hw/i2c: Implement Broadcom Serial Controller (BSC)

A few deficiencies in the current device model need to be noted.

1. FIFOs are not used. All sends and receives are done directly.
2. Repeated starts are not emulated. Repeated starts can be triggered in real
hardware by sending a new read transfer request in the window time between
transfer active set of write transfer request and done bit set of the same.

Signed-off-by: Rayhan Faizel <rayhan.faizel@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240224191038.2409945-2-rayhan.faizel@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/include/hw/i2c/bcm2835_i2c.h b/include/hw/i2c/bcm2835_i2c.h
new file mode 100644
index 0000000000..0a56df4720
--- /dev/null
+++ b/include/hw/i2c/bcm2835_i2c.h
@@ -0,0 +1,80 @@
+/*
+ * Broadcom Serial Controller (BSC)
+ *
+ * Copyright (c) 2024 Rayhan Faizel <rayhan.faizel@gmail.com>
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw/sysbus.h"
+#include "hw/i2c/i2c.h"
+#include "qom/object.h"
+
+#define TYPE_BCM2835_I2C "bcm2835-i2c"
+OBJECT_DECLARE_SIMPLE_TYPE(BCM2835I2CState, BCM2835_I2C)
+
+#define BCM2835_I2C_C       0x0                   /* Control */
+#define BCM2835_I2C_S       0x4                   /* Status */
+#define BCM2835_I2C_DLEN    0x8                   /* Data Length */
+#define BCM2835_I2C_A       0xc                   /* Slave Address */
+#define BCM2835_I2C_FIFO    0x10                  /* FIFO */
+#define BCM2835_I2C_DIV     0x14                  /* Clock Divider */
+#define BCM2835_I2C_DEL     0x18                  /* Data Delay */
+#define BCM2835_I2C_CLKT    0x20                  /* Clock Stretch Timeout */
+
+#define BCM2835_I2C_C_I2CEN     BIT(15)           /* I2C enable */
+#define BCM2835_I2C_C_INTR      BIT(10)           /* Interrupt on RXR */
+#define BCM2835_I2C_C_INTT      BIT(9)            /* Interrupt on TXW */
+#define BCM2835_I2C_C_INTD      BIT(8)            /* Interrupt on DONE */
+#define BCM2835_I2C_C_ST        BIT(7)            /* Start transfer */
+#define BCM2835_I2C_C_CLEAR     (BIT(5) | BIT(4)) /* Clear FIFO */
+#define BCM2835_I2C_C_READ      BIT(0)            /* I2C read mode */
+
+#define BCM2835_I2C_S_CLKT      BIT(9)            /* Clock stretch timeout */
+#define BCM2835_I2C_S_ERR       BIT(8)            /* Slave error */
+#define BCM2835_I2C_S_RXF       BIT(7)            /* RX FIFO full */
+#define BCM2835_I2C_S_TXE       BIT(6)            /* TX FIFO empty */
+#define BCM2835_I2C_S_RXD       BIT(5)            /* RX bytes available */
+#define BCM2835_I2C_S_TXD       BIT(4)            /* TX space available */
+#define BCM2835_I2C_S_RXR       BIT(3)            /* RX FIFO needs reading */
+#define BCM2835_I2C_S_TXW       BIT(2)            /* TX FIFO needs writing */
+#define BCM2835_I2C_S_DONE      BIT(1)            /* I2C Transfer complete */
+#define BCM2835_I2C_S_TA        BIT(0)            /* I2C Transfer active */
+
+struct BCM2835I2CState {
+    /* <private> */
+    SysBusDevice parent_obj;
+
+    /* <public> */
+    MemoryRegion iomem;
+    I2CBus *bus;
+    qemu_irq irq;
+
+    uint32_t c;
+    uint32_t s;
+    uint32_t dlen;
+    uint32_t a;
+    uint32_t div;
+    uint32_t del;
+    uint32_t clkt;
+
+    uint32_t last_dlen;
+};