dt-bindings: riscv: Add fine-grained IO memory PMP attributes

Introduce new macros to define bitfields for RISC-V Physical Memory
Protection (PMP) attributes, specifically for specifying Read, Write,
and Execute permissions for IO memory regions in device tree bindings.

The following macros are added:
- ATTR_RISCV_TYPE_IO_R: Read access (Bit 0)
- ATTR_RISCV_TYPE_IO_W: Write access (Bit 1)
- ATTR_RISCV_TYPE_IO_X: Execute access (Bit 2)

Corresponding macros for device tree usage are also added:
- DT_MEM_RISCV_TYPE_IO_R
- DT_MEM_RISCV_TYPE_IO_W
- DT_MEM_RISCV_TYPE_IO_X

These macros allow device tree source files to precisely describe the
intended access permissions for memory-mapped IO regions, enhancing
the system's memory protection configuration.

Signed-off-by: Firas Sammoura <[email protected]>

Author: fsammoura1980

include/zephyr/dt-bindings/memory-attr/memory-attr-riscv.h

@@ -16,18 +16,20 @@
 #define DT_MEM_RISCV_GET(x)			((x) & DT_MEM_RISCV_MASK)
 #define DT_MEM_RISCV(x)				((x) << DT_MEM_ARCH_ATTR_SHIFT)
 
-#define  ATTR_RISCV_TYPE_MAIN			BIT(0)
-#define  ATTR_RISCV_TYPE_IO			BIT(1)
-#define  ATTR_RISCV_TYPE_EMPTY			BIT(2)
+#define  ATTR_RISCV_TYPE_IO_R			BIT(0)
+#define  ATTR_RISCV_TYPE_IO_W			BIT(1)
+#define  ATTR_RISCV_TYPE_IO_X			BIT(2)
+#define  ATTR_RISCV_TYPE_MAIN			(BIT(0) | BIT(1))
 #define  ATTR_RISCV_AMO_SWAP			BIT(3)
 #define  ATTR_RISCV_AMO_LOGICAL			BIT(4)
 #define  ATTR_RISCV_AMO_ARITHMETIC		BIT(5)
 #define  ATTR_RISCV_IO_IDEMPOTENT_READ		BIT(6)
 #define  ATTR_RISCV_IO_IDEMPOTENT_WRITE		BIT(7)
 
+#define DT_MEM_RISCV_TYPE_IO_R			DT_MEM_RISCV(ATTR_RISCV_TYPE_IO_R)
+#define DT_MEM_RISCV_TYPE_IO_W			DT_MEM_RISCV(ATTR_RISCV_TYPE_IO_W)
+#define DT_MEM_RISCV_TYPE_IO_X			DT_MEM_RISCV(ATTR_RISCV_TYPE_IO_X)
 #define DT_MEM_RISCV_TYPE_MAIN			DT_MEM_RISCV(ATTR_RISCV_TYPE_MAIN)
-#define DT_MEM_RISCV_TYPE_IO			DT_MEM_RISCV(ATTR_RISCV_TYPE_IO)
-#define DT_MEM_RISCV_TYPE_EMPTY			DT_MEM_RISCV(ATTR_RISCV_TYPE_EMPTY)
 #define DT_MEM_RISCV_AMO_SWAP			DT_MEM_RISCV(ATTR_RISCV_AMO_SWAP)
 #define DT_MEM_RISCV_AMO_LOGICAL		DT_MEM_RISCV(ATTR_RISCV_AMO_LOGICAL)
 #define DT_MEM_RISCV_AMO_ARITHMETIC		DT_MEM_RISCV(ATTR_RISCV_AMO_ARITHMETIC)