wip uf2lukeshu/uf2

3 files changed, 110 insertions, 0 deletions

diff --git a/cmd/sbc_harness/CMakeLists.txt b/cmd/sbc_harness/CMakeLists.txt
index 7656ab6..4cf39a6 100644
--- a/cmd/sbc_harness/CMakeLists.txt
+++ b/cmd/sbc_harness/CMakeLists.txt
@@ -16,6 +16,7 @@ add_library(sbc_harness_objs OBJECT
 	fs_harness_uptime_txt.c
 
 	ihex.c
+	uf2.c
 )
 target_include_directories(sbc_harness_objs PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/config)
 target_include_directories(sbc_harness_objs PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/cmd/sbc_harness/uf2.c b/cmd/sbc_harness/uf2.c
new file mode 100644
index 0000000..30b3694
--- /dev/null
+++ b/cmd/sbc_harness/uf2.c
@@ -0,0 +1,82 @@
+/* sbc_harness/uf2.h - Universal Flashing Format
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <string.h> /* for memcpy(), memcmp() */
+
+#include <libmisc/endian.h>
+
+#define IMPLEMENTATION_FOR_UF2_H YES
+#include "uf2.h"
+
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+
+#define UF2_FLAG_NOTMAIN   0x00000001
+#define UF2_FLAG_CONTAINER 0x00001000
+#define UF2_FLAG_FAMILYID  0x00002000
+#define UF2_FLAG_MD5SUM    0x00004000
+#define UF2_FLAG_EXTENSION 0x00008000
+
+static const uint8_t uf2_magic_beg[8] = { 'U', 'F', '2', '\n', 0x57, 0x51, 0x5D, 0x9E };
+static const uint8_t uf2_magic_end[4] = { 0x30, 0x6F, 0xB1, '\n' };
+
+static size_t_and_error uf2_decoder_write(struct uf2_decoder *self, const char *dat, size_t len_in) {
+	assert(self);
+	assert(ctx);
+	if (!len_in)
+		return ERROR_AND(size_t, 0, ERROR_NULL);
+	assert(dat);
+
+	if (self->seen_err)
+		return ERROR_AND(size_t, 0, error_new(E_POSIX_ESPIPE, "write after error"));
+
+	size_t len_consumed = 0;
+
+	while (len_consumed < len_in) {
+		size_t n = MIN(512 - self->len_dat, /* how much we're willing to take */
+		               len_in - len_consumed); /* how much we're being offered */
+		memcpy(&self->dat[self->dat_len], &dat[len_consumed], n);
+		self->dat_len += n;
+		len_consumed += n;
+
+		if (self->dat_len != 512)
+			continue;
+
+		if (memcmp(&self->dat[0], uf2_magic_beg, 8)) {
+			self->seen_err = true;
+			return ERROR_AND(size_t, len_consumed, error_new(E_POSIX_EPROTO, "block does not begin with magic"));
+		}
+		if (memcmp(&self->dat[512-4], uf2_magic_end, 4)) {
+			self->seen_err = true;
+			return ERROR_AND(size_t, len_consumed, error_new(E_POSIX_EPROTO, "block does not end with magic"));
+		}
+		uint32_t flag = uint32le_decode(&self->dat[8]);
+		uint32_t addr = uint32le_decode(&self->dat[12]);
+		uint32_t size = uint32le_decode(&self->dat[16]);
+		uint32_t bnum = uint32le_decode(&self->dat[20]);
+		uint32_t bcnt = uint32le_decode(&self->dat[24]);
+		uint32_t famid = uint32le_decode(&self->dat[28]);
+		uint8_t *data = &self->dat[32];
+		// TODO
+	}
+
+	assert(len_consumed == len_in);
+	return ERROR_AND(size_t, len_in, ERROR_NULL);
+}
+
+size_t_and_error uf2_decoder_writev(struct uf2_decoder *self, const struct iovec *iov, int iovcnt) {
+	assert(self);
+	assert(iov);
+	assert(iovcnt);
+
+	size_t total = 0;
+	for (int i = 0; i < iovcnt; i++) {
+		size_t_and_error r = uf2_decoder_write(self, iov[i].iov_base, iov[i].iov_len);
+		total += r.size_t;
+		if (!ERROR_IS_NULL(r.err))
+			return ERROR_AND(size_t, total, r.err);
+	}
+	return ERROR_AND(size_t, total, ERROR_NULL);
+}
diff --git a/cmd/sbc_harness/uf2.h b/cmd/sbc_harness/uf2.h
new file mode 100644
index 0000000..bf9e032
--- /dev/null
+++ b/cmd/sbc_harness/uf2.h
@@ -0,0 +1,27 @@
+/* sbc_harness/uf2.h - Universal Flashing Format
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _SBC_HARNESS_FS_HARNESS_UF2_H_
+#define _SBC_HARNESS_FS_HARNESS_UF2_H_
+
+#include <stddef.h>  /* for size_t */
+#include <stdint.h>  /* for uint{n}_t */
+
+#include <libhw/generic/io.h>
+#include <libmisc/private.h>
+
+struct uf2_decoder {
+	BEGIN_PRIVATE(UF2_H);
+	bool            seen_err;
+	size_t          dat_len;
+	uint8_t         dat[512];
+	uint32_t        bnum;
+	uint32_t        bcnt;
+	END_PRIVATE(UF2_H);
+};
+LO_IMPLEMENTATION_H(io_writer, struct uf2_decoder, uf2_decoder);
+
+#endif /* _SBC_HARNESS_FS_HARNESS_UF2_H_ */