hw/i2c: Implement NPCM7XX SMBus Module Single Mode

This commit implements the single-byte mode of the SMBus.

Each Nuvoton SoC has 16 System Management Bus (SMBus). These buses
compliant with SMBus and I2C protocol.

This patch implements the single-byte mode of the SMBus. In this mode,
the user sends or receives a byte each time. The SMBus device transmits
it to the underlying i2c device and sends an interrupt back to the QEMU
guest.

Reviewed-by: Doug Evans<dje@google.com>
Reviewed-by: Tyrong Ting<kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Reviewed-by: Corey Minyard <cminyard@mvista.com>
Message-id: 20210210220426.3577804-2-wuhaotsh@google.com
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 90 insertions, 0 deletions

diff --git a/include/hw/arm/npcm7xx.h b/include/hw/arm/npcm7xx.h
index f6227aa8aa..cea1bd1f62 100644
--- a/include/hw/arm/npcm7xx.h
+++ b/include/hw/arm/npcm7xx.h
@@ -20,6 +20,7 @@
 #include "hw/adc/npcm7xx_adc.h"
 #include "hw/cpu/a9mpcore.h"
 #include "hw/gpio/npcm7xx_gpio.h"
+#include "hw/i2c/npcm7xx_smbus.h"
 #include "hw/mem/npcm7xx_mc.h"
 #include "hw/misc/npcm7xx_clk.h"
 #include "hw/misc/npcm7xx_gcr.h"
@@ -85,6 +86,7 @@ typedef struct NPCM7xxState {
     NPCM7xxMCState      mc;
     NPCM7xxRNGState     rng;
     NPCM7xxGPIOState    gpio[8];
+    NPCM7xxSMBusState   smbus[16];
     EHCISysBusState     ehci;
     OHCISysBusState     ohci;
     NPCM7xxFIUState     fiu[2];
diff --git a/include/hw/i2c/npcm7xx_smbus.h b/include/hw/i2c/npcm7xx_smbus.h
new file mode 100644
index 0000000000..b9761a6993
--- /dev/null
+++ b/include/hw/i2c/npcm7xx_smbus.h
@@ -0,0 +1,88 @@
+/*
+ * Nuvoton NPCM7xx SMBus Module.
+ *
+ * Copyright 2020 Google LLC
+ *
+ * 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.
+ */
+#ifndef NPCM7XX_SMBUS_H
+#define NPCM7XX_SMBUS_H
+
+#include "exec/memory.h"
+#include "hw/i2c/i2c.h"
+#include "hw/irq.h"
+#include "hw/sysbus.h"
+
+/*
+ * Number of addresses this module contains. Do not change this without
+ * incrementing the version_id in the vmstate.
+ */
+#define NPCM7XX_SMBUS_NR_ADDRS 10
+
+typedef enum NPCM7xxSMBusStatus {
+    NPCM7XX_SMBUS_STATUS_IDLE,
+    NPCM7XX_SMBUS_STATUS_SENDING,
+    NPCM7XX_SMBUS_STATUS_RECEIVING,
+    NPCM7XX_SMBUS_STATUS_NEGACK,
+    NPCM7XX_SMBUS_STATUS_STOPPING_LAST_RECEIVE,
+    NPCM7XX_SMBUS_STATUS_STOPPING_NEGACK,
+} NPCM7xxSMBusStatus;
+
+/*
+ * struct NPCM7xxSMBusState - System Management Bus device state.
+ * @bus: The underlying I2C Bus.
+ * @irq: GIC interrupt line to fire on events (if enabled).
+ * @sda: The serial data register.
+ * @st: The status register.
+ * @cst: The control status register.
+ * @cst2: The control status register 2.
+ * @cst3: The control status register 3.
+ * @ctl1: The control register 1.
+ * @ctl2: The control register 2.
+ * @ctl3: The control register 3.
+ * @ctl4: The control register 4.
+ * @ctl5: The control register 5.
+ * @addr: The SMBus module's own addresses on the I2C bus.
+ * @scllt: The SCL low time register.
+ * @sclht: The SCL high time register.
+ * @status: The current status of the SMBus.
+ */
+typedef struct NPCM7xxSMBusState {
+    SysBusDevice parent;
+
+    MemoryRegion iomem;
+
+    I2CBus      *bus;
+    qemu_irq     irq;
+
+    uint8_t      sda;
+    uint8_t      st;
+    uint8_t      cst;
+    uint8_t      cst2;
+    uint8_t      cst3;
+    uint8_t      ctl1;
+    uint8_t      ctl2;
+    uint8_t      ctl3;
+    uint8_t      ctl4;
+    uint8_t      ctl5;
+    uint8_t      addr[NPCM7XX_SMBUS_NR_ADDRS];
+
+    uint8_t      scllt;
+    uint8_t      sclht;
+
+    NPCM7xxSMBusStatus status;
+} NPCM7xxSMBusState;
+
+#define TYPE_NPCM7XX_SMBUS "npcm7xx-smbus"
+#define NPCM7XX_SMBUS(obj) OBJECT_CHECK(NPCM7xxSMBusState, (obj), \
+                                        TYPE_NPCM7XX_SMBUS)
+
+#endif /* NPCM7XX_SMBUS_H */