cli: Add new `config' CLI for status/config registers

Add a new CLI mode to query and update status and configuration
registers of SPI NOR chips.  Programmer initialization and chip
initialization works the same as with the classic CLI (`-p' and
`-c' options). There are two commands `get' and `set' where the
former is implied if no command is given. For a start, only the
`quad-enable' bit can be accessed  (for chips that advertise it
in the database).

The `--temporary' option  allows to use a volatile write status
register command if the flash chip supports it. So changes made
with this option will not be written to flash and are lost when
the chip is reset.

For instance, the quad-enable bit can then be queried like this

  $ flashprog config get -p ch341a_spi quad-enable

or written with

  $ flashprog config set -p ch341a_spi quad-enable 1

or

  $ flashprog config set -p ch341a_spi --temporary quad-enable 1

Change-Id: I6b9d26c67e6ad65be5df367d2db7942bb98f27ac
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/195
diff --git a/cli_config.c b/cli_config.c
new file mode 100644
index 0000000..3ffa048
--- /dev/null
+++ b/cli_config.c
@@ -0,0 +1,264 @@
+/*
+ * This file is part of the flashprog project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <limits.h>
+#include <unistd.h>
+
+#include "libflashprog.h"
+#include "chipdrivers.h"
+#include "flash.h"
+#include "cli.h"
+
+enum settings {
+	QUAD_ENABLE,
+};
+
+static const struct reg_bit_info *get_bit_info(
+		const struct flashctx *flash, enum settings setting)
+{
+	switch (setting) {
+	case QUAD_ENABLE:
+		return &flash->chip->reg_bits.qe;
+	default:
+		return NULL;
+	}
+}
+
+static int config_get(const struct flashctx *flash, enum settings setting)
+{
+	const struct reg_bit_info *const bit = get_bit_info(flash, setting);
+	uint8_t reg_val;
+
+	if (!bit)
+		return 1;
+
+	const int ret = spi_read_register(flash, bit->reg, &reg_val);
+	if (ret)
+		return 1;
+
+	printf("%u\n", reg_val >> bit->bit_index & 1);
+	return 0;
+}
+
+static int config_set(const struct flashctx *flash, enum settings setting, unsigned int value)
+{
+	const struct reg_bit_info *const bit = get_bit_info(flash, setting);
+	uint8_t reg_val;
+	int ret;
+
+	if (!bit)
+		return 1;
+
+	ret = spi_read_register(flash, bit->reg, &reg_val);
+	if (ret)
+		return 1;
+
+	reg_val &= ~(1 << bit->bit_index);
+	reg_val |= (value & 1) << bit->bit_index;
+
+	ret = spi_write_register(flash, bit->reg, reg_val, default_wrsr_target(flash));
+	if (ret)
+		return 1;
+
+	return 0;
+}
+
+static void usage(const char *const name, const char *const msg)
+{
+	if (msg)
+		fprintf(stderr, "\nError: %s\n", msg);
+
+	fprintf(stderr, "\nUsage:"
+			"\t%s [get] <options> <setting>\n"
+			"\t%s  set  <options> [--temporary] <setting> <value>\n",
+			name, name);
+	print_generic_options();
+	fprintf(stderr, "\n<setting> can be\n"
+			"    qe | quad-enable        Quad-Enable (QE) bit\n"
+			"\nand <value> can be `true', `false', or a number.\n"
+			"\nBy default, the setting is queried (`get').\n"
+			"\n");
+	exit(1);
+}
+
+static int parse_setting(const char *const setting)
+{
+	if (!strcmp(setting, "qe") ||
+	    !strcmp(setting, "quad-enable"))
+		return QUAD_ENABLE;
+	return -1;
+}
+
+static int parse_value(const char *const value)
+{
+	if (!strcmp(value, "true"))
+		return 1;
+	if (!strcmp(value, "false"))
+		return 0;
+
+	char *endptr;
+	const unsigned long i = strtoul(value, &endptr, 0);
+	if (value[0] && !endptr[0] && i <= INT_MAX)
+		return i;
+
+	return -1;
+}
+
+int flashprog_config_main(int argc, char *argv[])
+{
+	static const char optstring[] = "+p:c:Vo:h";
+	static const struct option long_options[] = {
+		{"programmer",		1, NULL, 'p'},
+		{"chip",		1, NULL, 'c'},
+		{"verbose",		0, NULL, 'V'},
+		{"output",		1, NULL, 'o'},
+		{"help",		0, NULL, 'h'},
+		{"get",			0, NULL, OPTION_CONFIG_GET},
+		{"set",			0, NULL, OPTION_CONFIG_SET},
+		{"temporary",		0, NULL, OPTION_CONFIG_VOLATILE},
+		{NULL,			0, NULL, 0},
+	};
+	static const struct opt_command cmd_options[] = {
+		{"get",		OPTION_CONFIG_GET},
+		{"set",		OPTION_CONFIG_SET},
+		{NULL,		0},
+	};
+
+	unsigned int ops = 0;
+	int ret = 1, opt;
+	struct log_args log_args = { FLASHPROG_MSG_INFO, FLASHPROG_MSG_DEBUG2, NULL };
+	struct flash_args flash_args = { 0 };
+	bool get = false, set = false, volat1le = false;
+
+	if (cli_init()) /* TODO: Can be moved below argument parsing once usage() uses `stderr` directly. */
+		goto free_ret;
+
+	if (argc < 2)
+		usage(argv[0], NULL);
+
+	while ((opt = getopt_long(argc, argv, optstring, long_options, NULL)) != -1 ||
+	       (opt = getopt_command(argc, argv, cmd_options)) != -1) {
+		switch (opt) {
+		case 'V':
+		case 'o':
+			ret = cli_parse_log_args(&log_args, opt, optarg);
+			if (ret == 1)
+				usage(argv[0], NULL);
+			else if (ret)
+				goto free_ret;
+			break;
+		case 'p':
+		case 'c':
+			ret = cli_parse_flash_args(&flash_args, opt, optarg);
+			if (ret == 1)
+				usage(argv[0], NULL);
+			else if (ret)
+				goto free_ret;
+			break;
+		case OPTION_CONFIG_GET:
+			get = true;
+			++ops;
+			break;
+		case OPTION_CONFIG_SET:
+			set = true;
+			++ops;
+			break;
+		case OPTION_CONFIG_VOLATILE:
+			volat1le = true;
+			break;
+		case '?':
+		case 'h':
+			usage(argv[0], NULL);
+			break;
+		}
+	}
+
+	if (!ops) {
+		get = true;
+		++ops;
+	}
+
+	if (ops > 1)
+		usage(argv[0], "Only one operation may be specified.");
+
+	if (!set && volat1le)
+		usage(argv[0], "`--temporary' may only be specified for `set'.");
+	if (get && optind != argc - 1)
+		usage(argv[0], "`get' requires exactly one argument.");
+	if (set && optind != argc - 2)
+		usage(argv[0], "`set' requires exactly two arguments.");
+
+	if (!flash_args.prog_name)
+		usage(argv[0], "No programmer specified.");
+
+	const int setting = parse_setting(argv[optind]);
+	if (setting < 0) {
+		fprintf(stderr, "\nError: Unknown <setting> argument `%s'.\n", argv[optind]);
+		usage(argv[0], NULL);
+	}
+	int value = 0;
+	if (set) {
+		value = parse_value(argv[optind + 1]);
+		if (value < 0) {
+			fprintf(stderr, "\nError: Cannot parse value `%s'.\n", argv[optind + 1]);
+			usage(argv[0], NULL);
+		}
+	}
+
+	struct flashprog_programmer *prog;
+	struct flashprog_flashctx *flash;
+	ret = 1;
+
+	if (log_args.logfile && open_logfile(log_args.logfile))
+		goto free_ret;
+	verbose_screen = log_args.screen_level;
+	verbose_logfile = log_args.logfile_level;
+	start_logging();
+
+	if (flashprog_programmer_init(&prog, flash_args.prog_name, flash_args.prog_args))
+		goto free_ret;
+	if (flashprog_flash_probe(&flash, prog, flash_args.chip)) {
+		fprintf(stderr, "No EEPROM/flash device found.\n");
+		goto shutdown_ret;
+	}
+
+	if (flash->chip->bustype != BUS_SPI || flash->chip->spi_cmd_set != SPI25) {
+		fprintf(stderr, "Only SPI25 flash chips are supported.\n");
+		goto shutdown_ret;
+	}
+
+	flashprog_flag_set(flash, FLASHPROG_FLAG_NON_VOLATILE_WRSR, set && !volat1le);
+
+	if (get)
+		ret = config_get(flash, setting);
+
+	if (set)
+		ret = config_set(flash, setting, value);
+
+	flashprog_flash_release(flash);
+shutdown_ret:
+	flashprog_programmer_shutdown(prog);
+free_ret:
+	free(flash_args.chip);
+	free(flash_args.prog_args);
+	free(flash_args.prog_name);
+	free(log_args.logfile);
+	close_logfile();
+	return ret;
+}