Merge tag 'pull-aspeed-20220630' of https://github.com/legoater/qemu into staging

aspeed queue:

* m25p80 improvements (Iris)
* Code cleanup in preparation of multi SoC machine (Peter)
* New MAX31785 model (Mahesh)
* New Qualcomm machines (Jae and Graeme)
* Core I2C slave mode (Klaus)
* Aspeed I2C slave mode for old and new register interface (Peter and Klaus)
* New Aspeed PECI model (Peter)
* Various small fixes

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# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: A0F6 6548 F048 95EB FE6B  0B60 51A3 43C7 CFFB ECA1

* tag 'pull-aspeed-20220630' of https://github.com/legoater/qemu: (27 commits)
  hw/misc/aspeed: Add PECI controller
  hw/i2c/aspeed: Add new-registers DMA slave mode RX support
  hw/i2c/aspeed: add slave device in old register mode
  hw/i2c: add asynchronous send
  hw/i2c: support multiple masters
  hw/i2c/aspeed: Fix MASTER_EN missing error message
  hw/i2c/aspeed: Fix DMA len write-enable bit handling
  hw/i2c/aspeed: Fix R_I2CD_FUN_CTRL reference
  hw/arm/aspeed: firework: add I2C MUXes for VR channels
  hw/arm/aspeed: firework: Add Thermal Diodes
  hw/arm/aspeed: Add MAX31785 Fan controllers
  hw/sensor: add Maxim MAX31785 device
  hw/i2c: pmbus: Page #255 is valid page for read requests.
  hw/arm/aspeed: add Qualcomm Firework BMC machine
  hw/arm/aspeed: add support for the Qualcomm DC-SCM v1 board
  aspeed: Remove use of qemu_get_cpu
  aspeed: Map unimplemented devices in SoC memory
  aspeed: Remove usage of sysbus_mmio_map
  aspeed: Add memory property to Aspeed SoC
  aspeed: Set CPU memory property explicitly
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

5 files changed, 283 insertions, 35 deletions

diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c
index 37ae1f2e04..42c6d69b82 100644
--- a/hw/i2c/aspeed_i2c.c
+++ b/hw/i2c/aspeed_i2c.c
@@ -58,7 +58,7 @@ static inline void aspeed_i2c_bus_raise_interrupt(AspeedI2CBus *bus)
                ARRAY_FIELD_EX32(bus->regs, I2CD_INTR_STS, SLAVE_ADDR_RX_MATCH) ?
                                                "slave-match|" : "",
                SHARED_ARRAY_FIELD_EX32(bus->regs, reg_intr_sts, NORMAL_STOP) ?
-                                               "normal|" : "",
+                                               "stop|" : "",
                SHARED_ARRAY_FIELD_EX32(bus->regs, reg_intr_sts, ABNORMAL) ?
                                                "abnormal"  : "");
 
@@ -78,6 +78,18 @@ static inline void aspeed_i2c_bus_raise_interrupt(AspeedI2CBus *bus)
     }
 }
 
+static inline void aspeed_i2c_bus_raise_slave_interrupt(AspeedI2CBus *bus)
+{
+    AspeedI2CClass *aic = ASPEED_I2C_GET_CLASS(bus->controller);
+
+    if (!bus->regs[R_I2CS_INTR_STS]) {
+        return;
+    }
+
+    bus->controller->intr_status |= 1 << bus->id;
+    qemu_irq_raise(aic->bus_get_irq(bus));
+}
+
 static uint64_t aspeed_i2c_bus_old_read(AspeedI2CBus *bus, hwaddr offset,
                                         unsigned size)
 {
@@ -140,8 +152,17 @@ static uint64_t aspeed_i2c_bus_new_read(AspeedI2CBus *bus, hwaddr offset,
     case A_I2CM_DMA_LEN_STS:
     case A_I2CC_DMA_ADDR:
     case A_I2CC_DMA_LEN:
+
+    case A_I2CS_DEV_ADDR:
+    case A_I2CS_DMA_RX_ADDR:
+    case A_I2CS_DMA_LEN:
+    case A_I2CS_CMD:
+    case A_I2CS_INTR_CTRL:
+    case A_I2CS_DMA_LEN_STS:
         /* Value is already set, don't do anything. */
         break;
+    case A_I2CS_INTR_STS:
+        break;
     case A_I2CM_CMD:
         value = SHARED_FIELD_DP32(value, BUS_BUSY_STS, i2c_bus_busy(bus->bus));
         break;
@@ -547,12 +568,7 @@ static void aspeed_i2c_bus_new_write(AspeedI2CBus *bus, hwaddr offset,
 
     switch (offset) {
     case A_I2CC_FUN_CTRL:
-        if (SHARED_FIELD_EX32(value, SLAVE_EN)) {
-            qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
-                          __func__);
-            break;
-        }
-        bus->regs[R_I2CD_FUN_CTRL] = value & 0x007dc3ff;
+        bus->regs[R_I2CC_FUN_CTRL] = value;
         break;
     case A_I2CC_AC_TIMING:
         bus->regs[R_I2CC_AC_TIMING] = value & 0x1ffff0ff;
@@ -580,6 +596,7 @@ static void aspeed_i2c_bus_new_write(AspeedI2CBus *bus, hwaddr offset,
                 bus->controller->intr_status &= ~(1 << bus->id);
                 qemu_irq_lower(aic->bus_get_irq(bus));
             }
+            aspeed_i2c_bus_raise_slave_interrupt(bus);
             break;
         }
         bus->regs[R_I2CM_INTR_STS] &= ~(value & 0xf007f07f);
@@ -601,7 +618,7 @@ static void aspeed_i2c_bus_new_write(AspeedI2CBus *bus, hwaddr offset,
         }
 
         if (!aspeed_i2c_bus_is_master(bus)) {
-            qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: Master mode is not enabled\n",
                           __func__);
             break;
         }
@@ -644,18 +661,18 @@ static void aspeed_i2c_bus_new_write(AspeedI2CBus *bus, hwaddr offset,
                                                      RX_BUF_LEN) + 1;
         break;
     case A_I2CM_DMA_LEN:
-        w1t = ARRAY_FIELD_EX32(bus->regs, I2CM_DMA_LEN, RX_BUF_LEN_W1T) ||
-                   ARRAY_FIELD_EX32(bus->regs, I2CM_DMA_LEN, TX_BUF_LEN_W1T);
+        w1t = FIELD_EX32(value, I2CM_DMA_LEN, RX_BUF_LEN_W1T) ||
+              FIELD_EX32(value, I2CM_DMA_LEN, TX_BUF_LEN_W1T);
         /* If none of the w1t bits are set, just write to the reg as normal. */
         if (!w1t) {
             bus->regs[R_I2CM_DMA_LEN] = value;
             break;
         }
-        if (ARRAY_FIELD_EX32(bus->regs, I2CM_DMA_LEN, RX_BUF_LEN_W1T)) {
+        if (FIELD_EX32(value, I2CM_DMA_LEN, RX_BUF_LEN_W1T)) {
             ARRAY_FIELD_DP32(bus->regs, I2CM_DMA_LEN, RX_BUF_LEN,
                              FIELD_EX32(value, I2CM_DMA_LEN, RX_BUF_LEN));
         }
-        if (ARRAY_FIELD_EX32(bus->regs, I2CM_DMA_LEN, TX_BUF_LEN_W1T)) {
+        if (FIELD_EX32(value, I2CM_DMA_LEN, TX_BUF_LEN_W1T)) {
             ARRAY_FIELD_DP32(bus->regs, I2CM_DMA_LEN, TX_BUF_LEN,
                              FIELD_EX32(value, I2CM_DMA_LEN, TX_BUF_LEN));
         }
@@ -668,15 +685,53 @@ static void aspeed_i2c_bus_new_write(AspeedI2CBus *bus, hwaddr offset,
     case A_I2CC_DMA_LEN:
         /* RO */
         break;
-    case A_I2CS_DMA_LEN_STS:
-    case A_I2CS_DMA_TX_ADDR:
-    case A_I2CS_DMA_RX_ADDR:
     case A_I2CS_DEV_ADDR:
+        bus->regs[R_I2CS_DEV_ADDR] = value;
+        break;
+    case A_I2CS_DMA_RX_ADDR:
+        bus->regs[R_I2CS_DMA_RX_ADDR] = value;
+        break;
+    case A_I2CS_DMA_LEN:
+        assert(FIELD_EX32(value, I2CS_DMA_LEN, TX_BUF_LEN) == 0);
+        if (FIELD_EX32(value, I2CS_DMA_LEN, RX_BUF_LEN_W1T)) {
+            ARRAY_FIELD_DP32(bus->regs, I2CS_DMA_LEN, RX_BUF_LEN,
+                             FIELD_EX32(value, I2CS_DMA_LEN, RX_BUF_LEN));
+        } else {
+            bus->regs[R_I2CS_DMA_LEN] = value;
+        }
+        break;
+    case A_I2CS_CMD:
+        if (FIELD_EX32(value, I2CS_CMD, W1_CTRL)) {
+            bus->regs[R_I2CS_CMD] |= value;
+        } else {
+            bus->regs[R_I2CS_CMD] = value;
+        }
+        i2c_slave_set_address(bus->slave, bus->regs[R_I2CS_DEV_ADDR]);
+        break;
     case A_I2CS_INTR_CTRL:
+        bus->regs[R_I2CS_INTR_CTRL] = value;
+        break;
+
     case A_I2CS_INTR_STS:
-    case A_I2CS_CMD:
-    case A_I2CS_DMA_LEN:
-        qemu_log_mask(LOG_UNIMP, "%s: Slave mode is not implemented\n",
+        if (ARRAY_FIELD_EX32(bus->regs, I2CS_INTR_CTRL, PKT_CMD_DONE)) {
+            if (ARRAY_FIELD_EX32(bus->regs, I2CS_INTR_STS, PKT_CMD_DONE) &&
+                FIELD_EX32(value, I2CS_INTR_STS, PKT_CMD_DONE)) {
+                bus->regs[R_I2CS_INTR_STS] &= 0xfffc0000;
+            }
+        } else {
+            bus->regs[R_I2CS_INTR_STS] &= ~value;
+        }
+        if (!bus->regs[R_I2CS_INTR_STS]) {
+            bus->controller->intr_status &= ~(1 << bus->id);
+            qemu_irq_lower(aic->bus_get_irq(bus));
+        }
+        aspeed_i2c_bus_raise_interrupt(bus);
+        break;
+    case A_I2CS_DMA_LEN_STS:
+        bus->regs[R_I2CS_DMA_LEN_STS] = 0;
+        break;
+    case A_I2CS_DMA_TX_ADDR:
+        qemu_log_mask(LOG_UNIMP, "%s: Slave mode DMA TX is not implemented\n",
                       __func__);
         break;
     default:
@@ -696,9 +751,7 @@ static void aspeed_i2c_bus_old_write(AspeedI2CBus *bus, hwaddr offset,
     switch (offset) {
     case A_I2CD_FUN_CTRL:
         if (SHARED_FIELD_EX32(value, SLAVE_EN)) {
-            qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
-                          __func__);
-            break;
+            i2c_slave_set_address(bus->slave, bus->regs[R_I2CD_DEV_ADDR]);
         }
         bus->regs[R_I2CD_FUN_CTRL] = value & 0x0071C3FF;
         break;
@@ -719,12 +772,15 @@ static void aspeed_i2c_bus_old_write(AspeedI2CBus *bus, hwaddr offset,
             bus->controller->intr_status &= ~(1 << bus->id);
             qemu_irq_lower(aic->bus_get_irq(bus));
         }
-        if (handle_rx && (SHARED_ARRAY_FIELD_EX32(bus->regs, R_I2CD_CMD,
-                                                  M_RX_CMD) ||
-                      SHARED_ARRAY_FIELD_EX32(bus->regs, R_I2CD_CMD,
-                                              M_S_RX_CMD_LAST))) {
-            aspeed_i2c_handle_rx_cmd(bus);
-            aspeed_i2c_bus_raise_interrupt(bus);
+        if (handle_rx) {
+            if (SHARED_ARRAY_FIELD_EX32(bus->regs, R_I2CD_CMD, M_RX_CMD) ||
+                SHARED_ARRAY_FIELD_EX32(bus->regs, R_I2CD_CMD,
+                                        M_S_RX_CMD_LAST)) {
+                aspeed_i2c_handle_rx_cmd(bus);
+                aspeed_i2c_bus_raise_interrupt(bus);
+            } else if (aspeed_i2c_get_state(bus) == I2CD_STXD) {
+                i2c_ack(bus->bus);
+            }
         }
         break;
     case A_I2CD_DEV_ADDR:
@@ -744,7 +800,7 @@ static void aspeed_i2c_bus_old_write(AspeedI2CBus *bus, hwaddr offset,
         }
 
         if (!aspeed_i2c_bus_is_master(bus)) {
-            qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: Master mode is not enabled\n",
                           __func__);
             break;
         }
@@ -1036,6 +1092,127 @@ static const TypeInfo aspeed_i2c_info = {
     .abstract   = true,
 };
 
+static int aspeed_i2c_bus_new_slave_event(AspeedI2CBus *bus,
+                                          enum i2c_event event)
+{
+    switch (event) {
+    case I2C_START_SEND_ASYNC:
+        if (!SHARED_ARRAY_FIELD_EX32(bus->regs, R_I2CS_CMD, RX_DMA_EN)) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: Slave mode RX DMA is not enabled\n", __func__);
+            return -1;
+        }
+        ARRAY_FIELD_DP32(bus->regs, I2CS_DMA_LEN_STS, RX_LEN, 0);
+        bus->regs[R_I2CC_DMA_ADDR] =
+            ARRAY_FIELD_EX32(bus->regs, I2CS_DMA_RX_ADDR, ADDR);
+        bus->regs[R_I2CC_DMA_LEN] =
+            ARRAY_FIELD_EX32(bus->regs, I2CS_DMA_LEN, RX_BUF_LEN) + 1;
+        i2c_ack(bus->bus);
+        break;
+    case I2C_FINISH:
+        ARRAY_FIELD_DP32(bus->regs, I2CS_INTR_STS, PKT_CMD_DONE, 1);
+        ARRAY_FIELD_DP32(bus->regs, I2CS_INTR_STS, SLAVE_ADDR_RX_MATCH, 1);
+        SHARED_ARRAY_FIELD_DP32(bus->regs, R_I2CS_INTR_STS, NORMAL_STOP, 1);
+        SHARED_ARRAY_FIELD_DP32(bus->regs, R_I2CS_INTR_STS, RX_DONE, 1);
+        aspeed_i2c_bus_raise_slave_interrupt(bus);
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: i2c event %d unimplemented\n",
+                      __func__, event);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int aspeed_i2c_bus_slave_event(I2CSlave *slave, enum i2c_event event)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(slave));
+    AspeedI2CBus *bus = ASPEED_I2C_BUS(qbus->parent);
+    uint32_t reg_intr_sts = aspeed_i2c_bus_intr_sts_offset(bus);
+    uint32_t reg_byte_buf = aspeed_i2c_bus_byte_buf_offset(bus);
+    uint32_t value;
+
+    if (aspeed_i2c_is_new_mode(bus->controller)) {
+        return aspeed_i2c_bus_new_slave_event(bus, event);
+    }
+
+    switch (event) {
+    case I2C_START_SEND_ASYNC:
+        value = SHARED_ARRAY_FIELD_EX32(bus->regs, reg_byte_buf, TX_BUF);
+        SHARED_ARRAY_FIELD_DP32(bus->regs, reg_byte_buf, RX_BUF, value << 1);
+
+        ARRAY_FIELD_DP32(bus->regs, I2CD_INTR_STS, SLAVE_ADDR_RX_MATCH, 1);
+        SHARED_ARRAY_FIELD_DP32(bus->regs, reg_intr_sts, RX_DONE, 1);
+
+        aspeed_i2c_set_state(bus, I2CD_STXD);
+
+        break;
+
+    case I2C_FINISH:
+        SHARED_ARRAY_FIELD_DP32(bus->regs, reg_intr_sts, NORMAL_STOP, 1);
+
+        aspeed_i2c_set_state(bus, I2CD_IDLE);
+
+        break;
+
+    default:
+        return -1;
+    }
+
+    aspeed_i2c_bus_raise_interrupt(bus);
+
+    return 0;
+}
+
+static void aspeed_i2c_bus_new_slave_send_async(AspeedI2CBus *bus, uint8_t data)
+{
+    assert(address_space_write(&bus->controller->dram_as,
+                               bus->regs[R_I2CC_DMA_ADDR],
+                               MEMTXATTRS_UNSPECIFIED, &data, 1) == MEMTX_OK);
+
+    bus->regs[R_I2CC_DMA_ADDR]++;
+    bus->regs[R_I2CC_DMA_LEN]--;
+    ARRAY_FIELD_DP32(bus->regs, I2CS_DMA_LEN_STS, RX_LEN,
+                     ARRAY_FIELD_EX32(bus->regs, I2CS_DMA_LEN_STS, RX_LEN) + 1);
+    i2c_ack(bus->bus);
+}
+
+static void aspeed_i2c_bus_slave_send_async(I2CSlave *slave, uint8_t data)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(slave));
+    AspeedI2CBus *bus = ASPEED_I2C_BUS(qbus->parent);
+    uint32_t reg_intr_sts = aspeed_i2c_bus_intr_sts_offset(bus);
+    uint32_t reg_byte_buf = aspeed_i2c_bus_byte_buf_offset(bus);
+
+    if (aspeed_i2c_is_new_mode(bus->controller)) {
+        return aspeed_i2c_bus_new_slave_send_async(bus, data);
+    }
+
+    SHARED_ARRAY_FIELD_DP32(bus->regs, reg_byte_buf, RX_BUF, data);
+    SHARED_ARRAY_FIELD_DP32(bus->regs, reg_intr_sts, RX_DONE, 1);
+
+    aspeed_i2c_bus_raise_interrupt(bus);
+}
+
+static void aspeed_i2c_bus_slave_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
+
+    dc->desc = "Aspeed I2C Bus Slave";
+
+    sc->event = aspeed_i2c_bus_slave_event;
+    sc->send_async = aspeed_i2c_bus_slave_send_async;
+}
+
+static const TypeInfo aspeed_i2c_bus_slave_info = {
+    .name           = TYPE_ASPEED_I2C_BUS_SLAVE,
+    .parent         = TYPE_I2C_SLAVE,
+    .instance_size  = sizeof(AspeedI2CBusSlave),
+    .class_init     = aspeed_i2c_bus_slave_class_init,
+};
+
 static void aspeed_i2c_bus_reset(DeviceState *dev)
 {
     AspeedI2CBus *s = ASPEED_I2C_BUS(dev);
@@ -1060,6 +1237,8 @@ static void aspeed_i2c_bus_realize(DeviceState *dev, Error **errp)
     sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
 
     s->bus = i2c_init_bus(dev, name);
+    s->slave = i2c_slave_create_simple(s->bus, TYPE_ASPEED_I2C_BUS_SLAVE,
+                                       0xff);
 
     memory_region_init_io(&s->mr, OBJECT(s), &aspeed_i2c_bus_ops,
                           s, name, aic->reg_size);
@@ -1219,6 +1398,7 @@ static const TypeInfo aspeed_1030_i2c_info = {
 static void aspeed_i2c_register_types(void)
 {
     type_register_static(&aspeed_i2c_bus_info);
+    type_register_static(&aspeed_i2c_bus_slave_info);
     type_register_static(&aspeed_i2c_info);
     type_register_static(&aspeed_2400_i2c_info);
     type_register_static(&aspeed_2500_i2c_info);
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index d0cb2d32fa..d4ba8146bf 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -13,6 +13,7 @@
 #include "migration/vmstate.h"
 #include "qapi/error.h"
 #include "qemu/module.h"
+#include "qemu/main-loop.h"
 #include "trace.h"
 
 #define I2C_BROADCAST 0x00
@@ -62,6 +63,7 @@ I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
 
     bus = I2C_BUS(qbus_new(TYPE_I2C_BUS, parent, name));
     QLIST_INIT(&bus->current_devs);
+    QSIMPLEQ_INIT(&bus->pending_masters);
     vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_i2c_bus, bus);
     return bus;
 }
@@ -74,7 +76,7 @@ void i2c_slave_set_address(I2CSlave *dev, uint8_t address)
 /* Return nonzero if bus is busy.  */
 int i2c_bus_busy(I2CBus *bus)
 {
-    return !QLIST_EMPTY(&bus->current_devs);
+    return !QLIST_EMPTY(&bus->current_devs) || bus->bh;
 }
 
 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
@@ -159,7 +161,8 @@ static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
            start condition.  */
 
         if (sc->event) {
-            trace_i2c_event("start", s->address);
+            trace_i2c_event(event == I2C_START_SEND ? "start" : "start_async",
+                            s->address);
             rv = sc->event(s, event);
             if (rv && !bus->broadcast) {
                 if (bus_scanned) {
@@ -180,6 +183,26 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
                                                : I2C_START_SEND);
 }
 
+void i2c_bus_master(I2CBus *bus, QEMUBH *bh)
+{
+    if (i2c_bus_busy(bus)) {
+        I2CPendingMaster *node = g_new(struct I2CPendingMaster, 1);
+        node->bh = bh;
+
+        QSIMPLEQ_INSERT_TAIL(&bus->pending_masters, node, entry);
+
+        return;
+    }
+
+    bus->bh = bh;
+    qemu_bh_schedule(bus->bh);
+}
+
+void i2c_bus_release(I2CBus *bus)
+{
+    bus->bh = NULL;
+}
+
 int i2c_start_recv(I2CBus *bus, uint8_t address)
 {
     return i2c_do_start_transfer(bus, address, I2C_START_RECV);
@@ -190,6 +213,11 @@ int i2c_start_send(I2CBus *bus, uint8_t address)
     return i2c_do_start_transfer(bus, address, I2C_START_SEND);
 }
 
+int i2c_start_send_async(I2CBus *bus, uint8_t address)
+{
+    return i2c_do_start_transfer(bus, address, I2C_START_SEND_ASYNC);
+}
+
 void i2c_end_transfer(I2CBus *bus)
 {
     I2CSlaveClass *sc;
@@ -206,6 +234,16 @@ void i2c_end_transfer(I2CBus *bus)
         g_free(node);
     }
     bus->broadcast = false;
+
+    if (!QSIMPLEQ_EMPTY(&bus->pending_masters)) {
+        I2CPendingMaster *node = QSIMPLEQ_FIRST(&bus->pending_masters);
+        bus->bh = node->bh;
+
+        QSIMPLEQ_REMOVE_HEAD(&bus->pending_masters, entry);
+        g_free(node);
+
+        qemu_bh_schedule(bus->bh);
+    }
 }
 
 int i2c_send(I2CBus *bus, uint8_t data)
@@ -229,6 +267,23 @@ int i2c_send(I2CBus *bus, uint8_t data)
     return ret ? -1 : 0;
 }
 
+int i2c_send_async(I2CBus *bus, uint8_t data)
+{
+    I2CNode *node = QLIST_FIRST(&bus->current_devs);
+    I2CSlave *slave = node->elt;
+    I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(slave);
+
+    if (!sc->send_async) {
+        return -1;
+    }
+
+    trace_i2c_send_async(slave->address, data);
+
+    sc->send_async(slave, data);
+
+    return 0;
+}
+
 uint8_t i2c_recv(I2CBus *bus)
 {
     uint8_t data = 0xff;
@@ -265,6 +320,17 @@ void i2c_nack(I2CBus *bus)
     }
 }
 
+void i2c_ack(I2CBus *bus)
+{
+    if (!bus->bh) {
+        return;
+    }
+
+    trace_i2c_ack();
+
+    qemu_bh_schedule(bus->bh);
+}
+
 static int i2c_slave_post_load(void *opaque, int version_id)
 {
     I2CSlave *dev = opaque;
diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
index 62885fa6a1..749a33af82 100644
--- a/hw/i2c/pmbus_device.c
+++ b/hw/i2c/pmbus_device.c
@@ -284,14 +284,10 @@ static uint8_t pmbus_receive_byte(SMBusDevice *smd)
 
     /*
      * Reading from all pages will return the value from page 0,
-     * this is unspecified behaviour in general.
+     * means that all subsequent commands are to be applied to all output.
      */
     if (pmdev->page == PB_ALL_PAGES) {
         index = 0;
-        qemu_log_mask(LOG_GUEST_ERROR,
-                      "%s: tried to read from all pages\n",
-                      __func__);
-        pmbus_cml_error(pmdev);
     } else if (pmdev->page > pmdev->num_pages - 1) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: page %d is out of range\n",
diff --git a/hw/i2c/smbus_slave.c b/hw/i2c/smbus_slave.c
index 5d10e27664..feb3ec6333 100644
--- a/hw/i2c/smbus_slave.c
+++ b/hw/i2c/smbus_slave.c
@@ -143,6 +143,10 @@ static int smbus_i2c_event(I2CSlave *s, enum i2c_event event)
             dev->mode = SMBUS_CONFUSED;
             break;
         }
+        break;
+
+    default:
+        return -1;
     }
 
     return 0;
diff --git a/hw/i2c/trace-events b/hw/i2c/trace-events
index 209275ed2d..af181d43ee 100644
--- a/hw/i2c/trace-events
+++ b/hw/i2c/trace-events
@@ -4,7 +4,9 @@
 
 i2c_event(const char *event, uint8_t address) "%s(addr:0x%02x)"
 i2c_send(uint8_t address, uint8_t data) "send(addr:0x%02x) data:0x%02x"
+i2c_send_async(uint8_t address, uint8_t data) "send_async(addr:0x%02x) data:0x%02x"
 i2c_recv(uint8_t address, uint8_t data) "recv(addr:0x%02x) data:0x%02x"
+i2c_ack(void) ""
 
 # aspeed_i2c.c