Date:	Wed, 06 Nov 2013 07:43:13 +1100
From:	Ryan Mallon <rmallon@...il.com>
To:	Frank Haverkamp <haver@...ux.vnet.ibm.com>
CC:	linux-kernel@...r.kernel.org, arnd@...db.de,
	gregkh@...uxfoundation.org, cody@...ux.vnet.ibm.com,
	schwidefsky@...ibm.com, utz.bacher@...ibm.com, mmarek@...e.cz,
	jsvogt@...ibm.com, MIJUNG@...ibm.com, cascardo@...ux.vnet.ibm.com,
	michael@...ra.de
Subject: Re: [PATCH 5/6] GenWQE Sysfs interfaces

On 05/11/13 19:44, Frank Haverkamp wrote:

> Sysfs interfaces for the GenWQE card. There are attributes to query
> the version of the bitstream as well as some for the driver. For
> debugging, please also see the debugfs interfaces of this driver.
> 
> Signed-off-by: Frank Haverkamp <haver@...ux.vnet.ibm.com>
> Co-authors: Joerg-Stephan Vogt <jsvogt@...ibm.com>,
>             Michael Jung <MIJUNG@...ibm.com>,
>             Michael Ruettger <michael@...ra.de>


Handful of small comments below,

~Ryan

> ---
>  Documentation/ABI/testing/sysfs-driver-genwqe |   55 +++++
>  drivers/misc/genwqe/card_sysfs.c              |  290 +++++++++++++++++++++++++
>  2 files changed, 345 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-genwqe
>  create mode 100644 drivers/misc/genwqe/card_sysfs.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-genwqe b/Documentation/ABI/testing/sysfs-driver-genwqe
> new file mode 100644
> index 0000000..0976901
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-genwqe
> @@ -0,0 +1,55 @@
> +What:           /sys/class/genwqe/genwqe<n>_card/version
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Unique bitstream identification e.g.
> +                '0000000330336283.00000000475a4950'.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/appid
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Identifies the currently active card application e.g. 'GZIP'
> +                for compression/decompression.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/type
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Type of the card e.g. 'GenWQE5-A7'.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/cpld_version
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Version id of the cards CPLD.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/curr_bitstream
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Currently active bitstream. 1 is default, 0 is backup.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/next_bitstream
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Interface to set the next bitstream to be used.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/tempsens
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Interface to read the cards temperature sense register.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/state
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    State of the card: "unused", "used", "error".
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/base_clock
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Base clock frequency of the card.
> +
> +What:           /sys/class/genwqe/genwqe<n>_card/device/sriov_numvfs
> +Date:           Oct 2013
> +Contact:        haver@...ux.vnet.ibm.com
> +Description:    Enable VFs (1..15):
> +                  sudo sh -c 'echo 15 > \
> +                    /sys/bus/pci/devices/0000\:1b\:00.0/sriov_numvfs'
> +                Disable VFs:
> +                  Write a 0 into the same sysfs entry.
> diff --git a/drivers/misc/genwqe/card_sysfs.c b/drivers/misc/genwqe/card_sysfs.c
> new file mode 100644
> index 0000000..f29ce55
> --- /dev/null
> +++ b/drivers/misc/genwqe/card_sysfs.c
> @@ -0,0 +1,290 @@
> +/**
> + * IBM Accelerator Family 'GenWQE'
> + *
> + * (C) Copyright IBM Corp. 2013
> + *
> + * Author: Frank Haverkamp <haver@...ux.vnet.ibm.com>
> + * Author: Joerg-Stephan Vogt <jsvogt@...ibm.com>
> + * Author: Michael Jung <mijung@...ibm.com>
> + * Author: Michael Ruettger <michael@...ra.de>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License (version 2 only)
> + * 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.
> + */
> +
> +/*
> + * Sysfs interfaces for the GenWQE card. There are attributes to query
> + * the version of the bitstream as well as some for the driver. For
> + * debugging, please also see the debugfs interfaces of this driver.
> + */
> +
> +#include <linux/version.h>
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/string.h>
> +#include <linux/fs.h>
> +#include <linux/sysfs.h>
> +#include <linux/ctype.h>
> +#include <linux/device.h>
> +
> +#include "card_base.h"
> +#include "card_ddcb.h"
> +
> +static const char * const genwqe_types[] = {
> +	[GENWQE_TYPE_ALTERA_230] = "GenWQE4-230",
> +	[GENWQE_TYPE_ALTERA_530] = "GenWQE4-530",
> +	[GENWQE_TYPE_ALTERA_A4]  = "GenWQE5-A4",
> +	[GENWQE_TYPE_ALTERA_A7]  = "GenWQE5-A7",
> +};
> +
> +static ssize_t status_show(struct device *dev, struct device_attribute *attr,
> +			   char *buf)
> +{
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +	const char *cs[GENWQE_CARD_STATE_MAX] = { "unused", "used", "error" };
> +
> +	return scnprintf(buf, PAGE_SIZE, "%s\n", cs[cd->card_state]);
> +}
> +static DEVICE_ATTR_RO(status);
> +
> +static ssize_t appid_show(struct device *dev, struct device_attribute *attr,
> +			  char *buf)
> +{
> +	char app_name[5];
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	genwqe_read_app_id(cd, app_name, sizeof(app_name));
> +	return scnprintf(buf, PAGE_SIZE, "%s\n", app_name);
> +}
> +static DEVICE_ATTR_RO(appid);
> +
> +static ssize_t version_show(struct device *dev, struct device_attribute *attr,
> +			    char *buf)
> +{
> +	u64 slu_id, app_id;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	slu_id = __genwqe_readq(cd, IO_SLU_UNITCFG);
> +	app_id = __genwqe_readq(cd, IO_APP_UNITCFG);
> +
> +	return scnprintf(buf, PAGE_SIZE, "%016llx.%016llx\n", slu_id, app_id);
> +}
> +static DEVICE_ATTR_RO(version);
> +
> +static ssize_t type_show(struct device *dev, struct device_attribute *attr,
> +			 char *buf)
> +{
> +	u8 card_type;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	card_type = genwqe_card_type(cd);
> +	return scnprintf(buf, PAGE_SIZE, "%s\n",
> +			 (card_type >= ARRAY_SIZE(genwqe_types)) ?
> +			 "invalid" : genwqe_types[card_type]);
> +}
> +static DEVICE_ATTR_RO(type);
> +
> +static ssize_t driver_show(struct device *dev, struct device_attribute *attr,
> +			   char *buf)
> +{
> +	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERS_STRING);
> +}
> +static DEVICE_ATTR_RO(driver);
> +
> +static ssize_t tempsens_show(struct device *dev, struct device_attribute *attr,
> +			     char *buf)
> +{
> +	u64 tempsens;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	tempsens = __genwqe_readq(cd, IO_SLU_TEMPERATURE_SENSOR);
> +	return scnprintf(buf, PAGE_SIZE, "%016llx\n", tempsens);
> +}
> +static DEVICE_ATTR_RO(tempsens);
> +
> +static ssize_t base_clock_show(struct device *dev,
> +			       struct device_attribute *attr,
> +			       char *buf)
> +{
> +	u64 base_clock;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	base_clock = genwqe_base_clock_frequency(cd);
> +	return scnprintf(buf, PAGE_SIZE, "%lld\n", base_clock);
> +}
> +static DEVICE_ATTR_RO(base_clock);
> +
> +/**
> + * curr_bitstream_show() - Show the current bitstream id
> + *
> + * There is a bug in some old versions of the CPLD which selects the
> + * bitstream, which causes the IO_SLU_BITSTREAM register to report
> + * unreliable data in very rare cases. This makes this sysfs
> + * unreliable up to the point were a new CPLD version is being used.
> + *
> + * Unfortunately there is no automatic way yet to query the CPLD
> + * version (See show_cpld_version() ;-)), such that you need to
> + * manually ensure via programming tools that you have a recent
> + * version of the CPLD software.
> + *
> + * The proposed circumvention is to use a special recovery bitstream
> + * on the backup partition (0) to identify problems while loading the
> + * image.
> + */
> +static ssize_t curr_bitstream_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	int curr_bitstream;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	curr_bitstream = __genwqe_readq(cd, IO_SLU_BITSTREAM) & 0x1;
> +	return scnprintf(buf, PAGE_SIZE, "%d\n", curr_bitstream);
> +}
> +static DEVICE_ATTR_RO(curr_bitstream);
> +
> +/**
> + * next_bitstream_show() - Show the next activated bitstream
> + *
> + * IO_SLC_CFGREG_SOFTRESET: This register can only be accessed by the PF.
> + */
> +static ssize_t next_bitstream_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	int next_bitstream;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	switch ((cd->softreset & 0xcull) >> 2) {


The ull suffix isn't really necessary here, and can just be removed.

> +	case 0x2:
> +		next_bitstream =  0;
> +		break;
> +	case 0x3:
> +		next_bitstream =  1;
> +		break;
> +	default:
> +		next_bitstream = -1;
> +		break;		/* error */
> +	}
> +	return scnprintf(buf, PAGE_SIZE, "%d\n", next_bitstream);


sprintf is fine, a %d is not going to be larger than PAGE_SIZE.

> +}
> +
> +static ssize_t next_bitstream_store(struct device *dev,
> +				    struct device_attribute *attr,
> +				    const char *buf, size_t count)
> +{
> +	u64 partition;
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +
> +	if (kstrtoull(buf, 0, &partition) < 0)
> +		return -EINVAL;


Why are you using kstrtoull for a value which is only 0 or 1?

> +
> +	switch (partition) {
> +	case 0x0:
> +		cd->softreset = 0x78ull;
> +		break;
> +	case 0x1:
> +		cd->softreset = 0x7cull;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	__genwqe_writeq(cd, IO_SLC_CFGREG_SOFTRESET, cd->softreset);
> +	return count;
> +}
> +static DEVICE_ATTR_RW(next_bitstream);
> +
> +/**
> + * FIXME Implement me!
> + */
> +static ssize_t cpld_version_show(struct device *dev,
> +				 struct device_attribute *attr, char *buf)
> +{
> +	return scnprintf(buf, PAGE_SIZE, "unknown (FIXME)\n");
> +}
> +static DEVICE_ATTR_RO(cpld_version);


Why provide this if it doesn't work? User-space obviously can't do the
right thing with it, so just remove it until it gets implemented
properly.

> +
> +/*
> + * Create device_attribute structures / params: name, mode, show, store
> + * additional flag if valid in VF
> + */
> +static struct attribute *genwqe_attributes[] = {
> +	&dev_attr_tempsens.attr,
> +	&dev_attr_next_bitstream.attr,
> +	&dev_attr_curr_bitstream.attr,
> +	&dev_attr_base_clock.attr,
> +	&dev_attr_driver.attr,
> +	&dev_attr_type.attr,
> +	&dev_attr_version.attr,
> +	&dev_attr_appid.attr,
> +	&dev_attr_status.attr,
> +	&dev_attr_cpld_version.attr,
> +	NULL,
> +};
> +
> +static struct attribute *genwqe_normal_attributes[] = {
> +	&dev_attr_driver.attr,
> +	&dev_attr_type.attr,
> +	&dev_attr_version.attr,
> +	&dev_attr_appid.attr,
> +	&dev_attr_status.attr,
> +	NULL,
> +};
> +
> +/**
> + * genwqe_is_visible() - Determine if sysfs attribute should be visible or not
> + *
> + * VFs have restricted mmio capabilities, so not all sysfs entries
> + * are allowed in VFs.
> + */
> +static umode_t genwqe_is_visible(struct kobject *kobj,
> +				 struct attribute *attr, int n)

> +{
> +	unsigned int j;
> +	struct device *dev = container_of(kobj, struct device, kobj);
> +	struct genwqe_dev *cd = dev_get_drvdata(dev);
> +	umode_t mode = attr->mode;
> +
> +	if (genwqe_is_privileged(cd))
> +		return mode;
> +
> +	for (j = 0; genwqe_normal_attributes[j] != NULL;  j++)
> +		if (genwqe_normal_attributes[j] == attr)
> +			return mode;
> +
> +	return 0;
> +}
> +
> +static struct attribute_group genwqe_attribute_group = {
> +	.is_visible = genwqe_is_visible,
> +	.attrs      = genwqe_attributes,
> +};
> +
> +/**
> + * genwqe_init_sysfs() - Setup sysfs entries of the card device
> + */
> +int genwqe_init_sysfs(struct genwqe_dev *cd)
> +{
> +	int rc;
> +
> +	rc = sysfs_create_group(&cd->dev->kobj, &genwqe_attribute_group);
> +	if (rc)
> +		return -ENXIO;
> +
> +	return 0;
> +}
> +
> +/**
> + * genwqe_exit_sysfs() - Remove sysfs entries
> + */
> +void genwqe_exit_sysfs(struct genwqe_dev *cd)
> +{
> +	sysfs_remove_group(&cd->dev->kobj, &genwqe_attribute_group);
> +}


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