From 2523670f8b1c11850e45e26f65b68c2d7fecf639 Mon Sep 17 00:00:00 2001
From: Ben Wynn <bwynn@glowie.com>
Date: Sat, 15 Nov 2025 12:12:09 -0500
Subject: [PATCH] sdcard: Adding tests for csd parsing.

Signed-off-by: Ben Wynn <bwynn@glowie.com>
---
 micropython/drivers/storage/sdcard/sdcard.py | 21 ++++++----
 micropython/drivers/storage/sdcard/sdtest.py | 44 ++++++++++++++++++++
 2 files changed, 57 insertions(+), 8 deletions(-)

diff --git a/micropython/drivers/storage/sdcard/sdcard.py b/micropython/drivers/storage/sdcard/sdcard.py
index 3df4788a2..01a249b24 100644
--- a/micropython/drivers/storage/sdcard/sdcard.py
+++ b/micropython/drivers/storage/sdcard/sdcard.py
@@ -92,10 +92,23 @@ def init_card(self, baudrate):
 
         # get the number of sectors
         # CMD9: response R2 (R1 byte + 16-byte block read)
+        csd = self.get_csd()
+        self.parse_csd(csd)
+
+        # CMD16: set block length to 512 bytes
+        if self.cmd(16, 512, 0) != 0:
+            raise OSError("can't set 512 block size")
+
+        # set to high data rate now that it's initialised
+        self.init_spi(baudrate)
+
+    def get_csd(self):
         if self.cmd(9, 0, 0, 0, False) != 0:
             raise OSError("no response from SD card")
         csd = bytearray(16)
         self.readinto(csd)
+
+    def parse_csd(self, csd):
         if csd[0] & 0xC0 == 0x40:  # CSD version 2.0
             self.sectors = ((csd[7] << 16 | csd[8] << 8 | csd[9]) + 1) * 1024
         elif csd[0] & 0xC0 == 0x00:  # CSD version 1.0 (old, <=2GB)
@@ -106,14 +119,6 @@ def init_card(self, baudrate):
             self.sectors = capacity // 512
         else:
             raise OSError("SD card CSD format not supported")
-        # print('sectors', self.sectors)
-
-        # CMD16: set block length to 512 bytes
-        if self.cmd(16, 512, 0) != 0:
-            raise OSError("can't set 512 block size")
-
-        # set to high data rate now that it's initialised
-        self.init_spi(baudrate)
 
     def init_card_v1(self):
         for i in range(_CMD_TIMEOUT):
diff --git a/micropython/drivers/storage/sdcard/sdtest.py b/micropython/drivers/storage/sdcard/sdtest.py
index ce700e2a8..50d6b2c41 100644
--- a/micropython/drivers/storage/sdcard/sdtest.py
+++ b/micropython/drivers/storage/sdcard/sdtest.py
@@ -6,6 +6,7 @@
 
 
 def sdtest():
+    """this test requires specific hardware, so is not run by CI"""
     spi = machine.SPI(1)
     spi.init()  # Ensure right baudrate
     sd = sdcard.SDCard(spi, machine.Pin.board.X21)  # Compatible with PCB
@@ -61,3 +62,46 @@ def sdtest():
         success = False
     print()
     print("Tests", "passed" if success else "failed")
+
+
+class MockSDCard(sdcard.SDCard):
+    """instantiates a sdcard object without talking to hardware"""
+
+    def __init__(self, spi, cs, baudrate=100_000):
+        super().__init__(spi, cs, baudrate=baudrate)
+
+    def init_card(self, baudrate):
+        """yeah, this is where we're just going to skip the whole hardware initalization thing"""
+        self.baudrate = baudrate
+
+
+def test_parse_csd(mockSD):
+    """test the parse_csd function"""
+    csd_tests = [
+        {
+            "name": "64g card",
+            "sectors": 122191872,
+            "csd": bytearray(b"@\x0e\x002[Y\x00\x01\xd2\x1f\x7f\x80\n@\x00S"),
+        },
+        {
+            "name": "128g card",
+            "sectors": 244277248,
+            "csd": bytearray(b"@\x0e\x002[Y\x00\x03\xa3\xd7\x7f\x80\n@\x00A"),
+        },
+    ]
+
+    for test in csd_tests:
+        mockSD.parse_csd(test["csd"])
+        sectors = mockSD.ioctl(4, None)
+        assert sectors == test["sectors"], "Failed to parse csd for test {}, {} != {}".format(
+            test["name"], sectors, test["sectors"]
+        )
+
+
+def run_tests():
+    mockSD = MockSDCard(None, None)
+    test_parse_csd(mockSD)
+    print("OK")
+
+
+run_tests()