Date:   Tue, 28 Aug 2018 15:53:40 +0530
From:   Sayali Lokhande <sayalil@...eaurora.org>
To:     Adrian Hunter <adrian.hunter@...el.com>, subhashj@...eaurora.org,
        cang@...eaurora.org, vivek.gautam@...eaurora.org,
        rnayak@...eaurora.org, vinholikatti@...il.com,
        jejb@...ux.vnet.ibm.com, martin.petersen@...cle.com,
        asutoshd@...eaurora.org, evgreen@...omium.org,
        riteshh@...eaurora.org
Cc:     linux-scsi@...r.kernel.org,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V10 2/2] scsi: ufs: Add configfs support for UFS
 provisioning

Hi Adrian,

On 8/24/2018 2:15 PM, Adrian Hunter wrote:
> 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@...eaurora.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
Agree. Will update.
>> +Date:		Jun 2018
>> +KernelVersion:	4.14
> 4.19 maybe
Done.
>> +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?
Yes, we should support config descriptors fully. My current 
implementation only supports config desc (index = 00h).
I m thinking I can add separate "index" field along with "ufs_provision" 
field and can use this index (instead of hard coding to 0)
to write repective config_desc. In this way, we should first set the 
"index" and then read/write to "ufs_provision".
Let me know if you have any concern with this approach ?

>> +		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
Done
>> +		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.
Agree. Will update to just refer to UFS spec (for Config_desc format).

>> +		> /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?
I will use ufshcd_read_desc_length() api for each index as required. 
Will remove this hard-code.
>> +	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.
Agree. Will update.
>
>> +		__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
Agree. I think I will have to move above 
declarations(ufscfg_subsys/ufscfg_type/ufshcd_attrs) in driver .c/.h 
file (to make it per ufs hba/probe).
Will check and update.
>> +	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);
>>   
>>

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