From 0b0bfa4b7897abeddfc0bf66a17a835b890a1246 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mikael=20=C3=85gren?= <mikael@tillitis.se>
Date: Thu, 17 Apr 2025 08:44:15 +0200
Subject: [PATCH] doc: Add ERASE_DATA syscall

---
 doc/release_notes.md             |  6 +++---
 hw/application_fpga/fw/README.md | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/doc/release_notes.md b/doc/release_notes.md
index e68a258..84e82de 100644
--- a/doc/release_notes.md
+++ b/doc/release_notes.md
@@ -79,9 +79,9 @@ For full change log [see](https://github.com/tillitis/tillitis-key1/compare/TK1-
 - Support a filesystem on flash.
 
 - Add a system call mechanism and system calls: `RESET`, `ALLOC_AREA`,
-  `DEALLOC_AREA`, `WRITE_DATA`, `READ_DATA`, `PRELOAD_DELETE`,
-  `PRELOAD_STORE`, `PRELOAD_STORE_FIN`, `PRELOAD_GET_DIGSIG`,
-  `STATUS`, and `GET_VIDPID`. See [firmware's
+  `DEALLOC_AREA`, `WRITE_DATA`, `READ_DATA`, `ERASE_DATA`,
+  `PRELOAD_DELETE`, `PRELOAD_STORE`, `PRELOAD_STORE_FIN`,
+  `PRELOAD_GET_DIGSIG`, `STATUS`, and `GET_VIDPID`. See [firmware's
   README](../hw/application_fpga/fw/README.md) for documentation.
 
 - Harmonize with [tkey-libs](https://github.com/tillitis/tkey-libs).
diff --git a/hw/application_fpga/fw/README.md b/hw/application_fpga/fw/README.md
index 17e9040..63bfc25 100644
--- a/hw/application_fpga/fw/README.md
+++ b/hw/application_fpga/fw/README.md
@@ -594,6 +594,20 @@ syscall(TK1_SYSCALL_READ_DATA, offset, (uint32_t)buf, sizeof(buf);
 
 Read into `buf` at byte `offset` from the app's flash area.
 
+#### `ERASE_DATA`
+
+```
+uint32_t offset = 0;
+uint32_t size = 4096;
+
+syscall(TK1_SYSCALL_ERASE_DATA, offset, size, 0);
+```
+
+Erase `size` bytes from `offset` within the area. Returns 0 on
+success.
+
+Both `size` and  `offset` must be a multiple of 4096 bytes.
+
 #### `PRELOAD_DELETE`
 
 ```