/*
 * RAM Oops/Panic logger
 *
 * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
 * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/pstore.h>
#include <linux/time.h>
#include <linux/ioport.h>
#include <linux/compiler.h>
#include <linux/pstore_ram.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/log2.h>
#include <linux/spinlock.h>
#include <malloc.h>
#include <printk.h>
#include <stdio.h>
#include <globalvar.h>
#include <init.h>
#include <common.h>

#define RAMOOPS_KERNMSG_HDR "===="
#define MIN_MEM_SIZE 4096UL

static const ulong record_size = CONFIG_FS_PSTORE_RAMOOPS_RECORD_SIZE;

static const ulong ramoops_console_size = CONFIG_FS_PSTORE_RAMOOPS_CONSOLE_SIZE;

static const ulong ramoops_ftrace_size = CONFIG_FS_PSTORE_RAMOOPS_FTRACE_SIZE;

static const ulong ramoops_pmsg_size = CONFIG_FS_PSTORE_RAMOOPS_PMSG_SIZE;

static const ulong mem_size = CONFIG_FS_PSTORE_RAMOOPS_SIZE;

static const int dump_oops = 1;

static const int ramoops_ecc = CONFIG_FS_PSTORE_ECC_SIZE;

struct ramoops_context {
	struct persistent_ram_zone **przs;
	struct persistent_ram_zone *cprz;
	struct persistent_ram_zone *fprz;
	struct persistent_ram_zone *mprz;
	phys_addr_t phys_addr;
	unsigned long size;
	unsigned int memtype;
	size_t record_size;
	size_t console_size;
	size_t ftrace_size;
	size_t pmsg_size;
	int dump_oops;
	struct persistent_ram_ecc_info ecc_info;
	unsigned int max_dump_cnt;
	unsigned int dump_write_cnt;
	/* _read_cnt need clear on ramoops_pstore_open */
	unsigned int dump_read_cnt;
	unsigned int console_read_cnt;
	unsigned int ftrace_read_cnt;
	unsigned int pmsg_read_cnt;
	struct pstore_info pstore;
};

static struct ramoops_platform_data *dummy_data;

static int ramoops_pstore_open(struct pstore_info *psi)
{
	struct ramoops_context *cxt = psi->data;

	cxt->dump_read_cnt = 0;
	cxt->console_read_cnt = 0;
	cxt->ftrace_read_cnt = 0;
	cxt->pmsg_read_cnt = 0;
	return 0;
}

static struct persistent_ram_zone *
ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
		     u64 *id,
		     enum pstore_type_id *typep, enum pstore_type_id type,
		     bool update)
{
	struct persistent_ram_zone *prz;
	int i = (*c)++;

	if (i >= max)
		return NULL;

	prz = przs[i];
	if (!prz)
		return NULL;

	/* Update old/shadowed buffer. */
	if (update)
		persistent_ram_save_old(prz);

	if (!persistent_ram_old_size(prz))
		return NULL;

	*typep = type;
	*id = i;

	return prz;
}

static bool prz_ok(struct persistent_ram_zone *prz)
{
	return !!prz && !!(persistent_ram_old_size(prz) +
			   persistent_ram_ecc_string(prz, NULL, 0));
}

static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
				   int *count, char **buf, bool *compressed,
				   struct pstore_info *psi)
{
	ssize_t size;
	ssize_t ecc_notice_size;
	struct ramoops_context *cxt = psi->data;
	struct persistent_ram_zone *prz;

	prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
				   cxt->max_dump_cnt, id, type,
				   PSTORE_TYPE_DMESG, 0);
	if (!prz_ok(prz))
		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
	if (!prz_ok(prz))
		prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
					   1, id, type, PSTORE_TYPE_FTRACE, 0);
	if (!prz_ok(prz))
		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
					   1, id, type, PSTORE_TYPE_PMSG, 0);
	if (!prz_ok(prz))
		return 0;

	if (!persistent_ram_old(prz))
		return 0;

	size = persistent_ram_old_size(prz);

	/* ECC correction notice */
	ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);

	*buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
	if (*buf == NULL)
		return -ENOMEM;

	memcpy(*buf, (char *)persistent_ram_old(prz), size);
	persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);

	return size + ecc_notice_size;
}

static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
					    enum kmsg_dump_reason reason,
					    u64 *id, unsigned int part,
					    const char *buf,
					    bool compressed, size_t size,
					    struct pstore_info *psi)
{
	struct ramoops_context *cxt = psi->data;
	struct persistent_ram_zone *prz;

	if (type == PSTORE_TYPE_CONSOLE) {
		if (!cxt->cprz)
			return -ENOMEM;
		persistent_ram_write(cxt->cprz, buf, size);
		return 0;
	} else if (type == PSTORE_TYPE_FTRACE) {
		if (!cxt->fprz)
			return -ENOMEM;
		persistent_ram_write(cxt->fprz, buf, size);
		return 0;
	} else if (type == PSTORE_TYPE_PMSG) {
		if (!cxt->mprz)
			return -ENOMEM;
		persistent_ram_write(cxt->mprz, buf, size);
		return 0;
	}

	if (type != PSTORE_TYPE_DMESG)
		return -EINVAL;

	/* Explicitly only take the first part of any new crash.
	 * If our buffer is larger than kmsg_bytes, this can never happen,
	 * and if our buffer is smaller than kmsg_bytes, we don't want the
	 * report split across multiple records.
	 */
	if (part != 1)
		return -ENOSPC;

	if (!cxt->przs)
		return -ENOSPC;

	prz = cxt->przs[cxt->dump_write_cnt];

	persistent_ram_write(prz, buf, size);

	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;

	return 0;
}

static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
				struct pstore_info *psi)
{
	struct ramoops_context *cxt = psi->data;
	struct persistent_ram_zone *prz;

	switch (type) {
	case PSTORE_TYPE_DMESG:
		if (id >= cxt->max_dump_cnt)
			return -EINVAL;
		prz = cxt->przs[id];
		break;
	case PSTORE_TYPE_CONSOLE:
		prz = cxt->cprz;
		break;
	case PSTORE_TYPE_FTRACE:
		prz = cxt->fprz;
		break;
	case PSTORE_TYPE_PMSG:
		prz = cxt->mprz;
		break;
	default:
		return -EINVAL;
	}

	persistent_ram_free_old(prz);
	persistent_ram_zap(prz);

	return 0;
}

static struct ramoops_context oops_cxt = {
	.pstore = {
		.name	= "ramoops",
		.open	= ramoops_pstore_open,
		.read	= ramoops_pstore_read,
		.write_buf	= ramoops_pstore_write_buf,
		.erase	= ramoops_pstore_erase,
	},
};

static void ramoops_free_przs(struct ramoops_context *cxt)
{
	int i;

	cxt->max_dump_cnt = 0;
	if (!cxt->przs)
		return;

	for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
		persistent_ram_free(cxt->przs[i]);
	kfree(cxt->przs);
}

static int ramoops_init_przs(struct ramoops_context *cxt, phys_addr_t *paddr,
			     size_t dump_mem_sz)
{
	int err = -ENOMEM;
	int i;

	if (!cxt->record_size)
		return 0;

	if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
		pr_err("no room for dumps\n");
		return -ENOMEM;
	}

	cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
	if (!cxt->max_dump_cnt)
		return -ENOMEM;

	cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
			     GFP_KERNEL);
	if (!cxt->przs) {
		pr_err("failed to initialize a prz array for dumps\n");
		goto fail_prz;
	}

	for (i = 0; i < cxt->max_dump_cnt; i++) {
		size_t sz = cxt->record_size;

		cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
						  &cxt->ecc_info,
						  cxt->memtype);
		if (IS_ERR(cxt->przs[i])) {
			err = PTR_ERR(cxt->przs[i]);
			pr_err("failed to request mem region (0x%zx@0x%llx): %d\n",
				sz, (unsigned long long)*paddr, err);
			goto fail_prz;
		}
		*paddr += sz;
	}

	return 0;
fail_prz:
	ramoops_free_przs(cxt);
	return err;
}

static int ramoops_init_prz(struct ramoops_context *cxt,
			    struct persistent_ram_zone **prz,
			    phys_addr_t *paddr, size_t sz, u32 sig)
{
	if (!sz)
		return 0;

	if (*paddr + sz - cxt->phys_addr > cxt->size) {
		pr_err("no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
			sz, (unsigned long long)*paddr,
			cxt->size, (unsigned long long)cxt->phys_addr);
		return -ENOMEM;
	}

	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
				  cxt->memtype);
	if (IS_ERR(*prz)) {
		int err = PTR_ERR(*prz);

		pr_err("failed to request mem region (0x%zx@0x%llx): %d\n",
			sz, (unsigned long long)*paddr, err);
		return err;
	}

	persistent_ram_zap(*prz);

	*paddr += sz;

	return 0;
}

static int ramoops_probe(struct ramoops_platform_data *pdata)
{
	struct ramoops_context *cxt = &oops_cxt;
	size_t dump_mem_sz;
	phys_addr_t paddr;
	int err = -EINVAL;
	char kernelargs[512];

	/* Only a single ramoops area allowed at a time, so fail extra
	 * probes.
	 */
	if (cxt->max_dump_cnt)
		goto fail_out;

	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
			!pdata->ftrace_size && !pdata->pmsg_size)) {
		pr_err("The memory size and the record/console size must be "
			"non-zero\n");
		goto fail_out;
	}

	if (pdata->record_size && !is_power_of_2(pdata->record_size))
		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
	if (pdata->console_size && !is_power_of_2(pdata->console_size))
		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);

	cxt->size = pdata->mem_size;
	cxt->phys_addr = pdata->mem_address;
	cxt->memtype = pdata->mem_type;
	cxt->record_size = pdata->record_size;
	cxt->console_size = pdata->console_size;
	cxt->ftrace_size = pdata->ftrace_size;
	cxt->pmsg_size = pdata->pmsg_size;
	cxt->dump_oops = pdata->dump_oops;
	cxt->ecc_info = pdata->ecc_info;

	paddr = cxt->phys_addr;

	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
			- cxt->pmsg_size;
	err = ramoops_init_przs(cxt, &paddr, dump_mem_sz);
	if (err)
		goto fail_out;

	err = ramoops_init_prz(cxt, &cxt->cprz, &paddr,
			       cxt->console_size, 0);
	if (err)
		goto fail_init_cprz;

	err = ramoops_init_prz(cxt, &cxt->fprz, &paddr, cxt->ftrace_size, 0);
	if (err)
		goto fail_init_fprz;

	err = ramoops_init_prz(cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
	if (err)
		goto fail_init_mprz;

	cxt->pstore.data = cxt;
	/*
	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
	 * have to handle dumps, we must have at least record_size buffer. And
	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
	 * ZERO_SIZE_PTR).
	 */
	if (cxt->console_size)
		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
	spin_lock_init(&cxt->pstore.buf_lock);
	if (!cxt->pstore.buf) {
		pr_err("cannot allocate pstore buffer\n");
		err = -ENOMEM;
		goto fail_clear;
	}

	err = pstore_register(&cxt->pstore);
	if (err) {
		pr_err("registering with pstore failed\n");
		goto fail_buf;
	}

	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
		cxt->size, (unsigned long long)cxt->phys_addr,
		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);

	scnprintf(kernelargs, sizeof(kernelargs),
		  "ramoops.record_size=0x%x "
		  "ramoops.console_size=0x%x "
		  "ramoops.ftrace_size=0x%x "
		  "ramoops.pmsg_size=0x%x "
		  "ramoops.mem_address=0x%llx "
		  "ramoops.mem_size=0x%lx "
		  "ramoops.ecc=%d",
		  cxt->record_size,
		  cxt->console_size,
		  cxt->ftrace_size,
		  cxt->pmsg_size,
		  (unsigned long long)cxt->phys_addr,
		  mem_size,
		  ramoops_ecc);
	globalvar_add_simple("linux.bootargs.ramoops", kernelargs);

	if (IS_ENABLED(CONFIG_OFTREE))
		of_add_reserve_entry(cxt->phys_addr, cxt->phys_addr + mem_size);

	return 0;

fail_buf:
	kfree(cxt->pstore.buf);
fail_clear:
	cxt->pstore.bufsize = 0;
	kfree(cxt->mprz);
fail_init_mprz:
	kfree(cxt->fprz);
fail_init_fprz:
	kfree(cxt->cprz);
fail_init_cprz:
	ramoops_free_przs(cxt);
fail_out:
	return err;
}
unsigned long arm_mem_ramoops_get(void);

static void ramoops_register_dummy(void)
{
	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
	if (!dummy_data) {
		pr_info("could not allocate pdata\n");
		return;
	}

	dummy_data->mem_size = mem_size;
	dummy_data->mem_address = arm_mem_ramoops_get();
	dummy_data->mem_type = 0;
	dummy_data->record_size = record_size;
	dummy_data->console_size = ramoops_console_size;
	dummy_data->ftrace_size = ramoops_ftrace_size;
	dummy_data->pmsg_size = ramoops_pmsg_size;
	dummy_data->dump_oops = dump_oops;
	/*
	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
	 * (using 1 byte for ECC isn't much of use anyway).
	 */
	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;

	ramoops_probe(dummy_data);
}

static int __init ramoops_init(void)
{
	ramoops_register_dummy();
	return 0;
}
postcore_initcall(ramoops_init);