From aaa2f9682df21ec2559e728fd3e31ae903307e74 Mon Sep 17 00:00:00 2001
From: Bruce Luckcuck <github@etracer.net>
Date: Sat, 25 May 2019 12:18:52 -0400
Subject: [PATCH] Use full erase when possible for FLASHFS erase If there is
 only a single partition, its type is FLASHFS, and it uses the entire
 geometry, then perform a full rather than a sector-based erase.

The full erase is significantly faster than erasing by individual sectors.
---
 src/main/drivers/flash.c |  5 +++++
 src/main/drivers/flash.h |  1 +
 src/main/io/flashfs.c    | 21 ++++++++++++++++++---
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/main/drivers/flash.c b/src/main/drivers/flash.c
index 1e16a370e..97aa946f1 100644
--- a/src/main/drivers/flash.c
+++ b/src/main/drivers/flash.c
@@ -395,4 +395,9 @@ bool flashInit(const flashConfig_t *flashConfig)
 
     return haveFlash;
 }
+
+int flashPartitionCount(void)
+{
+    return flashPartitions;
+}
 #endif // USE_FLASH_CHIP
diff --git a/src/main/drivers/flash.h b/src/main/drivers/flash.h
index 330674372..dac4df70b 100644
--- a/src/main/drivers/flash.h
+++ b/src/main/drivers/flash.h
@@ -94,3 +94,4 @@ void flashPartitionSet(uint8_t index, uint32_t startSector, uint32_t endSector);
 flashPartition_t *flashPartitionFindByType(flashPartitionType_e type);
 const flashPartition_t *flashPartitionFindByIndex(uint8_t index);
 const char *flashPartitionGetTypeName(flashPartitionType_e type);
+int flashPartitionCount(void);
diff --git a/src/main/io/flashfs.c b/src/main/io/flashfs.c
index 6c0e1a6f7..6599d6051 100644
--- a/src/main/io/flashfs.c
+++ b/src/main/io/flashfs.c
@@ -78,9 +78,24 @@ static void flashfsSetTailAddress(uint32_t address)
 
 void flashfsEraseCompletely(void)
 {
-    for (flashSector_t sectorIndex = flashPartition->startSector; sectorIndex <= flashPartition->endSector; sectorIndex++) {
-        uint32_t sectorAddress = sectorIndex * flashGeometry->sectorSize;
-        flashEraseSector(sectorAddress);
+    if (flashGeometry->sectors > 0 && flashPartitionCount() > 0) {
+        // if there's a single FLASHFS partition and it uses the entire flash then do a full erase
+        const bool doFullErase = (flashPartitionCount() == 1) && (FLASH_PARTITION_SECTOR_COUNT(flashPartition) == flashGeometry->sectors);
+        if (doFullErase) {
+            flashEraseCompletely();
+        } else {
+
+            // TODO - the partial sector-based erase needs to be completely reworked.
+            // All calls to flashfsEraseCompletely() currently expect the erase to run
+            // asynchronously and return immediately. The current implementation performs
+            // the erase synchronously and doesn't return until complete. This breaks calls
+            // from MSP and runtime mode-switched erasing.
+
+            for (flashSector_t sectorIndex = flashPartition->startSector; sectorIndex <= flashPartition->endSector; sectorIndex++) {
+                uint32_t sectorAddress = sectorIndex * flashGeometry->sectorSize;
+                flashEraseSector(sectorAddress);
+            }
+        }
     }
 
     flashfsClearBuffer();