kernel: Add mmio(9)

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 118 insertions, 0 deletions

diff --git a/sys/include/sys/mmio.h b/sys/include/sys/mmio.h
new file mode 100644
index 0000000..8f573c3
--- /dev/null
+++ b/sys/include/sys/mmio.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * For documentation: See mmio(9)
+ */
+
+#ifndef _SYS_MMIO_H_
+#define _SYS_MMIO_H_
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#if defined(_KERNEL)
+#include <vm/vm.h>
+#endif
+
+#if defined(_KERNEL)
+
+
+/*
+ * mmio_write<n> - Writes to MMIO address with specific size
+ *
+ * @addr: Address to write to.
+ * @val: Value to write.
+ *
+ * These functions will add the higher half
+ * offset (VM_HIGHER_HALF) if the MMIO address
+ * is less than VM_HIGHER_HALF as it'll be safe
+ * to assume it's a physical address. Page faults
+ * from writes could be due to the resulting virtual
+ * address not being mapped.
+ */
+#define _MMIO_WRITE_TYPE(TYPE, SUFFIX)                  \
+    static inline void                                  \
+    mmio_write##SUFFIX(volatile void *addr, TYPE val)   \
+    {                                                   \
+        uintptr_t tmp;                                  \
+                                                        \
+        tmp = (uintptr_t)addr;                          \
+        if (tmp < VM_HIGHER_HALF) {                     \
+            tmp += VM_HIGHER_HALF;                      \
+        }                                               \
+        *(volatile TYPE *)tmp = val;                    \
+        __ASMV("" ::: "memory");                        \
+    }
+
+/*
+ * mmio_read<n> - Does the same as mmio_write<n> but for reading
+ *
+ * @addr: Address to read from.
+ */
+#define _MMIO_READ_TYPE(TYPE, SUFFIX)                   \
+    static inline TYPE                                  \
+    mmio_read##SUFFIX(volatile void *addr)              \
+    {                                                   \
+        uintptr_t tmp;                                  \
+                                                        \
+        tmp = (uintptr_t)addr;                          \
+        if (tmp < VM_HIGHER_HALF) {                     \
+            tmp += VM_HIGHER_HALF;                      \
+        }                                               \
+                                                        \
+        __ASMV("" ::: "memory");                        \
+        return *(volatile TYPE *)tmp;                   \
+    }
+
+/*
+ * To write to an MMIO address of, for example,
+ * 8 bits, use mmio_write8(addr, val)
+ */
+_MMIO_WRITE_TYPE(uint8_t, 8)
+_MMIO_WRITE_TYPE(uint16_t, 16)
+_MMIO_WRITE_TYPE(uint32_t, 32)
+#if __SIZEOF_SIZE_T__ == 8
+_MMIO_WRITE_TYPE(uint64_t, 64)
+#endif
+__extension__
+
+/*
+ * To read from an MMIO address of, for example,
+ * 8 bits, use mmio_read8(addr)
+ */
+_MMIO_READ_TYPE(uint8_t, 8)
+_MMIO_READ_TYPE(uint16_t, 16)
+_MMIO_READ_TYPE(uint32_t, 32)
+#if __SIZEOF_SIZE_T__ == 8
+_MMIO_READ_TYPE(uint64_t, 64)
+#endif
+__extension__
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_MMIO_H_ */