From eb8a2074c8bfa3d44eea10b9b9127e14bf9736d8 Mon Sep 17 00:00:00 2001
From: Balazs Racz <balazs.racz@gmail.com>
Date: Sat, 10 Dec 2022 11:12:57 +0100
Subject: [PATCH] Adds EEPROMFile driver for TI Tiva microcontrollers. (#684)

* Adds EEPROMFile driver for TI Tiva microcontrollers.

The EEPROMFile allows using the built-in eeprom peripheral of the Tiva.
There are some limitations, for example only 4-byte aligned reads and
writes are supported.

* Switches from MAP_ to flash version of EEPROMinit and adds errata reference on why.
---
 src/freertos_drivers/ti/TivaEEPROMFile.hxx | 104 +++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 src/freertos_drivers/ti/TivaEEPROMFile.hxx

diff --git a/src/freertos_drivers/ti/TivaEEPROMFile.hxx b/src/freertos_drivers/ti/TivaEEPROMFile.hxx
new file mode 100644
index 000000000..f9e6a0331
--- /dev/null
+++ b/src/freertos_drivers/ti/TivaEEPROMFile.hxx
@@ -0,0 +1,104 @@
+/** \copyright
+ * Copyright (c) 2022, Balazs Racz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, 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.
+ *
+ * \file TivaEEPROMFile.hxx
+ *
+ * Implementation for persistent storage that uses Tiva EEPROM.
+ *
+ * @author Balazs Racz
+ * @date 9 Dec 2022
+ */
+
+#ifndef _FREERTOS_DRIVER_TI_TIVAEEPROMFILE_HXX_
+#define _FREERTOS_DRIVER_TI_TIVAEEPROMFILE_HXX_
+
+#include "driverlib/rom.h"
+#include "driverlib/rom_map.h"
+
+#include "driverlib/eeprom.h"
+#include "driverlib/sysctl.h"
+
+#include "freertos_drivers/common/DeviceFile.hxx"
+
+class TivaEEPROMFile : public DeviceFile
+{
+public:
+    TivaEEPROMFile(const char *name, unsigned byte_offset, unsigned byte_size)
+        : DeviceFile(name)
+        , byteOffset_(byte_offset)
+        , byteSize_(byte_size)
+    {
+        MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_EEPROM0);
+        // Due to Erratum MEM#11 we must never use ROM_EEPROMInit.
+        EEPROMInit();
+        // This is for Tiva 129. For 123 it would be okay to have 2*64.
+        HASSERT(byte_offset % (8 * 64) == 0);
+        HASSERT(byte_size % (8 * 64) == 0);
+        HASSERT(byteOffset_ + byteSize_ <= MAP_EEPROMSizeGet());
+    }
+
+    /// Implements querying the file size.
+    int fstat(File *file, struct stat *stat) override
+    {
+        DeviceFile::fstat(file, stat);
+        stat->st_size = byteSize_;
+        return 0;
+    }
+
+    /// Write to the eeprom.
+    /// @param index index within the file address space to start write
+    /// @param buf data to write
+    /// @param len length in bytes of data to write
+    /// @return number of bytes written upon success, -errno upon failure
+    ssize_t write(unsigned int index, const void *buf, size_t len) override
+    {
+        HASSERT(index % 4 == 0);
+        HASSERT(len % 4 == 0);
+        MAP_EEPROMProgram((uint32_t *)buf, index + byteOffset_, len);
+        return len;
+    }
+
+    /// Read from the eeprom.
+    /// @param index index within DeviceFile address space to start read
+    /// @param buf location to post read data
+    /// @param len length in bytes of data to read
+    /// @return number of bytes read upon success, -errno upon failure
+    ssize_t read(unsigned int index, void *buf, size_t len) override
+    {
+        HASSERT(index % 4 == 0);
+        HASSERT(len % 4 == 0);
+        MAP_EEPROMRead((uint32_t *)buf, index + byteOffset_, len);
+        return len;
+    }
+
+private:
+    /// Address in the EEPROM of the first byte of this file.
+    uint16_t byteOffset_;
+    /// Total number of bytes in this file.
+    uint16_t byteSize_;
+};
+
+#endif // _FREERTOS_DRIVER_TI_TIVAEEPROMFILE_HXX_