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Subject: Re: [PATCH V10 2/2] scsi: ufs: Add configfs support for UFS
 provisioning
To:     Sayali Lokhande <sayalil@codeaurora.org>, subhashj@codeaurora.org,
        cang@codeaurora.org, vivek.gautam@codeaurora.org,
        rnayak@codeaurora.org, vinholikatti@gmail.com,
        jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
        asutoshd@codeaurora.org, evgreen@chromium.org,
        riteshh@codeaurora.org
Cc:     linux-scsi@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>
References: <1535088810-20989-1-git-send-email-sayalil@codeaurora.org>
 <1535088810-20989-3-git-send-email-sayalil@codeaurora.org>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
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Message-ID: <5d2a6dea-e524-fca7-3c4b-a45bc9e6516a@intel.com>
Date:   Fri, 24 Aug 2018 11:45:25 +0300
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On 24/08/18 08:33, Sayali Lokhande wrote:
> This patch adds configfs support to provision UFS device at
> runtime. This feature can be primarily useful in factory or
> assembly line as some devices may be required to be configured
> multiple times during initial system development phase.
> Configuration Descriptors can be written multiple times until
> bConfigDescrLock attribute is zero.
> 
> Configuration descriptor buffer consists of Device and Unit
> descriptor configurable parameters which are parsed from vendor
> specific provisioning file and then passed via configfs node at
> runtime to provision ufs device.
> CONFIG_CONFIGFS_FS needs to be enabled for using this feature.
> 
> Usage:
> 1) To read current configuration descriptor :
>    cat /config/XXXX.ufshc/ufs_provision
> 2) To provision ufs device:
>    echo <config_desc_buf> > /config/XXXX.ufshc/ufs_provision
> 
> Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
> ---
>  Documentation/ABI/testing/configfs-driver-ufs |  18 +++
>  drivers/scsi/ufs/Kconfig                      |  10 ++
>  drivers/scsi/ufs/Makefile                     |   1 +
>  drivers/scsi/ufs/ufs-configfs.c               | 155 ++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.c                     |   3 +-
>  drivers/scsi/ufs/ufshcd.h                     |  17 +++
>  6 files changed, 203 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
>  create mode 100644 drivers/scsi/ufs/ufs-configfs.c
> 
> diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs
> new file mode 100644
> index 0000000..eeee499c
> --- /dev/null
> +++ b/Documentation/ABI/testing/configfs-driver-ufs
> @@ -0,0 +1,18 @@
> +What:		/config/ufshcd/ufs_provision

You are using the device name as the config subsystem name, so this is really:

	What:		/config/*/ufs_provision

> +Date:		Jun 2018
> +KernelVersion:	4.14

4.19 maybe

> +Description:
> +		This file shows the current ufs configuration descriptor set in device.

It is only the first config descriptor though isn't it?  There is no support
for the other 3.  Shouldn't we support config descriptors fully?

> +		This can be used to provision ufs device if bConfigDescrLock is 0.
> +		For more details, refer 14.1.6.3 Configuration Descriptor and
> +		Table 14-12 - Unit Descriptor configurable parameters from specs for
> +		description of each configuration descriptor parameter.
> +		Configuration descriptor buffer needs to be passed in space separated
> +		format specificied as below:

specificied -> specified

> +		echo <bLength> <bDescriptorIDN> <bConfDescContinue> <bBootEnable>
> +		<bDescrAccessEn> <bInitPowerMode> <bHighPriorityLUN>
> +		<bSecureRemovalType> <bInitActiveICCLevel> <wPeriodicRTCUpdate>
> +		<0Bh:0Fh_ReservedAs_0> <bLUEnable> <bBootLunID> <bLUWriteProtect>
> +		<bMemoryType> <dNumAllocUnits> <bDataReliability> <bLogicalBlockSize>
> +		<bProvisioningType> <wContextCapabilities> <0Dh:0Fh_ReservedAs_0>

This format is not exactly correct anymore because each byte has to be
represented separately.  Also theoretically it can be change, so maybe
better just to refer the user to the UFS specification.

> +		> /config/XXXX.ufshc/ufs_provision
> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> index e27b4d4..a9a0a58 100644
> --- a/drivers/scsi/ufs/Kconfig
> +++ b/drivers/scsi/ufs/Kconfig
> @@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
>  
>  	  Select this if you have UFS controller on QCOM chipset.
>  	  If unsure, say N.
> +
> +config UFS_PROVISION
> +	tristate "Runtime UFS Provisioning support"
> +	depends on SCSI_UFSHCD && CONFIGFS_FS
> +	help
> +	  This enables runtime UFS provisioning support. This can be used
> +	  primarily during assembly line as some devices may be required to
> +	  be configured multiple times during initial development phase.
> +
> +	  If unsure, say N.
> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
> index 918f579..00110ea 100644
> --- a/drivers/scsi/ufs/Makefile
> +++ b/drivers/scsi/ufs/Makefile
> @@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
>  obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>  obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>  ufshcd-core-objs := ufshcd.o ufs-sysfs.o
> +obj-$(CONFIG_UFS_PROVISION) += ufs-configfs.o
>  obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
>  obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
> diff --git a/drivers/scsi/ufs/ufs-configfs.c b/drivers/scsi/ufs/ufs-configfs.c
> new file mode 100644
> index 0000000..74563a4
> --- /dev/null
> +++ b/drivers/scsi/ufs/ufs-configfs.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +// Copyright (c) 2018, Linux Foundation.
> +
> +#include <linux/configfs.h>
> +#include <linux/err.h>
> +#include <linux/string.h>
> +
> +#include "ufs.h"
> +#include "ufshcd.h"
> +
> +static inline struct ufs_hba *config_item_to_hba(struct config_item *item)
> +{
> +	struct config_group *group = to_config_group(item);
> +	struct configfs_subsystem *subsys = to_configfs_subsystem(group);
> +	struct ufs_hba *hba = container_of(subsys, struct ufs_hba, subsys);
> +
> +	return subsys ? hba : NULL;
> +}
> +
> +static ssize_t ufs_provision_show(struct config_item *item, char *buf)
> +{
> +	u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};

Is it really ok to hard-code the descriptor size?

> +	int desc_buf_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
> +	int i, ret, curr_len = 0;
> +	struct ufs_hba *hba = config_item_to_hba(item);
> +
> +	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
> +		QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &desc_buf_len);
> +
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < desc_buf_len; i++)
> +		curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
> +				"0x%x ", desc_buf[i]);
> +
> +	return curr_len;
> +}
> +
> +ssize_t ufshcd_desc_configfs_store(struct ufs_hba *hba,
> +		const char *buf, size_t count)
> +{
> +	char *strbuf;
> +	char *strbuf_copy;
> +	u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
> +	int desc_buf_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
> +	char *token;
> +	int i, ret, value;
> +	u32 config_desc_lock = 0;
> +
> +	/* reserve one byte for null termination */
> +	strbuf = kmalloc(count + 1, GFP_KERNEL);
> +	if (!strbuf)
> +		return -ENOMEM;
> +
> +	strbuf_copy = strbuf;
> +	strlcpy(strbuf, buf, count + 1);
> +
> +	/* Just return if bConfigDescrLock is already set */
> +	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> +		QUERY_ATTR_IDN_CONF_DESC_LOCK, 0, 0, &config_desc_lock);
> +	if (ret)
> +		goto out;
> +
> +	if (config_desc_lock) {
> +		dev_err(hba->dev, "%s: bConfigDescrLock already set to %u, cannot re-provision device!\n",
> +		__func__, config_desc_lock);
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	for (i = 0; i < QUERY_DESC_CONFIGURATION_DEF_SIZE; i++) {
> +		token = strsep(&strbuf, " ");
> +		if (!token && i)
> +			break;
> +
> +		ret = kstrtoint(token, 0, &value);
> +		if (ret) {
> +			dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
> +				__func__, ret, token);
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		desc_buf[i] = (u8)value;
> +	}
> +
> +	/* Write configuration descriptor to provision ufs */
> +	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_WRITE_DESC,
> +		QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &desc_buf_len);
> +
> +	if (!ret)
> +		dev_info(hba->dev, "%s: UFS Provisioning done, reboot now!\n",

That is not necessarily true - bConfDescContinue might have been used or
bConfigDescrLock might need to be set.  Better just to say that
configuration descriptor 0 was written.

> +		__func__);
> +
> +out:
> +	kfree(strbuf_copy);
> +	if (ret)
> +		return ret;
> +	return count;
> +}
> +
> +static ssize_t ufs_provision_store(struct config_item *item,
> +		const char *buf, size_t count)
> +{
> +	struct ufs_hba *hba = config_item_to_hba(item);
> +
> +	return ufshcd_desc_configfs_store(hba, buf, count);
> +}
> +
> +static struct configfs_attribute ufshcd_attr_provision = {
> +	.ca_name	= "ufs_provision",
> +	.ca_mode	= 0644,
> +	.ca_owner	= THIS_MODULE,
> +	.show		= ufs_provision_show,
> +	.store		= ufs_provision_store,
> +};
> +
> +static struct configfs_attribute *ufshcd_attrs[] = {
> +	&ufshcd_attr_provision,
> +	NULL,
> +};
> +
> +static struct config_item_type ufscfg_type = {
> +	.ct_attrs	= ufshcd_attrs,
> +	.ct_owner	= THIS_MODULE,
> +};
> +
> +static struct configfs_subsystem ufscfg_subsys = {
> +	.su_group = {
> +		.cg_item = {
> +			.ci_type = &ufscfg_type,
> +		},
> +	},
> +};
> +
> +void ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
> +{
> +	int ret;
> +	struct configfs_subsystem *subsys = &hba->subsys;
> +
> +	strncpy(ufscfg_subsys.su_group.cg_item.ci_namebuf, name, strlen(name));
> +	subsys->su_group = ufscfg_subsys.su_group;

configfs_subsystem cannot share su_group with other configfs_subsystem i.e
you are not allowing for there being more than 1 hba

> +	config_group_init(&subsys->su_group);
> +	mutex_init(&subsys->su_mutex);
> +	ret = configfs_register_subsystem(subsys);
> +	if (ret)
> +		pr_err("Error %d while registering subsystem %s\n",
> +		       ret,
> +		       subsys->su_group.cg_item.ci_namebuf);
> +}
> +
> +void ufshcd_configfs_exit(void)
> +{
> +	configfs_unregister_subsystem(&ufscfg_subsys);
> +}
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e01cdc0..32a67b0 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -7711,6 +7711,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>  void ufshcd_remove(struct ufs_hba *hba)
>  {
>  	ufs_sysfs_remove_nodes(hba->dev);
> +	ufshcd_configfs_exit();
>  	scsi_remove_host(hba->host);
>  	/* disable interrupts */
>  	ufshcd_disable_intr(hba, hba->intr_mask);
> @@ -7965,7 +7966,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
>  
>  	async_schedule(ufshcd_async_scan, hba);
>  	ufs_sysfs_add_nodes(hba->dev);
> -
> +	ufshcd_configfs_init(hba, dev_name(hba->dev));
>  	return 0;
>  
>  out_remove_scsi_host:
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 45013b6..2275032 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -37,6 +37,7 @@
>  #ifndef _UFSHCD_H
>  #define _UFSHCD_H
>  
> +#include <linux/configfs.h>
>  #include <linux/module.h>
>  #include <linux/kernel.h>
>  #include <linux/init.h>
> @@ -515,6 +516,9 @@ struct ufs_hba {
>  
>  	struct Scsi_Host *host;
>  	struct device *dev;
> +#ifdef CONFIG_UFS_PROVISION
> +	struct configfs_subsystem subsys;
> +#endif
>  	/*
>  	 * This field is to keep a reference to "scsi_device" corresponding to
>  	 * "UFS device" W-LU.
> @@ -868,6 +872,19 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
>  int ufshcd_hold(struct ufs_hba *hba, bool async);
>  void ufshcd_release(struct ufs_hba *hba);
>  
> +/* Expose UFS configfs API's */
> +#ifndef CONFIG_UFS_PROVISION
> +static inline void ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
> +{
> +}
> +static inline void ufshcd_configfs_exit(void)
> +{
> +}
> +#else
> +void ufshcd_configfs_init(struct ufs_hba *hba, const char *name);
> +void ufshcd_configfs_exit(void);
> +#endif
> +
>  int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
>  	int *desc_length);
>  
>