1 files changed, 132 insertions, 0 deletions
diff --git a/cpukit/dev/i2c/fpga-i2c-slave.c b/cpukit/dev/i2c/fpga-i2c-slave.c
new file mode 100644
index 0000000000..cf00a57b41
--- /dev/null
+++ b/cpukit/dev/i2c/fpga-i2c-slave.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2016-2017 Chris Johns <chrisj@rtems.org>
+ * All rights reserved.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+/*
+ * I2C slave for testing:
+ *       https://github.com/oetr/FPGA-I2C-Slave
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <dev/i2c/i2c.h>
+#include <dev/i2c/fpga-i2c-slave.h>
+
+typedef struct {
+  i2c_dev  base;
+  uint16_t address;
+  size_t   size;
+} fpga_i2c_slave;
+
+static ssize_t
+fpga_i2c_slave_read(i2c_dev* base, void* buf, size_t n, off_t offset)
+{
+  fpga_i2c_slave* dev = (fpga_i2c_slave*) base;
+  off_t           avail = dev->size - offset;
+  uint8_t*        in = buf;
+  size_t          todo;
+
+  if (avail <= 0) {
+    return 0;
+  }
+
+  if (n > avail) {
+    n = (size_t) avail;
+  }
+
+  todo = n;
+
+  while (todo > 0) {
+    /*
+     * Limit the transfer size so that it can be stored in 8-bits.  This may
+     * help some bus controllers.
+     */
+    uint16_t cur = (uint16_t) (todo < 255 ?  todo : 255);
+    i2c_msg msgs = {
+      .addr = dev->base.address,
+      .flags = I2C_M_RD,
+      .buf = in,
+      .len = cur
+    };
+    int err;
+    err = i2c_bus_transfer(dev->base.bus, &msgs, 1);
+    if (err != 0) {
+      return err;
+    }
+    todo -= cur;
+    in += cur;
+  }
+
+  return (ssize_t) n;
+}
+
+static ssize_t
+fpga_i2c_slave_write(i2c_dev* base, const void* buf, size_t n, off_t offset)
+{
+  fpga_i2c_slave* dev = (fpga_i2c_slave*) base;
+  off_t           avail = dev->size - offset;
+  const uint8_t*  out = buf;
+  size_t          todo;
+
+  if (avail <= 0) {
+    return 0;
+  }
+
+  if (n > avail) {
+    n = (size_t) avail;
+  }
+
+  todo = n;
+
+  while (todo > 0) {
+    /*
+     * Limit the transfer size so that it can be stored in 8-bits.  This may
+     * help some bus controllers.
+     */
+    uint16_t cur = (uint16_t) (todo < 255 ?  todo : 255);
+    i2c_msg msgs = {
+      .addr = dev->base.address,
+      .flags = 0,
+      .buf = RTEMS_DECONST(uint8_t*, out),
+      .len = cur
+    };
+    int err;
+    err = i2c_bus_transfer(dev->base.bus, &msgs, 1);
+    if (err != 0) {
+      return err;
+    }
+    todo -= cur;
+    out += cur;
+  }
+
+  return (ssize_t) n;
+}
+
+int
+i2c_dev_register_fpga_i2c_slave(const char* bus_path,
+                                const char* dev_path,
+                                uint16_t    address,
+                                size_t      size)
+
+{
+  fpga_i2c_slave* dev;
+
+  dev = (fpga_i2c_slave*)
+    i2c_dev_alloc_and_init(sizeof(*dev), bus_path, address);
+  if (dev == NULL) {
+    return -1;
+  }
+
+  dev->base.read = fpga_i2c_slave_read;
+  dev->base.write = fpga_i2c_slave_write;
+  dev->size = size;
+
+  return i2c_dev_register(&dev->base, dev_path);
+}