Properties are now fetched through buffers

Author: Kamilosok

include/debug/debug_stdio.h

@@ -23,6 +23,7 @@ void dprintf(const char* fmt, ...);
 	#define DEBUG_PUTC(c)
 	#define DEBUG_PUTS(s)
 	#define DEBUG_PRINTF(fmt, ...) noop_printf(fmt __VA_OPT__(, ) __VA_ARGS__)
+	#define DEBUG_PUTGAP(n)
 
 #endif
 #endif

include/drivers/dt/dt_props.h

@@ -4,34 +4,12 @@
 #include <drivers/dt/dt_node.h>
 #include <stdbigos/types.h>
 
+// Can be used to check for bool-type props
 // Find a property of node by a name, dt_prop_t ptr if success, nullptr if error
 dt_prop_t* dt_find_prop(const dt_node_t* node, const char* name);
 
-// Read a single 32-bit value from a node's name prop and write it to out, 0 if success, <0 if error
-int dt_prop_read_u32(const dt_node_t* node, const char* name, u32* out);
-
-// Read a single 64-bit value from a node's name prop and write it to out, 0 if success, <0 if error
-int dt_prop_read_u64(const dt_node_t* node, const char* name, u64* out);
-
-// Read a single 32-bit value from a node's name prop's id index and write it to out, 0 if success, <0 if error
-int dt_prop_read_by_id_u32(const dt_node_t* node, const char* name, u32 index, u32* out);
-
-// Read an array of up to out_size node's name prop values and write them to out
-// number of successfully read values if success, <0 if error
-int dt_prop_read_array_u32(const dt_node_t* node, const char* name, u32 out[], u32 out_size);
-
-// Read a null-terminated string from node's name prop, const char ptr if succes, nullptr if error
-const char* dt_prop_read_str(const dt_node_t* node, const char* name);
-
-// Read an array of up to out_size node's name prop strings and write them to out
-// number of successfully read strings if success, <0 if error
-int dt_prop_read_array_str(const dt_node_t* node, const char* name, const char* out[], u32 out_size);
-
-// Read a bool ean value of node's name prop, 1 if exists or prop empty, 0 if doesn't exist, -1 if error
-int dt_prop_read_bool(const dt_node_t* node, const char* name);
-
-// Read a node's name phandle (a handle to a different node) and write it to out, 0 if success, -1 if error
-int dt_prop_read_phandle(const dt_node_t* node, const char* name, u32* out);
+// Get a buffer of node's name value, the buffer's BUFFER_ERROR field will have any potential errors
+buffer_t dt_prop_get_buffer(const dt_node_t* node, const char* name);
 
 // Print the node's properties
 void dt_print_props(const dt_node_t* node, u8 depth);

include/stdbigos/buffer.h

@@ -4,17 +4,26 @@
 #include <stdbigos/types.h>
 
 // Error codes
-#define BUFFER_OK            0
-#define BUFFER_OUT_OF_BOUNDS -1
+typedef enum : u32 {
+	BUFFER_OK = 0,
+	BUFFER_OUT_OF_BOUNDS = 1,
+	BUFFER_FETCH_ERROR = 2
+} BUFFER_ERROR;
 
 typedef struct buffer_t {
 	const void* data;
 	size_t size;
+	BUFFER_ERROR error;
 } buffer_t;
 
-// Helper to create a buffer
+// Helpers to create buffers
 static inline buffer_t make_buffer(const void* data, size_t size) {
-	buffer_t buf = {.data = data, .size = size};
+	buffer_t buf = {.data = data, .size = size, .error = BUFFER_OK};
+	return buf;
+}
+
+static inline buffer_t make_buffer_err(const void* data, size_t size, BUFFER_ERROR error) {
+	buffer_t buf = {.data = data, .size = size, .error = error};
 	return buf;
 }
 

src/drivers/dt/CMakeLists.txt

@@ -2,6 +2,10 @@ SETUP_LIBRARY(dt)
 
 target_link_libraries(dt PRIVATE stdbigos)
 
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+target_link_libraries(dt PRIVATE Debug)
+endif()
+
 
 target_include_directories(dt
   PUBLIC

src/drivers/dt/dt_access.c

@@ -1,6 +1,7 @@
 #include <debug/debug_stdio.h>
 #include <drivers/dt/dt.h>
 #include <drivers/dt/dt_node.h>
+#include <drivers/dt/dt_props.h>
 #include <stdbigos/bitutils.h>
 #include <stdbigos/string.h>
 
@@ -87,30 +88,18 @@ dt_prop_t* dt_find_prop(const dt_node_t* node, const char* name) {
 	return nullptr;
 }
 
-int dt_prop_read_u32(const dt_node_t* node, const char* name, u32* out) {
-	dt_prop_t* prop = dt_find_prop(node, name);
-
-	if (!prop || prop->data_length < 4 || !prop->value)
-		return -1;
-
-	u32 val = read_be32(prop->value);
-
-	*out = val;
+buffer_t dt_prop_get_buffer(const dt_node_t* node, const char* name) {
+	buffer_t buffer = make_buffer_err(nullptr, 0, BUFFER_FETCH_ERROR);
 
-	return 0;
-}
-
-int dt_prop_read_u64(const dt_node_t* node, const char* name, u64* out) {
 	dt_prop_t* prop = dt_find_prop(node, name);
+	if (!prop || !prop->value)
+		return buffer;
 
-	if (!prop || prop->data_length < 8 || !prop->value)
-		return -1;
-
-	u64 val = read_be64(prop->value);
-
-	*out = val;
+	buffer.data = prop->value;
+	buffer.size = prop->data_length;
+	buffer.error = BUFFER_OK;
 
-	return 0;
+	return buffer;
 }
 
 void dt_print_props(const dt_node_t* node, u8 depth) {

src/drivers/dt/dt_parser.c

@@ -9,14 +9,14 @@
 #include "dt_alloc.h"
 
 // FDT token values
-typedef enum FdtToken : u32 {
+typedef enum : u32 {
 	FDT_BEGIN_NODE = 0x1,
 	FDT_END_NODE = 0x2,
 	FDT_PROP = 0x3,
 	FDT_NOP = 0x4,
 	// Unused/Reserved 0x5 - 0x8
 	FDT_END = 0x9
-} FdtToken;
+} FDT_TOKEN;
 
 // Function to parse a block of properties starting at props_offset with props_size size in the FDT with fdt
 // being a ptr to the start of the flattened device tree blob
@@ -31,7 +31,7 @@ dt_prop_t* parse_props(const buffer_t* fdt_buf, u32 props_offset, u32 props_size
 		buffer_read_u32_be(*fdt_buf, curr_offset, &tag);
 
 		// Because of the separation of parsing properties and nodes, we don't want to parse non-properties
-		if ((FdtToken)tag != FDT_PROP)
+		if ((FDT_TOKEN)tag != FDT_PROP)
 			break;
 
 		curr_offset += 4;
@@ -78,8 +78,7 @@ dt_node_t* parse_subtree(const buffer_t* fdt_buf, u32* offset, u32 max_offset, u
 	u32 curr_offset = *offset;
 
 	u32 tag;
-
-	if (buffer_read_u32_be(*fdt_buf, curr_offset - 4, &tag) != BUFFER_OK || (FdtToken)tag != FDT_BEGIN_NODE)
+	if (buffer_read_u32_be(*fdt_buf, curr_offset - 4, &tag) != BUFFER_OK || (FDT_TOKEN)tag != FDT_BEGIN_NODE)
 		return nullptr;
 
 	const char* name;
@@ -98,7 +97,7 @@ dt_node_t* parse_subtree(const buffer_t* fdt_buf, u32* offset, u32 max_offset, u
 	while (curr_offset < max_offset) {
 		u32 tag;
 		buffer_read_u32_be(*fdt_buf, curr_offset, &tag);
-		if ((FdtToken)tag != FDT_PROP)
+		if ((FDT_TOKEN)tag != FDT_PROP)
 			break;
 
 		u32 p_len;
@@ -118,7 +117,7 @@ dt_node_t* parse_subtree(const buffer_t* fdt_buf, u32* offset, u32 max_offset, u
 		buffer_read_u32_be(*fdt_buf, curr_offset, &tag);
 
 		curr_offset += 4;
-		switch ((FdtToken)tag) {
+		switch ((FDT_TOKEN)tag) {
 		case FDT_BEGIN_NODE:
 			dt_node_t* child = parse_subtree(fdt_buf, &curr_offset, max_offset, str_offset, node);
 

src/example_dtree/entry.c

@@ -26,9 +26,11 @@ void main([[maybe_unused]] u32 hartid, const void* fdt) {
 	} else {
 		DEBUG_PRINTF("Found UART node: %s\n", dt_node_get_name(uart));
 
-		u64 base;
-		if (dt_prop_read_u64(uart, "reg", &base) == 0) {
-			DEBUG_PRINTF("UART base: %ld\n", base);
+		buffer_t buffer = dt_prop_get_buffer(uart, "reg");
+		if (buffer.error == BUFFER_OK) {
+			// Or other easy conversion methods, up to user
+			u64 val = read_be64(buffer.data);
+			DEBUG_PRINTF("UART base: %lu\n", val);
 		} else {
 			DEBUG_PRINTF("\"reg\" prop missing or invalid\n");
 		}