From e35771657648d0ce9d8df48188b3aa22889507b4 Mon Sep 17 00:00:00 2001
From: dragonmux <git@dragonmux.network>
Date: Tue, 22 Oct 2024 23:17:11 +0100
Subject: [PATCH] flashstub: Finished getting the RP2040 Flash stub integrated
 into the Meson build system

---
 meson.build                      |  9 ++--
 src/target/flashstub/meson.build | 82 ++++++++++++++++++++++----------
 src/target/flashstub/rp.c        |  7 ++-
 src/target/meson.build           |  4 +-
 4 files changed, 68 insertions(+), 34 deletions(-)

diff --git a/meson.build b/meson.build
index 531e3fe16c9..9da8c4eee12 100644
--- a/meson.build
+++ b/meson.build
@@ -156,6 +156,11 @@ endif
 probe_host = disabler()
 probe_bootloader = disabler()
 
+# Deal with the print memory usage option before recursing so the Flash stubs don't screw things up
+if is_firmware_build and get_option('print_memory_usage')
+	add_project_link_arguments('-Wl,--print-memory-usage', language: 'c')
+endif
+
 subdir('src')
 
 ## Black Magic Firmware (BMF) targets
@@ -171,10 +176,6 @@ If you did not touch the build system this is not your fault, please report it
 ''',
 	)
 
-	if get_option('print_memory_usage')
-		add_project_link_arguments('-Wl,--print-memory-usage', language: 'c')
-	endif
-
 	# System binary utilities
 	size = find_program('size')
 	objcopy = find_program('objcopy')
diff --git a/src/target/flashstub/meson.build b/src/target/flashstub/meson.build
index 83261011cab..e655f5bd0cb 100644
--- a/src/target/flashstub/meson.build
+++ b/src/target/flashstub/meson.build
@@ -28,19 +28,24 @@
 # 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.
 
-hexdump = find_program('hexdump', native: true, required: false)
+# Default definitions of the resulting stubs for all this that are harmless for, eg, BMDA
+rp2040_stub = []
 
-write_stub = generator(
-	hexdump,
-	arguments: [
-		'-v',
-		'-e', '/2 "0x%04X, "',
-		'@INPUT@'
-	],
-	ouptut: '@CURRENT_SOURCE_DIR@/@BASENAME@.stub'
-	capture: true,
-)
+# If we're doing a firmware build, type to find hexdump
+if is_firmware_build
+	hexdump = find_program('hexdump', required: false)
+else
+	hexdump = disabler()
+endif
+# If we cannot or we're not a firmware build, we're done
+if not hexdump.found()
+	subdir_done()
+endif
+
+# We found hexdump, so build the stubs and their conversions to text files containing suitably formatted
+# hexadecimal of their code, ready to go onto a target.
 
+# Default options for all stub builds
 stub_build_args = [
 	'-mthumb',
 	'-nostartfiles',
@@ -49,26 +54,53 @@ stub_build_args = [
 	'-ffreestanding',
 ]
 
-lmi_stub_elf = executable(
-	'lmi_stub',
-	'lmi.c',
-	c_args: [
-		'-mcpu=cortexm-m4',
-		stub_build_args,
-	]
-)
+# Flash stub for Stellaris/Tiva-C parts
+# lmi_stub_elf = executable(
+# 	'lmi_stub',
+# 	'lmi.c',
+# 	c_args: [
+# 		'-mcpu=cortex-m4',
+# 		stub_build_args,
+# 	]
+# )
 
-efm32_stub_elf = executable(
-	'efm32_stub'
-	'efm32.c',
-	c_args: stub_build_args,
-)
+# Flash stub for EFM32 parts
+# efm32_stub_elf = executable(
+# 	'efm32_stub',
+# 	'efm32.c',
+# 	c_args: [
+# 		'-mcpu=cortex-m3',
+# 		stub_build_args,
+# 	]
+# )
 
+# Flash stub for the RP2040
 rp2040_stub_elf = executable(
 	'rp_stub',
 	'rp.c',
 	c_args: [
-		'-mcpu=cortexm-m0plus',
+		'-mcpu=cortex-m0plus',
 		stub_build_args
 	],
+	link_args: [
+		'-mcpu=cortex-m0plus',
+		stub_build_args,
+		'-T', '@0@/rp.ld'.format(meson.current_source_dir()),
+	],
+	link_depends: files('rp.ld'),
+	pie: false,
+	install: false,
+)
+
+rp2040_stub = custom_target(
+	'rp_stub-hex',
+	command: [
+		hexdump,
+		'-v',
+		'-e', '/2 "0x%04X, "',
+		'@INPUT@'
+	],
+	input: rp2040_stub_elf,
+	output: 'rp.stub',
+	capture: true,
 )
diff --git a/src/target/flashstub/rp.c b/src/target/flashstub/rp.c
index 2a521febba6..9600a3b0ab1 100644
--- a/src/target/flashstub/rp.c
+++ b/src/target/flashstub/rp.c
@@ -71,8 +71,7 @@ static gpio_qspi_s *const gpio_qspi = (gpio_qspi_s *)RP_GPIO_QSPI_BASE_ADDR;
 
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
 
-void __attribute__((naked, used, section(".entry")))
-rp_flash_write_stub(const uint16_t command, const uint32_t dest, const uint8_t *const src, const uint32_t length)
+void __attribute__((naked, used, section(".entry"))) rp_flash_write_stub()
 {
 	/* Create a stack for our own sanity */
 	__asm__("ldr r4, =#0x20042000\n"
@@ -150,8 +149,8 @@ static void rp_spi_write(const uint32_t address, const uint8_t *const src, const
 	rp_spi_flash_deselect();
 }
 
-static void __attribute__((used, section(".entry")))
-rp_flash_write(const uint32_t dest, const uint8_t *const src, const size_t length, const uint32_t page_size)
+static void __attribute__((used, section(".entry"))) rp_flash_write(
+	const uint32_t dest, const uint8_t *const src, const size_t length, const uint32_t page_size)
 {
 	for (size_t offset = 0; offset < length; offset += page_size) {
 		/* Try to write-enable the Flash */
diff --git a/src/target/meson.build b/src/target/meson.build
index 95167c95d87..bffa93b89b0 100644
--- a/src/target/meson.build
+++ b/src/target/meson.build
@@ -31,6 +31,8 @@
 
 target_common_includes = include_directories('.')
 
+subdir('flashstub')
+
 target_common_sources = files(
 	'adi.c',
 	'adiv5.c',
@@ -241,7 +243,7 @@ target_rp = declare_dependency(
 	sources: files(
 		'rp2040.c',
 		'rp2350.c',
-	),
+	) + rp2040_stub,
 	dependencies: target_cortexm,
 )