSRR (0x14)
+
+FIELD(I2CCR, MEN, 7, 1)
+FIELD(I2CCR, MIEN, 6, 1)
+FIELD(I2CCR, MSTA, 5, 1)
+FIELD(I2CCR, MTX, 4, 1)
+FIELD(I2CCR, TXAK, 3, 1)
+FIELD(I2CCR, RSTA, 2, 1)
+FIELD(I2CCR, BCST, 0, 1)
+
+FIELD(I2CSR, MCF, 7, 1)
+FIELD(I2CSR, MAAS, 6, 1)
+FIELD(I2CSR, MBB, 5, 1)
+FIELD(I2CSR, MAL, 4, 1)
+FIELD(I2CSR, BCSTM, 3, 1)
+FIELD(I2CSR, SRW, 2, 1)
+FIELD(I2CSR, MIF, 1, 1)
+FIELD(I2CSR, RXAK, 0, 1)
+
+typedef struct I2CState {
+    SysBusDevice parent_obj;
+
+    I2CBus *bus;
+
+    uint8_t ctrl, sts;
+    uint8_t freq, filt;
+    /* Reads are pipelined, this is the next data value */
+    uint8_t dbuf;
+
+    qemu_irq irq;
+
+    MemoryRegion mmio;
+} I2CState;
+
+#define I2CCR(BIT) FIELD_EX32(i2c->ctrl, I2CCR, BIT)
+#define I2CSR(BIT) FIELD_EX32(i2c->sts, I2CSR, BIT)
+
+#define I2CSR_SET(BIT, VAL) do {\
+        i2c->sts = FIELD_DP32(i2c->sts, I2CSR, BIT, VAL);\
+    } while (0)
+
+static
+void mpc8540_update_irq(I2CState *i2c)
+{
+    int ena = i2c->ctrl & 0x40,
+        sts = i2c->sts & 0x02,
+        act = !!(ena && sts);
+
+    DPRINTK(1, "IRQ %c ena %c sts %c\n",
+            act ? 'X' : '_',
+            ena ? 'X' : '_',
+            sts ? 'X' : '_');
+
+    qemu_set_irq(i2c->irq, act);
+}
+
+static
+uint64_t mpc8540_i2c_read(void *opaque, hwaddr addr, unsigned size)
+{
+    I2CState *i2c = opaque;
+    uint32_t val, offset = addr;
+
+    switch (offset) {
+    case R_I2CADR: /* ADDR */
+        val = 0;
+        break;
+    case R_I2CFDR: /* Freq Div. */
+        val = i2c->freq;
+        break;
+    case R_I2CCR: /* CONTROL */
+        val = i2c->ctrl & ~0x06;
+        break;
+    case R_I2CSR: /* STATUS */
+        val = i2c->sts;
+        break;
+    case R_I2CDR: /* DATA */
+        /* Reads are "pipelined" and so return the previous value of the
+         * register
+         */
+        val = i2c->dbuf;
+        if (I2CCR(MEN) && I2CSR(MBB)) { /* enabled and busy */
+            if (!i2c_bus_busy(i2c->bus) || I2CCR(MTX)) {
+                LOG(LOG_GUEST_ERROR, "Read during addr or tx\n");
+                i2c->dbuf = 0xff;
+            } else {
+                int ret = i2c_recv(i2c->bus);
+                i2c->dbuf = (uint8_t)ret;
+                DPRINTK(0, "READ %02x ('%c')\n", i2c->dbuf, (char)i2c->dbuf);
+                I2CSR_SET(MIF, 1);
+                I2CSR_SET(RXAK, 0);
+                mpc8540_update_irq(i2c);
+            }
+        } else {
+            i2c->dbuf = 0xff;
+            LOG(LOG_GUEST_ERROR, "Read when not enabled or busy\n");
+        }
+        break;
+    case R_I2CDFSRR: /* FILTER */
+        val = i2c->filt;
+        break;
+    default:
+        val = 0xff;
+    }
+
+    DPRINTK(offset == 0xc ? 2 : 1, " read %08x -> %08x\n",
+            (unsigned)offset, (unsigned)val);
+    return val;
+}
+
+static
+void mpc8540_i2c_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
+{
+    I2CState *i2c = opaque;
+    uint32_t offset = addr;
+
+    DPRINTK(1, " write %08x <- %08x\n", (unsigned)offset, (unsigned)val);
+
+    switch (offset) {
+    case R_I2CADR: /* ADDR */
+        break;
+    case R_I2CFDR: /* Freq Div. */
+        i2c->freq = val & 0x3f;
+        break;
+    case R_I2CCR: /* CONTROL CCR */
+        if (!FIELD_EX32(val, I2CCR, MEN)) {
+            DPRINTK(0, "Not Enabled\n");
+
+        } else if (!I2CCR(MSTA) && FIELD_EX32(val, I2CCR, MSTA)) {
+            /* MSTA 0 -> 1 is START */
+
+            I2CSR_SET(MBB, 1);
+            DPRINTK(0, "START\n");
+            i2c_end_transfer(i2c->bus); /* paranoia */
+
+        } else if (I2CCR(MSTA) && !FIELD_EX32(val, I2CCR, MSTA)) {
+            /* MSTA 1 -> 0 is STOP */
+
+            I2CSR_SET(MBB, 0);
+            DPRINTK(0, "STOP\n");
+            i2c_end_transfer(i2c->bus);
+
+        } else if (I2CCR(MSTA) && FIELD_EX32(val, I2CCR, RSTA)) {
+            i2c_end_transfer(i2c->bus);
+            I2CSR_SET(MBB, 1);
+            DPRINTK(0, "REP START\n");
+
+        }
+        /* RSTA always reads zero, bit 1 unusd */
+        val &= 0xf9;
+        i2c->ctrl = val;
+        mpc8540_update_irq(i2c);
+        break;
+    case R_I2CSR: /* STATUS CSR */
+        /* only MAL and MIF are writable */
+        val &= 0x12;
+        i2c->sts &= ~0x12;
+        i2c->sts |= val;
+        mpc8540_update_irq(i2c);
+        break;
+    case R_I2CDR: /* DATA CDR */
+        if (I2CCR(MEN) && I2CSR(MBB)) { /* enabled and busy */
+            if (!i2c_bus_busy(i2c->bus)) {
+                if (i2c_start_transfer(i2c->bus, val >> 1, val & 1)) {
+                    LOG(LOG_GUEST_ERROR, "I2C no device %02x\n",
+                        (unsigned)(val & 0xfe));
+                } else {
+                    DPRINTK(0, "ADDR %02x\n", (unsigned)(val & 0xfe));
+                }
+                I2CSR_SET(MIF, 1);
+                I2CSR_SET(RXAK, 0);
+
+            } else if (I2CCR(MTX)) {
+                DPRINTK(0, "WRITE %02x\n", (unsigned)val);
+                i2c_send(i2c->bus, val);
+                I2CSR_SET(MIF, 1);
+                I2CSR_SET(RXAK, 0);
+            } else {
+                LOG(LOG_GUEST_ERROR, "I2CDR Write during read\n");
+            }
+            mpc8540_update_irq(i2c);
+        } else {
+            LOG(LOG_GUEST_ERROR, "I2CDR Write when not enabled or busy\n");
+        }
+        break;
+    case R_I2CDFSRR: /* FILTER */
+        val &= 0x3f;
+        i2c->filt = val;
+        break;
+    }
+
+    DPRINTK(1, "I2CCR = %02x I2SCR = %02x\n", i2c->ctrl, i2c->sts);
+}
+
+static const MemoryRegionOps i2c_ops = {
+    .read = mpc8540_i2c_read,
+    .write = mpc8540_i2c_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static
+void mpc8540_i2c_reset(DeviceState *dev)
+{
+    I2CState *i2c = MPC8540_I2C(dev);
+
+    i2c->sts = 0x81; /* transfer complete and ack received */
+}
+
+static int mpc8540_i2c_inst_init(SysBusDevice *dev)
+{
+    I2CState *i2c = MPC8540_I2C(dev);
+
+    i2c->bus = i2c_init_bus(&dev->parent_obj, "bus");
+
+    memory_region_init_io(&i2c->mmio, &dev->parent_obj.parent_obj,
+                          &i2c_ops, i2c, TYPE_MPC8540_I2C, 0x18);
+
+    sysbus_init_mmio(dev, &i2c->mmio);
+    sysbus_init_irq(dev, &i2c->irq);
+    return 0;
+}
+
+static void mpc8540_i2c_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+    k->init = &mpc8540_i2c_inst_init;
+    dc->reset = &mpc8540_i2c_reset;
+}
+
+static const TypeInfo mpc8540_i2c_type = {
+    .name = TYPE_MPC8540_I2C,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(I2CState),
+    .class_size = sizeof(SysBusDeviceClass),
+    .class_init = mpc8540_i2c_class_init,
+};
+
+static void mpc8540_i2c_register(void)
+{
+    type_register_static(&mpc8540_i2c_type);
+}
+
+type_init(mpc8540_i2c_register)
-- 
2.11.0