Message-ID: <1337094779.2602.9.camel@lorien2>
Date:	Tue, 15 May 2012 09:12:59 -0600
From:	Shuah Khan <shuahkhan@...il.com>
To:	Anton Vorontsov <anton.vorontsov@...aro.org>
Cc:	shuahkhan@...il.com,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kees Cook <keescook@...omium.org>,
	Colin Cross <ccross@...roid.com>,
	Arnd Bergmann <arnd@...db.de>,
	John Stultz <john.stultz@...aro.org>, arve@...roid.com,
	Rebecca Schultz Zavin <rebecca@...roid.com>,
	Jesper Juhl <jj@...osbits.net>,
	Randy Dunlap <rdunlap@...otime.net>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Thomas Meyer <thomas@...3r.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Marco Stornelli <marco.stornelli@...il.com>,
	WANG Cong <xiyou.wangcong@...il.com>,
	linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	kernel-team@...roid.com
Subject: Re: [PATCH 08/11] ramoops: Move to fs/pstore/ram.c

On Fri, 2012-05-11 at 17:18 -0700, Anton Vorontsov wrote:
> Since ramoops was converted to pstore, it has nothing to do with character
> devices nowadays. Instead, today it is just a RAM backend for pstore.
> 
> The patch just moves things around. There are a few changes were needed
> because of the move:
> 
> 1. Kconfig and Makefiles fixups, of course.
> 
> 2. In pstore/ram.c we have to play a bit with MODULE_PARAM_PREFIX, this
>    is needed to keep user experience the same as with ramoops driver
>    (i.e. so that ramoops.foo kernel command line arguments would still
>    work).

Anton,

Could you please enhance Kconfig as well as ram.c with information with
the new functionality it supports. Also ram.c in my opinion doesn't
really reflect the feature it currently supports and its future plans.
ramoops doesn't either. ramdesg or ramkmsg probably are better suited.

Also leaving the ABI that ramoops specific might lead confusion in the
long run. It might make sense to update the ABI to reflect its new
features, if it doesn't impact existing ramoops users.

Would you be interested in adding a doc file for usage describing how
users can configure the driver - the details I would like to see are how
to pick a ram address especially when mem_address and mem_size are
passed in as module parameters.

Thanks,
-- Shuah
> 
> Signed-off-by: Anton Vorontsov <anton.vorontsov@...aro.org>
> ---
>  drivers/char/Kconfig       |    9 --
>  drivers/char/Makefile      |    1 -
>  drivers/char/ramoops.c     |  362 -------------------------------------------
>  fs/pstore/Kconfig          |    9 ++
>  fs/pstore/Makefile         |    1 +
>  fs/pstore/ram.c            |  367 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pstore_ram.h |   17 ++
>  include/linux/ramoops.h    |   17 --
>  8 files changed, 394 insertions(+), 389 deletions(-)
>  delete mode 100644 drivers/char/ramoops.c
>  create mode 100644 fs/pstore/ram.c
>  create mode 100644 include/linux/pstore_ram.h
>  delete mode 100644 include/linux/ramoops.h
> 
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index fab778d4..ea6f632 100644
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -585,15 +585,6 @@ config DEVPORT
>  
>  source "drivers/s390/char/Kconfig"
>  
> -config RAMOOPS
> -	tristate "Log panic/oops to a RAM buffer"
> -	depends on HAS_IOMEM
> -	depends on PSTORE
> -	default n
> -	help
> -	  This enables panic and oops messages to be logged to a circular
> -	  buffer in RAM where it can be read back at some later point.
> -
>  config MSM_SMD_PKT
>  	bool "Enable device interface for some SMD packet ports"
>  	default n
> diff --git a/drivers/char/Makefile b/drivers/char/Makefile
> index 0dc5d7c..d0b27a3 100644
> --- a/drivers/char/Makefile
> +++ b/drivers/char/Makefile
> @@ -58,7 +58,6 @@ obj-$(CONFIG_HANGCHECK_TIMER)	+= hangcheck-timer.o
>  obj-$(CONFIG_TCG_TPM)		+= tpm/
>  
>  obj-$(CONFIG_PS3_FLASH)		+= ps3flash.o
> -obj-$(CONFIG_RAMOOPS)		+= ramoops.o
>  
>  obj-$(CONFIG_JS_RTC)		+= js-rtc.o
>  js-rtc-y = rtc.o
> diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c
> deleted file mode 100644
> index b8b8542..0000000
> --- a/drivers/char/ramoops.c
> +++ /dev/null
> @@ -1,362 +0,0 @@
> -/*
> - * RAM Oops/Panic logger
> - *
> - * Copyright (C) 2010 Marco Stornelli <marco.stornelli@...il.com>
> - * Copyright (C) 2011 Kees Cook <keescook@...omium.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, write to the Free Software
> - * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> - * 02110-1301 USA
> - *
> - */
> -
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -
> -#include <linux/kernel.h>
> -#include <linux/err.h>
> -#include <linux/module.h>
> -#include <linux/pstore.h>
> -#include <linux/time.h>
> -#include <linux/io.h>
> -#include <linux/ioport.h>
> -#include <linux/platform_device.h>
> -#include <linux/slab.h>
> -#include <linux/ramoops.h>
> -
> -#define RAMOOPS_KERNMSG_HDR "===="
> -#define MIN_MEM_SIZE 4096UL
> -
> -static ulong record_size = MIN_MEM_SIZE;
> -module_param(record_size, ulong, 0400);
> -MODULE_PARM_DESC(record_size,
> -		"size of each dump done on oops/panic");
> -
> -static ulong mem_address;
> -module_param(mem_address, ulong, 0400);
> -MODULE_PARM_DESC(mem_address,
> -		"start of reserved RAM used to store oops/panic logs");
> -
> -static ulong mem_size;
> -module_param(mem_size, ulong, 0400);
> -MODULE_PARM_DESC(mem_size,
> -		"size of reserved RAM used to store oops/panic logs");
> -
> -static int dump_oops = 1;
> -module_param(dump_oops, int, 0600);
> -MODULE_PARM_DESC(dump_oops,
> -		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
> -
> -struct ramoops_context {
> -	void *virt_addr;
> -	phys_addr_t phys_addr;
> -	unsigned long size;
> -	size_t record_size;
> -	int dump_oops;
> -	unsigned int count;
> -	unsigned int max_count;
> -	unsigned int read_count;
> -	struct pstore_info pstore;
> -};
> -
> -static struct platform_device *dummy;
> -static struct ramoops_platform_data *dummy_data;
> -
> -static int ramoops_pstore_open(struct pstore_info *psi)
> -{
> -	struct ramoops_context *cxt = psi->data;
> -
> -	cxt->read_count = 0;
> -	return 0;
> -}
> -
> -static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
> -				   struct timespec *time,
> -				   char **buf,
> -				   struct pstore_info *psi)
> -{
> -	ssize_t size;
> -	char *rambuf;
> -	struct ramoops_context *cxt = psi->data;
> -
> -	if (cxt->read_count >= cxt->max_count)
> -		return -EINVAL;
> -	*id = cxt->read_count++;
> -	/* Only supports dmesg output so far. */
> -	*type = PSTORE_TYPE_DMESG;
> -	/* TODO(kees): Bogus time for the moment. */
> -	time->tv_sec = 0;
> -	time->tv_nsec = 0;
> -
> -	rambuf = cxt->virt_addr + (*id * cxt->record_size);
> -	size = strnlen(rambuf, cxt->record_size);
> -	*buf = kmalloc(size, GFP_KERNEL);
> -	if (*buf == NULL)
> -		return -ENOMEM;
> -	memcpy(*buf, rambuf, size);
> -
> -	return size;
> -}
> -
> -static int ramoops_pstore_write(enum pstore_type_id type,
> -				enum kmsg_dump_reason reason,
> -				u64 *id,
> -				unsigned int part,
> -				size_t size, struct pstore_info *psi)
> -{
> -	char *buf;
> -	size_t res;
> -	struct timeval timestamp;
> -	struct ramoops_context *cxt = psi->data;
> -	size_t available = cxt->record_size;
> -
> -	/* Currently ramoops is designed to only store dmesg dumps. */
> -	if (type != PSTORE_TYPE_DMESG)
> -		return -EINVAL;
> -
> -	/* Out of the various dmesg dump types, ramoops is currently designed
> -	 * to only store crash logs, rather than storing general kernel logs.
> -	 */
> -	if (reason != KMSG_DUMP_OOPS &&
> -	    reason != KMSG_DUMP_PANIC)
> -		return -EINVAL;
> -
> -	/* Skip Oopes when configured to do so. */
> -	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
> -		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;
> -
> -	buf = cxt->virt_addr + (cxt->count * cxt->record_size);
> -
> -	res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
> -	buf += res;
> -	available -= res;
> -
> -	do_gettimeofday(&timestamp);
> -	res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
> -	buf += res;
> -	available -= res;
> -
> -	if (size > available)
> -		size = available;
> -
> -	memcpy(buf, cxt->pstore.buf, size);
> -	memset(buf + size, '\0', available - size);
> -
> -	cxt->count = (cxt->count + 1) % cxt->max_count;
> -
> -	return 0;
> -}
> -
> -static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
> -				struct pstore_info *psi)
> -{
> -	char *buf;
> -	struct ramoops_context *cxt = psi->data;
> -
> -	if (id >= cxt->max_count)
> -		return -EINVAL;
> -
> -	buf = cxt->virt_addr + (id * cxt->record_size);
> -	memset(buf, '\0', cxt->record_size);
> -
> -	return 0;
> -}
> -
> -static struct ramoops_context oops_cxt = {
> -	.pstore = {
> -		.owner	= THIS_MODULE,
> -		.name	= "ramoops",
> -		.open	= ramoops_pstore_open,
> -		.read	= ramoops_pstore_read,
> -		.write	= ramoops_pstore_write,
> -		.erase	= ramoops_pstore_erase,
> -	},
> -};
> -
> -static int __init ramoops_probe(struct platform_device *pdev)
> -{
> -	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
> -	struct ramoops_context *cxt = &oops_cxt;
> -	int err = -EINVAL;
> -
> -	/* Only a single ramoops area allowed at a time, so fail extra
> -	 * probes.
> -	 */
> -	if (cxt->max_count)
> -		goto fail_out;
> -
> -	if (!pdata->mem_size || !pdata->record_size) {
> -		pr_err("The memory size and the record size must be "
> -			"non-zero\n");
> -		goto fail_out;
> -	}
> -
> -	pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
> -	pdata->record_size = rounddown_pow_of_two(pdata->record_size);
> -
> -	/* Check for the minimum memory size */
> -	if (pdata->mem_size < MIN_MEM_SIZE &&
> -			pdata->record_size < MIN_MEM_SIZE) {
> -		pr_err("memory size too small, minimum is %lu\n",
> -			MIN_MEM_SIZE);
> -		goto fail_out;
> -	}
> -
> -	if (pdata->mem_size < pdata->record_size) {
> -		pr_err("The memory size must be larger than the "
> -			"records size\n");
> -		goto fail_out;
> -	}
> -
> -	cxt->max_count = pdata->mem_size / pdata->record_size;
> -	cxt->count = 0;
> -	cxt->size = pdata->mem_size;
> -	cxt->phys_addr = pdata->mem_address;
> -	cxt->record_size = pdata->record_size;
> -	cxt->dump_oops = pdata->dump_oops;
> -
> -	cxt->pstore.data = cxt;
> -	cxt->pstore.bufsize = cxt->record_size;
> -	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");
> -		goto fail_clear;
> -	}
> -
> -	if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
> -		pr_err("request mem region (0x%lx@...llx) failed\n",
> -			cxt->size, (unsigned long long)cxt->phys_addr);
> -		err = -EINVAL;
> -		goto fail_buf;
> -	}
> -
> -	cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
> -	if (!cxt->virt_addr) {
> -		pr_err("ioremap failed\n");
> -		goto fail_mem_region;
> -	}
> -
> -	err = pstore_register(&cxt->pstore);
> -	if (err) {
> -		pr_err("registering with pstore failed\n");
> -		goto fail_iounmap;
> -	}
> -
> -	/*
> -	 * Update the module parameter variables as well so they are visible
> -	 * through /sys/module/ramoops/parameters/
> -	 */
> -	mem_size = pdata->mem_size;
> -	mem_address = pdata->mem_address;
> -	record_size = pdata->record_size;
> -	dump_oops = pdata->dump_oops;
> -
> -	pr_info("attached 0x%lx@...llx (%ux0x%zx)\n",
> -		cxt->size, (unsigned long long)cxt->phys_addr,
> -		cxt->max_count, cxt->record_size);
> -
> -	return 0;
> -
> -fail_iounmap:
> -	iounmap(cxt->virt_addr);
> -fail_mem_region:
> -	release_mem_region(cxt->phys_addr, cxt->size);
> -fail_buf:
> -	kfree(cxt->pstore.buf);
> -fail_clear:
> -	cxt->pstore.bufsize = 0;
> -	cxt->max_count = 0;
> -fail_out:
> -	return err;
> -}
> -
> -static int __exit ramoops_remove(struct platform_device *pdev)
> -{
> -#if 0
> -	/* TODO(kees): We cannot unload ramoops since pstore doesn't support
> -	 * unregistering yet.
> -	 */
> -	struct ramoops_context *cxt = &oops_cxt;
> -
> -	iounmap(cxt->virt_addr);
> -	release_mem_region(cxt->phys_addr, cxt->size);
> -	cxt->max_count = 0;
> -
> -	/* TODO(kees): When pstore supports unregistering, call it here. */
> -	kfree(cxt->pstore.buf);
> -	cxt->pstore.bufsize = 0;
> -
> -	return 0;
> -#endif
> -	return -EBUSY;
> -}
> -
> -static struct platform_driver ramoops_driver = {
> -	.remove		= __exit_p(ramoops_remove),
> -	.driver		= {
> -		.name	= "ramoops",
> -		.owner	= THIS_MODULE,
> -	},
> -};
> -
> -static int __init ramoops_init(void)
> -{
> -	int ret;
> -	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
> -	if (ret == -ENODEV) {
> -		/*
> -		 * If we didn't find a platform device, we use module parameters
> -		 * building platform data on the fly.
> -		 */
> -		pr_info("platform device not found, using module parameters\n");
> -		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
> -				     GFP_KERNEL);
> -		if (!dummy_data)
> -			return -ENOMEM;
> -		dummy_data->mem_size = mem_size;
> -		dummy_data->mem_address = mem_address;
> -		dummy_data->record_size = record_size;
> -		dummy_data->dump_oops = dump_oops;
> -		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
> -			NULL, 0, dummy_data,
> -			sizeof(struct ramoops_platform_data));
> -
> -		if (IS_ERR(dummy))
> -			ret = PTR_ERR(dummy);
> -		else
> -			ret = 0;
> -	}
> -
> -	return ret;
> -}
> -
> -static void __exit ramoops_exit(void)
> -{
> -	platform_driver_unregister(&ramoops_driver);
> -	kfree(dummy_data);
> -}
> -
> -module_init(ramoops_init);
> -module_exit(ramoops_exit);
> -
> -MODULE_LICENSE("GPL");
> -MODULE_AUTHOR("Marco Stornelli <marco.stornelli@...il.com>");
> -MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
> diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
> index 8007ae7..ad6e594 100644
> --- a/fs/pstore/Kconfig
> +++ b/fs/pstore/Kconfig
> @@ -11,3 +11,12 @@ config PSTORE
>  	   (e.g. ACPI_APEI on X86) which will select this for you.
>  	   If you don't have a platform persistent store driver,
>  	   say N.
> +
> +config PSTORE_RAM
> +	tristate "Log panic/oops to a RAM buffer"
> +	depends on HAS_IOMEM
> +	depends on PSTORE
> +	default n
> +	help
> +	  This enables panic and oops messages to be logged to a circular
> +	  buffer in RAM where it can be read back at some later point.
> diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
> index 760f4bc..804e376 100644
> --- a/fs/pstore/Makefile
> +++ b/fs/pstore/Makefile
> @@ -5,3 +5,4 @@
>  obj-y += pstore.o
>  
>  pstore-objs += inode.o platform.o
> +obj-$(CONFIG_PSTORE_RAM)	+= ram.o
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> new file mode 100644
> index 0000000..b26b58e
> --- /dev/null
> +++ b/fs/pstore/ram.c
> @@ -0,0 +1,367 @@
> +/*
> + * RAM Oops/Panic logger
> + *
> + * Copyright (C) 2010 Marco Stornelli <marco.stornelli@...il.com>
> + * Copyright (C) 2011 Kees Cook <keescook@...omium.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, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> + * 02110-1301 USA
> + *
> + */
> +#define pr_fmt(fmt) "ramoops: " fmt
> +
> +#include <linux/kernel.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/pstore.h>
> +#include <linux/time.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/pstore_ram.h>
> +
> +/* For historical reasons we name it ramoops when built-in. */
> +#ifndef MODULE
> +#undef MODULE_PARAM_PREFIX
> +#define MODULE_PARAM_PREFIX "ramoops."
> +#endif
> +
> +#define RAMOOPS_KERNMSG_HDR "===="
> +#define MIN_MEM_SIZE 4096UL
> +
> +static ulong record_size = MIN_MEM_SIZE;
> +module_param(record_size, ulong, 0400);
> +MODULE_PARM_DESC(record_size,
> +		"size of each dump done on oops/panic");
> +
> +static ulong mem_address;
> +module_param(mem_address, ulong, 0400);
> +MODULE_PARM_DESC(mem_address,
> +		"start of reserved RAM used to store oops/panic logs");
> +
> +static ulong mem_size;
> +module_param(mem_size, ulong, 0400);
> +MODULE_PARM_DESC(mem_size,
> +		"size of reserved RAM used to store oops/panic logs");
> +
> +static int dump_oops = 1;
> +module_param(dump_oops, int, 0600);
> +MODULE_PARM_DESC(dump_oops,
> +		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
> +
> +struct ramoops_context {
> +	void *virt_addr;
> +	phys_addr_t phys_addr;
> +	unsigned long size;
> +	size_t record_size;
> +	int dump_oops;
> +	unsigned int count;
> +	unsigned int max_count;
> +	unsigned int read_count;
> +	struct pstore_info pstore;
> +};
> +
> +static struct platform_device *dummy;
> +static struct ramoops_platform_data *dummy_data;
> +
> +static int ramoops_pstore_open(struct pstore_info *psi)
> +{
> +	struct ramoops_context *cxt = psi->data;
> +
> +	cxt->read_count = 0;
> +	return 0;
> +}
> +
> +static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
> +				   struct timespec *time,
> +				   char **buf,
> +				   struct pstore_info *psi)
> +{
> +	ssize_t size;
> +	char *rambuf;
> +	struct ramoops_context *cxt = psi->data;
> +
> +	if (cxt->read_count >= cxt->max_count)
> +		return -EINVAL;
> +	*id = cxt->read_count++;
> +	/* Only supports dmesg output so far. */
> +	*type = PSTORE_TYPE_DMESG;
> +	/* TODO(kees): Bogus time for the moment. */
> +	time->tv_sec = 0;
> +	time->tv_nsec = 0;
> +
> +	rambuf = cxt->virt_addr + (*id * cxt->record_size);
> +	size = strnlen(rambuf, cxt->record_size);
> +	*buf = kmalloc(size, GFP_KERNEL);
> +	if (*buf == NULL)
> +		return -ENOMEM;
> +	memcpy(*buf, rambuf, size);
> +
> +	return size;
> +}
> +
> +static int ramoops_pstore_write(enum pstore_type_id type,
> +				enum kmsg_dump_reason reason,
> +				u64 *id,
> +				unsigned int part,
> +				size_t size, struct pstore_info *psi)
> +{
> +	char *buf;
> +	size_t res;
> +	struct timeval timestamp;
> +	struct ramoops_context *cxt = psi->data;
> +	size_t available = cxt->record_size;
> +
> +	/* Currently ramoops is designed to only store dmesg dumps. */
> +	if (type != PSTORE_TYPE_DMESG)
> +		return -EINVAL;
> +
> +	/* Out of the various dmesg dump types, ramoops is currently designed
> +	 * to only store crash logs, rather than storing general kernel logs.
> +	 */
> +	if (reason != KMSG_DUMP_OOPS &&
> +	    reason != KMSG_DUMP_PANIC)
> +		return -EINVAL;
> +
> +	/* Skip Oopes when configured to do so. */
> +	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
> +		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;
> +
> +	buf = cxt->virt_addr + (cxt->count * cxt->record_size);
> +
> +	res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
> +	buf += res;
> +	available -= res;
> +
> +	do_gettimeofday(&timestamp);
> +	res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
> +	buf += res;
> +	available -= res;
> +
> +	if (size > available)
> +		size = available;
> +
> +	memcpy(buf, cxt->pstore.buf, size);
> +	memset(buf + size, '\0', available - size);
> +
> +	cxt->count = (cxt->count + 1) % cxt->max_count;
> +
> +	return 0;
> +}
> +
> +static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
> +				struct pstore_info *psi)
> +{
> +	char *buf;
> +	struct ramoops_context *cxt = psi->data;
> +
> +	if (id >= cxt->max_count)
> +		return -EINVAL;
> +
> +	buf = cxt->virt_addr + (id * cxt->record_size);
> +	memset(buf, '\0', cxt->record_size);
> +
> +	return 0;
> +}
> +
> +static struct ramoops_context oops_cxt = {
> +	.pstore = {
> +		.owner	= THIS_MODULE,
> +		.name	= "ramoops",
> +		.open	= ramoops_pstore_open,
> +		.read	= ramoops_pstore_read,
> +		.write	= ramoops_pstore_write,
> +		.erase	= ramoops_pstore_erase,
> +	},
> +};
> +
> +static int __init ramoops_probe(struct platform_device *pdev)
> +{
> +	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
> +	struct ramoops_context *cxt = &oops_cxt;
> +	int err = -EINVAL;
> +
> +	/* Only a single ramoops area allowed at a time, so fail extra
> +	 * probes.
> +	 */
> +	if (cxt->max_count)
> +		goto fail_out;
> +
> +	if (!pdata->mem_size || !pdata->record_size) {
> +		pr_err("The memory size and the record size must be "
> +			"non-zero\n");
> +		goto fail_out;
> +	}
> +
> +	pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
> +	pdata->record_size = rounddown_pow_of_two(pdata->record_size);
> +
> +	/* Check for the minimum memory size */
> +	if (pdata->mem_size < MIN_MEM_SIZE &&
> +			pdata->record_size < MIN_MEM_SIZE) {
> +		pr_err("memory size too small, minimum is %lu\n",
> +			MIN_MEM_SIZE);
> +		goto fail_out;
> +	}
> +
> +	if (pdata->mem_size < pdata->record_size) {
> +		pr_err("The memory size must be larger than the "
> +			"records size\n");
> +		goto fail_out;
> +	}
> +
> +	cxt->max_count = pdata->mem_size / pdata->record_size;
> +	cxt->count = 0;
> +	cxt->size = pdata->mem_size;
> +	cxt->phys_addr = pdata->mem_address;
> +	cxt->record_size = pdata->record_size;
> +	cxt->dump_oops = pdata->dump_oops;
> +
> +	cxt->pstore.data = cxt;
> +	cxt->pstore.bufsize = cxt->record_size;
> +	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");
> +		goto fail_clear;
> +	}
> +
> +	if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
> +		pr_err("request mem region (0x%lx@...llx) failed\n",
> +			cxt->size, (unsigned long long)cxt->phys_addr);
> +		err = -EINVAL;
> +		goto fail_buf;
> +	}
> +
> +	cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
> +	if (!cxt->virt_addr) {
> +		pr_err("ioremap failed\n");
> +		goto fail_mem_region;
> +	}
> +
> +	err = pstore_register(&cxt->pstore);
> +	if (err) {
> +		pr_err("registering with pstore failed\n");
> +		goto fail_iounmap;
> +	}
> +
> +	/*
> +	 * Update the module parameter variables as well so they are visible
> +	 * through /sys/module/ramoops/parameters/
> +	 */
> +	mem_size = pdata->mem_size;
> +	mem_address = pdata->mem_address;
> +	record_size = pdata->record_size;
> +	dump_oops = pdata->dump_oops;
> +
> +	pr_info("attached 0x%lx@...llx (%ux0x%zx)\n",
> +		cxt->size, (unsigned long long)cxt->phys_addr,
> +		cxt->max_count, cxt->record_size);
> +
> +	return 0;
> +
> +fail_iounmap:
> +	iounmap(cxt->virt_addr);
> +fail_mem_region:
> +	release_mem_region(cxt->phys_addr, cxt->size);
> +fail_buf:
> +	kfree(cxt->pstore.buf);
> +fail_clear:
> +	cxt->pstore.bufsize = 0;
> +	cxt->max_count = 0;
> +fail_out:
> +	return err;
> +}
> +
> +static int __exit ramoops_remove(struct platform_device *pdev)
> +{
> +#if 0
> +	/* TODO(kees): We cannot unload ramoops since pstore doesn't support
> +	 * unregistering yet.
> +	 */
> +	struct ramoops_context *cxt = &oops_cxt;
> +
> +	iounmap(cxt->virt_addr);
> +	release_mem_region(cxt->phys_addr, cxt->size);
> +	cxt->max_count = 0;
> +
> +	/* TODO(kees): When pstore supports unregistering, call it here. */
> +	kfree(cxt->pstore.buf);
> +	cxt->pstore.bufsize = 0;
> +
> +	return 0;
> +#endif
> +	return -EBUSY;
> +}
> +
> +static struct platform_driver ramoops_driver = {
> +	.remove		= __exit_p(ramoops_remove),
> +	.driver		= {
> +		.name	= "ramoops",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static int __init ramoops_init(void)
> +{
> +	int ret;
> +	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
> +	if (ret == -ENODEV) {
> +		/*
> +		 * If we didn't find a platform device, we use module parameters
> +		 * building platform data on the fly.
> +		 */
> +		pr_info("platform device not found, using module parameters\n");
> +		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
> +				     GFP_KERNEL);
> +		if (!dummy_data)
> +			return -ENOMEM;
> +		dummy_data->mem_size = mem_size;
> +		dummy_data->mem_address = mem_address;
> +		dummy_data->record_size = record_size;
> +		dummy_data->dump_oops = dump_oops;
> +		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
> +			NULL, 0, dummy_data,
> +			sizeof(struct ramoops_platform_data));
> +
> +		if (IS_ERR(dummy))
> +			ret = PTR_ERR(dummy);
> +		else
> +			ret = 0;
> +	}
> +
> +	return ret;
> +}
> +
> +static void __exit ramoops_exit(void)
> +{
> +	platform_driver_unregister(&ramoops_driver);
> +	kfree(dummy_data);
> +}
> +
> +module_init(ramoops_init);
> +module_exit(ramoops_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Marco Stornelli <marco.stornelli@...il.com>");
> +MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
> diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
> new file mode 100644
> index 0000000..484fef8
> --- /dev/null
> +++ b/include/linux/pstore_ram.h
> @@ -0,0 +1,17 @@
> +#ifndef __RAMOOPS_H
> +#define __RAMOOPS_H
> +
> +/*
> + * Ramoops platform data
> + * @mem_size	memory size for ramoops
> + * @mem_address	physical memory address to contain ramoops
> + */
> +
> +struct ramoops_platform_data {
> +	unsigned long	mem_size;
> +	unsigned long	mem_address;
> +	unsigned long	record_size;
> +	int		dump_oops;
> +};
> +
> +#endif
> diff --git a/include/linux/ramoops.h b/include/linux/ramoops.h
> deleted file mode 100644
> index 484fef8..0000000
> --- a/include/linux/ramoops.h
> +++ /dev/null
> @@ -1,17 +0,0 @@
> -#ifndef __RAMOOPS_H
> -#define __RAMOOPS_H
> -
> -/*
> - * Ramoops platform data
> - * @mem_size	memory size for ramoops
> - * @mem_address	physical memory address to contain ramoops
> - */
> -
> -struct ramoops_platform_data {
> -	unsigned long	mem_size;
> -	unsigned long	mem_address;
> -	unsigned long	record_size;
> -	int		dump_oops;
> -};
> -
> -#endif


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