[PATCH 067/120] MIPS: PS2: IOP: Module linking support

[Fredrik Noring <noring@nocrew.org>]

IOP modules are IRX objects based on the executable and linkable format
(ELF). All valid IOP modules have a special .iopmod section containing
the module name, version, etc.

When the IOP is reset, a set of modules are automatically linked from
read-only memory (ROM). Non-ROM modules are handled as firmware by the
IOP module linker.

IOP modules may import and export any number of library functions,
including non at all. Imported libraries must be resolved and prelinked
before the given module is allowed to link itself. Other modules can
link with its exported libraries.

IOP modules begin to execute their entry function immediately after
linking. The modules can either stay resident in the IOP, and provide
services, or unlink themselves when exiting the entry function. Many
modules provide remote procedure call (RPC) services via the sub-system
interface (SIF).

Signed-off-by: Fredrik Noring <noring@nocrew.org>
---
 arch/mips/include/asm/mach-ps2/iop-module.h |  13 +
 drivers/Makefile                            |   1 +
 drivers/ps2/Makefile                        |   1 +
 drivers/ps2/iop-module.c                    | 277 ++++++++++++++++++++
 4 files changed, 292 insertions(+)
 create mode 100644 arch/mips/include/asm/mach-ps2/iop-module.h
 create mode 100644 drivers/ps2/iop-module.c

diff --git a/arch/mips/include/asm/mach-ps2/iop-module.h b/arch/mips/include/asm/mach-ps2/iop-module.h
new file mode 100644
index 000000000000..f61141031de0
--- /dev/null
+++ b/arch/mips/include/asm/mach-ps2/iop-module.h
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PlayStation 2 input/output processor (IOP) module linker
+ *
+ * Copyright (C) 2019 Fredrik Noring
+ */
+
+#ifndef __ASM_MACH_PS2_IOP_MODULE_H
+#define __ASM_MACH_PS2_IOP_MODULE_H
+
+int iop_module_request(const char *name, int version, const char *arg);
+
+#endif /* __ASM_MACH_PS2_IOP_MODULE_H */
diff --git a/drivers/Makefile b/drivers/Makefile
index 6d37564e783c..1ed5b83dc528 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -141,6 +141,7 @@ obj-y				+= clocksource/
 endif
 obj-$(CONFIG_DCA)		+= dca/
 obj-$(CONFIG_HID)		+= hid/
+obj-$(CONFIG_SONY_PS2)		+= ps2/
 obj-$(CONFIG_PPC_PS3)		+= ps3/
 obj-$(CONFIG_OF)		+= of/
 obj-$(CONFIG_SSB)		+= ssb/
diff --git a/drivers/ps2/Makefile b/drivers/ps2/Makefile
index 6f193007ebc6..b04e4d3c3374 100644
--- a/drivers/ps2/Makefile
+++ b/drivers/ps2/Makefile
@@ -1,3 +1,4 @@
 obj-m				+= iop-memory.o
+obj-m				+= iop-module.o
 obj-m				+= iop-registers.o
 obj-m				+= sif.o
diff --git a/drivers/ps2/iop-module.c b/drivers/ps2/iop-module.c
new file mode 100644
index 000000000000..0e4a2173c001
--- /dev/null
+++ b/drivers/ps2/iop-module.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PlayStation 2 input/output processor (IOP) module linker
+ *
+ * Copyright (C) 2019 Fredrik Noring
+ */
+
+/**
+ * DOC: PlayStation 2 input/output processor (IOP) module linker
+ *
+ * IOP modules are IRX objects based on the executable and linkable format
+ * (ELF). All valid IOP modules have a special `.iopmod` section containing
+ * the module name, version, etc.
+ *
+ * When the IOP is reset, a set of modules are automatically linked from
+ * read-only memory (ROM). Non-ROM modules are handled as firmware by the
+ * IOP module linker.
+ *
+ * IOP modules may import and export any number of library functions,
+ * including non at all. Imported libraries must be resolved and prelinked
+ * before the given module is allowed to link itself. Other modules can link
+ * with its exported libraries.
+ *
+ * IOP modules begin to execute their entry function immediately after linking.
+ * The modules can either stay resident in the IOP, and provide services, or
+ * unlink themselves when exiting the entry function. Many modules provide
+ * remote procedure call (RPC) services via the sub-system interface (SIF).
+ */
+
+#include <linux/bcd.h>
+#include <linux/device.h>
+#include <linux/firmware.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "uapi/linux/elf.h"
+
+#include <asm/mach-ps2/iop-error.h>
+#include <asm/mach-ps2/iop-heap.h>
+#include <asm/mach-ps2/iop-memory.h>
+#include <asm/mach-ps2/iop-module.h>
+#include <asm/mach-ps2/rom.h>
+#include <asm/mach-ps2/sif.h>
+
+enum iop_module_rpc_ops {
+	rpo_mod_load = 0,
+	rpo_elf_load = 1,
+	rpo_set_addr = 2,
+	rpo_get_addr = 3,
+	rpo_mg_mod_load = 4,
+	rpo_mg_elf_load = 5,
+	rpo_mod_buf_load = 6,
+	rpo_mod_stop = 7,
+	rpo_mod_unload = 8,
+	rpo_search_mod_by_name = 9,
+	rpo_search_mod_by_address = 10
+};
+
+/** The @iop_module_lock must be taken for all IOP module linking operations */
+static DEFINE_MUTEX(iop_module_lock);
+
+static struct device *iop_module_device;
+static struct sif_rpc_client load_file_rpc_client;
+
+#define IOPMOD_MAX_PATH		252
+#define IOPMOD_MAX_ARG		252
+
+/**
+ * major_version - major version of version in BCD
+ * @version: 16-bit version in BCD, with 8-bit minor and 8-bit major
+ *
+ * Return: major version
+ */
+static unsigned int major_version(unsigned int version)
+{
+	return bcd2bin((version >> 8) & 0xff);
+}
+
+/**
+ * minor_version - minor version of version in BCD
+ * @version: 16-bit version in BCD, with 8-bit minor and 8-bit major
+ *
+ * Return: minor version
+ */
+static unsigned int minor_version(unsigned int version)
+{
+	return bcd2bin(version & 0xff);
+}
+
+/**
+ * iop_module_link_buffer - link IOP module given in buffer
+ * @buf: buffer containing the IOP module to link
+ * @nbyte: size in bytes of given buffer
+ * @arg: arguments to the IOP module entry function, or %NULL
+ *
+ * Return: 0 on success, otherwise a negative error number
+ */
+static int iop_module_link_buffer(const void *buf, size_t nbyte,
+	const char *arg)
+{
+	const char * const arg_ = arg ? arg : "";
+	const size_t arg_size = strlen(arg_) + 1;
+	struct {
+		u32 addr;
+		u32 arg_size;
+		char filepath[IOPMOD_MAX_PATH];
+		char arg[IOPMOD_MAX_ARG];
+	} link = {
+		.addr = iop_alloc(nbyte),
+		.arg_size = arg_size
+	};
+	struct {
+		s32 status;
+		u32 modres;
+	} result;
+	int err;
+
+	BUILD_BUG_ON(sizeof(link) != 512);
+
+	if (!link.addr)
+		return -ENOMEM;
+
+	/* Copy the module to IOP memory. */
+	memcpy(iop_bus_to_virt(link.addr), buf, nbyte);
+
+	/* Make the module visible to the IOP. */
+	dma_cache_wback((unsigned long)iop_bus_to_virt(link.addr), nbyte);
+
+	if (arg_size >= sizeof(link.arg)) {
+		err = -EOVERFLOW;
+		goto err_out;
+	}
+	memcpy(link.arg, arg_, arg_size);
+
+	err = sif_rpc(&load_file_rpc_client, rpo_mod_buf_load,
+		&link, sizeof(link), &result, sizeof(result));
+	if (err < 0)
+		goto err_out;
+
+	if (result.status < 0) {
+		pr_err("iop-module: %s: sif_rpc failed with %d: %s\n", __func__,
+			result.status, iop_error_message(result.status));
+		err = errno_for_iop_error(result.status);
+		goto err_out;
+	}
+
+	iop_free(link.addr);
+	return 0;
+
+err_out:
+	iop_free(link.addr);
+	return err;
+}
+
+static int iop_module_request_firmware(
+	const char *name, int version, const char *arg);
+
+/**
+ * iop_module_request_firmware - link IOP module as firmware
+ * @name: name of requested module
+ * @version: requested version in BCD, where major must match with a least
+ * 	the same minor
+ * @arg: module arguments or %NULL
+ *
+ * Return: 0 on success, otherwise a negative error number
+ */
+static int iop_module_request_firmware(
+	const char *name, int version, const char *arg)
+{
+	const struct firmware *fw = NULL;
+	const struct elf32_hdr *ehdr;
+	char filepath[32];
+	int err;
+
+	pr_debug("iop-module: %s module linking as firmware\n", name);
+
+	if (snprintf(filepath, sizeof(filepath),
+			"ps2/%s.irx", name) == sizeof(filepath) - 1) {
+		err = -ENAMETOOLONG;
+		goto err_name;
+	}
+
+	err = request_firmware(&fw, filepath, iop_module_device);
+	if (err < 0)
+		goto err_request;
+
+	ehdr = (const struct elf32_hdr *)fw->data;
+
+	err = iop_module_link_buffer(fw->data, fw->size, arg);
+
+err_request:
+err_name:
+
+	if (err < 0)
+		pr_err("iop-module: %s module version %u.%u request failed with %d\n",
+			filepath, major_version(version),
+			minor_version(version), err);
+
+	release_firmware(fw);
+
+	return err;
+}
+
+/**
+ * iop_module_request - link requested IOP module unless it is already linked
+ * @name: name of requested module
+ * @version: requested version in BCD, where major must match with a least
+ * 	the same minor
+ * @arg: module arguments or %NULL
+ *
+ * Module library dependencies are resolved and prelinked as necessary. Module
+ * files are handled as firmware by the IOP module linker.
+ *
+ * IOP module link requests are only permitted if the major versions match
+ * and the version is at least of the same minor as the requested version.
+ *
+ * Context: mutex
+ * Return: 0 on success, otherwise a negative error number
+ */
+int iop_module_request(const char *name, int version, const char *arg)
+{
+	int err;
+
+	mutex_lock(&iop_module_lock);
+
+	pr_debug("iop-module: %s module version %u.%u requested%s%s\n",
+		name, major_version(version), minor_version(version),
+		arg ? " with argument " : "", arg ? arg : "");
+
+	err = iop_module_request_firmware(name, version, arg);
+
+	if (err)
+		pr_debug("iop-module: %s module request resulted in %d\n",
+			name, err);
+	else
+		pr_debug("iop-module: %s module request successful\n", name);
+
+	mutex_unlock(&iop_module_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(iop_module_request);
+
+static int __init iop_module_init(void)
+{
+	int err;
+
+	iop_module_device = root_device_register("iop-module");
+	if (!iop_module_device) {
+		pr_err("iop-module: Failed to register root device\n");
+		return -ENOMEM;
+	}
+
+	err = sif_rpc_bind(&load_file_rpc_client, SIF_SID_LOAD_MODULE);
+	if (err < 0) {
+		pr_err("iop-module: Failed to bind load module with %d\n", err);
+		goto err_bind;
+	}
+
+	return 0;
+
+err_bind:
+	root_device_unregister(iop_module_device);
+
+	return err;
+}
+
+module_init(iop_module_init);
+
+MODULE_DESCRIPTION("PlayStation 2 input/output processor (IOP) module linker");
+MODULE_AUTHOR("Fredrik Noring");
+MODULE_LICENSE("GPL");
-- 
2.21.0