[PATCH 044/120] MIPS: PS2: ROM: Sysfs module to inspect ROM files

[Fredrik Noring <noring@nocrew.org>]

The ROM sysfs module gives information on the ROM file names, sizes,
and addresses. For example, listing all files of ROM0:

	# cat /sys/rom/rom0/file/*/name | column
	RESET       VBLANK      RMRESET     MCSERV      XSIFCMD
	ROMDIR      IOMAN       OSDVER      PADMAN      XCDVDMAN
	EXTINFO     MODLOAD     -           CDVDMAN     XCDVDFSV
	ROMVER      ROMDRV      IOPBOOT     CDVDFSV     XFILEIO
	SBIN        ADDDRV      OSDCNF      FILEIO      XSIO2MAN
	LOGO        STDIO       -           CLEARSPU    XMTAPMAN
	IOPBTCONF   SIFMAN      TBIN        UDNL        XMCMAN
	...

Viewing for example the contents of the ROM file ROMVER using /dev/mem:

	# grep -l ROMVER /sys/rom/rom0/file/*/name
	/sys/rom/rom0/file/3/name
	# cd /sys/rom/rom0/file/3
	# dd if=/dev/mem bs=$(cat size) iflag=skip_bytes \
		skip=$(( $(cat data) )) count=1 status=none
	0170EC20030227

For convenience, the ROMVER file is also available directly in sysfs:

	# ls /sys/rom/rom0/version
	date    number  region  type
	# cat /sys/rom/rom0/version/*
	2003-02-27
	0x0170
	Europe
	CEX

The CEX type indicates that it is a retail machine, as opposed to for
example DEX that would be a debug machine.

Signed-off-by: Fredrik Noring <noring@nocrew.org>
---
 arch/mips/ps2/Makefile    |   1 +
 arch/mips/ps2/rom-sysfs.c | 288 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 289 insertions(+)
 create mode 100644 arch/mips/ps2/rom-sysfs.c

diff --git a/arch/mips/ps2/Makefile b/arch/mips/ps2/Makefile
index 1101ad0d702b..a56ea782120e 100644
--- a/arch/mips/ps2/Makefile
+++ b/arch/mips/ps2/Makefile
@@ -3,5 +3,6 @@ obj-y		+= intc-irq.o
 obj-y		+= irq.o
 obj-y		+= memory.o
 obj-y		+= rom.o
+obj-m		+= rom-sysfs.o
 obj-y		+= scmd.o
 obj-y		+= time.o
diff --git a/arch/mips/ps2/rom-sysfs.c b/arch/mips/ps2/rom-sysfs.c
new file mode 100644
index 000000000000..158d36763af5
--- /dev/null
+++ b/arch/mips/ps2/rom-sysfs.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PlayStation 2 read-only memory (ROM) sysfs
+ *
+ * Copyright (C) 2019 Fredrik Noring
+ *
+ * FIXME: Is /sys/rom the proper placement?
+ */
+
+///
+// DOC:
+//
+// ROM0 and ROM1 contain simple file systems that can be inspected with this
+// sysfs module. For example, listing all files of ROM0::
+//
+// 	# cat /sys/rom/rom0/file/*/name | column
+// 	RESET       VBLANK      RMRESET     MCSERV      XSIFCMD
+// 	ROMDIR      IOMAN       OSDVER      PADMAN      XCDVDMAN
+// 	EXTINFO     MODLOAD     -           CDVDMAN     XCDVDFSV
+// 	ROMVER      ROMDRV      IOPBOOT     CDVDFSV     XFILEIO
+// 	SBIN        ADDDRV      OSDCNF      FILEIO      XSIO2MAN
+// 	LOGO        STDIO       -           CLEARSPU    XMTAPMAN
+// 	IOPBTCONF   SIFMAN      TBIN        UDNL        XMCMAN
+// 	...
+//
+// Viewing for example the contents of the ROM file ROMVER using /dev/mem::
+//
+//	# grep -l ROMVER /sys/rom/rom0/file/*/name
+//	/sys/rom/rom0/file/3/name
+//	# cd /sys/rom/rom0/file/3
+//	# dd if=/dev/mem bs=$(cat size) iflag=skip_bytes
+//		skip=$(( $(cat data) )) count=1 status=none
+//	0170EC20030227
+//
+// For convenience, the ROMVER file is also available directly in sysfs::
+//
+//	# ls /sys/rom/rom0/version
+//	date    number  region  type
+//	# cat /sys/rom/rom0/version/*
+//	2003-02-27
+//	0x0170
+//	Europe
+//	CEX
+//
+// The CEX type indicates that it is a retail machine, as opposed to for
+// example DEX that would be a debug machine.
+//
+
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include <asm/page.h>
+#include <asm/uaccess.h>
+
+#include <asm/mach-ps2/rom.h>
+
+static int rom0_sysfs(struct kobject *romn_kobj);
+
+/* FIXME */
+static const struct {
+	const char *name;
+	const struct rom_dir *dir;
+	int (*func)(struct kobject *romn_kobj);
+} rom_dirs[] = {
+	{ "rom0", &rom0_dir, rom0_sysfs },
+	{ "rom1", &rom1_dir, NULL },
+};
+
+static struct rom_dir rom_dir_from_kobj(const struct kobject *kobj)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(rom_dirs); i++)
+		if (strcmp(rom_dirs[i].name, kobj->parent->name) == 0)
+			return *rom_dirs[i].dir;
+
+	pr_err("%s: ROM dir for \"%s\" does not exist\n", __func__,
+		kobj->parent->name);
+
+	return (struct rom_dir) { };
+}
+
+static struct rom_file rom_file_from_kobj(const struct kobject *kobj)
+{
+	const size_t rom_id = simple_strtoull(kobj->name, NULL, 0);
+	const struct rom_dir dir = rom_dir_from_kobj(kobj->parent);
+	struct rom_file file;
+	size_t id = 0;
+
+	rom_for_each_file(file, dir)
+		if (id++ == rom_id)
+			return file;
+
+	pr_err("%s: ROM id %zu for \"%s\" does not exist\n", __func__,
+		rom_id, kobj->parent->name);
+
+	return (struct rom_file) { .name = "<undefined>" };
+}
+
+static ssize_t rom_version_number_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "0x%04x\n", rom_version().number);
+}
+
+static ssize_t rom_version_region_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%s\n",
+		rom_region_name(rom_version().region));
+}
+
+static ssize_t rom_version_type_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%s\n",
+		rom_type_name(rom_version().type));
+}
+
+static ssize_t rom_version_date_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	const struct rom_ver v = rom_version();
+
+	return scnprintf(buf, PAGE_SIZE, "%04d-%02d-%02d\n",
+		v.date.year, v.date.month, v.date.day);
+}
+
+static ssize_t rom_file_name_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%s\n",
+		rom_file_from_kobj(kobj).name);
+}
+
+static ssize_t rom_file_size_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%zu\n",
+		rom_file_from_kobj(kobj).size);
+}
+
+static ssize_t rom_file_data_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "0x%lx\n",
+		virt_to_phys(rom_file_from_kobj(kobj).data));
+}
+
+#define DEFINE_ROM_FIELD_ATTR(prefix, field)				\
+	static struct kobj_attribute rom_attribute_##prefix##_##field =	\
+		__ATTR(field, S_IRUGO, rom_##prefix##_##field##_show, NULL)
+
+DEFINE_ROM_FIELD_ATTR(version, number);
+DEFINE_ROM_FIELD_ATTR(version, region);
+DEFINE_ROM_FIELD_ATTR(version, type);
+DEFINE_ROM_FIELD_ATTR(version, date);
+
+static struct attribute *rom_version_attributes[] = {
+	&rom_attribute_version_number.attr,
+	&rom_attribute_version_region.attr,
+	&rom_attribute_version_type.attr,
+	&rom_attribute_version_date.attr,
+	NULL
+};
+
+static struct attribute_group rom_version_attribute_group = {
+	.attrs = rom_version_attributes
+};
+
+DEFINE_ROM_FIELD_ATTR(file, name);
+DEFINE_ROM_FIELD_ATTR(file, size);
+DEFINE_ROM_FIELD_ATTR(file, data);
+
+static struct attribute *rom_file_attributes[] = {
+	&rom_attribute_file_name.attr,
+	&rom_attribute_file_size.attr,
+	&rom_attribute_file_data.attr,
+	NULL
+};
+
+static struct attribute_group rom_file_attribute_group = {
+	.attrs = rom_file_attributes
+};
+
+static int rom0_sysfs(struct kobject *rom0_kobj)
+{
+	struct kobject *version_kobj;
+
+	version_kobj = kobject_create_and_add("version", rom0_kobj);
+	if (!version_kobj)
+		return -ENOMEM;
+
+	return sysfs_create_group(version_kobj, &rom_version_attribute_group);
+}
+
+static int __init rom_init_file(struct kobject *file_kobj, size_t index,
+	const struct rom_file file)
+{
+	struct kobject *index_kobj;
+	char index_string[20];
+	int err;
+
+	scnprintf(index_string, sizeof(index_string), "%zu", index);
+
+	index_kobj = kobject_create_and_add(index_string, file_kobj);
+	if (!index_kobj)
+		return -ENOMEM;
+
+	return sysfs_create_group(index_kobj, &rom_file_attribute_group);
+}
+
+static int __init rom_init_dir(struct kobject *romn_kobj,
+	const struct rom_dir dir)
+{
+	struct kobject *file_kobj = kobject_create_and_add("file", romn_kobj);
+	struct rom_file file;
+	size_t i = 0;
+
+	if (!file_kobj)
+		return -ENOMEM;
+
+	rom_for_each_file(file, dir) {
+		int err = rom_init_file(file_kobj, i++, file);
+
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int __init rom_init_rom(struct kobject *rom_kobj,
+	const char *name, const struct rom_dir dir,
+	int (*func)(struct kobject *romn_kobj))
+{
+	struct kobject *romn_kobj = kobject_create_and_add(name, rom_kobj);
+	int err;
+
+	if (!romn_kobj)
+		return -ENOMEM;
+
+	err = rom_init_dir(romn_kobj, dir);
+	if (!err && func)
+		err = func(romn_kobj);
+
+	return err;
+}
+
+static struct kobject *rom_kobj;
+
+static int __init rom_sysfs_init(void)
+{
+	size_t i;
+
+	rom_kobj = kobject_create_and_add("rom", NULL);
+	if (!rom_kobj)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(rom_dirs); i++) {
+		int err = rom_init_rom(rom_kobj, rom_dirs[i].name,
+			*rom_dirs[i].dir, rom_dirs[i].func);
+
+		if (err) {
+			kobject_del(rom_kobj);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void __exit rom_sysfs_exit(void)
+{
+	kobject_del(rom_kobj);
+}
+
+module_init(rom_sysfs_init);
+module_exit(rom_sysfs_exit);
+
+MODULE_DESCRIPTION("PlayStation 2 read-only memory (ROM) sysfs");
+MODULE_AUTHOR("Fredrik Noring");
+MODULE_LICENSE("GPL");
-- 
2.21.0