eeprom sim: Enhance & refactor native part so it works w emb libCs

For the parts of the simulator which are dedicated for the native
platforms (POSIX arch based):
* Refactor the parts that interacts with the host, so it is possible to
  use it also with embedded libCs
* Enhance it with more options to allow:
  * Keeping the content just in RAM
  * Erasing the EEPROM file at exit
  * Clearing the file at boot
* Also show in the command line help the default file name.

As part of this:

* Update the kconfig dependencies, so we allow building it with other
  C libraries in the native targets
* Update the table in the native_sim docs to indicate all C libraries
  are supproted now

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

boards/native/native_sim/doc/index.rst

@@ -702,7 +702,7 @@ host libC (:kconfig:option:`CONFIG_EXTERNAL_LIBC`):
      Console backend, :ref:`POSIX arch console <nsim_back_console>`, :kconfig:option:`CONFIG_POSIX_ARCH_CONSOLE`, All
      Display, :ref:`Display SDL <nsim_per_disp_sdl>`, :kconfig:option:`CONFIG_SDL_DISPLAY`, All
      Entropy, :ref:`Native posix entropy <nsim_per_entr>`, :kconfig:option:`CONFIG_FAKE_ENTROPY_NATIVE_POSIX`, All
-     EEPROM, EEPROM simulator, :kconfig:option:`CONFIG_EEPROM_SIMULATOR`, Host libC
+     EEPROM, EEPROM simulator, :kconfig:option:`CONFIG_EEPROM_SIMULATOR`, All
      EEPROM, EEPROM emulator, :kconfig:option:`CONFIG_EEPROM_EMULATOR`, All
      Ethernet, :ref:`Eth native_posix <nsim_per_ethe>`, :kconfig:option:`CONFIG_ETH_NATIVE_POSIX`, All
      Flash, :ref:`Flash simulator <nsim_per_flash_simu>`, :kconfig:option:`CONFIG_FLASH_SIMULATOR`, All

drivers/eeprom/CMakeLists.txt

@@ -10,7 +10,14 @@ zephyr_library_sources_ifdef(CONFIG_EEPROM_SHELL eeprom_shell.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_AT2X eeprom_at2x.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_LPC11U6X eeprom_lpc11u6x.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_STM32 eeprom_stm32.c)
-zephyr_library_sources_ifdef(CONFIG_EEPROM_SIMULATOR eeprom_simulator.c)
+if(CONFIG_EEPROM_SIMULATOR)
+  zephyr_library_sources(eeprom_simulator.c)
+  if(CONFIG_NATIVE_LIBRARY)
+    target_sources(native_simulator INTERFACE eeprom_simulator_native.c)
+  elseif(CONFIG_ARCH_POSIX)
+    zephyr_library_sources(eeprom_simulator_native.c)
+  endif()
+endif()
 zephyr_library_sources_ifdef(CONFIG_EEPROM_EMULATOR eeprom_emulator.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_TMP116 eeprom_tmp116.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_XEC eeprom_mchp_xec.c)

drivers/eeprom/Kconfig

@@ -104,7 +104,6 @@ config EEPROM_SIMULATOR
 	bool "Simulated EEPROM driver"
 	default y
 	depends on DT_HAS_ZEPHYR_SIM_EEPROM_ENABLED
-	depends on !(ARCH_POSIX && !EXTERNAL_LIBC)
 	select STATS
 	select STATS_NAMES
 	help

drivers/eeprom/eeprom_simulator.c

@@ -8,18 +8,10 @@
 #define DT_DRV_COMPAT zephyr_sim_eeprom
 
 #ifdef CONFIG_ARCH_POSIX
-#undef _POSIX_C_SOURCE
-/* Note: This is used only for interaction with the host C library, and is therefore exempt of
- * coding guidelines rule A.4&5 which applies to the embedded code using embedded libraries
- */
-#define _POSIX_C_SOURCE 200809L
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <fcntl.h>
+#include "eeprom_simulator_native.h"
 #include "cmdline.h"
 #include "soc.h"
-#endif
+#endif /* CONFIG_ARCH_POSIX */
 
 #include <zephyr/device.h>
 #include <zephyr/drivers/eeprom.h>
@@ -87,10 +79,13 @@ STATS_NAME(eeprom_sim_thresholds, max_len)
 STATS_NAME_END(eeprom_sim_thresholds);
 
 #ifdef CONFIG_ARCH_POSIX
-static uint8_t *mock_eeprom;
+static char *mock_eeprom;
 static int eeprom_fd = -1;
 static const char *eeprom_file_path;
-static const char default_eeprom_file_path[] = "eeprom.bin";
+#define DEFAULT_EEPROM_FILE_PATH "eeprom.bin"
+static bool eeprom_erase_at_start;
+static bool eeprom_rm_at_exit;
+static bool eeprom_in_ram;
 #else
 static uint8_t mock_eeprom[DT_INST_PROP(0, size)];
 #endif /* CONFIG_ARCH_POSIX */
@@ -218,36 +213,23 @@ static const struct eeprom_sim_config eeprom_sim_config_0 = {
 
 static int eeprom_mock_init(const struct device *dev)
 {
-	if (eeprom_file_path == NULL) {
-		eeprom_file_path = default_eeprom_file_path;
+	int rc;
+
+	ARG_UNUSED(dev);
+
+	if (eeprom_in_ram == false && eeprom_file_path == NULL) {
+		eeprom_file_path = DEFAULT_EEPROM_FILE_PATH;
 	}
 
-	eeprom_fd = open(eeprom_file_path, O_RDWR | O_CREAT, (mode_t)0600);
-	if (eeprom_fd == -1) {
-		posix_print_warning("Failed to open eeprom device file "
-				    "%s: %s\n",
-				    eeprom_file_path, strerror(errno));
+	rc = eeprom_mock_init_native(eeprom_in_ram, &mock_eeprom, DT_INST_PROP(0, size), &eeprom_fd,
+				     eeprom_file_path, 0xFF, eeprom_erase_at_start);
+
+	if (rc < 0) {
 		return -EIO;
-	}
-
-	if (ftruncate(eeprom_fd, DT_INST_PROP(0, size)) == -1) {
-		posix_print_warning("Failed to resize eeprom device file "
-				    "%s: %s\n",
-				    eeprom_file_path, strerror(errno));
-		return -EIO;
-	}
-
-	mock_eeprom = mmap(NULL, DT_INST_PROP(0, size),
-			  PROT_WRITE | PROT_READ, MAP_SHARED, eeprom_fd, 0);
-	if (mock_eeprom == MAP_FAILED) {
-		posix_print_warning("Failed to mmap eeprom device file "
-				    "%s: %s\n",
-				    eeprom_file_path, strerror(errno));
-		return -EIO;
-	}
-
+	} else {
 		return 0;
 	}
+}
 
 #else
 
@@ -269,35 +251,43 @@ static int eeprom_sim_init(const struct device *dev)
 	return eeprom_mock_init(dev);
 }
 
-DEVICE_DT_INST_DEFINE(0, &eeprom_sim_init, NULL,
-		    NULL, &eeprom_sim_config_0, POST_KERNEL,
+DEVICE_DT_INST_DEFINE(0, &eeprom_sim_init, NULL, NULL, &eeprom_sim_config_0, POST_KERNEL,
 		      CONFIG_EEPROM_INIT_PRIORITY, &eeprom_sim_api);
 
 #ifdef CONFIG_ARCH_POSIX
 
 static void eeprom_native_cleanup(void)
 {
-	if ((mock_eeprom != MAP_FAILED) && (mock_eeprom != NULL)) {
-		munmap(mock_eeprom, DT_INST_PROP(0, size));
-	}
-
-	if (eeprom_fd != -1) {
-		close(eeprom_fd);
-	}
+	eeprom_mock_cleanup_native(eeprom_in_ram, eeprom_fd, mock_eeprom, DT_INST_PROP(0, size),
+				   eeprom_file_path, eeprom_rm_at_exit);
 }
 
 static void eeprom_native_options(void)
 {
 	static struct args_struct_t eeprom_options[] = {
-		{ .manual = false,
-		  .is_mandatory = false,
-		  .is_switch = false,
-		  .option = "eeprom",
+		{.option = "eeprom",
 		 .name = "path",
 		 .type = 's',
 		 .dest = (void *)&eeprom_file_path,
-		  .call_when_found = NULL,
-		  .descript = "Path to binary file to be used as eeprom" },
+		 .descript = "Path to binary file to be used as EEPROM, by default "
+			     "\"" DEFAULT_EEPROM_FILE_PATH "\""},
+		{.is_switch = true,
+		 .option = "eeprom_erase",
+		 .type = 'b',
+		 .dest = (void *)&eeprom_erase_at_start,
+		 .descript = "Erase the EEPROM content at startup"},
+		{.is_switch = true,
+		 .option = "eeprom_rm",
+		 .type = 'b',
+		 .dest = (void *)&eeprom_rm_at_exit,
+		 .descript = "Remove the EEPROM file when terminating the execution"},
+		{.is_switch = true,
+		 .option = "eeprom_in_ram",
+		 .type = 'b',
+		 .dest = (void *)&eeprom_in_ram,
+		 .descript = "Instead of a file, keep the file content just in RAM. If this is "
+			     "set, eeprom, eeprom_erase & eeprom_rm are ignored, and the EEPROM "
+			     "content is always erased at startup"},
 		ARG_TABLE_ENDMARKER
 	};
 

drivers/eeprom/eeprom_simulator_native.c

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Part of EEPROM simulator which interacts with the host OS / Linux
+ *
+ * When building for the native simulator, this file is built in the
+ * native simulator runner/host context, and not in Zephyr/embedded context.
+ */
+
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <nsi_tracing.h>
+
+/*
+ * Initialize the EEPROM buffer.
+ * And, if the content is to be kept on disk map it to the buffer to the file.
+ *
+ * Returns -1 on failure
+ *	    0 on success
+ */
+int eeprom_mock_init_native(bool eeprom_in_ram, char **mock_eeprom, unsigned int size,
+			    int *eeprom_fd, const char *eeprom_file_path, unsigned int erase_value,
+			    bool eeprom_erase_at_start)
+{
+	struct stat f_stat;
+	int rc;
+
+	if (eeprom_in_ram == true) {
+		*mock_eeprom = (char *)malloc(size);
+		if (*mock_eeprom == NULL) {
+			nsi_print_warning("Could not allocate EEPROM in the process heap %s\n",
+					  strerror(errno));
+			return -1;
+		}
+	} else {
+		*eeprom_fd = open(eeprom_file_path, O_RDWR | O_CREAT, (mode_t)0600);
+		if (*eeprom_fd == -1) {
+			nsi_print_warning("Failed to open EEPROM device file %s: %s\n",
+					  eeprom_file_path, strerror(errno));
+			return -1;
+		}
+
+		rc = fstat(*eeprom_fd, &f_stat);
+		if (rc) {
+			nsi_print_warning("Failed to get status of EEPROM device file %s: %s\n",
+					  eeprom_file_path, strerror(errno));
+			return -1;
+		}
+
+		if (ftruncate(*eeprom_fd, size) == -1) {
+			nsi_print_warning("Failed to resize EEPROM device file %s: %s\n",
+					  eeprom_file_path, strerror(errno));
+			return -1;
+		}
+
+		*mock_eeprom = mmap(NULL, size, PROT_WRITE | PROT_READ, MAP_SHARED, *eeprom_fd, 0);
+		if (*mock_eeprom == MAP_FAILED) {
+			nsi_print_warning("Failed to mmap EEPROM device file %s: %s\n",
+					  eeprom_file_path, strerror(errno));
+			return -1;
+		}
+	}
+
+	if ((eeprom_erase_at_start == true) || (eeprom_in_ram == true) || (f_stat.st_size == 0)) {
+		/* Erase the EEPROM by setting all bits to the configured erase value */
+		(void)memset(*mock_eeprom, erase_value, size);
+	}
+
+	return 0;
+}
+
+/*
+ * If in RAM: Free the mock buffer
+ * If in disk: unmap the eeprom file from RAM, close the file, and if configured to do so,
+ * delete the file.
+ */
+void eeprom_mock_cleanup_native(bool eeprom_in_ram, int eeprom_fd, char *mock_eeprom,
+				unsigned int size, const char *eeprom_file_path,
+				bool eeprom_rm_at_exit)
+{
+
+	if (eeprom_in_ram == true) {
+		if (mock_eeprom != NULL) {
+			free(mock_eeprom);
+		}
+		return;
+	}
+
+	if ((mock_eeprom != MAP_FAILED) && (mock_eeprom != NULL)) {
+		munmap(mock_eeprom, size);
+	}
+
+	if (eeprom_fd != -1) {
+		close(eeprom_fd);
+	}
+
+	if ((eeprom_rm_at_exit == true) && (eeprom_file_path != NULL)) {
+		/* We try to remove the file but do not error out if we can't */
+		(void)remove(eeprom_file_path);
+	}
+}

drivers/eeprom/eeprom_simulator_native.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef DRIVERS_EEPROM_EEPROM_SIMULATOR_NATIVE_H
+#define DRIVERS_EEPROM_EEPROM_SIMULATOR_NATIVE_H
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int eeprom_mock_init_native(bool eeprom_in_ram, char **mock_eeprom, unsigned int size,
+			    int *eeprom_fd, const char *eeprom_file_path, unsigned int erase_value,
+			    bool eeprom_erase_at_start);
+
+void eeprom_mock_cleanup_native(bool eeprom_in_ram, int eeprom_fd, char *mock_eeprom,
+				unsigned int size, const char *eeprom_file_path,
+				bool eeprom_rm_at_exit);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DRIVERS_EEPROM_EEPROM_SIMULATOR_NATIVE_H */