From bedf052341235668cce21b930025aa38278b216b Mon Sep 17 00:00:00 2001
From: Charlie Birks <charlie@daft.games>
Date: Sat, 11 Jun 2022 20:47:43 +0100
Subject: [PATCH] stm32: work around QSPI failing to read the last 32 bytes

Locking up everything including debugging...
---
 32blit-stm32/Src/quadspi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/32blit-stm32/Src/quadspi.c b/32blit-stm32/Src/quadspi.c
index b7db3568a..cb0d179ba 100644
--- a/32blit-stm32/Src/quadspi.c
+++ b/32blit-stm32/Src/quadspi.c
@@ -33,7 +33,10 @@ void MX_QUADSPI_Init(void)
   hqspi.Init.ClockPrescaler = 2;
   hqspi.Init.FifoThreshold = 1;
   hqspi.Init.SampleShifting = QSPI_SAMPLE_SHIFTING_NONE;
-  hqspi.Init.FlashSize = QSPI_FLASH_SIZE;
+
+  // Use a flash size 2x what we should to avoid "Memory-mapped read of last memory byte fails"
+  // (due to prefetch, it's actually the last 32 bytes)
+  hqspi.Init.FlashSize = QSPI_FLASH_SIZE + 1;
   hqspi.Init.ChipSelectHighTime = QSPI_CS_HIGH_TIME_1_CYCLE;
   hqspi.Init.ClockMode = QSPI_CLOCK_MODE_3;
   hqspi.Init.FlashID = QSPI_FLASH_ID_2;